The costs (battery wear-and-tear, replacement, etc) associated with the possible use of electric vehicles as energy storage participants in the wider grid were recently analyzed by the people over at Plug In America, giving us some of our first insights into the possible specifics of such a program.
Such a program would of course allow for a fairly cheap distributed energy storage solution (in some cases anyways), thereby functioning as an alternative to grid-scale energy storage projects, or on-demand fossil fuel generators. Hence the interest.
The new findings are the result of the analysis of data gathered via the Plug In America EV Battery studies. Here are some of the highlights (concerning the costs of battery wear for electric vehicle owners that would participate):
For each vehicle, we consider battery pack replacement at either 70% or 80% of original capacity to figure out a per-kWh battery pack amortization cost. The results are shown in the chart below. As you can see from the chart (below), the LEAF and Model S suggest a battery amortization cost between $0.19 and $0.40 per kWh.
As batteries continue to drop in price, we expect these numbers will decrease, but this analysis suggests at least a starting point for considering the cost to owners for participating in a V2G program, and presumably owners will need to be compensated above their amortization cost to justify the inconvenience of early battery pack replacement.
EV owners may be wondering how this relates to driving. Letting the utility cycle one kWh out and back into your car is about the same, in terms of battery wear, as driving it between 3 and 4 miles, depending on the model and how you drive. We can use the EPA ratings to calculate how many miles can be driven for each kWh. When combined with the above data, we can see the the cost in battery wear associated with each mile driven. (Note that this is just a measure of the cost of using the battery, not considering any cost of purchasing the electricity to charge the battery or tire wear, etc.)
So a LEAF owner who plans to drive it forever, just replacing the battery pack as needed, should budget between 5 and 8 cents per mile for battery pack replacements. A similarly minded Model S owner should budget between 6 and 11.5 cents per mile.
How does this compare to a gas car? Edmunds.com says that, on average, a new $30,000 car loses $17,804 in value over 5 years and 75,000 miles of driving. That’s 23.7 cents per mile. For a $70,000 car, it’s $43,953 or 58 cents per mile. So, battery amortization cost is pretty small compared to typical gas car depreciation, which just adds to the money you save driving on cheap electricity.
Interesting. Of course, there’s a lot more to this story than just the parameters analyzed above. And the matter of whether or not you even could get enough EV owners to participate in such a program for it to be viable is still undetermined. How many of our readers would be interested in participating in such a program if it were available?