Gridco Systems is one of the more mysterious contenders working at the grid edge. Since its 2010 founding, the stealthy Woburn, Mass.-based startup has been developing an unspecified set of technologies, centered on advanced power electronics, to apply to grid needs. Now, it appears that it’s finally ready to unveil the form that this technology is taking.
Last month, Gridco closed a $10 million funding round, according to a Securities and Exchange Commission filing initially flagged by the Boston Business Journal. That brings total investment in the company to more than $30 million from backers, including General Catalyst Partners, North Bridge Venture Partners, RockPort Capital and Lux Capital. In January, it plans to reveal its first product at the DistribuTECH conference in San Antonio, Texas.
So what does Gridco have in store for the grid? CEO Naimish Patel, a co-founder of networking company Sycamore Networks, declined an interview request this week. But he did send an email reply that helps fill in some of the gaps -- even if it does lack much detail beyond a variation of grid buzzwords:
“Leveraging a combination of power electronics, distributed networking and advanced control systems, Gridco Systems has developed a new class of active grid infrastructure that will enable utilities globally to more effectively integrate renewable energy, increase energy efficiency and improve reliability. With our power regulation solutions, we’re well positioned to partner with utilities to address the rapidly changing challenges of today and tomorrow, throughout the grid.”
Patel’s description, along with a recently released white paper available on Gridco’s website (PDF), indicate that Gridco has chosen a particular utility challenge to tackle first. That’s managing the voltage fluctuations that emerge along distribution circuits, particularly those connected to increasing amounts of distributed generation resources like solar PV systems.
The unpredictable and fast-occurring voltage disruptions caused by lots of distributed generation are quite hard for traditional distribution grid systems to handle. Namely, the electromechanical load tap changers and voltage regulators used for this purpose today are slow to react to voltage changes, and because they’re mechanical devices, the more they’re used, the faster they wear out and need to be replaced.
Gridco’s white paper lays out the case for “series-connected, voltage-controlled power regulation platforms” to provide a faster-reacting, finer-grained and longer-lasting alternative. Indeed, it calls that solution “unique in its ability not only to provide the widest dynamic voltage regulation range at the lowest capital cost, but also to maintain grid-wide stability via the decoupling of primary and secondary feeders” -- or, in other words, making changes to one section of the distribution grid without altering the other sections it’s connected to.
That’s an important differentiation from alternative methods to control distribution line voltages that don’t occur in isolation from the grid at large. Namely, the ability of capacitor banks, STATCOMs and advanced solar inverters to alter line voltages via injection or absorption of reactive power creates effects across the local system as a whole, which can cause unintended effects that can’t be isolated to specific portions of the grid.
“In contrast to current-controlled devices, series-connected voltage-controlled devices impact voltage downstream of them, but have no effect on the feeder voltage upstream of them,” Gridco’s white paper notes.
This ability to alter line voltages in isolation could also be helpful for volt/VAR optimization (VVO) and conservation voltage reduction (CVR) systems, which lower grid voltages to save energy. Centrally controlled VVO and CVR schemes may not keep end-of-line voltages within acceptable minimum boundaries, a problem that decentralized and independently operating systems could help solve.
This vision isn’t unique to Gridco. Rival grid power electronics startup Varentec is aiming at similar capabilities with its “Edge of Network Grid Optimization” system, now being deployed in pilots by U.S. utilities including Duke Energy and Southern Company. It's noteworthy, however, that Varentec has described its distribution grid devices using reactive power injection as a key method of managing line voltages, which appears to contrast with Gridco's description of its preferred method.
Grid giant ABB has also been experimenting with “solid-state transformer” technologies for the distribution grid, in essence seeking to shrink the power electronics components of high-voltage direct current (HVDC) systems for lower-voltage grid needs. Using power electronics to decouple different parts of the grid from one another is a focus of Japan's Digital Grid Consortium, which is working on modeling and equipment specifications that could allow large-scale grids to operate as independent “cells.”
All of these grid-scale power electronics contenders will have to answer a lot of questions from utilities, of course. One important question concerns how well these digital power management technologies will stand up under the high-power conditions of the grid, both in terms of reliability and cost competitiveness. The Department of Energy’s ARPA-E program recently announced $27 million in funding for next-generation power conversion devices, indicating that much work remains to be done to perfect these technologies.
The other key question is how these novel technologies can be integrated into everyday utility operations. As Gridco’s white paper notes, “New solutions must entail lower overall capital expenditures than conventional solutions, while unlocking operational savings and adapting to evolving demands.”
They’ll also have to involve little maintenance, a decades-long lifespan in outdoor environments, and the ability to run in “set-and-forget” mode or as part of a broader utility distribution control scheme, according to the white paper. Presumably, Gridco intends to unveil an offering that meets these requirements at DistribuTECH next month. Stay tuned for more details to come in the new year.