Fossil Fuel InnovationProfessor Stephen LawrenceLeeds School of BusinessUniversity of Colorado at Boulder

National Energy Technology LabOnly US National Laboratory Devoted to Fossil Fuel Energy TechnologyEnabling domestic coal, natural gas, and oil to economically power our Nations homes, industries, businesses, and transportation While protecting our environment and enhancing our energy independence. NETL has expertise in coal, natural gas, and oil technologies, contract and project management, analysis of energy systems, and international energy issues. http://www.netl.doe.gov

Types of Fossil FuelsPetroleum (oil)Natural GasCoalOil ShaleTar Sands

Petroleumhttp://www.lakesoil.com.au/photo6.jpg

Drilling for Oilhttp://www.umich.edu/~gs265/society/fossilfuels.htm

Coalhttp://buildingsdatabook.eren.doe.gov/default.asp?id=fow&num=30

Coal MiningUnderground MineOpen Pit Minehttp://www.ornl.gov/sci/fossil/http://pubs.usgs.gov/fs/fs004-02/

Sulfur in Coalhttp://www.fossil.energy.gov/education/energylessons/coal/coal_cct2.html

Natural Gashttp://www.energy.gov.ab.ca/222.aspwww.citypublicservice.com

Natural Gas Well, Storage, Pipelinehttp://www.isgs.uiuc.edu/isgshome/gas_well.jpghttp://www.call-adc.com/justiss/rig54pic.htmhttp://www.dom.com/about/gas-transmission/imp/ngp.jsp

US Natural Gas Pipeline Networkhttp://services.unitil.com/fge/bus_natural_gas_equipment.asp

North American Natural Gas Flowshttp://www2.nrcan.gc.ca/es/erb/prb/english/View.asp?x=447&oid=603

Tar Sandshttp://www.protectowire.com/applications/profiles/electric_shovels.htmhttp://www.aapg.org/explorer/2005/05may/dinning.cfm

Oil Shalehttp://nandotimes.nandomedia.com/ips_rich_content/896-shale_rock.jpghttp://geosurvey.state.co.us/Default.aspx?tabid=104

Problems with Fossil Fuels/CoalLarge source of atmospheric pollutionCreate carbon dioxide (CO2) when burnedImplicated in global warmingNitrous oxides (NOx) smog Sulfur dioxide (SO2) acid rainMeasurable amounts of radioactive materialNaturally present in coalMore than a nuclear power plant

Typical Coal-Fired Power Plant

Need forClean Coalhttp://www.enecho.meti.go.jp/english/policy/coal/images/81.gif

CO2 Mitigation Optionshttp://www.netl.doe.gov

CO2 Mitigation Optionshttp://www.netl.doe.gov

Improving Power Plant Efficiency

Basic Idea of a Power PlantSpinning turbine blades and generatorBoiling waterSteam

Conventional Coal Power Planthttp://www.worldcoal.org/pages/content/index.asp?PageID=108

Modern Coal PP Waste Disposalhttp://www.ornl.gov/sci/fossil/NewFiles/feaz277.jpg

Fluidized Bedhttp://www.fossil.energy.gov/education/energylessons/coal/coal_cct4.html

Fluidized Bed Combustion Detailhttp://envfor.nic.in/cpcb/newsletter/coal/ccombs.html

Pressurized Fluidized Bed Combined Cycle

Circulating Fluidized Bed Combustionhttp://envfor.nic.in/cpcb/newsletter/coal/ccombs.html

Integrated Gasification Combined Cyclehttp://envfor.nic.in/cpcb/newsletter/coal/ccombs.html

Pressurized Fluidized Bed Combustion Combined Cycle (PFBC) http://envfor.nic.in/cpcb/newsletter/coal/ccombs.html

Supercritical & Ultrasupercritical

Increasing Efficiency with Coalhttp://www.worldcoal.org/pages/content/index.asp?PageID=24

Carbon Capture and Sequestrationhttp://www.ornl.gov/info/ornlreview/v33_2_00/research.htm

CO2 Mitigation Optionshttp://www.netl.doe.gov

Carbon Capture & StorageCapture and store emissions of carbon dioxide Removed from the exhaust gases of the power stationStored so as not to enter the atmospherethus reducing global warming.Carbon storage is not yet cost-effectiveRequired technologies are already proven Similar technologies used commercially in food and chemicals industryhttp://www.worldcoal.org

Goals of Carbon SequestrationEffective and cost-competitiveStable, long term storageEnvironmentally benign

http://www.fossil.energy.gov/programs/sequestration

Carbon CaptureAbsorption (chemical and physical) Adsorption (physical and chemical) Low-temperature distillation Gas separation membranes Mineralization and biomineralization http://www.fossil.energy.gov/programs/sequestration

Carbon Sequestration Optionshttp://www.whitehouse.gov/omb/budget/fy2006/energy.html

Types of Carbon SequestrationGeologic SequestrationOcean SequestrationTerrestrial SequestrationNovel Sequestration Conceptshttp://www.fossil.energy.gov/programs/sequestration

Geologic SequestrationPorous rock bodies surrounded by impermeable rock are ideal for CO2 storageOil and gas reservoirsInject CO2 to improve recoveryCoal bed methaneInject CO2 into coal seams to extract methaneInject into deep saline (salt) formationsNo direct economic benefithttp://www.fossil.energy.gov/programs/sequestration

Geologic Sequestrationhttp://www.midcarb.org/Graphics/CO2flooding.gif

Ocean SequestrationIce-like CO2/H2O (water) hydratesForm in the deep ocean at low temperatures and high pressuresOceans will naturally absorb 80-90% of CO2 in atmosphereEventually transferred to deep oceanToo slow to prevent CO2 spike in next 100s yearsResearch investigating direct injection of CO2 into the deep oceanhttp://www.fossil.energy.gov/programs/sequestration

Ocean Sequestrationhttp://www.lbl.gov/Science-Articles/Archive/sea-carb-bish.html

Terrestrial SequestrationForest lands. Below-ground carbon and long-term management and utilization of standing stocks, understory, ground cover, and litter. Agricultural lands. Crop lands, grasslands, and range landsEmphasis on increasing long-lived soil carbon. Biomass croplandsIncrease soil carbon and value-added organic productsComplement to ongoing efforts related to biofuels,theDeserts and degraded landsRestoration of degraded lands significant benefits and carbon sequestration potential in both below-and above-ground systems. Boreal wetlands and peatlandsSoil carbon pools Limited conversion to forest or grassland where ecologically acceptable.

http://www.netl.doe.gov/technologies/carbon_seq/core_rd/storage.html

Terrestrial SequestrationClick image for video cliphttp://earthobservatory.nasa.gov/Newsroom/MediaResources/Carbon/global_biosphere.mpeg

Novel CS ConceptsBiological systems; Advanced catalysts for CO2 or CO conversion; Novel solvents, sorbents, membranes, and thin films for gas separation; Engineered photosynthesis systems; Non-photosynthetic mechanisms for CO2 fixation (methanogenesis and acetogenesis); Genetic manipulation of agricultural and tree to enhance CO2 sequestering potential; Advanced decarbonization systems; and Biomimetic systems. http://www.fossil.energy.gov/programs/sequestration

Carbon Sequestrationhttp://www.fossil.energy.gov/programs/sequestration

Federal Initiatives

DOE Vision 21http://www.fossil.energy.gov/programs/powersystems/vision21/

DOE Vision 21By 2015, develop the core modules for a fleet of fuel-flexible, multi-product energy plants that boost power efficiencies to 60+ percent, emit virtually no pollutants, and with carbon sequestration release minimal or no carbon emissions.Wide variety of fuels such as coal, natural gas, biomass, petroleum coke (from oil refineries), and municipal wastehttp://www.fossil.energy.gov/programs/powersystems/vision21/

