December 17, 2008
Wind, Water and Sun Beat Biofuels, Nuclear and Coal for
Energy Generation, Study Says
Wind power is the most promising alternative source of
energy, according to Mark Jacobson.
by Louis Bergeron, Stanford News Writer
California, United States [RenewableEnergyWorld.com]
The best ways to improve energy security, mitigate global warming and reduce
the number of deaths caused by air pollution are blowing in the wind and
rippling in the water, not growing on prairies or glowing inside nuclear
power plants, says Mark Z. Jacobson, a professor of civil and environmental
engineering at Stanford.
"That is exactly the wrong place to be spending our money. Biofuels are the
most damaging choice we could make in our efforts to move away from using
fossil fuels. We should be spending to promote energy technologies that
cause significant reductions in carbon emissions and air-pollution
mortality, not technologies that have either marginal benefits or no
benefits at all."
-- Mark Z. Jacobson, Professor, Civil and Environmental Engineering,
Stanford
And "clean coal," which involves capturing carbon emissions and sequestering
them in the earth, is not clean at all, he asserts.
Jacobson has conducted the first quantitative, scientific evaluation of the
proposed, major, energy-related solutions by assessing not only their
potential for delivering energy for electricity and vehicles, but also their
impacts on global warming, human health, energy security, water supply,
space requirements, wildlife, water pollution, reliability and
sustainability. His findings indicate that the options that are getting the
most attention are between 25 to 1,000 times more polluting than the best
available options. The paper with his findings will be published in the next
issue of Energy and Environmental Science and is available online here.
Jacobson is also director of the Atmosphere/Energy Program at Stanford.
"The energy alternatives that are good are not the ones that people have
been talking about the most. And some options that have been proposed are
just downright awful," Jacobson said. "Ethanol-based biofuels will actually
cause more harm to human health, wildlife, water supply and land use than
current fossil fuels." He added that ethanol may also emit more
global-warming pollutants than fossil fuels, according to the latest
scientific studies.
The raw energy sources that Jacobson found to be the most promising are, in
order, wind, concentrated solar (the use of mirrors to heat a fluid),
geothermal, tidal, solar photovoltaics (rooftop solar panels), wave and
hydroelectric. He recommends against nuclear, coal with carbon capture and
sequestration, corn ethanol and cellulosic ethanol, which is made of prairie
grass. In fact, he found cellulosic ethanol was worse than corn ethanol
because it results in more air pollution, requires more land to produce and
causes more damage to wildlife.
To place the various alternatives on an equal footing, Jacobson first made
his comparisons among the energy sources by calculating the impacts as if
each alternative alone were used to power all the vehicles in the United
States, assuming only "new-technology" vehicles were being used. Such
vehicles include battery electric vehicles (BEVs), hydrogen fuel cell
vehicles (HFCVs), and "flex-fuel" vehicles that could run on a high blend of
ethanol called E85.
Wind was by far the most promising, Jacobson said, owing to a better-than 99
percent reduction in carbon and air pollution emissions; the consumption of
less than 3 square kilometers of land for the turbine footprints to run the
entire U.S. vehicle fleet (given the fleet is composed of battery-electric
vehicles); the saving of about 15,000 lives per year from premature
air-pollution-related deaths from vehicle exhaust in the United States; and
virtually no water consumption. By contrast, corn and cellulosic ethanol
will continue to cause more than 15,000 air pollution-related deaths in the
country per year, Jacobson asserted.
Because the wind turbines would require a modest amount of spacing between
them to allow room for the blades to spin, wind farms would occupy about 0.5
percent of all U.S. land, but this amount is more than 30 times less than
that required for growing corn or grasses for ethanol. Land between turbines
on wind farms would be simultaneously available as farmland or pasture or
could be left as open space.
Indeed, a battery-powered U.S. vehicle fleet could be charged by 73,000 to
144,000 5-megawatt wind turbines, fewer than the 300,000 airplanes the U.S.
produced during World War II and far easier to build. Additional turbines
could provide electricity for other energy needs.
"There is a lot of talk among politicians that we need a massive jobs
program to pull the economy out of the current recession," Jacobson said.
"Well, putting people to work building wind turbines, solar plants,
geothermal plants, electric vehicles and transmission lines would not only
create jobs but would also reduce costs due to health care, crop damage and
climate damage from current vehicle and electric power pollution, as well as
provide the world with a truly unlimited supply of clean power."
Jacobson said that while some people are under the impression that wind and
wave power are too variable to provide steady amounts of electricity, his
research group has already shown in previous research that by properly
coordinating the energy output from wind farms in different locations, the
potential problem with variability can be overcome and a steady supply of
baseline power delivered to users.
