A lot of our residential customers in Rhode Island ask about solar batteries. It’s the next logical question when you install panels: why not store the power so you can use it later?
But the policies and pricing around solar energy storage make it difficult. The Tesla Powerwall and other retail batteries add a considerable cost to your project. It’s usually between $6,000 and $12,000 more to have a fully integrated solar + battery system.
However, the market for solar storage is rapidly evolving. Bloomberg New Energy Finance (BNEF) forecasts that the energy storage market will see explosive growth between 2016 and 2030, similar to the current growth in solar power.
It’s nearly guaranteed that the prices for solar batteries will drop in a competitive market.
New developments for solar + battery storage systems in Rhode Island
On November 28, 2017, the Rhode Island Public Utilities Commission (PUC) approved regulations for solar projetcs with battery integration. And they approved installation for solar + battery systems under 25 kW AC (small commercial or residential).
Systems that connect to the power grid and use net metering (Renewable Energy Growth Program candidates) must meet certain conditions.
These provisions came after National Grid expressed concern over ratepayers finding “loopholes” in the system.
- Solar batteries can only be powered by solar-generated electricity.
Solar batteries can only receive charge from your solar panels. This rule stops ratepayers from charging their batteries by other means, and then selling that electricity to the Grid through net-metering.
- Restricted from using time-of-use (TOU) pricing for electricity.
TOU is a common rate assessment method used by utility suppliers. The rates change with demand, so there are “peak hours” for pricing. National Grid didn’t want people producing and storing energy at low cost, and then selling it back at peak times. However, Rhode Island does not utilize time-of-use pricing at the moment, so that could not happen.
- Solar + battery projects cannot send stored energy to the Grid.
This rule directly connects to the one regarding TOU. Since Rhode Island doesn’t use TOU pricing, it doesn’t seem necessary to restrict stored energy being sent to the Grid. If ratepayers can’t sell back at “peak hours,” then abuse of the system isn’t possible.
Major solar and energy companies questioning new PUC regulations
On November 30, Tesla and Sunrun jointly filed a request for the PUC to rescind the final provision and allow stored energy to be sent to the grid. The PUC is expected to respond within 10 days, so we’ll update you when that happens.
If you have questions or would like to find if your system supports battery back-up, shoot us an email at [email protected].