Vision 21 Multidisciplinaryhttp://www.netl.doe.gov/

Vision 21 GoalsEfficienciesCoal-fueled: >60% HHV Gas-Fueled: >75% Combined Heat & Power: 75-80% thermalEmissionsAir/Wastes: Zero CO2: Zero (with sequestration)CostsElectricity at market prices

http://www.fossil.energy.gov/programs/powersystems/vision21/

Vision 21 Technology Roadmaphttp://www.netl.doe.gov/

Vision 21 Power Planthttp://www.netl.doe.gov/

DOE FutureGenFutureGen is an initiative to build the world's first integrated sequestration and hydrogen production research power plant. The $1 billion dollar project is intended to create the world's first zero-emissions fossil fuel plant. When operational, the prototype will be the cleanest fossil fuel fired power plant in the world.http://www.fossil.energy.gov/programs/powersystems/futuregen

FutureGenTomorrow's Pollution-Free Power Plant "Today I am pleased to announce that the United States will sponsor a $1 billion, 10-year demonstration project to create the world's first coal-based, zero-emissions electricity and hydrogen power plant..."President George W. Bush February 27, 2003http://www.fossil.energy.gov/programs/powersystems/futuregen

FutureGenhttp://www.fossil.energy.gov/programs/powersystems/futuregen

FutureGen

FutureGen

Orlando Clean Coal Power Planthttp://www.dep.state.fl.us/energy/fla_energy/h_projects.htm

Polk Power Station Tampahttp://www.fossil.energy.gov/education/energylessons/coal/coal_cct5.html

Next:Renewable Energy Integrationhttp://www.eia.doe.gov/kids/energyfacts/sources/images/left.gifhttp://www.re-energy.ca/

Extra Slides

Ultra-Clean Coal (UCC)Primarily in AustraliaProcess coal to have

Ultra-Clean Coal

http://www.bgr.bund.de/DE/Themen/Energie/energie__node.html

Coal Gasificationhttp://www.fossil.energy.gov/education/energylessons/coal/coal_cct5.html

Fluidized Bed Technologyhttp://www.fossil.energy.gov/education/energylessons/coal/coal_cct4.html

http://www.netl.doe.gov/

Oceanic Carbon Cycle

The National Energy Technology Laboratory (NETL), part of DOEs national laboratory system, is owned and operated by the U.S. Department of Energy (DOE). NETL supports DOEs mission to advance the national, economic, and energy security of the United States. The only U.S. national laboratory devoted to fossil energy research, NETL implements a broad spectrum of energy and environmental research and development (R&D) programs that will return benefits for generations to come: Enabling domestic coal, natural gas, and oil to economically power our Nations homes, industries, businesses, and transportation While protecting our environment and enhancing our energy independence. NETL has expertise in coal, natural gas, and oil technologies, contract and project management, analysis of energy systems, and international energy issues. In addition to research conducted onsite, NETLs project portfolio includes R&D conducted through partnerships, cooperative research and development agreements, financial assistance, and contractual arrangements with universities and the private sector. Together, these efforts focus a wealth of scientific and engineering talent on creating commercially viable solutions to national energy and environmental problems. Although coal is primarily a mixture of carbon (black) and hydrogen (red) atoms, sulfur atoms (yellow) are also trapped in coal, primarily in two forms. In one form, the sulfur is a separate particle often linked with iron (green) with no connection to the carbon atoms, as in the center of the drawing. In the second form, sulfur is chemically bound to the carbon atoms, such as in the upper left. http://www.fossil.energy.gov/education/energylessons/coal/coal_cct2.htmlAll steam-electric power plantsnuclear, coal, gas and oilrun according to the same principles. Water is boiled to make steam. The steam is used to drive a turbine. The blades of the turbine spin the shaft of a generator. Inside the generator, coils of wire and magnetic fields interactand electricity is created. Steam coal, also known as thermal coal, is used in power stations to generate electricity.Coal is first milled to a fine powder, which increases the surface area and allows it to burn more quickly. In these pulverised coal combustion (PCC) systems, the powdered coal is blown into the combustion chamber of a boiler where it is burnt at high temperature (see diagram below). The hot gases and heat energy produced converts water in tubes lining the boiler into steam.The high pressure steam is passed into a turbine containing thousands of propeller-like blades. The steam pushes these blades causing the turbine shaft to rotate at high speed. A generator is mounted at one end of the turbine shaft and consists of carefully wound wire coils. Electricity is generated when these are rapidly rotated in a strong magnetic field. After passing through the turbine, the steam is condensed and returned to the boiler to be heated once again.The electricity generated is transformed into the higher voltages up to 400,000 volts used for economic, efficient transmission via power line grids. When it nears the point of consumption, such as our homes, the electricity is transformed down to the safer 100-250 voltage systems used in the domestic market.Improvements continue to be made in conventional PCC power station design and new combustion techniques are being developed. These allow more electricity to be produced from less coal this is known as improving the thermal efficiency of the power station. During the seventies and also in eighties,, it appeared that conventional pulverised coal-fired power plants had reached a plateau in terms of thermal efficiency. The efficiency levels achieved were of the order of 40 percent in the US and the UK.The corresponding figures for India, however, were lower at 36 to 37 percent.An alternative technology, Fluidised Bed Combustion (FBC), was developed to raise the efficiency levels. In this technology, high pressure air is blown through finely ground coal. The particles become entrained in the air and form a floating or fluidised bed. This bed behaves like a fluid in which the constituent particles move to and fro and collide with one another. Fluidised bed can burn a variety of fuels-coal as well other non-conventional fuels like biomass, petro-coke, coal cleaning waste and wood. This bed contains only around 5 percent coal or fuel. The rest of the bed is primarily an inert material such as ash or sand.

The temperature in FBC is around 800-900 C compared with 1,300-1,500 C in Pulverised Coal Combution (PCC). Low temperature helps minimise the production of NOx. With the addition of a sorbent into the bed (mostly limestone), much of the SO2 formed can be captured. The other advantages of FBC are compactness, ability to burn low calorific values (as low as 1,800 kcal/kg) and production of ash which is less erosive. Moreover, in FBC, oil support is needed for 20-30 percent of the load versus 40-60 percent in PCC. FBC-based plants also have lower capital costs compared to PCC-based plants. The capital costs could be 8-15 percent lower.

FBCs are essentially of two types bubbling and circu-lating. While bubbling beds have low fluidisation veloci-ties to prevent solids from being elutraited, circulating beds employ high velocities to actually promote elutriation. Both these tech-nologies operate on atmos-pheric temperature. The circulating bed can remove 90-95 percent of the sulphur content from the coal while the bubbling bed can achieve 70-90 percent removal.FBC thus offers an option for burning fuels economically, efficiently and in an environmentally acceptable way. Currently, size is the only limitation of this technology. While the maximum size of a PCC-based power plant unit could be 1,300 MW, FBC has achieved a maximum unit size of 250 MW. According to some estimates, FBC represents only about 2 percent of the total coal fired capacity worldwide, but is of particular interest and significance for use of those coals which are difficult to mill and fire in PCC boilers. _________________________________________________________________

Fluidised Bed Combustion (FBC)FBC can reduce SOx and NOx by 90% or more and are very flexible almost any combustible material can be burnt. In the USA for example, FBC systems are increasingly used for abandoned coal waste, turning what could otherwise be an environmental problem into a useful source of power.In fluidised bed combustion, coal is burned in a reactor comprised of a bed through which gas is fed to keep the fuel in a turbulent state. This improves combustion, heat transfer and recovery of waste products. The higher heat exchanger efficiencies and better mixing of FBC systems allows them to operate at lower temperatures than conventional (pulverised) coal-burning systems. By elevating pressures within a bed, a high-pressure gas stream can be used to drive a gas turbine, generating electricity.Fluidised bed combustion technologies:include atmospheric pressure fluidised bed combustion in both bubbling (BFBC) and circulating (CFBC) beds pressurised fluidised bed combustion (PFBC) pressurised circulating fluidised bed combustion (PCFBC), whichis being demonstrated. Circulating Fluidised Bed Combustion (CFBC) is the version of the technology that has been most widely applied and for which there is the most extensive operating history. CFBC uses the same thermodynamic cycle as PCC and therefore its power generation efficiency is in the same range, which is normally between 38% and 40%. Pressurised Fluidised Bed Combustion (PFBC) is based on the combustion of coal under pressure in a deep bubbling fluidised bed at 850C. Depending on the velocity of the air through the fluidised bed, two PFBC variants exist bubbling bed PFBC (lower velocities) and circulating bed PFBC (higher velocities).http://www.worldcoal.org/pages/content/index.asp?PageID=130

A new type of fluidised bed design, the pressurised bed, was developed in the late eighties to further improve the efficiency levels in coal-fired plants. In this concept, the conventional combustion chamber of the gas turbine is replaced by a pressurised fluidised bed combustor. The products of combustion pass through a hot gas cleaning system before entering the turbine. The heat of the exhaust gas from the gas turbine is utilised in the downstream steam turbine. This technology is called pressurised fluidised bed combustion combined cycle (PFBC) (Fig. 8).

