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COAL FACTSTRANSCRIPT
SHP Columbia University
(King?) Coal Diego Villarreal SHP Columbia University October 17th,
2015 COAL FACTS What is the role of coal Coal is the most
widespread fuel in electricity generation Over 40% of worlds
installed base of electricity generating capacity is coal-fired
Main source of industrial energy for about 200 years Until recently
it was also the least expensive Today wind and gas (in US) are
competitive or perhaps less costly. Not the case everywhere. Coal
produces a lot of CO2 and is sensitive to a price on carbon &
environmental regulations. Coal has enormous environmental
externalities. Coal is also used as a fuel for other energy
intensive industries such as steel, cement, and paper. In the USA,
about 93% of coal is used in the electric sector. C(as coal) + O2
CO2 (not including all S, NOx, PPM) How is coal used (world)
Source: IEA Key World Energy Statistics 2014 Electricity Production
by Fuel/Region
Source: IEA Key World Energy Statistics 2014 TPES in the US US EIA
Annual Review Supplies in quadrillion BTUs. How is coal used in the
US?
Source: EIA Monthly Energy Review September 2014 Coal by the
numbers (Production)
Source: IEA Key World Energy Statistics 2014 Coal by the numbers
(Consumption)
Consumption by region (million tons of oil equivalent) Consumption
per-capita (toe)
BP Statistical Review of World Energy 2013 BP 2013 Thinking about
reserves
Resources in the lower right corner of the grid have highly
speculative existence and would be very expensive to mine even if
they did exist. Resources in the upper left corner are proven to
exist (for example, an as-yet-unmined area in an existing mine) and
can be mined at lower cost than the price they can be sold for,
under existing market prices and technologies. These resources are
known as reserves. As the price of coal increases, some of the
demonstrated subeconomic resources will become economic, and shift
into the reserves box. As more resources are proven or
hypothesized, they will shift to the left in the grid. The entire
resource base has the potential to become reserves, but only if we
can find everything (and know conclusively that it is everything)
and it can all be extracted profitably. The outline of this diagram
can be used to understand the risk of future coal and gas
availability. Fossil Fuel Reserves Ultimately recoverable
resources, the measure of long-term fossil fuel production
potential, are considerably higher than proven reserves. As market
conditions change and technology advances, some of these resources
are set to move into the proven category, providing further
reassurance that the resource base will not constrain production
for many decades to come. Source: IEA WEO 2012 Distribution of
proved coal reserves in 1992, 2002 and 2012 (percentage)
BP Statistical Review of World Energy 2013 BP 2013 Recent trends
world in supply/demand
Coals share in the global primary fuel mix has increased by five
percentage points over the past decade to reach 29% in 2013. Coal
strengthened its position as the second-largest primary energy
source, behind oil. China continues to be the engine of coal demand
growth. As the most carbon-intensive fossil fuel, coal is the
leading source of carbon-dioxide (CO2) emissions, as well as a
major contributor to local air pollution. In the absence of rapid
and widespread adoption of high-efficiency coal-fired generation
technologies and, in the longer term, of CCS, the increased use of
coal will be incompatible with climate goals. IEA WEO 2014 Recent
Trends supply/demand (US)
In short/medium term coal losing market share in electricity
generation to natural gas and renewables. New EPA rules and Mercury
and Air Toxic Standards (2016) will lead to a wave to coal-fired
capacity retirements. Future GHG policies will directly affect
coal. Recent Trends supply/demand (US) TECHNICAL CONSIDERATIONS
Types of coal Coal is classified into four main types:
Lignite -Lowest rank of coal and used almost exclusively as fuel
for electric power generation % Subbituminous Used primarily as
fuel for steam-electric power generation and is an important source
of light aromatics for chemical industry % carbon content
Bituminous - Dense sedimentary rock, used primarily as fuel in
steam-electric power generation, with substantial quantities used
for heat and power applications in manufacturing and to make coke.