Jacobson's research is particularly timely in light of the growing push to
develop biofuels, which he calculated to be the worst of the available
alternatives. In their effort to obtain a federal bailout, the Big Three
Detroit automakers are increasingly touting their efforts and programs in
the biofuels realm, and federal research dollars have been supporting a
growing number of biofuel-research efforts.
"That is exactly the wrong place to be spending our money. Biofuels are the
most damaging choice we could make in our efforts to move away from using
fossil fuels," Jacobson said. "We should be spending to promote energy
technologies that cause significant reductions in carbon emissions and
air-pollution mortality, not technologies that have either marginal benefits
or no benefits at all."
"Obviously, wind alone isn't the solution," Jacobson said. "It's got to be a
package deal, with energy also being produced by other sources such as
solar, tidal, wave and geothermal power."
During the recent presidential campaign, nuclear power and clean coal were
often touted as energy solutions that should be pursued, but nuclear power
and coal with carbon capture and sequestration were Jacobson's lowest-ranked
choices after biofuels. "Coal with carbon sequestration emits 60- to
110-times more carbon and air pollution than wind energy, and nuclear emits
about 25-times more carbon and air pollution than wind energy," Jacobson
said. Although carbon-capture equipment reduces 85-90 percent of the carbon
exhaust from a coal-fired power plant, it has no impact on the carbon
resulting from the mining or transport of the coal or on the exhaust of
other air pollutants. In fact, because carbon capture requires a roughly
25-percent increase in energy from the coal plant, about 25 percent more
coal is needed, increasing mountaintop removal and increasing non-carbon air
pollution from power plants, he said.
Nuclear power poses other risks. Jacobson said it is likely that if the
United States were to move more heavily into nuclear power, then other
nations would demand to be able to use that option.
"Once you have a nuclear energy facility, it's straightforward to start
refining uranium in that facility, which is what Iran is doing and Venezuela
is planning to do," Jacobson said. "The potential for terrorists to obtain a
nuclear weapon or for states to develop nuclear weapons that could be used
in limited regional wars will certainly increase with an increase in the
number of nuclear energy facilities worldwide." Jacobson calculated that if
one small nuclear bomb exploded, the carbon emissions from the burning of a
large city would be modest, but the death rate for one such event would be
twice as large as the current vehicle air pollution death rate summed over
30 years.
Finally, both coal and nuclear energy plants take much longer to plan,
permit and construct than do most of the other new energy sources that
Jacobson's study recommends. The result would be even more emissions from
existing nuclear and coal power sources as people continue to use
comparatively "dirty" electricity while waiting for the new energy sources
to come online, Jacobson said.
Jacobson received no funding from any interest group, company or government
agency.
Energy and vehicle options, from best to worst, according to Jacobson's
calculations:
Best to worst electric power sources:
1. Wind power 2. concentrated solar power (CSP) 3. geothermal power 4. tidal
power 5. solar photovoltaics (PV) 6. wave power 7. hydroelectric power 8. a
tie between nuclear power and coal with carbon capture and sequestration
(CCS).
Best to worst vehicle options:
1. Wind-BEVs (battery electric vehicles) 2. wind-HFCVs (hydrogen fuel cell
vehicles) 3.CSP-BEVs 4. geothermal-BEVs 5. tidal-BEVs 6. solar PV-BEVs 7.
Wave-BEVs 8.hydroelectric-BEVs 9. a tie between nuclear-BEVs and coal-CCS-BEVs
11. corn-E85 12.cellulosic-E85.
Hydrogen fuel cell vehicles were examined only when powered by wind energy,
but they could be combined with other electric power sources. Although HFCVs
require about three times more energy than do BEVs (BEVs are very
efficient), HFCVs are still very clean and more efficient than pure
gasoline, and wind-HFCVs still resulted in the second-highest overall
ranking. HFCVs have an advantage in that they can be refueled faster than
can BEVs (although BEV charging is getting faster). Thus, HFCVs may be
useful for long trips (more than 250 miles) while BEVs more useful for trips
less than 250 miles. An ideal combination may be a BEV-HFCV hybrid.
Louis Bergeron is a science writer for Stanford University News Service
covering earth sciences, biology, chemistry and environmental science. He
has written on research findings as varied as the importance of circadian
rhythm to learning retention in Siberian hamsters, energy transfer in
near-collisions at the molecular scale, and tagging and tracking studies of
bluefin tuna, white sharks and leatherback turtles. Before joining the News
Service he worked as a freelance science writer and editor, contributing to
print and online publications such as New Scientist, ScienceNOW,
Exploratorium Magazine, PC World, SWARA (the magazine of the East African
Wild Life Society) and Stanford Medicine. He earned a bachelor's degree in
geology from the University of Illinois at Urbana-Champaign and a master's
degree in earth sciences from the University of California-Santa Cruz.
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