The bed is operated at a pressure of between 5 bar and 20 bar and operating the plant at such low pressures allows some additional energy to be captured by venting the exhaust gases through a gas turbine which is then combined with the normal steam turbine to achieve plant efficiency levels of upto 50 percent. The steam turbine is the major source of power in PFBC, contributing about 80 percent of the total power output. The remaining 20 percent is produced in gas turbines. PFBC plants are smaller in size than the atmospheric FBC and PCC plants and therefore have the advantage of siting in urban areas. The fuel consumption is about 10-15 percent lower than in PCC technology.PFBC has been used only over the last few years. The development of this technology is dependent upon the compatibility of the hog gas clean-up system with the gas turbine inlet temperatures and maximum particulate size. Improvements on these two fronts would lead to greater acceptance of PFBC. Status of PFBC Technology DevelopmentThe first demonstration plant of capacity of 130 MWe (+224 MW, co-generation) has been operating in Stockholm, Sweden since 1991 meeting all the stringent environmental conditions. Another demonstration plant of 80 MWe capacity is operating in Escatron, Spain using 36% ash black lignite. The third demonstration plant of 70 MWe at TIDD station, OHIO, USA was shut down in 1994 after a eight year demonstration period in which a large amount of useful data and experience were obtained. A 70 MWe demo plant has been operated at Wakamatsu from 1993 to 1996. Presently, a 350 MWe PFBC power plant is planned in Japan and another is on order in USA (to be operated at SPORN). UK has gathered a large amount of data on a 80 MWe PFBC plant in Grimethrope during its operation from 1980-1992 and is now offering commercial PFBC plants and developing second generation PFBC. ABB-Sweden is the leading international manufacturer which has supplied the first three demonstration plants in the world and is now offering 300 MWe units plants. In India, BHEL-Hyderabad has been operating a 400 mm PFBC for the last eight years and has collected useful research data. IIT Madras has a 300 mm diameter research facility built with NSF (USA) grant. A proposal by BHEL for a 60 MWe PFBC plant is under consideration with the Government of India.

Unlike conventional PC-fired boiler, the CFBC boiler is capable of burning fuel with volatile content as low as 8 to 9 percent (e.g. anthracite coke, petroleum etc. with minimal carbon loss). Fuels with low ash-melting temperature such as wood, and bio-mass have been proved to be feedstocks in CFBC due to the low operating temperature of 850-900 C. CFBC boiler is not bound by the tight restrictions on ash content either. It can effectively burn fuels with ash content upto 70 percent (Fig. 7). CFBC can successfully burn agricultural wastes, urban waste, wood, bio-mass, etc which are the low melting temperature as fuels. The low furnace temperature precludes the production of "thermal NOX" which appears above a temperature of 1200 to 1300 C. Besides, in a CFBC boiler, the lower bed is operated at near sub-stoichiometric conditions to minimise the oxidation of "fuel-bound nitrogen". The remainder of the combustion air is added higher up in the furnace to complete the combustion. With the staged-combustion about 90 percent of fuel-bound nitrogen is converted to elemental nitrogen ( N2) as main product.

The first CFBC power plant of 110 MW at Nuclu. Colorado, USA is operating since 1990. Several such CFBC power plants are operating in Germany, UK, Canada and Japan using various kinds of coal and bio-mass fuels. The largest CFBC power plant is the 250 MWe unit in Gardane, France, commissioned in 1996. Presently, 350 MWe units are being constructed in Canada and Japan. CFBC is a mature technology with more than 300 CFBC boilers in operation world wide ranging from 5 MWe to 250 MWe. With line stone addition, 90 percent of the sulfur emission can be retained. With staged combustion and with relatively low combustion temperature of 850 / 900 C, NO2 formation is about 300 to 400 mg/Nm3 only against 500 to 1000 mg/Nm3 in conventional PF fired boilers.

The integrated gassification combined cycle is a process in which the fuel is gasified in an oxygen or air-blown gasifier operating at high pressure. The raw gas thus produced is cleaned of most pollutants (almost 99 percent of its sulphur and 90 percent of nitrogen pollutants). It is then burned in the combustion chamber of the gas turbine generator for power generation. The heat from the raw gas and hot exhaust gas from the turbine is used to generate steam which is fed into the steam turbine for power generation. Often, IGCC is referred to as "Cool Water" technology, a name drawn from the ranch in California's Mojave Desert that once occupied the site where it was developed. Coal all shorts burns so well with the Cool Water technology -upto 99 percent of sulphur contamination is eliminated.The main subsystems of a power plant with integrated gasification are: Gasification plant Raw gas heat recovery systems Gas purification with sulphur recovery Air separation plant (only for oxygen blown gasification) Gas turbine with heat recovery steam generator Steam turbine generator The feedstock which is fed into the gasifier is more or less completely gasified to synthesis gas (syngas) with the addition of steam and enriched oxygen or air. The gasifier can be fixed bed, entrained or fluidised bed. The selection of the gasifier to achieve best cost efficiency and emission levels depends upon the type of fuel. In the gas purification system, initial dust is removed from the cooled raw gas. Chemical pollutants such as hydrogen sulphide, hydrogen chloride and others are also removed. Downstream of the gas purification system, the purified gas is reheated, saturated with water if necessary (for reduction of the oxides of nitrogen) and supplied to the gas turbine combustion chamber. The IGCC technology scores over others as it is not sensitive with regard to fuel quality. Depending on the type of gasifier, liquid residues, slurries or a mixture of petcoke and coal can be used. In fact, the IGCC technology was developed to take advantage of combined cycle efficiency of such low-grade fuels (Fig. 9)

IGCC technology is also environment friendly. In IGCC, pollutants like sulphur dioxide and oxides of nitrogen are reduced to very low levels by primary measures alone, without down-stream plant components and additives like limestone. The low NOx values are achieved by dilution of the purified syngas with nitrogen from air separation unit and by saturation with water. The direct removal of sulphur compounds from the syngas results in the effective recovery of elemental sulphur, yielding a saleable raw chemical product. Gasification and gas cleaning are an extremely effective filter for contaminants harmful to both gas turbines as well as environment. The IGCC technology is not only environment friendly, but also efficient in power generation (upto 50 percent). However, IGCC is an expensive option. Some companies claim that they have found an answer to the cost issue with a new technology for producing methanol. They believe that fitting this system, which produces methanol at twice the rate of conventional methods, on the back end of the gasifier units on an IGCC plant can cut the capital cost by 25 percent. The technology achieves this saving by reducing the number of gasifiers the IGCC plant needs - provided the full capacity of the power station is not required for base load running. This enables the operator to make full use of the gasifers, which account for 50-60 percent of the cost of an IGCC and become prohibitively expensive under part-time operation. When power is not required, they can be switched to methanol production. This provides the additional fuel to meet full power output at time of peak demand. The additional benefits will not make an IGCC unit competitive with a combined cycle gas turbine (CCGT) plant where there is adequate supply of natural gas. However, a 500 MW unit could compete with traditional coal-fired technology. The biggest difficulty may arise in securing a long-term purchase contract for methanol that will allow the plant operator to keep the gasifiers in continuous operation. The use of gasification for power generation is perceived by many as a complex and expensive technology. However, recent experience in both developed and developing countries reinforces its relevance to power generation. In India, in particular, the IGCC technology is of great relevance as we do not have huge reserves of hydrocarbons. Since coal is available, more project developers can go in for coal-based IGCC plants.

