green power presentation
DESCRIPTION
This is a presentation I did for my Electrical Power & PLC class at Michigan Technological UniversityTRANSCRIPT
GREEN POWER
EET 3700
Presented by: Dan Ehlke
OVERVIEW
What is Green Power? Why Green Power? Kinds of Green Power
Hydro Wind Biomass Solar Geothermal
Conclusion
WHAT IS GREEN POWER?
“Green” Power: any energy source with a negligible impact on greenhouse gas emissions.
Includes: hydro, wind, biomass, geothermal, & solar
WHY GREEN POWER?
In the 1970s & 1980s the interest in green power was driven by the goal of replacing fossil fuels after the first oil shock in the mid 1970s
Now, the broader goal includes minimizing the emission of CO2.
WHY GREEN POWER?
There are considerable external costs for electricity from fossil fuels that someday must be taken into account as concerns about global warming become real.
While contributions from renewable energy is small, with the exception of hydro, their market penetration is growing at a much faster rate than from conventional sources.
WHY GREEN POWER?
Competition: green option as a means of differentiating their service & winning customer loyalty.
More than 190 electric utilities offer green power in the U.S.
50% of consumers surveyed are willing to pay an extra $15 per month to receive green electricity.
HYDRO
Most mature renewable source of electricity around the world. 700,000 MW contributes 21% of electricity worldwide (year
2000)
Negetive: Limited exploitable sites Potential damage to environment – Indiginous
people of developing countries.
HYDRO
Types Impoundment
Allows operators to stabilize power with fluctuating water levels.
Reduce flooding River – flow.
Relies on river flowing water to keep producing electricity.
HYDRO
Impoundment type Water turns turbines at bottom of the penstock (powerhouse) Turbine attached to series of gears which increase the speed of
rotation. When there is too much water, the spillway allows extra water to
bypass the penstock.
WIND
Second most popular source of green power. 17,500 MW worldwide (70% of which was in
Europe) in 2000 However, in 2001 1,695 MW was added in the
U.S. making it the second largest concentration of wind power in the world.
WIND HAWT: Horizontal-axis wind turbine
Axis about which blades rotate is horizontal Higher height for greater wind speeds All commercially available wind turbine
generators. Utility-scale
Utility-scale typically have greater requirements Solid towers, concrete pads, built on-site.
Individual-scale
VAWT: Vertical-axis wind turbine Axis about which blades rotate is vertical Must be mounted closer to the ground
WIND The nacelle houses the gearbox, generator, and
associated controls. Rotor blades pitch angle may
be controlled to optimize energy
capture with changing wind speeds Prevent damage past design rotational speed
Rounded tips reduce minimum speed
needed to start, and increases aerodynamic
efficiency Cut-in speed: wind speed necessary to
begin producing electricity (as low as 3 m/s)
BIOMASS
Plant matter, trees, grasses, agricultural crops or other biological materials.
14,000 MW of annual worldwide generation capacity.
The U.S. is the largest biomass generator in the world with 7,000 MW.
Expected to grow more than 30,000MW by 2020. Developing countries: availability of cheap feedstock
Bio Materials steam turbine Bio Materials fuel gas engine, turbine or fuel cell Biomass gas may also be integrated into industrial
manufacturing plants for power, heat or cooling needs.
SOLAR -THERMAL Concentrating sunlight and trapping its’ heat
to produce steam 3 types:
Central receiver 2,000 sun-tracking heliostats to single collection vessel Molten salt flowing through the receiver and
transferred to a hot salt storage tank, then steam generator when needed.
Trough based Mirrors are parabolic Tracks the sun on one axis due to linear focus Lower concentration factor Lower cost potential
Dish based Point focused – 2 axis tracking
SOLAR - PHOTOVOLTAIC
800 MW worldwide capacity Fundamental unit: cell Material: semiconductor material
Gallium arsenide Crystalline silicon Amorphous silicon
Available current is a function of cell area & light intensity.
Formed into modules (series & parallel configs) to obtain greater voltage & current.
GEOTHERMAL
Heat at the core of the earth exploited to produce electricity through steam.
7,974 MW generated worldwide (1999) Capital intensive:
enough steam supply wells have to be drilled up-front to provide the full plant capacity at startup.
CONCLUSION
As the concerns about the availability & environmental impacts of fossil fuels become
more wide spread, the interest on environmentally benign renewable energy technologies will surely take center stage
among engineers & policymakers.
Questions?