In regions with significant amounts of solar, wholesale power prices at the sunniest hours can dip, reducing revenue from solar generation. That’s most likely to happen where PV deployment outpaces storage deployment. Meanwhile, consumers keep buying electric vehicles, increasing overall electricity demand.
Looking at these trends in combination, a study funded by the California Energy Commission examines how daytime EV charging can “maintain solar value on the grid” while serving increased EV load.
The study, published in The Electricity Journal, considers strategies to promote daytime EV charging.
One strategy is to deploy inexpensive level-1 chargers at workplaces, enabling build-out of EV charging infrastructure at lower cost than with faster level-2 or level-3 chargers.
Level-1 chargers deliver “roughly one kilowatt” of power, according to Car & Driver magazine.
The lower-cost chargers “are a good option for those traveling shorter distances and parking for several hours at workplaces,” the study says, but to date, they represent less than 1% of the installed public chargers in the U.S.
Another strategy is to “update” time-of-use electricity rates “to more forward-looking rates” that encourage daytime use of electricity. By supporting daytime electricity prices, that would also encourage adoption of more solar energy, the study says. The rates “should also be dynamic,” reflecting real-time cost signals to maximize the benefits and “prevent adverse effects such as local distribution grid overload.”
In California, utilities are already communicating dynamic prices to customers using the OpenADR 3.0 standard, and the state expects to work with stakeholders to develop a flexible demand appliance standard for EV chargers.
If time-of-use rates are used, the study points to Western Australia and Hawaii as “leaders in identifying time-of-use rates that reflect sun hours.”
Installing solar canopies over parking lots can synchronize solar generation with EV charging load, and can also mitigate grid-level impacts of EV charging, the study says.
Regarding charging management, the study says there is a tradeoff “between the selection of smart charging management with additional hardware and installation costs, and inexpensive charging management with a higher risk of grid overloading, which results in higher costs associated with electric grid upgrades.” Daytime charging “becomes more attractive and feasible when these costs are decreased, for example through research and development or more infrastructure investment.”
An earlier paper from the Energy Systems Integration Group similarly made the case that with increasing adoption of electric vehicles and heat pumps, whose demand can be flexible, “marrying” that trend with the upward trend of variable renewable generation “could accelerate both.”
An earlier study by researchers at UC Berkeley found that a transition to EVs would enable the lowest-cost clean grid, partly because it would require lower investments in bulk transmission.
The new open-access study, based on nearly 70 previous studies and other sources, is titled “Aligning electric vehicle charging with the sun: An opportunity for daytime charging?”
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While that could work, the labor is the same at little more cost
going L2.
Why this is important is V2G most all new EVs will have, is the key to a 100% RE grid buying power cheap and selling it on demand.
In 10 yrs they will be in the 1,000GWh range effectively free storage, as just so many of them, that can’t be ignored.