By Johanna R. Thibault, Esq.
April 19, 2012
April 19, 2012
Electric vehicles (EV) produce zero emissions from the tailpipe, but how much these vehicles contribute towards green house gas emissions depends entirely on the source used for powering the vehicle. The Union for Concerned Scientists released a report on Monday analyzing the green house gas emissions for electric vehicles. According to the report, as predicted, the amount of green house gas emissions depends entirely on where the EV is charged. The unanticipated part of the results is just how significant the difference can be from one region to another.
In the report, the greenhouse gas emissions incident to electric production for each locality are converted to EV emissions (based on the power needed to charge a vehicle) and then compared to the same emissions from a standard vehicle in miles per gallon (mpg). For example, the charging of an EV in Texas would emit the same amount of greenhouse gases as a vehicle with a rating of 47 mpg. Where the numbers really tell the whole story is when comparing a region that relies heavily on coal-fired plants for electric generation versus those regions that emplore more alternative means, such as hydro-power, wind, solar, or nuclear for power. The numbers demonstrate that an EV in Denver, Colorado, rates at 33 mpg versus an EV in Juneau, Alaska, rates at 112 mpg. That is a staggering difference.
Taking into account how the energy is produced, the country was divided into three separate regions defined as "Good," "Better," and "Best." The good news is that "nearly half of Americans live in BEST regions where charging an EV on the electric grid emits less global warming pollution than driving even the best hybrids." Contrary to what some might believe, the report was not discouraging the use of EV's in regions defined as "good," where mpg ratings were in the low 30's in contrast to those in the "best" regions where EV's emissions were equivalent to vehicles averaging 70 mpg or greater. Instead, the report is rather a tool that policymakers can use to support decisions for alternative energy production. The Union for Concerned Scientists took a snapshot of the global emissions picture of today with the full understanding that conditions are anticipated to keep getting better.
Global emissions from coal-fired power plants are nearly twice that of natural gas-fired power plants. Renewable energy sources such as wind, solar, and hydro emit no operational green house gas emissions. Accordingly, the total contribution of these emissions from an EV is affected by the mix of energy sources. As a result of state and federal emissions policies and other regulatory controls, these emissions standards are predicted to improve by nearly 30 percent by 2020. Such an improvement also means that if you buy an EV today, the global emissions will continue to improve over the lifetime of that vehicle; something that you could never be promised from the other standard vehicles we are driving today.
Will reports like this one increase support for alternative energy? Will the increased demand for electricity from a large fleet of electric vehicles justify potentially huge capital investment required to make the grid more efficient?
This is, indeed, a valid analysis. However, there is another computation or two required for the environmental and health considerations. (This is above and beyond the fact that in America, coal is being replaced by gas...)
ReplyDeleteThe first, is that as demand increases, newer plants will have to be built to accommodate the demand. And, they will be cleaner than the existing ones (and may even be built large enough to retire an existing older technology plant).
The second- and related to this- is that many new fuels are not conducive to power a motive element. A large solar plant can generate plenty of electricity- including the vehicle, which is limited in its solar capacity. Water power can be harnessed- which will never be useful for motive technologies. Assuming we can develop a safe nuclear plant, the same logic applies. Coal that has been gasified and natural gas itself can supply the electricity at the power plant, which is less problematic than using same to power a vehicle....
Yes, these are in fact excellent considerations. The study took into account these (I believe) and many others to create a valid illustration of EV carbon footprint. You have most certainly identified two very critical factors. Natural gas is overwhelmingly popular for power generation (and by far the cheapest).
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