Sunil Cherian is the CEO of Spirae, a company that makes software to coordinate communication between smart-grid participants. Photo: Dan Bihn
It’s the question on everyone’s minds: What if alternative energy projects could distribute power on a separate line or lease capacity on existing lines, allowing homes and businesses to integrate green energy with power from the public utility company? Okay, not everyone is asking that. But for those in the energy sector, it’s a question with game-changing implications. Not only could large-scale dairy methane digesters power houses down the street, but homes with small amounts of surplus solar energy might aggregate resources to sell to the neighborhood.
Spirae, a technology company based in Fort Collins, Colorado, offers a software platform called BlueFin that makes such revolutionary action possible. BlueFin communicates directly with wind turbines, battery systems, flexible loads, and generators. It clusters all inputs and allows customers to incorporate additional power sources over time. The system can even adjust thermostats and turn off lights to save energy. Most importantly, users rely on automated control—there is no need to flip a switch to turn on the public power supply if green energy becomes unavailable. “We are like the conductor at an orchestra,” says Sunil Cherian, Spirae’s CEO.
Planners from the City of Fort Collins recently put the technology to the test. Through its FortZED program, the city aims to transform several blocks into a zero-energy district (ZED) by distributing energy between high-efficiency buildings and businesses with greater demand. In 2011, the city started small by asking five sites connected to the same two circuits to reduce their energy use, generate more of their own power, and distribute energy. Solar panels were already installed at City Hall, Colorado State University (CSU), the Larimer County Courthouse, and New Belgium Brewing, which also makes green energy from a methane digester fed with brewery waste. To reduce energy, a fountain was turned off at the county building and thermostats at CSU and city hall were continually adjusted to ease the load on air-conditioning systems.
Spirae technology coordinated the cross-talk. “The Spirae system made requests to building managers, and sites had the final say in whether to allow automatic control or approve each request,” says Dennis Sumner, the city’s senior electrical engineer.
Spirae’s control room in Fort Collins, CO, a facility known as the InteGrid Lab. Photo: Dan Bihn
Funded in part by a US Department of Energy grant awarded to the city, the project, successfully accomplished a 20 percent reduction in peak energy use—although the triumph is only proof-of-concept. None of the buildings generated enough power to meet their own needs, much less create a power surplus from renewable resources. The city did reduce the percentage of power drawn from the Platte River Power Authority, which aggregates energy from natural gas turbines, coal plants, wind turbines, and hydro sources, but this reduction required local diesel and natural gas generators to supplement green energy.
“Of course, diesel isn’t as environmentally friendly as desired, but this was a test of distributed generation,” Sumner says. If Fort Collins can expand its solar capacity, it will achieve a substantial net environmental benefit. In the mean time, other communities suffering from a surplus of renewable energy stand to benefit from BlueFin technology. Take methane. In California, a single dairy with 1,500 cows can generate enough methane energy to continuously power 500 homes. Many cornfields in the Midwest are also capable of generating wind power.
These projects require expensive turbines, digesters, and generators. To pay off the investment, farmers sell energy back to the grid. But it might be more economical to work directly with consumers. Dairies need to bring in 12 to 14 cents per kilowatt, according to Nettie Drake, a consultant for several methane digester projects in Northern California. Utility companies in California have previously offered eight or nine cents per kilowatt, but in 2011, hydropower began to under-bid methane. Utility companies in Northern California and Oregon signed fifteen-year contracts with providers along the Columbia River for two cents per kilowatt. “The Columbia River had excess water, and this changed everything,” Drake says.
If dairy digesters can’t sell to the grid, their renewable energy will go to waste. Distributed generation offers a potential solution, though there are issues. “The problem is that you need to have quite a lot of distributed resources to have something you can count on,” Sumner says. Peak energy loads vary between sites and over time, and each building has a unique energy demand. The power contribution from distributed energy systems can also vary greatly over different time periods. This makes it difficult to budget an exact balance between customer loads and distributed resources.
Spirae’s software may help solve many of these problems. It works with the existing grid, allowing communities to remain connected to the public utility system. It can also juggle power supplies with changing demand to help energy islands stay afloat. BlueFin is currently used by NRG Energy to help Necker Island in the Caribbean integrate diesel generators with solar and wind—the goal is to meet at least 75 percent of demand with renewable energy. The company also is working with Canadian partners to add more renewables and stabilize energy sources in northern Canada, where communities are entirely separate from the grid.
