Two truths are clear about electric vehicles today: Charging them is cheaper than filling up with gasoline, and they hold immense potential to boost renewable energy integration by serving grid operators as countless energy storage units. So what if those benefits were combined?
The answer, say researchers at Carnegie Mellon University, is at least a 50% reduction in EV charging costs – and an even higher cost reduction in areas with high levels of wind energy capacity.
According to the study of various EV charging scenarios modeled across New York State’s regional grid, controlled EV charging by grid operators holds the key to unlocking the combination of lower power prices, higher wind energy integration, and more emission-free vehicles on the road.
Misplaced Fears Of EV Charging Spiking Power Costs?
It stands to reason as more EVs plug into the grid, grid operators will have to dispatch more generation to keep all those Leafs and Teslas juiced up. “If owners regularly plug in these electric vehicles when they get home from work, this would add to greater demand when the most expensive power plants are running,” said Allison Weis of CMU.
Even though the number of EVs on American roads (and their associated power demands) may still be relatively low, their numbers grow exponentially larger every year, giving grid operators one more factor to fret about for long-term capacity planning and reliability forecasts.
Not necessarily so, found the CMU researchers. “Controlled charging can shift loads later in the night when cheaper power plants are again available,” said Paulina Jaramillo of CMU. In this case, controlled charging means shifting generation to cheaper plants and off-peak hours, and can run from full to partial charging speeds.
Controlled Charging + Wind Energy = Big Savings
If grid operators have the ability to control when and how fast EVs are charging across the grid, the CMU researchers reported power generation costs would be reduced $65-110 million per year compared to uncontrolled charging.
That’s roughly 1.5-2.3% of total modeled system costs, between 54%-73% the cost of integrating plug-in hybrid electric vehicles, and roughly $100 annually per vehicle when EV penetration reaches 10%. Variations in overall costs resulted in different capacity scenarios, where more or less generation was available for use.
However, regardless of power generation capacity scenarios, EV charging costs fall even further when large amounts of wind energy are present on the grid. In fact, when wind penetration reaches 20%, controlled charging creates an additional 6-13% in cost reductions.
That level of wind penetration isn’t typically sustained on U.S. grids, but it has absolutely been reached with growing frequency on regional grid systems in Texas and the Midwest – meaning the CMU results could already be manifesting themselves if proper vehicle-to-grid controls were in place.
Even better, the CMU research underlines the value EVs can have on maximizing renewable energy when it’s available. “Controlled charging could also help manage fluctuations from renewable energy sources like wind and solar power,” said Jaramillo.
Accelerating Toward A Smarter, Cleaner, Cheaper Future
While the researchers noted additional studies were needed to fully understand the total cost and emissions implications of EV charging, the CMU study is yet another example of how important EVs are to our clean energy future and adds to research showing the the grid can handle EV integration without crashing.
Considering NREL’s recent report that wind energy could increase grid reliability, the link between smart grids, clean cars, and renewable electricity just keeps getting clearer and clearer.
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