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RENEWABLE DISTRICT ENERGY
In February 2009, prominent politicians in Washington D.C. met to discuss the future of renewable energy development. The half-day National Clean Energy Project forum featured members of Congress and members of the President’s cabinet, with labor, environmental, and business leaders. Their goal was to raise the visibility of climate change and alternatives to fossil fuels among policymakers. Former Vice President Al Gore, Speaker of the House Nancy Pelosi, and others spoke about the importance of massive infusions of capital into power plants fueled by the sun and wind and into an upgraded transmission grid to move that power around the country. The consensus appeared to be the opinion articulated by Secretary of the Interior Ken Salazar who said: “Our big question becomes, ‘How do we get the energy that is produced from those [remote] areas to the places where it’s going to be consumed?’” The forum members seemed to envision acres of solar arrays in the Southwest and huge wind farms in the Midwest, all sending electrical power—via high-voltage transmission towers— to distant population centers. Although it’s refreshing to hear Washington insiders discuss renewable energy, centralizing largescale renewable power production poses several problems. Siting the expensive towers will take time and endless red tape, and they’ll face local opposition for health and safety concerns. Long-distance lines are notorious for substantial transmission losses. And these massive projects would probably be the domain of large utility companies eager to claim the profits from this power production and distribution.

HOMEGROWN ECONOMY
In November 2008, the Institute for Local Self-Reliance (ILSR) published a study as part of the New Rules Project that examined the availability of various renewable sources—primarily wind, solar, and biomass—around the United States. Authors John Farrell and David Morris tallied the amount of energy that could be generated by states tapping into renewable resources within their borders. They calculate at least half of the 50 states could meet all their internal energy needs, and most of the rest could meet a significant percentage.

“For example,” say the authors, “if Ohio’s electricity came from North Dakota wind farms—1,000 miles away—the cost of constructing new transmission lines to carry that power and the electricity losses during transmission would surpass the lower cost of production, resulting in an electricity cost 15 percent higher than local generation with minimal transmission upgrades.” Moreover, local production would help protect states from multi-state blackouts. Farrell and Morris conclude: “While significant variations in renewable energy among states exist, in most cases, when transmission or transportation costs are taken into account, the net cost variations are quite modest. Homegrown energy is almost always cheaper than imports, especially when you factor in social, environmental, and economic benefits.” ILSR argues that federal policies should concentrate on helping states develop local resources rather than transport energy long distances.

DISTRICT ENERGY
Decentralizing the heating and cooling of buildings has been the preoccupation of the International District Energy Association (IDEA) for about a century. District energy, according to IDEA, is a system that produces steam, hot water, or chilled water at a central plant and pipes it out to buildings in the district for space heating, domestic hot water heating, or air conditioning. Individual buildings don’t need their own boilers or chillers. Such systems have long been popular on university campuses; they are also found on military bases, at airports, and in office parks. Central physical plants may be most obviously practical in situations where one owner controls a group of buildings, but some district energy systems are run by municipal utilities in urban centers. One of the oldest and largest is Consolidated Edison, which serves steam to 1,800 buildings in Manhattan. Steam-driven cooling reduces peak demand for electricity and eases demand on the local power grid. District energy reduces the cost of HVAC equipment and equipment rooms in buildings, and frees rooftops for other functions.

One big advantage of district energy systems is that, because they are much larger than the physical plant of a single building, they can support combined heat and power (CHP), also known as cogeneration. CHP increases the efficiency of a power plant because the highest-grade energy generates electricity, and lower-grade, “waste” heat is still usable to heat or cool buildings. When remote power plants generate electricity, the lower-grade heat is literally wasted. IDEA estimates cogeneration doubles the efficiency of any fuel.

