How Schneider Electric's Micro-Grid Powered the Solar Decathlon
As one of the world’s marquee collegiate level engineering competitions the Solar Decathlon spotlights some of the brightest young minds working in home design, engineering and green technology. This year’s competition in Irvine, Calif., featured 19 teams—representing many of the top collegiate engineering programs in the world—as they battled in 10 different efficiency competitions en route to declaring a winner. (This year’s winner was Team Austria, with its LISI Home.)
But the students and their advisors weren’t out there alone. Sponsorships by some of the leading green and renewable energy companies in the world helped keep everything running smoothly. And one of the major sponsors of this year’s competition was Schneider Electric. Schneider describes itself as an energy management firm, and is truly a global giant in its field, with $31 billion in revenues, and 140,000 employees, in over 100 countries.
In addition to providing a dollar sponsorship for the entire event, they wouldn’t disclose the cost, Schneider also provided equipment to the teams, including: power equipment, solar invertors, meters, and lots, and lots, of wire. But perhaps their key contribution was that Schneider set up, and managed, the event’s so-called micro-grid, which connected, controlled and regulated all the electric power both used and generated by the homes during the event.
What is a micro-grid? We spoke with Phil Davis, a 35-year Schneider veteran, and senior manager at the firm, who had attended the Solar Decathlon.
|Schneider's Phil Davis|
The basic answer is that a micro-grid is a subset of the traditional power grid, but, as the name implies smaller. Davis described it as a group of energy customers who can form a sort of energy network within the larger grid that can, when needed, isolate (industry term “island”) themselves from the larger utility or energy distribution network. “It has the ability to stand on its own, through some sort of backup generation,” he said.
In this light micro-grids help decentralize the traditional electric grid system, which is a good thing, because as it stands now the main electric grid is huge, inefficient, and prone to system-wide outages.
Micro-grids can be as small as an office building, or as large as a college campus. The military is especially interested in making micro-grids for its military bases, as this decentralization will help contain the risk if the main grid is hacked, or if there is a natural disaster. Presently the largest domestic micro-grid is used to power a Navy yard in Philadelphia, and is several hundred acres.
An added boost occurs when micro-grids are paired with smart grid technology. Smart grids are typically defined as allowing for two way interactivity between the grid and the customer. If the customer has an efficient, energy-generating, home this can mean being able to pump excess electricity back into the grid, generating income for the homeowner. Smart grids also allow power to flow more efficiently throughout the grid, flattening its demand curve during times of peak usage. This can help prevent energy crashes or blackouts caused by too much demand all at once.
|Schneider's equipment kept the Solar Decathlon humming.|
At the Solar Decathlon Schneider set up the village micro-grid by connecting it to a nearby naval pumping station. “This also was used for backup generation, because things happen,” Davis said.
This backup generation was never needed. In fact the homes generated so much solar power that by the end of the event, and for the first time ever at a Solar Decathlon, all the homes had, together, generated more power than needed, said Elizabeth DeCastro, director of press relations at Schneider.
This is all the more impressive because Davis said he doesn’t believe any of the homes had any storage capabilities for the solar power they generated. Also, they drew power at night when the sun went down. This means they created excess during the day, balancing their total use to net zero.
While the micro-grid performed as expected Davis was still impressed by how the energy generated was put to use by the teams, beyond just electricity. “Many houses had solar that they used for thermal purposes, like heating domestic hot water, and radiant pipes for flooring,” he said.
He also said the homes were exceptionally efficient when it came to converting what solar energy they did gather into electricity. The typical standard is that 77% of energy generated by solar becomes actual, useable energy. But the teams found ways to up that by keeping their solar panels clean, using oversized wiring in multiple channels to reduce voltage losses, and using high efficiency invertors. Davis said he did not know what the final efficiency was exactly, but that it was absolutely higher than 77 percent.
One takeaway? “These homes were proof that we are a lot closer to being able to run a net zero home in this country than you might think,” he said. “In ways that don’t disrupt the typical suburban lifestyle.”