As the global electric vehicle fleet increases, the focus on vehicle-to-grid (V2G) is growing with the need to develop expertise and technologies for charging management and storage aggregation for flexibility.
However, an alternative likely to be demanded by the savvy homeowner and building energy manager – and that needs to be incorporated in V2G strategies – is vehicle-to-home or vehicle-to-building in which the stored energy in the battery is used to power the building.
EVs can power buildings
Pioneering work last year at the UK’s University of Warwick together with Jaguar Land Rover indicated the feasibility of EVs powering buildings.
Using a smart grid algorithm, the researchers at Warwick Manufacturing Group’s (WMG) Energy and Electrical Systems estimated that the number of EVs parked on the campus – around 2.1% of the cars – could spare the energy to power WMG’s International Digital Laboratory. This is a large building containing a 100-seater auditorium, two electrical laboratories, teaching laboratories and meeting rooms, and housing approximately 360 staff.
Notably, with the study focussed on storage technologies, it found also that the capacity fade in participant EV batteries would be reduced by up to 9.1% and power fade by up to 12.1% over a year. This amounts to an improvement in battery life of around 10% and is contrary to the earlier traditional wisdom that V2G activities could degrade battery life.
“These findings reinforce the attractiveness of vehicle-to-grid technologies to automotive original equipment manufacturers,” commented Dr Kotub Uddin, who led the research. “Not only is vehicle-to-grid an effective solution for grid support but we have shown that there is a real possibility of extending the lifetime of traction batteries in tandem.”
The study involved the development of battery degradation models taking into account various ageing factors including temperature, state of charge, current and depth of discharge. Based on this model, the smart grid algorithm calculates how much energy a vehicle requires to carry out daily journeys, and how much energy can be taken from its battery without it being negatively affected.
Putting vehicle-to-home to the test
Vehicle-to-home is now set to be tested as part of a broader V2G project by UK independent renewable supplier Good Energy together with Honda, the University of Salford and local flexibility provider Upside Energy.
The trial will integrate EVs into a test home, the Energy House, on the Salford University campus that runs solar panels, home battery storage and a smart heating system. It also offers simulation of year-round climate conditions.
“EVs, battery storage, V2G and now vehicle-to-home are all technologies that will be part of a decentralised energy system of the future,” says Juliet Davenport, CEO and Founder of Good Energy. “This project means that we can truly see the impact for people’s homes and their lives.”
The goal of the so-called HAVEN project, which is supported from the government’s Innovate UK fund, is to explore the use of EV batteries to provide flexibility to the energy system within the context of other distributed systems in the home. EV battery and other storage system configurations will be tested to build models for the value that the EV batteries can bring within an integrated home energy storage system.
Neil Jones, Programme Manager at Upside Energy, adds: “These tests will help us establish a baseline of data which could be scaled up to hundreds if not thousands of homes and vehicles and start to identify what services can be offered to householders and the grid in the future.”
For Good Energy as the supplier, the project is intended to inform an EV charging proposition for customers, which is being developed with the EV charging solution provider NewMotion. As part of the initiative, Good Energy has itself been testing a NewMotion chargepoint at its offices