Supercritical & UltrasupercriticalThese power plants operate at higher temperatures and pressures than traditional coal-fired plant, which results in higher efficiencies up to 50% for ultrasupercritical - and thus lower emissions, including CO2. More than 400 supercritical plant are in operation worldwide and China is now installing supercritical plant as standard. Supercritical is a thermodynamic expression describing the state of a substance where there is no clear distinction between the liquid and the gaseous phase. The cycle medium is a single phase fluid with homogeneous properties and there is no need to separate steam from water. Once-through boilers are therefore used in supercritical cycles. Supercritical plant offer higher efficiencies than conventional, sub-critical plant.These power plants operate at higher temperatures and pressures than traditional coal-fired plant, which results in higher efficiencies up to 50% for ultrasupercritical - and thus lower emissions, including CO. More than 400 supercritical plant are in operation worldwide and China is now installing supercritical plant as standard. Supercritical is a thermodynamic expression describing the state of a substance where there is no clear distinction between the liquid and the gaseous phase. The cycle medium is a single phase fluid with homogeneous properties and there is no need to separate steam from water. Once-through boilers are therefore used in supercritical cycles. Supercritical plant offer higher efficiencies than conventional, sub-critical plant. Ultrasupercritical plant operate at very high temperatures and pressures and have the potential to offer efficiencies of over 50%. ________________________Supercritical TechnologyThe steam temperature can be raised to levels as high as 580 to 600 C and pressure over 300 bar. Under these conditions, water enters a phase called "supercritical" with properties in between those of liquid and gas. This supercritical water can dissolve a variety of organic compounds and gases, and when hydrogen per-oxide and liquid oxygen are added, combustion is triggered. Turbines based on this principle are called Supercritical Turbines. These turbines offer outputs of over 500 MW. Some manufacturers are planning to commission steam turbines of 800-1,000 MW output in the next few years. The supercritical turbines can burn low grade fossil fuels and can completely stop Oxides of Nitrogen (NOx) emissions and keep emissions of sulphur dioxide to a minimum. For example, lignite or brown coal has a high water content. So, it is normally not used for power generation. Yet, when lignite is added to water that has been heated to 600 C at a pressure of 300 bar, it will completely burn up in one minute while emitting no NOx and only 1 percent of its original sulphur content as SOx. This also eliminates the need for desulphurisation and denitrification equipment and soot collectors. Although large amounts of energy are required to create supercritical water, operating costs could be significantly different from existing power generating facilities because there would be no need to control gas emissions. The demand for cooling water is also reduced, almost proportionally to an increase in the efficiency. Currently, supercritical power plants reach thermal efficiencies of just over 40 percent, although a few of the more plants have attained high efficiency upto 45 percent. A number of steam generator and turbine manufacturers around the world now claim that steam temperatures upto 700 C ("ultra" supercritical conditions) are possible which might raise plant efficiencies to over 50 percent, but by using expensive nickel-based alloys. Because supercritical water is corrosive, expensive nickel alloys must be used for the reaction equipment and power generators. The main competition to supercritical system is from new gas turbine combined cycle plants which are now expedited to achieve an overall efficiency of 60 percent, making a huge difference in generating and life-cycle costs. However, the new gas turbines will release exhaust into waste heat recovery steam generator at temperatures above 600 C, thus necessitating the use of the high chromium steel and nickel alloys as used in the supercritical coal-fired plants. The economic benefits of taking steam temperature above 635 C, the costs of nickel-based alloys are yet to be resolved. The extra costs of using nickel-based alloys can probably be compensated by reduction in the amount of material required through thinner tube walls and smaller overall dimensions of both plant and site requirements. Efforts are also afoot to develop materials which can withstand high temperatures and pressures to improve thermal efficiency. However, increased live steam pressure may lower potential for improved performance due to auxiliary power consumption. In addition, increased pressure leads to a loss of thermal flexibility and this can also increase costs.

Carbon capture and storage technologies allow emissions of carbon dioxide to be captured and stored i.e. they are removed from the exhaust gases of the power station (either from conventional combustion or from gasification), and stored in such a way that they do not enter the atmosphere thus reducing global warming.Carbon storage is not yet cost-effective, but the required technologies are already proven and have been used commercially in other areas such as the food industry and chemicals industry. The key is to bring the different elements together at an acceptable cost, and research is ongoing to achieve this goal.

Carbon Capture Research Before carbon dioxide (CO2) gas can be sequestered from power plants and other point sources, it must be captured as a relatively pure gas. On a mass basis, CO2 is the 19th largest commodity chemical in the United States, and CO2 is routinely separated and captured as a by-product from industrial processes such as synthetic ammonia production, H2 production, and limestone calcination.Existing capture technologies, however, are not cost-effective when considered in the context of sequestering CO2 from power plants. Most power plants and other large point sources use air-fired combustors, a process that exhausts CO2 diluted with nitrogen. Flue gas from coal-fired power plants contains 10-12 percent CO2 by volume, while flue gas from natural gas combined cycle plants contains only 3-6 percent CO2. For effective carbon sequestration, the CO2 in these exhaust gases must be separated and concentrated.CO2 is currently recovered from combustion exhaust by using amine absorbers and cryogenic coolers. The cost of CO2 capture using current technology, however, is on the order of $150 per ton of carbon - much too high for carbon emissions reduction applications. Analysis performed by SFA Pacific, Inc. indicates that adding existing technologies for CO2 capture to an electricity generation process could increase the cost of electricity by 2.5 cents to 4 cents/kWh depending on the type of process.Furthermore, carbon dioxide capture is generally estimated to represent three-fourths of the total cost of a carbon capture, storage, transport, and sequestration system.The program is pursuing evolutionary improvements in existing CO2 capture systems and also exploring revolutionary new capture and sequestration concepts. The most likely options currently identifiable for CO2 separation and capture include:Absorption (chemical and physical) Adsorption (physical and chemical) Low-temperature distillation Gas separation membranes Mineralization and biomineralization Opportunities for significant cost reductions exist since very little R&D has been devoted to CO2 capture and separation technologies. Several innovative schemes have been proposed that could significantly reduce CO2 capture costs, compared to conventional processes. "One box" concepts that combine CO2 capture with reduction of criteria pollutant emissions are being explored as well.Examples of activities for this program element include:Research on revolutionary improvements in CO2 separation and capture technologies new materials (e.g., physical and chemical absorbents, carbon fiber molecular sieves, polymeric membranes); micro-channel processing units with rapid kinetics; CO2 hydrate formation and separation processes; oxygen-enhanced combustion approaches; Development of retrofittable CO2 reduction and capture options for existing large point sources of CO2 emissions such as electricity generation units, petroleum refineries, and cement and lime production facilities; Integration of CO2 capture with advanced power cycles and technologies and with environmental control technologies for criteria pollutants.

http://www.fossil.energy.gov/programs/sequestrationDeveloping Cleaner Coal TechnologiesCarbon sequestration is a family of methods for capturing and permanently isolating carbon dioxide. Sequestration of carbon dioxide emissions from coal could help retain coals strategic value as a low-cost, abundant, domestic fuel. The 2006 Budget provides $286 million for the Presidents Coal Research Initiative to improve the environmental performance of coal power plants by reducing emissions and improving efficiency. This includes $68 million for the Clean Coal Power Initiative, of which $18 million is allocated to continue development of the FutureGen coal-fueled, zero-emissions, electricity and hydrogen generation project announced by the President in February 2003. FutureGen is guided by an industry and international partnership that will work cooperatively on research, development, and deployment of technologies that will dramatically reduce air pollution from coal-fueled electricity generation plants, generate hydrogen, and capture and store greenhouse gas emissions. The Budget ensures that unexpended funds available from prior years clean coal projects are available to fund future clean coal activities, beginning with FutureGen. The Budget also increases funding for research and development of other clean coal technologies, such as Integrated Gasification Combined Cycle systems, carbon sequestration, and next-generation turbines. Geologic Sequestration Research