Carbon content 60-80% Anthracite - Highest rank of coal used
primarily for residential and commercial space heating. Petrified
Oil. Carbon content 92.1%-98% Coals with a high heat content are
generally higher priced. Coal extraction methods
Dragline Longwall Typical coal-fired power plant
SO2, NOx and CO/CO2 emissions Reduced if Natural gas or hybrid
coal-gas is used Electricity is produced by the process of heating
water in a boiler to produce steam. The steam, under tremendous
pressure, flows into a turbine, which spins a generator to produce
electricity. Kingston Fossil Plant near Knoxville, Tennessee (1.7
GW plant) Boiler heats the water to about 1,000 F (540 C) to create
steam. Pressure ~ 122 atm. Plant generates about 10 billion
kilowatt-hours a year, or enough electricity to supply 700,000
homes. Burns ~ 14,000 tons of coal a day, an amount that would fill
140 railroad cars. 20 IGCC Typical pulverized coal power plants
thermal efficiency ~ 35%
Can also gasify coal using IGCC technology Integrated Gasification
Combined Cycle Turn coal into syngas then burn in combined cycle
power plant much cleaner than conventional power stations. Greater
efficiency & potential ability to capture CO2 Only 2 IGCC power
plants in the US. Capital costs higher. IGCC Wikipedia Coal plant
example A 500 MW power plant burns Bituminous coal. The heat rate
of this Bituminous coal is found to be ~ kJ/kg. If the plant has a
capacity factor of 70% and a thermal efficiency of 38.9%, calculate
the following: How much electricity is produced by the power plant
in one year? How much coal does the power plant use per year? How
much CO2? (assume complete combustion). What volume would this CO2
occupy? If one railcar holds 100 tons of coal, how many railcars
enter the plant each year. If ash is 9.8% of the initial mass of
coal, how much ash is produced per year The coal that is being used
has 1.5% sulfur by mass. How much SO2 does this power plant produce
each year? CO2/Fuel energy? SO2/Fuel energy? Useful information: 1
kWh = kJ Molar mass C = 12 g/mol; M.M O = 16 g/mol; M.M S = 32
g/mol. Coal in the USA Mostly used for power generation.
Most of the coal comes from WY and WV. Wyoming is the largest
regional coal producer, as well as the largest coal-producing state
in the nation. Nine of the top ten producing coal mines in the
United States are located in Wyoming. For many years the dominance
of coal in electricity generation was unquestioned. The recent
gloat of NG is shifting this dynamic (more on this later). However,
production is not down as coal displaced by gas in the USA is
finding a home in other markets abroad. Price of coal Coal in the
US (2) EIA projects total coal consumption of 941 MMst in 2014, an
increase of 1.7% from last year. Total coal consumption is
projected to fall by 2.0% in 2015, as retirements of coal power
plants rise in response to the implementation of the Mercury and
Air Toxics Standards, electricity sales growth slows to 0.6%, and
natural gas prices fall relative to coal prices. Price of coal vs
natural gas
The recent glut of natural gas has dramatically decreased the cost
of natural gas in the US. This has an enormous impact on the coal
vs. gas competition for power generation. Electricity Production in
the US COAL AND THE ENVIRONMENT Environmental Issues With
Coal
Coal abundant, cheap and easy to extract. However, it is also a
very dirty fuel with a lot of environmental externalities. When
coal is combusted, a series of unwanted and harmful substances and
particulates. Mainly: Sulfur dioxide (SO2), which contributes to
acid rain and respiratory illnesses. Nitrogen oxides (NOx), which
contributes to smog and respiratory illnesses. Particulates, which
contribute to smog, haze, and respiratory illnesses and lung
disease. Carbon dioxide (CO2), which is the primary greenhouse gas
emission from the burning of fossil fuels. Mercury and other heavy
metals (Cd, Pb, etc), have been linked with both neurological and
developmental damage in humans and other animals. Fly ash and
bottom ash are residues created when coal is burned at power
plants. Must be captured by pollution control devices, like
scrubbers. In the United States, fly ash is generally stored at
coal power plants or placed in landfills. Pollution leaching from
ash storage and landfills into groundwater has emerged as a new
environmental concern. Environmental Issues with Coal (2)
In 2008 the World Health Organization (WHO) and other organizations
calculated that coal particulates pollution cause approximately one
million deaths annually across the world, which is approximately
one third of all premature deaths related to all air pollution
sources. There are other environmental (devastating) issues related
to the mining of coal. In addition coal mining is dangerous and
leads to accidents over 5,000 deaths annually worldwide (most of
them in China). External costs of coal Provides 40% of worlds
electric power and >50% of its GHGs External costs in US of
about $350 billion annually Mining accidents Pollution impacts on
health 20-50,000 deaths annually in US from particulate pollution
Charging for these would send cost of power from coal from 7
cents/kWh to 25 cents Would radically change inter-fuel competition
Full cost accounting for the life cycle of coal
This graph shows the best estimates of the externalities due to
coal, along with low and high estimates, normalized to per kWh of
electricity produced. (In color in Annals online.) This slide is
made available for non-commercial use only. Please note that
permission may be required for re-use of images in which the
copyright is owned by a third party. Annals of the New York Academy
of Sciences Volume 1219, Issue 1, pages 73-98, 17 FEB 2011 DOI: /j
x Coal-Burning Factories in Shanhi Province, China, 2006
images
Gu Dian steel plant Beijing, Jan 10, 2013 Beijing January 12, 2013.
