What Is V2G?

A number of announcements have been made about vehicle-to-grid (V2G) lately – exciting developments that represent the first steps in the deployment of a technology that could have a considerable impact and help accelerate the transition to electric vehicles, and more broadly a low carbon economy.

- Hamish Ainsley

So what is V2G? It describes a set of technologies that allow for electric vehicles to discharge the energy in their batteries to power a home or a grid on some level. The theory is that any excess energy left in a battery after a daily commute can cover stationary energy needs as well. Scale that up to the grid, locally or nationally, and the stored energy capacity of an electric vehicle fleet could meet or even exceed all our energy needs.

To give some context, the battery in a typical Tesla can power an average family home for about a week. You have to let that sink in for a while. The energy it takes to shift a car and its occupants 300 miles is roughly equivalent to what it takes for a whole family to have the lights on at home, watch television while eating microwave popcorn, run the dishwasher, kettle, iron, cooker, and the list goes on - for an entire week.

A recent article by OVO Energy outlines average household energy use around the world. It states that in the UK in 2014, annual usage per annum dropped below 4,000kWh (76kWh per week) and don’t be surprised if that average continues to drop thanks to gains in energy efficiency - energy consumption in the country is projected to be 5% below 2013 levels by 2020; not bad in a (moderately) growing economy, even if there is considerable room for improvement. So, even a modest 75kWh Tesla battery (Tesla’s largest battery on offer is now 100kWh) can easily cover the average household’s electricity needs. Add charging from renewable sources to keep the car topped up whenever it is stationary, and both daily travel needs and stationary energy consumption are covered, all in one neat package. OK, so a Model S is an expensive way to power your home, but for anyone who plans to buy one anyway, and who has solar panels on their roof, the case for using excess stored energy from the car to power the house becomes all the more compelling.