Carbon dioxide sequestration in geologic formations includes oil and gas reservoirs, unmineable coal seams, and deep saline reservoirs. These are structures that have stored crude oil, natural gas, brine and CO2 over millions of years. Many power plants and other large emitters of CO2 are located near geologic formations that are amenable to CO2 storage. Further, in many cases, injection of CO2 into a geologic formation can enhance the recovery of hydrocarbons, providing value-added byproducts that can offset the cost of CO2 capture and sequestration.The primary goal of the Energy Department's sequestration research is to understand the behavior of CO2 when stored in geologic formations. For example, studies are being done to determine the extent to which the CO2 moves within the geologic formation, and what physical and chemical changes occur to the formation when CO2 is injected. This information is key to ensure that sequestration will not impair the geologic integrity of an underground formation and that CO2 storage is secure and environmentally acceptable.Oil and Gas Reservoirs. In some cases, production from an oil or natural gas reservoir can be enhanced by pumping CO2 gas into the reservoir to push out the product, which is called enhanced oil recovery. The United States is the world leader in enhanced oil recovery technology, using about 32 million tons of CO2 per year for this purpose. From the perspective of the sequestration program, enhanced oil recovery represents an opportunity to sequester carbon at low net cost, due to the revenues from recovered oil/gas.In an enhanced oil recovery application, the integrity of the CO2 that remains in the reservoir is well-understood and very high, as long as the original pressure of the reservoir is not exceeded. The scope of this EOR application is currently economically limited to point sources of CO2 emissions that are near an oil or natural gas reservoir.Coal Bed Methane. Coal beds typically contain large amounts of methane-rich gas that is adsorbed onto the surface of the coal. The current practice for recovering coal bed methane is to depressurize the bed, usually by pumping water out of the reservoir. An alternative approach is to inject carbon dioxide gas into the bed. Tests have shown thatthe adsorption rate for CO2 to be approximately twice that of methane,giving it the potential to efficiently displace methane and remain sequestered in the bed. CO2 recovery of coal bed methane has been demonstrated in limited field tests, but much more work is necessary to understand and optimize the process.Similar to the by-product value gained from enhanced oil recovery, the recovered methane provides a value-added revenue stream to the carbon sequestration process, creating a low net cost option. The U.S. coal resources are estimated at 6 trillion tons, and 90 percent of it is unmineable due to seam thickness, depth, and structural integrity. Another promising aspect of CO2 sequestration in coal beds is that many of the large unmineable coal seams are near electricity generating facilities that are large point sources of CO2 gas. Thus, limited pipeline transport of CO2 gas would be required. Integration of coal bed methane with a coal-fired electricity generating system can provide an option for additional power generation with low emissions.Saline Formations. Sequestration of CO2 in deep saline formations does not produce value-added by-products, but it has other advantages. First, the estimated carbon storage capacity of saline formations in the United States is large, making them a viable long-term solution. It has been estimated that deep saline formations in the United States could potentially store up to 500 billion tonnes of CO2.Second, most existing large CO2 point sources are within easy access to a saline formation injection point, and therefore sequestration in saline formations is compatible with a strategy of transforming large portions of the existing U.S. energy and industrial assets to near-zero carbon emissions via low-cost carbon sequestration retrofits.Assuring the environmental acceptability and safety of CO2 storage in saline formations is a key component of this program element. Determining that CO2 will not escape from formations and either migrate up to the earths surface or contaminate drinking water supplies is a key aspect of sequestration research. Although much work is needed to better understand and characterize sequestration of CO2 in deep saline formations, a significant baseline of information and experience exists. For example, as part of enhanced oil recovery operations, the oil industry routinely injects brines from the recovered oil into saline reservoirs, and the U.S. Environmental Protection Agency (EPA) has permitted some hazardous waste disposal sites that inject liquid wastes into deep saline formations.The Norwegian oil company, Statoil, is injecting approximately one million tonnes per year of recovered CO2 into the Utsira Sand, a saline formation under the sea associated with the Sleipner West Heimdel gas reservoir. The amount being sequestered is equivalent to the output of a 150-megawatt coal-fired power plant.

http://www.fossil.energy.gov/programs/sequestration___________________________________________________

Geologic formations considered for CO2 storage are layers of porous rock deep underground that are capped by a layer of non-porous rock above them. Sequestration practitioners drill a well down into the porous rock and inject pressurized CO2 into it. The CO2 is buoyant and flows upward until it encounters the layer of non-porous rock and becomes trapped. There are other mechanisms for CO2 trapping as well. CO2 molecules can dissolve in brine, react with minerals to form solid carbonates, or adsorb in the pores of the porous rock. The degree to which a specific underground formation is amenable to CO2 storage can be difficult to discern. Research is aimed at developing the ability to characterize a formation before CO2-injection to be able to predict its CO2 storage capacity. Another area of research is the development of CO2 injection techniques that achieve broad dispersion of CO2 throughout the formation, overcome low diffusion rates, and avoid fracturing the cap rock. These two areas, site characterization and injection techniques, are interrelated because improved formation characterization will help determine the best injection procedure. There are three priority types of geologic formations in which CO2 can be stored, and each has different opportunities and challenges: Depleted oil and gas reservoirs. These are formations that held crude oil and natural gas over geologic time frames. In general they are a layer of porous rock with a layer of non-porous rock above such that the non-porous layer forms a dome. It is the dome shape that trapped the hydrocarbons. This same dome offers great potential to trap CO2 and makes these formations excellent sequestration opportunities. As a value-added benefit, CO2 injected into a depleting oil reservoir can enable incremental oil to be recovered. The CO2 lowers the viscosity of the oil enabling it to slip through the pores in the rock and flow with the pressure differential toward a recovery well. Typically, primary oil recovery and secondary recovery via a water flood produce 30-40% of a reservoir's original oil in place (OOIP). A CO2 flood enables recovery of an additional 10-15% of the OOIP. CO2 enhanced oil recovery (EOR) is a commercial process and in demand recently with high crude oil prices. However, commercial practitioners operate their injections with the goal of minimizing the amount of CO2 left in the ground so that the CO2 can be used for another well. NETL's work in this area is focused on CO2 EOR injection practices that maximize the amount of CO2 sequestered. Unmineable coal seams. Unmineable coal seams are too deep or too thin to be mined economically. All coals have varying amounts of methane adsorbed onto pore surfaces, and wells can be drilled into unmineable coal beds to recover this coal bed methane (CBM ). Initial CBM recovery methods, dewatering and depressurization, leave a fair amount of CBM in the reservoir. Additional CBM recovery can be achieved by sweeping the coalbed with nitrogen. CO2 offers an alternative to nitrogen. It preferentially adsorbs onto the surface of the coal, releasing the methane. Two or three molecules of CO2 are adsorbed for each molecule of methane released, thereby providing an excellent storage sink for CO2. The maximum domestic capacity for CO2 enhanced coalbed methane (ECBM) has been estimated at 90 billion metric tons CO2,* 40 billion metric tons of which are in Alaska . Like depleting oil reservoirs, unmineable coal beds are a good early opportunity for CO2 storage. Coal swelling is a potential barrier to CO2 ECBM. It has been observed that when coal adsorbs CO2, it swells in volume. In an underground formation swelling can cause a sharp drop in permeability, which not only restricts the flow of CO2 into the formation but also impedes the recovery of displaced CBM. NETL is pursuing angled drilling techniques and fracturing as possible means of overcoming the negative effects of swelling. Saline formations. Saline formations are layers of porous rock that are saturated with brine. They are much more commonplace than coal seams or oil and gas bearing rock, and represent an enormous potential for CO2 storage capacity. However, much less is known about saline formations than is known about crude oil reservoirs and coal seams and there is a greater amount of uncertainty associated with their amenability to CO2 storage. Saline formations tend to have a lower permeability than do hydrocarbon-bearing formations, and work is directed at hydraulic fracturing and other field practices to increase injectivity. Saline formations contain minerals that could react with injected CO2 to form solid carbonates. The carbonate reactions have the potential to be both a positive and a negative. They can increase permanence but they also may plug up the formation in the immediate vicinity of an injection well. Researchers seek injection techniques that promote advantageous mineralization reactions.