Pollution times higher than safe levels Tiananmen Square in Beijing
Sunday, Jan. 13, 2013 Visitors gather near an entrance to the
Forbidden city during a very hazy day in Beijing Sunday, Jan. 13,
2013 Beijing, Jan 13, 2013 Beijing,January 14 West Virginia
Satellite image of air pollution spreading out over eastern China
and winding a course across the East China Sea, past the Korean
Peninsula and northeastwards toward Japan (Image by NASA) Typical
westerly wind flows across the mid-latitudes of the Northern
Hemisphere mean air pollution from China is often carried over the
Pacific Ocean. If the weather conditions are right, contaminants
including mercury, ozone, sulphur and nitrogen oxides, black carbon
and desert dust, can reach the west coast of the US within days. Is
Coal Going Away? Although global share of coal in power production
is expected to go down, total number of coal-fired power plants
expected to increase. This is largely driven by demand increases in
non-OECD countries (specially China). Without CCS, this becomes a
real problem for global CO2 emissions Source: IEA WEO 2012 Coal
& Climate Change The burning of fossil fuels is the main driver
for the increase in CO2 concentrations in the atmosphere. Increases
in the concentration of CO2 leads to climate change (more of this
in a second!). Climate Change raises global average temperatures,
disrupt ecosystems, change precipitation patterns, increase
sea-level rise. Coal is the most carbon intensive fossil fuel fuel.
Moving away from (and other FFs) is key to curbing climate change.
DATOS NECESARIOS: Calores de combustin:
Calor_Combustion_C_Antracita = MJ/kg Calor_Combustion_CH4 = MJ/kg.
Masa molecular: C ~ 12 g/mol CH4 ~ 16 g/mol Para simplificar el
problema, asumamos que tanto en el caso del carbn como en el caso
del metano tenemos comubstiones completas: C + O2 --> CO2 (1)
CH4 + 2O2 --> CO2 + 2H2O (2) Energa liberada por mol de carbn:
32.50 MJ/kg * 12 g/molC * 1kg/1000g= 0.39 MJ/molC Energa liberada
por mol de CH4: 55.5 MJ/kg * 16 g/molCH4 * 1 kg/1000g = 0.88
MJ/molCH4 Las ecuaciones (1) y (2) nos demuestran que por cada mol
de carbon = 1 mol CO2 y que cada mol CH4 = 1 mol CO2. Emissiones de
CO2 por MJ (carbon): 1 molC/0.39MJ * 1 molCO2/molC = mol CO2/MJ
Emisiones de CO2 por MJ (CH4): 1 molCH4/0.88MJ * 1molCO2/molCH4 =
mol CO2/MJ Factor de emisiones de CO2 entre Carbon y CH4 (C/CH4) =
molCO2/MJ /(2.56molCO2/MJ) = 0.443 Source: IEA WEO 2012 END Example
Fossil Fuel Power Plant Energy Conversion and Byproducts
A 500 MW power plant burns bituminous coal. The Annual Energy input
of the plant = 2.847*1013 KJ/yr Heat rate of bituminous coal ~
kJ/kg Mass of Coal used? CO2, SO2, Ash, NOx emission? Mass of Coal
= 2.847*1013/28400 (KJ/Kg) = 109 Kg/yr Mass of Ash = 9.8% Mass of
Coal = 9.82*107 Kg/yr Mass of Sulfur coming in = 1.5% of Coal =
1.5*107 Kg/yr C+O2 -> CO2 => =44or CO2/C mass = 44/12=2.46
Mass of CO2 = 2.46*109 Kg/yr CO2/Fuel energy = 2.46 kg CO2/Kg Coal
/28400 KJ/Kg Coal = 86.5*10-6kg/kJ 48 SO2 produced = 3*107 Kg/yr if
all S is converted
S+O2 -> SO2 SO2 produced = 3*107 Kg/yr if all S is converted
SO2/Energy input = 3*107 / 2.85*1013 = g/MJ Acid Rain Clean Air Act
Emission standard of g/MJ Flyash = 80% of AshBottom Ash =20%
Flyash/Energy Input = 0.8*9.82*107/ 2.85*1013 = 2.76 g/MJ Clean Air
Act Standard =0.013 g/MJ => 99.53% removal needed 49