Market Insights

# Using EVs as Mobile Battery Storage Could Boost Decarbonization

December 12, 2022 by Claire Turvill

## MIT researchers have published a paper on vehicle-to-grid (V2G) technology, which allows electric vehicles to return energy to the power grid and provide an eventually renewable power alternative.

Electric and hybrid vehicles accounted for 11 percent of market sales in 2021. Of those sales, 4.8 percent were battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs). The drivers of these cars are familiar with using charging stations while at home or work to give their batteries a full charge.

##### A battery energy storage system in a garage. Image used courtesy of Adobe Stock

A Massachusetts Institute of Technology (MIT) team has published a paper in the Energy Advances journal that considers the possibility of reversing the charge flow so that when plugged in, cars with full batteries could give back to the power grid

The hope is that as the number of electric vehicles (EVs) on the road continues to increase rapidly, the vehicle-to-grid (V2G) technology could become a cost-effective and mobile energy storage option for a smoother transition into renewable energy.

Jim Owens, the lead author on the MIT paper and a doctoral student at MIT in Chemical Engineering, believes V2G offers the possibility of boosting renewable energy growth and decreasing dependency on stationary storage and always-on generators.

### Research Team Calculates Energy Savings from V2G

A challenge in increasing the use of renewable energy sources is the capacity and the limited number of existing energy storage batteries. Solar and wind provide irregular energy production, and the batteries necessary to hold the energy for later use can be large and incredibly expensive. Buildings and homes that use solar panels tend to rely on the power grid for backup.

##### Generation and demand profiles over a week with 50 percent V2G participation. Image used courtesy of Energy Advances

Models that consider the impact of tight carbon restraints are most representative of how the V2G technology could be most beneficial in supporting a decarbonized future.

While the percentage of renewable energy sources powering the U.S. power grid increases every year, nuclear, coal, and natural gas still account for 79 percent of electricity generation as of 2021. This means that unless an EV is plugged into a charging station that is directly powered by a solar panel, the electricity used to charge EVs is coming from fossil fuels.

V2G supports a smoother transition to an all-electric power grid as an economical and long-term energy storage option. Adapting to an all-electric power grid requires ample battery storage to hold onto electricity when not actively produced by solar and wind. Ideally, EVs will be charged using renewable sources and then be able to give back to the power grid in times of low production.

However, until EVs are charged entirely from renewable sources, using their battery power to give back to the grid will not be an inherently net-zero process.

### V2G Prospects Point to Promising Future

EV owners are not expected to jump at the opportunity to give their car’s battery power to a utility or power systems operator. Any future software used to facilitate the battery dispatch could be tailored to individual needs to best suit each car owner.

Similar to the adoption of residential solar panels, car owners could be paid for their contribution back to the power grid.

Outside of personal vehicles, Owens is also considering the impact of heavy-duty EVs, such as delivery trucks from Amazon and FedEx that are likely to be early adopters of EVs. These trucks have a regular schedule during the day and are mostly idle overnight, making them appealing to V2G services.

Even if fleet and personal vehicles choose not to participate round-the-clock, expanding access to V2G technology could be impactful in times including energy blackouts, hot-day congestion, and peak demand putting stress on transmission lines.