http://www.netl.doe.gov/technologies/carbon_seq/core_rd/storage.htmlOcean Sequestration Research MORE INFONational Lab scientists at DOE's Center for Research on Ocean Carbon Sequestration are studying deep injection and ocean fertilization. [Leave site]CO2 is soluble in ocean water, and through natural processes the oceans both absorb and emit huge amounts of CO2 into the atmosphere. In fact, the amount of carbon stored in the ocean dwarfs the carbon stored in terrestrial ecosystems.It is widely believed that the oceans will eventually absorb 80-90 percent of the CO2 in the atmosphere and transfer it to the deep ocean. However, the kinetics of ocean uptake are unacceptably slow, causing a peak atmospheric CO2 concentration of several hundred years.The program will explore options for speeding up the natural processes by which the oceans transport CO2 and for injecting CO2 directly into the deep ocean.Enhancement of Natural Carbon Sequestration in the OceanOne approach to enhancing export production of carbon to the deep ocean is via the addition of iron chelates (a micronutrient) to high nutrient, low chlorophyll (HNLC) regions, in order to increase the drawdown of CO2 as a result of stimulated phytoplankton blooms. Another related technique would be the addition of nitrates and phosphorus (macronutrients) to low nutrient, low chlorophyll (LNLC) ocean regions. The magnitude of these enhancements to the biological pump and the depth of vertical transport are unknown, and require additional research, as well as investigation into unknown biological consequences from such perturbations, e.g., eutrophication, or increasing number of unwanted events (toxic blooms).Direct Injection of CO2Technology currently exists to performthe direct injection of CO2 into the deepocean. However,the knowledge base is inadequate to determine what biological, physical or chemical impacts might occur from interaction of this hydrate plume with the marine ecosystem. Additionally, there is insufficient information to perform any process optimization pertaining to costs and engineering activities. To assure environmental acceptability, developing a better understanding of the ecological impacts of both ocean fertilization and direct injection of CO2 into the deep ocean is a primary focus of this program element. It is known that small changes in biogeochemical cycles may have large consequences, many of which are secondary and difficult to predict. Of particular concern is the potential for adverse effects due to localized depressed pH, and elevated localizedCO2 concentrations (hypercapnia).

http://www.fossil.energy.gov/programs/sequestration______________________________________________________

Compared to terrestrial ecosystems and geologic formations, the concept of ocean sequestration is in a much earlier stage of development. The ocean has huge potential as a carbon storage sink, but the scientific understanding to enable ocean sequestration to be considered as a real option is not yet available. A small level of funding is provided to leading researchers in this area to develop the necessary scientific understanding of the feasibility of ocean sequestration. Work is focused on understanding the mechanisms of CO2 uptake in the ocean and assessing the environmental impacts of CO2 storage. NETL is also funding laboratory studies of the behavior of CO2 droplets and CO2/water hydrate structures in simulated ocean environments. One of the most promising places to sequester carbon is in the oceans, which currently take up a third of the carbon emitted by human activity, roughly two billion metric tons each year. The amount of carbon that would double the load in the atmosphere would increase the concentration in the deep ocean by only two percent. Two sequestration strategies are under intense study at the Department of Energy's Center for Research on Ocean Carbon Sequestration (DOCS), where Jim Bishop of Berkeley Lab's Earth Sciences Division is codirector with Livermore Lab's Ken Caldeira. One is direct injection, which would pump liquefied carbon dioxide a thousand meters deep or deeper, either directly from shore stations or from tankers trailing long pipes at sea.

"At great depths, CO2 is denser than sea water, and it may be possible to store it on the bottom as liquid or deposits of icy hydrates," Bishop explains. "At depths easy to reach with pipes, CO2 is buoyant; it has to be diluted and dispersed so it will dissolve."What happens to carbon dioxide introduced into the ocean in this way may soon be field-tested in Hawaii. Over a two-week period researchers plan to inject 40 to 60 metric tons of pure liquid CO2 over 2,500 feet deep in the ocean near the Big Island.One variable they will be measuring is acidity. Water and carbon dioxide form carbonic acid, "but once diluted in sea water, carbonic acid is not the dominant chemical species," Bishop says, "because of seawater's high alkalinity and buffering capacity." If calcium carbonate sediments are involved, acidity is even less. "Think of Tums," he suggests.Fertilizing the oceanThe other major approach to sequestration is to "prime the biological pump" by fertilizing the ocean. Near the surface, carbon is fixed by plant-like phytoplankton, which are eaten by sea animals; some eventually rains down as waste and dead organisms. Bacteria feed on this particulate organic carbon and produce CO2, which dissolves, while the rest of the detritus ends on the sea floor."There are areas of the ocean that are rich in nutrients like nitrogen and phosphorus but poor in phytoplankton," says Bishop. "Adding a little iron to the mix allows the plankton to use the nutrients and bloom. The energy for the process is supplied by sunlight. Already commercial outfits are dropping iron filings overboard, hoping to increase fisheries -- meanwhile claiming they are helping to prevent global warming." THE GLOBAL CARBON CYCLE AND THE ROLE OF THE OCEANIn fact, Bishop explains, "if the excess fixed carbon in plants is eaten by fish near the ocean surface, the net effect is no gain. And in every part of the ocean there are open mouths."No one really knows where the carbon trapped by fertilization ends up. In one iron-fertilization experiment in warm equatorial waters, chlorophyll increased 30-fold in a week, and there was increased carbon sedimentation down through 100 meters. But the bloom shortly dissipated, the fate of the carbon in deeper waters wasn't followed, and long-term effects weren't measured.In a more recent experiment in cold Antarctic Ocean waters the plankton bloom persisted much longer. Seven weeks after the experiment ended a distinct pattern of iron-fertilized plankton was still visible from space -- "which means the fixed carbon was still at the surface."Bishop says that "people who want to add iron think the particulate matter will fall straight to the bottom; I have sampled natural plankton blooms, and I have not seen that happen. These guys have a potentially effective method of sequestering carbon, but as yet there is no scientific basis for their claims."Terrestrial Sequestration Research Vegetation and soils are widely recognized as carbon storage sinks. The global biosphere absorbs roughly 2 billion tons of carbon annually, an amount equal to roughly one third of all global carbon emissions from human activity. Significant amounts of this carbon remains stored in the roots of certain plants and in the soil. In fact, the inventory of carbon stored in the global ecosystem equals rougly 1,000 years worth of annual absorption, or 2 trillion tons of carbon.Another important area of research in terrestrial sequestration is the development of technologies for quantifying carbon stored in a given ecosystem. Should the United States and other nations one day adopt a carbon emissions trading program, high precisions and reliability in these measuring techniques will be necessary.Terrestrial carbon sequestration is defined as either the net removal of CO2 from the atmosphere or the prevention of CO2 net emissions from the terrestrial ecosystems into the atmosphere.Enhancing the natural processes that remove CO2 from the atmosphere is thought to be one of the most cost-effective means of reducing atmospheric levels of CO2, and forestation and deforestation abatement efforts are already under way. R&D in this program area seeks to increase this rate while properly considering all the ecological, social, and economic implications. There are two fundamental approaches to sequestering carbon in terrestrial ecosystems: (1) protection of ecosystems that store carbon so thatcarbon stores can be maintained or increased; and (2) manipulation of ecosystems to increase carbon sequestration beyond current conditions.This program area is focused on integrating measures for improving the full life-cycle carbon uptake of terrestrial ecosystems,including farmland and forests,with fossil fuel production and use. The following ecosystems offer significant opportunity for carbon sequestration:Forest lands. The focus includes below-ground carbon and long-term management and utilization of standing stocks,understory, ground cover,and litter. Agricultural lands. The focus includes crop lands, grasslands, and range lands,with emphasis on increasing long-lived soil carbon. Biomass croplands. As a complement to ongoing efforts related to biofuels,the focus is on long-term increases in soil carbon and value-added organic products. Deserts and degraded lands. Restoration of degraded lands offers significant benefits and carbon sequestration potential in both below-and above-ground systems. Boreal wetlands and peatlands. The focus includes management of soil carbon pools and perhaps limited conversion to forest or grassland vegetation where ecologically acceptable. The program area is being conducted in collaboration with DOEs Office of Science and the U.S.Forest Service of the U.S. Department of Agriculture.______________________________________

