What’s the difference between the traditional microgrid and the new residential energy storage paradigms now gaining traction in the marketplace?
Not much, according to Ken Munson, president and CEO of Sunverge, a company offering an integrated energy storage platform that – if it delivers on its promise — could contribute to a redefinition of the grid and the microgrid.
The virtual power plant
Sunverge combines batteries, power electronics, energy inputs, cloud-based software controls and analytics in a single 2 kW/hour appliance, the company’s Solar Integration System (SIS). The platform aggregates and orchestrates a range of distributed energy resources into a virtual power plant, designed to meet the needs of utilities, as well as consumers.
Founded in 2009, the company traces its beginnings to 2008 when, observing utilities struggling to confront a strong new direction in renewables, Munson realized that effective photovoltaic/energy storage solutions of the future would have to take a grid-centric approach.
“For us the question was: What would it take to create a win-win scenario where the consumer achieves cost effectiveness while the utility operator stays relevant, able to innovate their way into beneficial business relationships with customers?” he says. “Our central premise from the beginning was that serving the needs of both the grid and the consumer at the same time doesn’t have to be an either or proposition.”
Key to his vision was a decentralized entity at the edge of the grid that could be collected in a cloud and resourced as a feed.
“Putting just enough at the edge of the grid to get the maximum consumer benefit changes the amount of assets that you actually have to deploy,” he says. “The more power generated and used on site, the stronger the grid.”
As Munson sees it, the core conundrum lies less in the technologies than in a flawed understanding of the goal itself, traditionally the elusive $500kWh price point. The real determining issue, he says, hinges not on cost per kWh but in the total life cycle of the kWh — a totally different math problem.
“If you consider that every charge and every discharge comes at a cost, how you use that battery becomes relevant to the business case,” he said. Suddenly, you’re looking at the economics of something that not only reduces demand charges, but also renders value back to the grid, according to Munson.
How the SIS works
Sunverge’s core intellectual property is its SIS unit, an 11.7 or 7.7 kWh system comprised of a maximum power point tracking charge controller, a bi-directional inverter, a lithium-ion battery pack and a field-hardened computer that, enclosed in a UL-certified enclosure, mounts on the house. The proprietary cloud-based controls and analytics provide a grid-interfacing intelligence system that allows the unit to self-monitor, controlling individually or as part of an orchestrated group of systems.
As with other systems, customers can draw from the grid during peak hours. But instead of exporting power to the grid all day and buying it back later, they can now choose to shift more of their usage to off-peak times, saving as much as 60 percent on electricity bills in time-of-use regions. To date, Sunverge has 4 MWh of storage capacity installed and under management, serving 330 customers.
“Operators can look at all the devices connected in a few homes or a thousand homes on a feeder, a microgrid or a cluster of some geographic configuration,” says Munson. “They can then aggregate those resources, orchestrate how they want them to behave, and dispatch them as one suite of resources.”
The software also integrates with enabling “smart” technologies in the home to monitor power use in real time. Understanding that few people sustain consistent monitoring behaviors, no matter how cool the gadget on the wall, Sunverge designed the system to “think” self-autonomously for whoever uses it—whether homeowner, developer or utility.
“After all, utilities want what consumers want,” he says. “They may not want the granular level of detail a homeowner wants, but in aggregate they want to know how they can resource one or 500 MW on their grid to best use.”
Virtualizing residential energy storage
Munson sees residential energy storage “virtualizing” into microgrid status within a few years because the very definition of the microgrid itself is undergoing wider interpretation as the life cycle shifts. Initially centralized, the concept has segued from substation to community and now to residential storage.
“Coupling PV and storage on the demand side with the metering for control is what ultimately makes sense in a business case,” he says. “And a system that optimizes the rate of storage via the right series of algorithms to control that platform—only makes that case stronger.” — Lynnda Greene
