Costs of generating electricity
(http://www.iea.org/Textbase/npsum/ElecCostSUM.pdf $US quoted)
• Coal (Avg of 27 plants) $1K-$1.5K/kWe capital
– $45-60/MW.h (Inv. 50%, O&M 15%, Fuel 35%)
• Gas (23) $0.6-0.8K/kWe
– $40-63/MWh (Inv. 20%, O&M 7%, Fuel 73%)
• Nuclear (13) $1-$2K/kWe
– $30-50/MWh (Inv. 70%, O&M 13%, Fuel 10%)
• Wind (19)
$1-2K/kWe
– $45-140/MWh (O&M 12-40%)
– Load factor variability is a major factor in setting the
costs of running a wind plant
• Solar (6) approaches $300/MWh
• Cogeneration (24) estimated $30-70/MWh
Types of Windmills/turbines
7% efficiency,
but work at
low wind
speeds
Altogether, there are 150,000
windmills operating in the US
alone (mainly for water
extraction/distribution)
According to wikipedia, as of
2006 installed world-wide
capacity is 74 GW (same
capacity as only 3.5 dams the
size of the three-Gorges
project in China).
Up to 56 % efficiency with
3 blades, do very little at
low wind speeds
Wind Energy
According the article from the IEA
(previous slide), the typical availability
of a wind farm is 17-38% for landbased plants and 40-45% for offshore plants.
http://www.windpower.org/en/tour/wres/euromap.htm
An extensive site for Wind
Information!!
Worldwide Wind Capacity
http://en.wikipedia.org/wiki/Wind_power
US Wind Distribution
http://en.wikipedia.org/wiki/Wind_power
Types of Windmills (cont.)
Altamont Pass (CA)
http://www.ilr.tu-berlin.de/WKA/windfarm/altcal.html
6000 turbines, built 1980’s
San Gorgonio Pass (CA)
http://www.ilr.tu-berlin.de/WKA/windfarm/sgpcal.html
3500 turbines, built 1980’s
Basics of a Wind Turbine
http://www.nrel.gov/wind/animation.html
Blade diameter:
100m
Wind range:
3.5m/s to 25m/s
Rated wind speed: 11.5 m/s
GE 2.5MW generator
http://www.gepower.com/prod_serv/products/wind_turbines/en/downloads/ge_25mw_brochure.pdf
GE 3.5 MW
Blade diameter:
111m
Wind range:
3.5m/s to 27 m/s
Rated wind speed: 14 m/s
Specifically designed for off-shore
deployment
Web site for movie on wind turbine construction
http://www.gepower.com/businesses/ge_wind_energy/en/image_gallery/index.htm
Wind Turbines
http://www.afm.dtu.dk/wind/turbines/img0003.jpg
Water wheels through the ages
ITAIPU (Brazil/Paraguay)
http://www.solar.coppe.ufrj.br/itaipu.html
ITAIPU (Brazil/Paraguay)
http://www.solar.coppe.ufrj.br/itaipu.html
Essentials of PV design
Basics of Photo-Voltaics
A useful link demonstrating the design of a basic solar cell
may be found at:
http://jas.eng.buffalo.edu/education/pnapp/solarcell/index.html
• There are several different types of solar cells:
– Single crystal Si (NASA): most efficient (up to 30%) and most
expensive (have been $100’s/W, now much lower)
– Amorphous Si: not so efficient (5-10% or so) degrade with use
(but improvements have been made), cheap ($2.5/W)
– Recycled/polycrystalline Si (may be important in the future)
Engineering work-around # 2:
Martin Green’s record cell. The grid deflects light into
a light trapping structure
Power characteristics (Si)
100 cm2 silicon
Cell under different
Illumination conidtions
Material
Level of
efficiency in
% Lab
Level of efficiency in %
Production
Monocrystalline
Silicon
approx. 24
14 to17
Polycrystalline
Silicon
Amorphous
Silicon
approx. 18
approx. 13
http://www.solarserver.de/wissen/photovoltaik-e.html
13 to15
5 to7
Solar Cell Costs
http://www.nrel.gov/pv/pv_manufacturing/cost_capacity.html
Costs have dropeed from about $5.89/pk Watt output in 1992 to $2.73/pW in 2005
Solar House
This house in Oxford produces more electricity than it uses
(but only about 4kWh/yr!! According to the NREL, hardly worth selling)
http://www.nrel.gov/pv/pv_manufacturing/cost_capacity.html
Advanced designs-multilayers
http://www.nrel.gov/highperformancepv/
Typical products
Flood light system for
$390 (LED’s plus xtal.
