A fleet of electric buses in North London could soon be pumping electricity back into the grid when they’re not carrying passengers.
There are nearly 100 electric buses at the Northumberland Park bus garage, and while they are charged overnight when some of them are not in use during the day, they could pump unused electricity back into the grid when power demand is high.
The project, called Bus2Grid, is believed to be the world’s largest vehicle-to-grid (V2G) trial site. The initial trial will use the batteries of 28 double-decker buses, capable of returning over 1MW energy to the grid.
The key advantage of doing that is the ability to provide power to the grid locally, where it’s needed, so there is less waste in transmission. Being able to sell electricity back to the network can also help reduce the hefty upfront costs of converting bus garages to electric.
This is a principle that is also being tested with electric cars which spend most of their days idle and can act as local power storage units when not being driven around. By recharging vehicle batteries when demand is low and putting energy into the grid when it is high, V2G helps manage the peaks and troughs, balance the network and make it more efficient.
The downside is that cycling the battery more often can reduce its life, although battery manufacturers are working on much longer life batteries. At the moment, typical car batteries are rated for around 8 years, or 200,000km, but the 1.6 million km battery is now available, and 3 million km batteries are under development. The distance in km is just a rating, what the longer life batteries enable is for many more recharge cycles to be performed, which is necessary if electric vehicles are to also be used as local storage for the mains grid.
These longer life batteries are now also making V2G set-ups more cost-effective for the vehicle owners.
The 3-year Bus2Grid trial is being led by SSE Enterprise in partnership with the Mayor of London, TfL and Go-Ahead London. Go Ahead London was chosen by TfL to run the first electric buses in London back in 2013. It has now grown its fleet to 240 – making it the largest electric bus operator in Britain.