EV's & Solar
With the increasing uptake of EVs on the road a lot of buyers are aware that the technology exists for bi-directional charging, which is the umbrella term for any of several energy flow technologies to and from the vehicle. Potentially, a bi-directional EV can be connected to the home electrical network and its battery supply the home energy requirements via a compatible 2-way charger during the grid supply's high tariff hours and be recharged at night with low-tariff energy or by solar energy during daylight hours. Due to the fragmented and uncoordinated market-driven energy setup in New Zealand, we are not able to utilise this technology, and it seems unlikely there is any imminent change on the way. But there are a couple of potential ways to gain some traction from what is available, even though options are limited.
The promise of V2H (Vehicle-To-House) technology has been around since it was introduced with the Nissan Leaf back in 2013, with the use of an external adapter. The Leaf is no longer produced, but there are lots of second-hand ones around and there are a couple of other new vehicles with V2H capability. The difficulty we still have is sourcing the required bi-directional wall-charger and getting a solar company to complete a compliant installation. There is the possibility that, as EVs become more common and they age beyond their original warranty, it may be that V2G updates may become more common.
Many EVs now feature Vehicle-to-Load (V2L) technology, allowing them to power external devices, and this leads to the question as to whether V2L can serve as a temporary backup power source for homes, effectively functioning as a makeshift Vehicle-to-Home (V2H) system. This may have potential as a practical emergency power solution but there are significant limitations, risks, and safety considerations, particularly regarding earthing and electrical integration. There may be issues to do with home insurance with makeshift V2L connections. In a normal solar installation it is common to have the household c/bk board divided into two isolated sections, and this arrangement might be carried over to connect with a V2L vehicle with the appropriate sefety considerations. In this way the EV might privide energy for a small selection of critical loads. You may only get around 2-3kw out of this setup, but that amount can be very useful as a backup energy supply for critical loads in an emergency or for running the fridge, lights, power points for the TV and internet and even a heatpump during high-tariff periods.
The third bi-directional charging technology is Vehicle-to Grid (V2G), allowing energy from the EV's battery to be exported back to the grid. There are serious grid support possibilities with this, reducing the risk of grid outages and stabilising the system, as well as potential cost savings for EV owners by selling power back to the grid. This is not available yet but is in the loop of energy sector/government considerations.