Electrifying a Fleet Presents Opportunities for Local Grid Stability and Revenue for Fleet Owners

Electric vehicles are a good choice for fleets because they have reduced maintenance costs, government subsidization, and are predicted to operate more reliably than current fossil fuel consuming alternatives. When you look at an EV, it’s more than just a hunk of metal, rubber, and fuel. It also has a large battery pack that can store a lot of energy. Is there the potential to use large battery packs to store energy for the grid, normalize demand, and provide backup power? The answer is yes!

For many, ICE vehicles (Internal Combustion Engines) are a great choice for transportation. They are reliable and the fuel is easy to find. They can also move people and goods at a low cost over long distances. However, when they are not in use, they become a cost center for the business. This means that they don't help make money when they are not being used. You can't really rent out your bus fleet overnight without risking availability for the morning route. The average school bus is in use for about 6 hours each day, 200 days a year. When they're not being used, they're usually parked or idle. But during the summer, when demand for electricity is high, clean energy stored in idled electric school buses can provide an energy resource to the grid that traditional ICE vehicles can't provide.

Electric Vehicles (EVs) are different from other cars. They have a collection of battery packs that can store energy. This energy can come from renewable or traditional sources, like nuclear or fossil fuels. The battery packs are important because they can charge and discharge without any problems.

The potential energy stored within, and the ability to consistently replace it, can be harnessed to help stabilize the grid when energy supply and demand are volatile. The grid can also use this energy as a backup power supply when it goes down, as a mobile power supply source, or to store energy and sell back to the grid when electric prices are more favorable. This usage underpins the concepts of Vehicle-2-Grid (V2G) and the microgrid application for EVs.

Vehicle-2-Grid allows electric vehicles to send and receive power from the grid. This is helpful because it can make sure that the grid always has enough power and that electric vehicles always have enough power. The U.S. Department of Energy defines a microgrid as a group of interconnected machines (or loads) that can generate, store, or use energy. Microgrids often have a form of energy generation (like localized renewable or fossil fuel generation systems), load, and storage (like a fleet of EV buses), all locally defined within a boundary, and typically controlled by a microgrid controller.

In a microgrid, V2G technology can be used to fill the role of a home or community battery backup or energy storage unit. Unlike large, single-use battery banks that can only store and discharge electricity, the integration of V2G technology into the microgrid provides multiple uses for batteries. With V2G, you have a primary usage as transportation fleet, and energy storage in the form of batteries when transportation services are not needed.

Vehicle-2-Grid and microgrids are a perfect match. When there is extra power, electric vehicles can store it. Then, if there is a power outage or someone needs power, the vehicle can provide it. Right now, these storage banks are usually large battery packs that are stored away from homes. There have also been cases where vehicles have been used to provide power to people's homes during natural disasters. These two applications are put together to create a new technology called V2G. This technology is used in microgrid systems, which have fleets of vehicles that serve two purposes at the same time.

There are already real-world applications of V2G and the microgrid process. In December 2020, the White Plains district’s five EV buses started selling excess power stored on their bus battery packs back to Con Edison, the community’s local energy provider. According to news reports, “[t]he buses serve as mobile microgrids, charging and discharging at a depot in North White Plains. They plug into a charger when demand for power from Con Ed is low, and reverse the flow into the grid when the buses aren’t taking kids to and from school.”

The Beverly, MA school district used electric school buses to generate power for the electric grid. The buses discharged nearly three megawatt-hours of electricity to the grid over 30 events that summer. The district found that "by delivering stored clean energy back to the grid when it’s needed most, electric school buses can help create a more resilient local power system and reduce the dependence on expensive fossil fuel power plants."

And with the added benefit of the local energy grid compensating participants for distributing stored energy to the grid, participants are able to further defray the cost of V2G early adoption as well as improving the economics of community transportation systems.

Recently, the Santa Clara Valley Transportation Authority (VTA) announced their plan to install a microgrid. This will include 34 new bus chargers, solar panels, and over 45 electric buses. The California Air Resources Board has required all public transit agencies to be 100% zero emission by 2040. This microgrid is expected to provide power during grid disruptions and also allow for purchasing power from the grid.

The VTA said that this project will help them reach their goal of using greener sources of energy. The project will also save the VTA money, which can be used for other needs. This project will also provide the infrastructure to charge zero-emission buses. Riders will benefit from a newer, quieter fleet. This project will also help the VTA decrease their contribution to climate change and poor air quality.

Fleet operators could make more money by using their electric vehicles for two purposes: transportation and energy storage. By storing energy from the electric grid, fleet operators can sell it back to the grid at a higher price. This has been shown to be successful in Beverly, MA. The future of greener mobility will likely have a strong foundation in electric vehicle fleets that help communities manage access to reliable and affordable energy resources.

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