We already have the technology we need to cure our addiction to oil, stabilize the climate and maintain our standard of living, all at the same time. Increasing transportation efficiency is the best place to start efforts to reduce emissions of carbon dioxide (CO2), which is a primary culprit in global warming. Of all CO2 emissions in the United States, about 33 percent comes from transportation.
There are overwhelming advantages of plug-in hybrid vehicles and all-electric vehicles (EVs) over gasoline vehicles. With gasoline-electric hybrid power and all-electric power, we can achieve significant cost and environmental savings. By adding more batteries and recharging capability to gasoline-electric hybrid vehicles, we can have plug-in hybrids that offer the range of hybrids (500 miles or more), plus the benefit of all-electric power for short trips, which dramatically reduces the amount of gasoline used. EVs require no gasoline whatsoever and, when recharged from renewable energy sources, produce zero total emissions.
In fact, even if we switched from gasoline cars to EVs and plug-in hybrids recharged by our existing utility grids (which mostly use fossil fuels), we would see a 42 percent national average reduction in CO2 emissions, according to research by Peter Lilienthal of the National Renewable Energy Laboratory.
Sun to Wheel
Transportation efficiency is usually measured without regard for how fuel ends up in the tank, we just assume it will be there. It's time to develop a better method, one that considers the finite nature of fossil fuels and how their use affects the planet's ability to support life. Ultimately, almost all energy on Earth comes from the sun, so fuel efficiencies should be measured from sun to wheel.
Fossil fuels are inherently very inefficient because of the hundreds of millions of years of solar energy and the rare geologic events it takes to produce them. About 350,000,000 terawatt (trillion watt) hours of solar energy strike the Earth every year. It took 3.5 billion years of photosynthesis to create world oil reserves that contain about 1,000,000 terawatt hours of energy. Do the math and you will find that using direct solar radiation is about a quadrillion times more efficient than burning fossil fuels. It is long past time to transition from ancient solar energy, aka fossil fuels, to using the solar energy we receive every day.
Biofuels, such as ethanol and biodiesel, may help us transition to cleaner vehicles, but let's not forget that overharvesting has contributed to the decline of many civilizations over the last 10,000 years. For the last 100 years, ever-increasing amounts of soil nutrients and fossil fuels have been consumed to grow and distribute food. As the needs of an increasing population collide with the realities of diminishing soil quality and fossil fuels, growing food will trump growing fuel.
Photosynthesis by plants is a maximum of 1 percent efficient at converting solar energy into carbohydrates. The efficiency of producing biofuels from carbohydrates and then getting refined fuel to vehicles varies from 10 percent to 35 percent, depending on the process and the distance to the use. Then there's the 10 percent to 20 percent efficiency of the internal-combustion engine and the transmission. So, the sun to wheel efficiency of biofuels is 0.01 percent to 0.07 percent.
Producing electricity from solar energy using photovoltaics (PV) is about 5 percent to 20 percent efficient, and solar-thermal electric generation can be more than 35 percent efficient. Current battery charge/discharge efficiency varies from 80 percent to 95 percent. Electric motors are more than 90 percent efficient. As a result, the sun to wheel efficiency of solar-electric power falls between 3 percent and 30 percent. This gives solar-electric vehicles an advantage 50 to 3,000 times greater than burning biofuels.
Of course, for EVs to truly have zero emissions, the electricity used to charge their batteries must be generated from renewable sources such as the sun or wind. If EVs are charged with electricity generated by nuclear or coal-fired power plants, the true costs will be passed on to future generations. Fortunately, renewables are ready and able to charge EVs and plug-in hybrids.
Recent History of Electric Cars
In 1990, the California Air Resource Board announced the Zero Emission Vehicle (ZEV) mandate. The ZEV mandate was an attempt to restore clean air to the smog-choked state and came on the heels of exciting new efforts by automakers on electric cars. The mandate required that by 1998 at least 2 percent of new cars sold in California emit zero emissions. The standard would rise to 5 percent by 2001 and 10 percent by 2003.
That same year, the Delco Remy division of GM worked on an 850-pound lead-acid battery pack that would give an electric car, which would eventually be named the EV1, a range of 124 miles at 55 mph. It was easily the most efficient car ever built with funding from an American automaker.
Through the late '90s and at the turn of the century, the auto industry and the federal government worked against EVs, suing the state of California and resisting the mandate. The ZEV mandate was scaled back several times. Finally, GM made a series of moves that would culminate in the recall and crushing of the EV1 and the end of GM's electric vehicle program. Then, in April 2003, the automakers and the federal government won, while the public lost: The Board abandoned the mandate.
Plug-In Future
Last year, in response to increasing concerns about the effects of global warming, California passed limits on cars' CO2 emissions. Though all the major automakers filed suit against the state of California, seven northeastern states also have adopted California's standards. Such moves are part of a growing grass-roots effort by local governments to deal with issues such as climate change and our reliance on oil.
Although the EV1 and other electric cars never reached mass production, gasoline-electric hybrids, such as the Toyota Prius and Honda Civic Hybrid, have seen runaway success in recent years. Interest in plug-in hybrids is booming as drivers are increasingly frustrated with skyrocketing gas prices and cars' poor fuel economy. Automakers, which previously dismissed the idea of plug-in hybrids, are now openly expressing interest. "We are pursuing a plug-in hybrid vehicle, which will conserve more oil and slice smog and greenhouse gases to nearly imperceptible levels," said Jim Press, Toyota's top U.S. executive, in a recent speech. Ford, GM and Nissan have also expressed interest in plug-in hybrids. Dodge has a prototype plug-in hybrid van being tested in several U.S. cities.
This time around, let's hope that enough people will demand that automakers offer better transportation choices. Please join the Plug-in Partners National Campaign ( www.pluginpartners.org ); together we can transform our transportation system.
Mother Earth News contributing editor Steve Heckeroth is the director for building-integrated photovoltaics for Energy Conversion Devices Ovonics. He's converted more than 12 cars to all-electric power.
Excerpted from Mother Earth News magazine, the original guide to living wisely. Read the full story at motherearthnews.com or call 800-234-3368 to subscribe. Copyright 2005 by Ogden Publications, Inc.
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