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Powerloop - Exploring how electric cars can help manage electricity bills

Energy Saving Trust has long promoted the benefits of electric vehicles (EVs) – they save carbon and money, with a smooth ride to boot. But what can driving an electric vehicle offer your home electricity supply?

Energy Saving Trust is part of a new project that aims to find out. ‘Powerloop’ is one of the first large-scale domestic trials of vehicle-to-grid (V2G) technology ever undertaken in the UK.

It aims to find out how:

  • EV batteries can help manage electricity grid load

  • ‘Vehicle to grid’ systems can save householders money

  • best to use the technology.

What is vehicle-to-grid (V2G)?

The V2G concept is straightforward: V2G enabled battery chargers are bidirectional, meaning they can either charge or discharge. While charging, the battery stores energy to use later. While the battery is discharging, the energy can be used at the point of connection (when you are driving) or in the electricity distribution network, and ultimately the electricity grid. So people could potentially make money from supplying energy back to the grid.

A real-world experience of two-way tech

Powerloop is an Innovate UK-funded trial which will install the two-way charging technology in 135 homes. The programme is led by the Which? Recommended Energy Provider 2018 winner, Octopus Energy, with a number of partners.

Our Senior Account Manager, Jacob Roberts explained: ‘While 135 vehicles may seem like a drop in the ocean compared to all the vehicles in the UK, in the context of V2G, it’s a big breakthrough. It’s the first large-scale domestic trial, and will have a valid research output that will help to grow the technology further.’


Image: Cenex

Guide needed to unlock potential

Energy Saving Trust has previously been involved in another Innovate UK project called Ebbs and Flows, which looked at various possibilities around energy management using electric vehicles. Roberts thinks this is exactly the area to be involved in:

‘This technology can only make the case for electric vehicles stronger. It turns an EV into a way to make money, by buying energy when it’s cheap and selling when it’s expensive. This chimes with what we’re about: green technologies that can save people money.’

The Powerloop project  began in April, with the soft launch coinciding with the Zero Emissions Vehicle Summit on Tuesday 11th September. The project will run until early 2021. Energy Saving Trust’s role involves working with the participants; to get their feedback and ultimately produce a best practice guide, based on the findings, around how vehicle to grid technologies should be deployed.

Complementing renewable energy

So where exactly is demand for V2G coming from?

Energy Saving Trust’s Jacob Roberts explained: ‘There’s already a role for V2G, but the technology needed to catch up. At the moment, we have instances where renewable electricity generation is higher than demand. If that electricity isn’t stored, it goes to waste. The potential for V2G to help here is massive.

There is a great deal of interest in V2G from both distribution network operators  (the companies licenced to bring electricity from the national network to our homes and businesses) and the National Grid. The technology can be used to help supply peak electricity demand, resulting in less of a need for network upgrades or extra generating capacity.’

Small parts lead to big impact

V2G technology is part of a broader principle: that the actions of individual households and businesses can have a role in managing electricity demand at a local level.

‘V2G is not a single purpose technology – that’s why it gets a lot of interest,’ said Roberts. ‘It takes something that was already useful – a vehicle – and gives it a new and complementary second purpose.  As V2G grows in popularity, all of the V2G-ready vehicles can be aggregated, unlocking a very large amount of electrical storage capacity.

The role of the householder

A key consideration in employing V2G technology is just how involved a householder needs to be in managing their electric vehicle battery’s role in home electricity supply and demand.

Roberts explained: ‘It’s mostly automated, but with user input. What that means is you tell the unit how much range you need from the vehicle and when, so there will always be enough charge in the vehicle battery for your use. Beyond that, it’s all about charging the battery when there’s most available capacity, so electricity is cheapest to buy. Then discharging when there’s the least capacity, so you can sell electricity at the highest price. Most of the charging will be managed automatically, but you can be as involved as you want. The aim is for a V2G charging system to be as intuitive as possible.’

Energy companies can enable technology

Funding for the project comes from a broader pool of government money dedicated to exploring different aspects of V2G – with Nissan leading one of the other eye-catching schemes, focusing on deployment of the technology in business fleets.

So what sets this work apart?

The Powerloop participants will receive ‘Time of use’ tariffs, which have half-hourly rates depending on when you use units of electricity. These tariffs are a fairly new concept in the domestic market, designed to encourage customers to use more energy at off-peak times, in order to balance demand. The tariffs become cheaper when demand is lowest, and charge higher rates at popular times.

In addition, this is the only V2G project which offers the whole leasing bundle as a package, including the vehicle, the charging unit and energy tariff – a one stop shop to get everything you need for V2G.

The tariff also includes plunge pricing. This allows users to take advantage of negative price events, where more electricity is generated than consumed and suppliers are paid to take energy off the grid, creating a scenario where users get paid for the electricity they use.

The benefits of these shifts in time of electricity use are two-fold:

  • demand is managed across the grid
  • customers can charge their cars at a low rate and allow their cars to be discharged at a high rate, making running costs for an electric vehicle even better value in comparison to a petrol or diesel car.

Grid gains

It’s not only energy firms, car manufacturers and EV users themselves that stand to benefit – V2G is of major interest to electricity grid managers.

Roberts explained: ‘One of the main benefits of this approach is that it helps to balance demand on the electricity grid. If it becomes widely-adopted, the implications are that fewer network upgrades will be necessary than if people charged their electric vehicles using conventional technology.’

Fiona Howarth, CEO of the project’s leading partner Octopus Electric Vehicles, thinks it’s high time for actions rather than words when it comes to V2G:

‘There has been a lot of talk from the side-lines about how vehicle-to-grid technology will change the face of energy,’ she said. ‘But with this consortium, we will be the first in the UK to actually deliver it to hundreds of households.’

As well as Energy Saving Trust and Octopus Energy, the consortium also includes UK Power Networks, ChargePoint Services, Open Energi and Navigant.

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