Vehicle-To-Grid (V2G) a false dawn or viable game changer — is it even worth the hype!
V2G technology has the potential to make electric vehicles the cornerstone of our future smart grids…but given the concept’s slow evolution, it may only be another solution looking for a problem.
According to EVConsult, there’s about 50 credible V2G projects worldwide that offer respectable case studies of looking at how this technology could work on a mass scale. The challenges however remain HUGE and would need a collective effort from electric car manufacturers, grid operators, charging equipment manufacturers, regulators, drivers, home owners, etc…there’s not enough of that happening.
So what exactly is V2G?
The best way to think about V2G is to remember that electricity is primarily made up of a sea of electrons flowing from one point to another, which in effect is an ‘electric current’. Rather than electric cars simply accepting that ‘electric current’ from the grid to charge their batteries, V2G technology (as allowed by the car, the charge point and the electric meter) allow the electric car’s battery to transfer back an ‘electric current’ to the grid at point of connection, i.e. it offers a two-way directional flow between electric car batteries and the grid.
And what’s behind the excitement surrounding V2G?
The ability to easily move energy between EVs and the grid becomes a seriously big deal when you consider how much energy could flow between our cars and the grid when mass adoption of electric vehicles really kicks off. What’s even more concerning is the alternative, i.e. what happens without V2G in a mass EV ecosystem where gigawatt hours of electricity will be required to charge up all our cars!
Another factor making V2G an exciting proposition is the economics and cost dynamics enhanced in electric vehicle ownership where V2G is effectively used when plugged in at home. The Driven, an EV-focused news and discussion site, offers a great example of comparing the cost of an EV (and its associated battery) versus home battery systems e.g. Tesla’s Powerwall. Effectively, if you paid £35,000 for a new Nissan Leaf with a 40kWh battery, the battery storage is costing you £875 per kWh. Purchasing a 14kWh Tesla Powerwall 2 home battery along with supporting hardware costs and typical installation costs could set you as far back as £8,000 i.e. about £600 per kWh. Considering this doesn’t include the costs of solar panel installation in the home battery case (still really doesn’t make sense having a home battery without solar pv), and the fact that with the Nissan Leaf option you are still getting an ACTUAL CAR; the Leaf becomes much more competitive if you could earn back from selling excess power to the grid or use its battery to offset your grid usage and insure against grid failures.
Why then hasn’t V2G ‘blown up’ yet?
Some of the key challenges facing V2G, is firstly the lack of effective hardware on board most EVs allowing two way battery management systems. Nissan Leaf and Renault Zoe have been the early movers in allowing this, with Tesla the notable exception given they are usually ahead of the innovation curve.
Another reason is differences in charging protocols and communication across the two main DC electric vehicle charging systems, CHAdeMO and CCS. The lack of standardisation with charge communication is an inconvenient hurdle in developing a unified charger to grid communication system.
And then there’s the old concerns some drivers have had on the impact of V2G on EV battery lifecycles given the multiple and short charge/discharge cycles V2G may involve. Although car manufacturers and other stakeholders have worked hard to disprove the concerns on battery degradation with Clean Technica showing that V2G could even extend battery life.
Although considerable the above challenges are not insurmountable, and as more manufacturers put out V2G compliant models and concerns on the impact on battery lifecycles dissipate, the technology is likely to improve as more investment goes into developing viable local solutions.
It’s not plain sailing though, as other solutions may be more cost effective in the medium term. As EV adoption picks up, it’s already been shown that EV battery second life usage as home batteries offers great potential. Nissan already offers home battery units made up from ex EV battery packs. If supply of these increase with more EVs on the road, this may be a much more cost effective investment for households and even for grid operators.
And from a simplistic starting base, V2H (Vehicle-to-Home) which involves building unitary systems allowing an electric vehicle to power an individual home (as its own node outside of the grid — back of the meter stuff) seems to us like a more viable starting base to validate, iterate and enhance from — before looking at system wide solutions.
In theory, V2G is a great concept and a necessary component in making a future EV ecosystem more sustainable, but lots of work still needs to be done to making it a viable mainstream contender. Therefore in the meantime, don’t believe the hype…yet.