Solar smart inverters are going to be a key grid edge technology. First, they’re going to enable rooftop solar PV systems to automatically stabilize their own collective disruptions to the grid. Then, they’re going to start communicating to utilities, giving them a much clearer view of what’s actually happening at the edges of the grid, as well as offering reactive power and ramping controls that could become a major resource.
That’s how California sees the future for smart inverters. Under the state’s Rule 21, since September of last year, Pacific Gas & Electric, Southern California Edison and San Diego Gas & Electric have required that all new solar systems come with inverters with “phase 1” smart inverter capabilities — seven specific autonomous functions, like not tripping off during minor voltage excursions and thus making them worse, and automatically adjusting power factor in case of emergencies.
Then, starting in February 2019, utilities will start requiring “phase 2” communications capabilities from all new solar systems, as well as certain “phase 3” advanced inverter capabilities, like giving utilities some control over how much reactive power they are injecting or absorbing.
But to tap these next-phase capabilities, California will have to solve a significant set of challenges — not just for utilities, but also for the third-party distributed energy resource providers seeking to aggregate smart inverters in the field.
On Wednesday, PG&E released an interim report on its flagship smart grid pilot project — the Electric Program Investment Charge-funded 2.03A project — which highlights these challenges.