Terrestrial sequestration is the enhancement of the CO2 uptake by plants that grow on land and in freshwater and, importantly, the enhancement of carbon storage in soils where it may remain more permanently stored. Terrestrial sequestration provides an opportunity for low-cost CO2 emissions offsets. Early efforts include tree-plantings, no till farming, and forest preservation. More advanced research includes the development of fast-growing trees and grasses and deciphering the genomes of carbon-storing soil microbes. Responsibility for terrestrial sequestration research is shared by many Federal agencies, and the program coordinates activities in this area with the DOE Office of Science, U.S. Department of Agriculture, U.S. Environmental Protection Agency, and U.S. Department of Interior Office of Surface Mining. The scope of terrestrial sequestration options addressed in NETL's core R&D is limited to the integration of energy production, conversion, and use with land reclamation. Specifically, this involves the reforestation and amendment of minelands and other damaged soils, when possible, using solid residuals from coal combustion.

http://www.netl.doe.gov/technologies/carbon_seq/core_rd/storage.htmlThe land and oceans are known to store half of the total carbon emitted annually from fossil fuel burning and industrial activities. The other half is accumulating as carbon dioxide in the atmosphere, which is thought by many to be responsible for global climate change. Researchers found that America's forests soaked up 140 million tons of carbon a year, while most Canada's boreal forests were found to be losing carbon. Russia, the country with most forests, accounted for almost 40 percent of the biomass carbon sink. Satellite observations of vegetation greenness is a measurement of the amount and functioning of plants which consume atmospheric carbon dioxide and synthesize sugars. Watching the greening over the three years shown is a good indication of carbon fixation. Vision 21 - the Ultimate Power Plant Concept Program Performance Goal: By 2015, develop the core modules for a fleet of fuel-flexible, multi-product energy plants that boost power efficiencies to 60+ percent, emit virtually no pollutants, and with carbon sequestration release minimal or no carbon emissions. Vision 21 is a futuristic energy concept unlike any power plant that exists today. TECHNOLOGY GOALS EfficienciesCoal-fueled: >60% HHV Gas-Fueled: >75% Combined Heat & Power: 75-80% thermalEmissionsAir/Wastes: Zero CO2: Zero (with sequestration)CostsElectricity at market pricesUnder development by the Department of Energy's Office of Fossil Energy, the concept envisions a virtually pollution-free energy plant. Unlike today's single purpose power plants that produce only electricity, a Vision 21 plant would produce multiple products - perhaps electricity in combination with liquid fuels and chemicals or hydrogen or industrial process heat. It also would not be restricted to a single fuel type; instead, it could process a wide variety of fuels such as coal, natural gas, biomass, petroleum coke (from oil refineries), and municipal waste. It would generate electricity at unprecedented efficiencies, and coupled with carbon sequestration technologies, it would emit little if any greenhouse gases into the atmosphere.Vision 21, if successful, could revolutionize the power and fuels industry within the next 15 years.The approach is to develop a suite of technology modules that can be interconnected in different configurations to produce selected products. These modular facilities will be capable of using a multiplicity of fuels to competitively produce a number of commodities at efficiencies greater than 60 percent for coal-based systems and 75 percent for natural gas-based systems with near-zero emissions.Vision 21 builds on a portfolio of technologies already being developed, including low-polluting combustion, gasification, high efficiency furnaces and heat exchangers, advanced gas turbines, fuel cells, and fuels synthesis, and adds other critical technologies and system integration techniques. When coupled with carbon dioxide capture and recycling or sequestration, Vision 21 systems would release no net carbon dioxide emissions and have no adverse environmental impacts.Many of the Vision 21 activities complement and extend focused activities to achieve intregated gasification combined cycle and other advanced high efficiency technologies. For example, hot gas particulate filtration, hot gas sulfur/alkali control, and air separation are critical elements to coal gasification. Vision 21 addresses gas separation and cleanup, but extends the development effort to:increasingly efficient and cost-effective measures for particulate and sulfur/alkali control and air separation; and measures dealing with a broader range of gases, such as hydrogen and carbon dioxide. Advanced gas separation and cleanup are critical to achieving hybrid systems, fuel and product flexibility, and carbon sequestration. Hybrids and fuel and product flexibility offer the potential for major improvements in cost and performance. And effective carbon dioxide capture is a prerequisite to carbon sequestration.A hybrid system showing great promise is integration of gasification with a fuel cell. Fuel cells offer very high efficiencies, with emerging fuel cells having 60 percent efficiency. These emerging fuel cells also produce very high-temperature exhaust gases that can either be used directly in combined-cycle or used to drive a gas turbine. Integrated gasification fuel cellhybrids have the potential to achieve up to 60 percent efficiency and near-zero emissions. Moreover, the concentration of carbon dioxide lends itself to removal by separation or other capture means. Such systems require that the syngas derived from gasification be free of contaminates for use in the fuel cell, or that the hydrogen be separated from the syngas (hydrogen is the fuel element for the fuel cell).Fuel flexibility enables the use of low-cost indigenous fuels, renewables, and waste materials. Use of renewables and wastes contributes to solving environmental problems as well as reducing operating costs. The challenge is to develop effective feed mechanisms for these alternative fuels, establish effective operating parameters, and provide the means to achieve the operating parameters and to control any new pollutants that might be formed. For advanced, high-performance gas turbines, and hybrids incorporating advanced turbines/fuel cells, fuel flexibility requires research to address combustion of low-Btu gases and maintain low-NOx emissions at increasingly higher temperatures.Product flexibility allows power suppliers to supplement revenues by designing plants to site- or region-specific markets for high-value by-products. Many chemical and fuel processes, however, require nearly contaminant-free syngas and warrant improvements to enhance product quality.Carbon sequestration is the ultimate solution to stabilizing global carbon emissions. A prerequisite to carbon sequestration is carbon capture, which for power systems is carbon dioxide capture. Power system developments are moving toward higher efficiency to lower carbon dioxide emissions on a per-Btu basis and toward more concentrated carbon dioxide emission streams through oxygen-rather than air-based gasification and combustion. Air separation efforts support the move to oxygen-based systems. Ultimately, carbon dioxide must be captured either through chemical or physical separation methods.Vision 21 is addressing the challenges outlined above through a cooperative effort involving industry, universities, and National Laboratories. It includes fundamental research in materials science, novel concept evaluation at bench-scale, and process verification at pilot-scale. Facilities such as the Power System Development Facility at Wilsonville, Alabama, along with industry/National Laboratory/university facilities, are being enlisted to address these challenges.FutureGen is an initiative to build the world's first integrated sequestration and hydrogen production research power plant. The $1 billion dollar project is intended to create the world's first zero-emissions fossil fuel plant. When operational, the prototype will be the cleanest fossil fuel fired power plant in the world.The initiative is a response to President Bush's directive to draw upon the best scientific research to address the issue of global climate change. The production of hydrogen will support the President's call to create a hydrogen economy and fuel pollution free vehicles; and the use of coal will help ensure America's energy security by developing technologies that utilize a plentiful domestic resource. Additionally, other countries will be invited to participate in the demonstration project through the Carbon Sequestration Leadership Forum and other mechanisms.The prototype plant will establish the technical and economic feasibility of producing electricity and hydrogen from coal (the lowest cost and most abundant domestic energy resource), while capturing and sequestering thecarbon dioxidegenerated in the process. The initiative will be a government/industry partnership to pursue an innovative 'showcase' project focused on the design, construction and operation of a technically cutting-edge power plant that is intended to eliminate environmental concerns associated with coal utilization. This will be a 'living prototype' with future technology innovations incorporated into the design as needed.The project will employ coal gasification technology integrated with combined cycle electricity generation and the sequestration of carbon dioxide emissions. The project will be supported by the ongoing coal research program, which will also be the principal source of technology for the prototype. The project will require 10 years to complete and will be led by an industrial consortium representing the coal and power industries, with the project results being shared among all participants, and industry as a whole.In the operational phase, the project will generate revenue streams from the sales of electricity, hydrogen and carbon dioxide. The revenue will be shared among the project participants (including the U.S. Government) in proportion to their respective cost-sharing percentage.Central Florida will become home to the world's cleanest and most efficient coal fired power plant. Southern Company is partnering with the Orlando Utilities Commission (OUC) to produce cleaner, more reliable and affordable electricity using the latest power generation technology. Located at OUC's Stanton Energy Center, Southern Company's 285-megawatt clean coal power plant will begin construction in 2007 and be complete by 2010, creating 1,800 new jobs in the area. One of the most advanced - and cleanest - coal power plants in the world is Tampa Electric's Polk Power Station in Florida. Rather than burning coal, it turns coal into a gas that can be cleaned of almost all pollutants. The Ultra-Clean Coal (UCC) process produces coal that has had virtually all of its mineral impurities chemically removed. This high-purity coal can be fired directly into gas turbines to provide high-efficiency, reduced-emission power generation. pilot scale UCC plant in the Hunter ValleyThrough a two-stage process, energy in UCC can be converted into electrical energy with very high efficiency of 50 to 55 percent. Most coal-fired power stations in Australia are typically reaching efficiencies of around 33 to 35 percent, while very modern coal-fired power stations can reach efficiencies of up to 40 percent.The UCC-fired, gas-turbine combined-cycle system has the potential to produce 25 percent less greenhouse gas than best practice in a conventional coal-fired system. This can be translated to an overall reduction of 10 percent during its life cycle when mining, UCC production and transport are taken into account.White Mining Limited is currently running a UCC pilot plant in the Hunter Valley of New South Wales using CSIRO Energy Technologys advances. The plant has provided UCC for turbine assessment in Japan.The UCC product is not designed to compete with traditional coal-fired power stations but has been developed as a replacement for oil and gas in power

