Sun, wind, algae: Future data-center power sources?

Researchers and policymakers gathered at E3 2008 to share progress in the development of renewable energy sources including wind, solar and biofuels

The potential for wind power in the upper Midwest United States has led some to dub the region the "Saudi Arabia of wind." But tapping that potential isn't easy. In particular, the difficulty of integrating wind power into utility companies' transmission grids is hampering adoption.

Experts from around the globe gathered last week in the US, to discuss ways to expand wind power, along with other renewable energy topics, such as the latest in photovoltaic technology and the potential for producing biofuels from algae.

"The global impact of our energy procurement and utilization choices on our environment is undisputed. For us, perhaps the most compelling challenge is to develop and deliver sustainable energy systems to the global marketplace," said Dick Hemmingsen, director of the Initiative for Renewable Energy and the Environment (IREE) at the University of Minnesota.

Hemmingsen addressed 700 attendees at E3 2008, a conference focused on energy, the economy and environmental issues, and he stressed the need for collaboration. "These developments cannot occur in a local vacuum," Hemmingsen said. "Within our academic institutions it's critical that researchers work in an interdisciplinary manner, integrating the work of agronomists, biologists, chemists, engineers and economists."

In addition, the academic community needs to be in tune with the business community, Hemmingsen said. "It means working to ensure that the needs and opportunities of the business sector are helping to focus the scientific agenda, and that the ideas and possibilities being developed by the academics are helping to inform the business opportunities."

Don't let the economy stop you

The E3 event drew speakers and exhibitors from private industry, government, nonprofit and education institutions, who shared ideas about new market opportunities and government policies that could accelerate the use of renewable energy sources and decrease our dependence on nuclear and fossil fuels.

A difficult economy is no reason to pull back on investments in renewable energy sources, said keynote speaker Gary Doer, who is premier of the Canadian province of Manitoba. In the nine years since Doer was first elected Manitoba's premier, the province climbed from 9th place to 1st place for energy efficiency among Canadian provinces. The region has boosted its hydroelectric power and plans are in place to deploy more wind farms and explore greater use of solar and geothermal energy sources. Long-term goals are aimed at reducing greenhouse gas emissions in the province to a level that's 6 percent below 1990 GHGs.

Page Break

"All of us should be very committed to not standing still, even with these economic challenges. The jurisdictions that stand still, that stand in the middle of the road, are going to get run over when we inevitably come out of this. Those who don't invest in education, training and skills development are not going to be able to compete with other economies," Doer said. "We have to continue to make the argument that the costs of doing nothing are much greater than anybody has ever anticipated."

On the topic of wind, attorney William Holmes discussed how the unpredictability and intermittent nature of wind makes it hard to incorporate into utilities' transmission grids. Wind energy cannot be dispatched to meet load in the way that traditional fossil fuel sources can, since wind energy typically is consumed as soon as it's produced, said Holmes, who leads the energy and telecommunications practice group at law firm Stoel Rives.

"Wind is either blowing or it's not," Holmes said. "If it blows at an inconvenient time or it blows when it's not expected, that result has to be managed into the system."

Other issues include: upgrading transmission lines to deliver wind energy from where it's produced to where the energy is needed; system storage and exchange limitations; lack of dynamic scheduling capabilities; and the high costs of interconnection facilities and transmission upgrades, Holmes said.

One company making strides in the area of wind storage is Xcel Energy, an electricity and natural gas company that operates in eight Western and Midwestern US states.

Xcel this month completed installation of a 1-megawatt battery in Luverne, Minn., that's designed to allow it to store wind energy and move it to the electricity grid when needed, said John Bryan, who manages the Minneapolis company's Utility Innovations program.

Xcel's wind-to-battery energy storage project uses a sodium-sulfur battery from NGK Insulators and represents the first US application of the battery as a direct wind energy storage device. With 20 50-kilowatt battery modules, the batteries will be able to store about 7.2 megawatt-hours of electricity. When the wind blows, the batteries will be charged, and when the wind calms down, the batteries will supplement the power flow, according to Xcel.

"The variability of wind during the day costs a ton of money. If you can actually match your forecasts by dispatching wind, you can save wear and tear on power plants" and save on contracts pricing, Bryan said. "Storage [of wind energy] should be able to flatten the cost curve."

Page Break

Solar advances

On the topic of solar power, Dan Frisbie shared research being done to lower the cost of solar cells by incorporating plastics. "Making efficient plastic solar cells -- flexible, cheap solar cells -- is going to require many advances in materials technology," said Frisbie, who directs the graduate program in materials science and engineering at the University of Minnesota.

The research revolves around organic semiconductors, and with respect to photovoltaics, "the idea is that you could use methods of coating to make solar cells over large areas on flexible substrates at low costs," Frisbie said. For example, a semitransparent solar film might be adhered to the windows of a bus, or a tent might be constructed of fabric with integrated solar cells. The technology exists today, but it needs to be refined to produce more efficient solar cells and become commercially viable, Frisbie said.

Also seeking commercial viability is Gerardo Ruiz, founder of freEner-g, a start-up that offers solar electricity leasing plans. In its business model, freEner-g designs a solar system for a home or small business and then installs, maintains and supports it for the duration of a customer's lease. Customers don't have to spend a lot of upfront cash to buy and install solar arrays, which makes solar power more feasible for consumers, Ruiz said.

Similar solar leasing projects are being tested in California and Connecticut, Ruiz said. "It is very exciting for us to be able to try that here in the Midwest, too," he said. "I think ultimately there is great potential for a brand to emerge, one that gets equated in people's minds with solar for the home, delivered as a service."