Smart inverters can do a lot more than turn rooftop solar DC into grid-ready AC. The boxes that accompany every rooftop PV installation can also provide valuable data-collection and grid-support services, as shown in pilot projects in Hawaii, California and other solar-rich regions.
Now microinverter maker Enphase is taking these kinds of capabilities to commercial scale. On Wednesday, the Petaluma, Calif.-based company announced its new grid optimization service, meant to turn its existing fleet of networked, behind-the-module microinverters into endpoints of grid intelligence for utilities and grid operators.
Enphase has already been doing this kind of work in pilot projects with Hawaiian Electric, to give the utility visibility into voltage and bidirectional power flow characteristics of solar-rich distribution grid circuits. It’s also testing its smart inverter chops in California, and is adding energystoragesystems in Australia and a few still-unnamed U.S. projects, Ameet Konkar, Enphase's senior director of strategic initiatives, said in a recent interview.
But the new grid optimization service adds some core utility software support to the mix, he said. Enphase is partnering with OSIsoft, the market leader for data historian software for North American utilities, and uses geographic information system (GIS) software tools from big utility vendotrs such as Esri, to integrate what it's so far done at pilot scale into a commercial product.
“The last thing people want in the utility control room is another screen to look at,” he said. Partnering with OSIsoft and Esri allows a “very seamless integration” for its PV generation profile, voltage and power quality, and other key end-of-network data, “in a format they’re very, very familiar with. This data can now go through their existing applications, to the screens they’re using now.”
Enphase is primarily pitching its grid optimization service to utilities in regions where it holds significant rooftop PV market share, Konkar said. But it doesn’t have to have near-complete penetration, as it does in much of Hawaii’s residential PV market, in order to provide valuable data, he noted. “In places like California, Massachusetts or New Jersey, where we’re about 30 percent of the installations...that’s still statistically significant,” he said, in terms of providing important information on the edges of the distribution grid.
Most rooftop solar systems aren’t visible to utilities, leaving them with little information about how they’re interacting with the distribution network, from substations to feeder lines and down to neighborhood transformers. Smart meters can collect some important data, and a handful of utilities have started tapping them for this purpose.
Enphase provides a parallel source of information. For years now, it’s been collecting 5-minute interval data from its systems via on-premise powerline carrier (PLC) communications to gateways that use cellular or broadband to connect to the company’s cloud-based software platform.
Other rooftop solar contenders, such as SolarCity, have networked their systems to allow for two-way data exchange and, potentially, real-time controls. Enphase is one of the first to package that kind of data for use by utilities and grid operators -- though it’s likely that more are working on similar ideas.
Mostly, utilities are asking for visibility into this rich store of edge-of-network information, he said. That can allow utilities to see where PV generation is creating voltage disturbances or causing power to flow back up circuits toward substations.
Its work with Hawaiian Electric last year, for example, allowed the utility to clear its backlog of PV interconnection requests on distribution circuits where data showed little risk of new solar causing grid instability problems.
While that study was based on historical data, “We can relatively quickly flip a switch, and they can start taking a look into what real-time voltages are on its network,” Konkar said.
Enphase, which has been struggling to cut costs and retain market share against competitors like SolarEdge, plans to charge utilities for its grid optimization services based on how much data they want, how often, he said. “If they’re interested in getting information on their network, we have standard pricing,” he said. “The closer you get to real time, the more it tends to cost.”
But inverters can also provide valuable grid support services, such as enabling low-voltage ride-through, injecting or absorbing reactive power, or controlling the rise and fall of solar output as clouds pass overhead. Enphase has started work on pilot projects to enable its inverters for volt-VAR optimization and other grid control functions.
The utility industry is still waiting on some key standards and certification regimes to be finished before these kinds of capabilities can be put to use in real-world environments, however. “On the control, we’re not there yet,” he said -- but “as the regulatory side catches up, we will be there.”