Vehicle-to-grid (V2G) technology is not new, but it is extremely nascent. To many, it is the natural progression from “smart charging,” whereby electric vehicles (EVs) are only recharged at the best time for the network, to a more holistic grid scheme. But V2G trials are unfolding slowly, as finding the right business model has so far proved rather elusive.
One ambitious and exciting experiment is underway by Dominion Energy, in Virginia. In an attempt to support the integration of a large offshore wind farm, the company has incorporated electric school buses as a grid flexibility asset. When the buses are not expected to be used, the utility will store any unneeded energy in the batteries, saving it for peak hours.
A New Way of Sharing Energy
Dominion Energy’s experiment, which is set to be fully functional at the end of this year, is looking to share the energy capacity of the batteries in the school buses, creating a new opportunity for shared battery use. The idea is that at the end of the school rush the buses will return to their depots where they will be hooked up to so-called bidirectional V2G chargers, and, by extension, a digital distributed energy-management system. This “smart” system charges the electric batteries quickly at the optimal time, and then transfers the rest to the grid. Although the grid, called APEX and provided by a California-based company called Proterra, is in its infancy, the ambition is that it will eventually be expanded to manage all distributed assets, including wind and solar power technology.
The hope is that the efforts of the buses will mitigate the need to build additional forms of capacity for the existing grid, and also will open the door for more renewable energy integration. In this example, offshore wind will produce clean energy primarily in the afternoon or at night when the bus batteries are being charged. This should stabilize the distribution grid in terms of voltage levels, among other things. Dominion’s experiment is targeting more than 1,500 buses by 2025, which theoretically will provide the storage and supply excess capacity to power more than 15,000 homes for a good portion of the day.
Mainstream Alternatives and Business Models
While school buses provide an interesting experiment, it is a limited one when making the case for V2G technology. For a really impactful scalability, V2G will need to be deployed in a commercial sense for those who operate EV fleets, not to mention consumers.
In the southwest of England, a co-funded consumer-focused V2G experiment is already underway, conducted by Octopus Energy and known as Powerloop. The experiment involves paying participants to lease a Nissan Leaf car, which is currently one of only two cars available in the UK with bidirectional charging capabilities, and giving them a free bidirectional charger—the only one of its kind that can function from home.
The participants are required to charge their Nissan Leaf between 4p.m. and 5 p.m. so that the energy can support peak demand at 6 p.m. Similar projects are being conducted by EDF Energy and Ovo Energy. But the experiments are hindered by the complicated and ageing nature of the UK’s grid infrastructure.
Long-term, the idea is for customers to seek cash incentives by selling energy back to the grid at flexible times. The major obstacle, at the moment, is the value placed on V2G energy is not yet high enough.
To get things moving, a similar approach might need to be applied that has already worked for rooftop solar in which the government propped up feed-in-tariffs, or for utilities to inflate the price in order to make the service viable. The major obstacle, however, remains the complicated (segregated) structure of national energy systems and particularly the UK energy system.
Challenges to V2G and the Future
Aside from problems with archaic grid models, there are no clear regulations in place for V2G and the infrastructure to make it possible is expensive. There is little desire to take up bidirectional inverters that can convert DC to AC and vice versa, because unidirectional inverters are most common to use for the fast-charging of vehicles. This lack of desire for bidirectional inverters only adds to the expense of V2G.
Unpredictability is also an issue, as for V2G to work properly customers will need to plug in their cars at the same time. At least for the experiments currently being trialed, participants have to be closely monitored for when they hook up to the network. But this unpredictability could be waived when large commercial fleets are utilized, as many vehicles in such circumstances are often based and not used at the same time—they would make ideal opportunities for battery-energy extraction to relieve pressure on grid networks. Interesting proposals to make V2G more attractive to consumers include offering free parking for hook-ups at airports and shopping centers, for example.
Increasingly, more investors are optimistic that V2G will work and see it as an opportunity to reduce the number of upgrades needed when more EVs start to use the power grid. It is estimated that in the UK, a high of about 4.1 million EVs could be on the road by 2030, and that the energy they could provide could be as much as 16% of the overall demand across the country.
The future looks mostly positive for V2G technology, even if the way forward isn’t always clear. Other promising news includes the development of one company, U.S.-based Fermata Energy, that has manufactured a bidirectional charger for EVs that can be used at home, the first of its kind. And, of course, the giant Tesla is integrating V2G capabilities into the Model 3. Things certainly seem to be moving up a gear, but time will tell.
—Neil Wright is a content writer and researcher for We Buy Any Motorcaravan. He has a special interest in climate change, the prospect of renewable energy, and eco-socialism.