cells)
15W systems for
$150
Battery charges (flexible
Amorphous cells)
http://www.siliconsolar.com/
Example of a retrofit
Dick Swanson
Martin Green
Fuel Cells- sample schematics
http://www.iit.edu/~smart/garrear/fuelcells.htm
For more details on these and other types, see also:
http://www.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html
Ballard Power Systems (PEM)
•85kW basic module power
(scalable from 10 to 300kW
They say) for passenger cars.
•212 lb (97 kg)
•284 V 300 A
•Volume 75 liters
•Operates at 80oC
•H2 as the fuel (needs a
reformer to make use of
Methanol etc.)
•300kW used for buses
Fuel Cell Energy (“Direct Fuel Cell”)
•Appears to be a molten
carbonate systme based on
their description
•Standard line includes units
of 0.3,1.5 and 3 MW
•Fuel is CH4 (no need for
external reformer) can also
use “coal gas”, biogas and
methanol
•Marketed for high-quality power
applications (fixed location)
This is a nominal 300kW unit (typically delivers
250kW according to their press releases). Most
of the units installed to date are of this size.
http://www.netl.doe.gov/publications/proceedings/03/dcfcw/dcfcw03.html
http://www.netl.doe.gov/publications/proceedings/03/dcfcw/Cooper%202.pdf
The Hydrogen Hype
•H2 burns with 02 to make water
•H2 comes from the oceans (lots of it)
•Fuel cells can “burn” it efficiently
The Realities
•Can’t mine it, it is NOT an energy source
–Why not just use electricity directly?
•Even as a liquid, energy density is low
–Storage and transport are difficult issues
•More dangerous (explosive) than CH4
• No existing infrastructure
Hydrogen Economy
•Hydrogen seems to be an attractive
alternative to fossil fuels, but it cannot be
mined. You need to treat it more like
electricity than gasoline (i.e. as a carrier
of energy, not as a primary source).
•Need lots of research in areas such as:
–Production
–Transmission/storage
–Distribution/end use
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/review04/4_science_stevens_04.pdf
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/review04/4_science_stevens_04.pdf
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/review04/4_science_stevens_04.pdf
Storage Possabilities
Physisorbtion
Chemical Reaction
Chemisorbtion
Encapsulation
Weak binding energy -> Low T required
Carbon nanotubes
Porous materials
Zeolites
Reversible Hydrides
PdH, LiH, …
Large energy input to release H2
Slow Dynamics
H
Al
Very large energy input to release H2
Not technologically feasible
H2 trapped in cages or pores
Variation of physical properties
(T or P) to trap/release H2
4 H molecules
in 51264 cage
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/review04/4_science_stevens_04.pdf
DOE report from 2004
is available at:
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/review04/4_science_stevens_04.pdf
Nature and Physics Today articles:
Nature Vol. 414, p353-358 (2001)
Physics Today, vol 57(12) p39-44 (2004)
MIT web site on photo-production:
http://web.mit.edu/chemistry/dgn/www/research/e_conversion.html
http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/review04/4_science_stevens_04.pdf
Three Gorges Dam (China)
http://www.physicstoday.org/vol-59/iss-12/p38.html