Ultra Clean Coal as a Gas Turbine Fuel An Ultra Clean Coal (UCC) technology and process to produce an ultra low ash solid fuel for direct firing in gas turbines is currently being piloted in Australia. The UCC technology and process is being developed by UCC Energy Pty Limited, a wholly owned R&D subsidiary of White Mining Limited, in co-operation with the CSIRO (Commonwealth Scientific and Industrial Research Organisation) and is supported by both the Federal and State Governments. The patented technology is well developed and has many environmental advantages including greenhouse gas (GHG) reduction, minimal ash disposal and potentially cheaper electricity production. (Pictured: General view of the UCC pilot plant, Cessnock NSW.)By definition, ultra clean coals are coals with less than 1% ash. The CSIRO/Whites UCC process is producing a new clean solid fuel with ash levels between 0.1% and 0.2%. The UCC process uses alkali/acid digestion to dissolve the minerals out of the coal under moderate temperature and pressure conditions, without the loss of coal properties. UCC, although based on coal, is not a substitute for conventional coal in conventional power generating systems; its major application is in areas where conventional coal cannot be used. It is an alternative for heavy fuel oil and gas. UCC is cost competitive with these fuels on an equal energy basis. When UCC is directly fired into a gas turbine, it is estimated that thermal efficiency is increased from around 38% for a conventional coal fired power station to approximately 53% with direct injection of UCC into a gas turbine with combined cycle. In addition a UCC fired gas turbine combined cycle power plant is more amenable to locating close to the electricity users than is the case for conventional coal fired generators, and this opens the possibility of reaching overall energy conversion efficiencies of close to 60%. With the increase in thermal efficiency there is a very significant reduction in GHG emissions at the power station, for the same amount of electricity generated. Also, life cycle (from mining to electrical power to the customer) GHG reductions of more than 20% are likely to be achieved compared to the conventional coal case. These benefits in emission reduction resulting from UCC are dependent on it being used in advanced combined cycle power-generating systems, not suitable for conventional coal feeds, to obtain the maximum possible thermal efficiency. The UCC process is suited to most black coals and is therefore of strategic importance to developing countries with indigenous coal supplies, but limited in other energy resources. Additionally the process will also be of interest to other major coal producing countries. Although the major application of the UCC product is as a fuel, it can also be used as a clean carbon source for metallurgical processes; for instance, in carbon anodes for aluminium production. Mineral by-products from the process may also have industrial application, though little work has been done to date in this area. For further information see: http://www.uccenergy.com.au/

Don't think of coal as a solid black rock. Think of it as a mass of atoms. Most of the atoms are carbon. A few are hydrogen. And there are some others, like sulfur and nitrogen, mixed in. Chemists can take this mass of atoms, break it apart, and make new substances like gas! How do you break apart the atoms of coal? You may think it would take a sledgehammer, but actually all it takes is water and heat. Heat coal hot enough inside a big metal vessel, blast it with steam (the water), and it breaks apart. Into what?The carbon atoms join with oxygen that is in the air (or pure oxygen can be injected into the vessel). The hydrogen atoms join with each other. The result is a mixture of carbon monoxide and hydrogen a gas.Now, what do you do with the gas?You can burn it and uses the hot combustion gases to spin a gas turbine to generate electricity. The exhaust gases coming out of the gas turbine are hot enough to boil water to make steam that can spin another type of turbine to generate even more electricity. But why go to all the trouble to turn the coal into gas if all you are going to do is burn it?A major reason is that the impurities in coal like sulfur, nitrogen and many other trace elements can be almost entirely filtered out when coal is changed into a gas (a process called gasification). In fact, scientists have ways to remove 99.9% of the sulfur and small dirt particles from the coal gas. Gasifying coal is one of the best ways to clean pollutants out of coal.Another reason is that the coal gases carbon monoxide and hydrogen don't have to be burned. They can also be used as valuable chemicals. Scientists have developed chemical reactions that turn carbon monoxide and hydrogen into everything from liquid fuels for cars and trucks to plastic toothbrushes!Today,outside ofTampa, Florida (near the town of Lakeland), and in West Terre Haute, Indiana, there are power plants generating electricity by gasifying coal, rather than burning it. At a plant in Kingsport, Tennessee, coal gas is being used to make plastic for photographic film and to make methanol (a fuel that can be burned in automobile engines).Coal gasification could be one of the most promising ways to use coal in the future to generate electricity and other valuable products. Yet, it is only one of an entirely new family of energy processes called "Clean Coal Technologies" technologies that can make fossil fuels future fuels.In a typical coal boiler, coal would be crushed into very fine particles, blown into the boiler, and ignited to form a long, lazy flame. Or in other types of boilers, the burning coal would rest on grates. But in a "fluidized bed boiler," crushed coal particles float inside the boiler, suspended on upward-blowing jets of air. The red-hot mass of floating coal called the "bed" would bubble and tumble around like boiling lava inside a volcano. Scientists call this being "fluidized." That's how the name "fluidized bed boiler" came about.Why does a "fluidized bed boiler" burn coal cleaner?There are two major reasons. One, the tumbling action allows limestone to be mixed in with the coal. Remember limestone from a couple of pages ago (> go back)? Limestone is a sulfur sponge it absorbs sulfur pollutants. As coal burns in a fluidized bed boiler, it releases sulfur. But just as rapidly, the limestone tumbling around beside the coal captures the sulfur. A chemical reaction occurs, and the sulfur gases are changed into a dry powder that can be removed from the boiler. (This dry powder called calcium sulfate can be processed into the wallboard we use for building walls inside our houses.)The second reason a fluidized bed boiler burns cleaner is that it burns "cooler." Now, cooler in this sense is still pretty hot about 1400 degrees F. But older coal boilers operate at temperatures nearly twice that (almost 3000 degrees F). Remember NOx from the page before (> go back)? NOx forms when a fuel burns hot enough to break apart nitrogen molecules in the air and cause the nitrogen atoms to join with oxygen atoms. But 1400 degrees isn't hot enough for that to happen, so very little NOx forms in a fluidized bed boiler.The result is that a fluidized bed boiler can burn very dirty coal and remove 90% or more of the sulfur and nitrogen pollutants while the coal is burning. Fluidized bed boilers can also burn just about anything else wood, ground-up railroad ties, even soggy coffee grounds.Today, fluidized bed boilers are operating or being built that are 10 to 20 times larger than the small unit built almost 20 years ago at Georgetown University. There are more than 300 of these boilers around this country and the world. The Clean Coal Technology Program helped test these boilers in Colorado, in Ohio and most recently, in Florida.