IDEA President Robert Thornton is skeptical of the emphasis on the national grid by federal policymakers. He says: “Building transmission systems to support large renewable assets outside the business district or population centers strike me as not the wisest use of capital in all cases. I’m more in favor of community-scaled distribution.” He also believes heating and cooling of buildings—responsible for 40 percent of U.S. energy use—is “better done with fluids than with wires.” Of course there are transmission losses in district systems, but they are not as great as those from high-voltage transmission lines across vast distances. Con Edison’s well-insulated steam lines lose 3-12 percent of their energy within Manhattan. In general, Thornton says, you need about 10,000 tons of cooling load within about a half-mile radius for optimum efficiency. The number varies for heating, but IDEA offers computer tools for calculating optimization depending on project location and other factors. The organization is working with the U.S. Green Building Council to formalize credits for district energy in the LEED rating system. A building can receive Energy and Atmosphere credits if the district energy system that serves it meets certain efficiency standards. The potential for savings are vast. Worldwide, Thornton says, about two-thirds of the fuel used to make electricity is lost as unused heat. “Fifty thousand gigajoules of energy goes into the global electric grid, and only 16,000 comes out as useful electricity.” Recouping that loss would make a huge impact on global energy consumption. The concept becomes still more compelling when the fuel source is renewable.

LOCAL + RENEWABLE
This is the case at the Oregon Institute of Technology. The southwestern Oregon campus has been heated geothermally since the 1960s. The 192-degree Fahrenheit water from 1,800-foot-deep wells saves the institution an estimated million dollars per year. A new project is expected to satisfy all the campus’s electricity needs as well. Drilling to 5,300 feet has tapped 300-degree geothermal fluids that will run a power plant rated at between 1.5 to 3.0 megawatts. “Waste” heat from electrical production will be sold to adjacent property owners, and excess electricity will be sold back to the local grid. The plant is scheduled for completion by early 2010 when, according to OIT’s Geo-Heat Center, the school will be an “all green-energy campus.”

Of course, not every location has ready access to geothermal energy, but each state has its own mix of resources. In 2007, Minnesota lawmakers initiated a study of the potential of in-state wind generation as an alternative to a proposed $1.7-billion investment in new transmission lines to bring wind power from the Dakotas. Technical and policy experts studied the feasibility of many small wind farms scattered across the state. They looked at wind availability and excess interconnection capacity of electrical substations. They found 20 locations where small (10- to 40-megawatt) wind farms could produce a total of 600 megawatts—output similar to that of a new power plant—without further investment in high-voltage transmission.

One member of the study’s technical review committee was independent consultant Mike Michaud. He says that Minnesota’s community-based energy development (C-BED) initiative requires utilities to consider small-scale local projects in any siting decisions. Michaud explains the goal was to optimize the efficiency of the existing power grid before investing in expanding it. He says developing small, instate wind farms will also foster local economic development. Since the study was released, there’s been a rush of applications for permits to connect to the existing grid, a precursor to actual wind-farm construction. Michaud is proud of the study’s achievement. “I’m not aware that this kind of study has been done before,” he says. “We’re hoping other states will pick up the ball and do similar types of analyses in their areas.”

In the May 1, 2009 issue of Environmental Building News, Executive Editor Alex Wilson (also consulting editor at GreenSource) argued persuasively that wind energy is best sited on wind farms, not building rooftops because of numerous concerns for efficiency, noise, cost, and safety. This is another reminder of the importance of “right-sizing” energy generation. Bigger is not always better; nor is smaller.

A continent away from where OIT is “mining” geologic heat, the campus of Cornell University, in Ithaca, New York, is tapping the earth’s natural “coolth” from the cold water of nearby Cayuga Lake. The ingenious system is made of two separate water circulation loops. First, an open loop pumps water from 250 feet below the surface of the lake, where the temperature remains at 39 to 41 degrees Fahrenheit year round. The water travels two miles to a heat exchange facility on the lake shore, where it gives up some of its “coolth” and is returned to the warmer lake’s surface. A second, closed loop takes water, which is cooled to 43 degrees by the lake water without contacting it directly, another three miles uphill to the campus where it circulates to cool the buildings, saving 25 million kilowatt-hours per year of conventional cooling. Spurred by community concerns about the lake’s ecology, the project has been heavily monitored and controlled to minimize harm to fish and their habitat.

A more recent example of thermal district energy is at Dockside Green, a 15-acre mixed-use development in Victoria, BC, by Busby Perkins+Will. Eventually consisting of 1.3 million square feet, the project—combining residential, retail, office, cultural, and industrial uses’is heated by a central gas-fired plant. In this part of North America, cooling is a relatively small load. The gas is not a fossil fuel but rather “syngas” generated on site using a nonpolluting “biomass gasification” technology from Nexterra Energy Corp. The biomass is primarily waste wood from local demolition projects, which would otherwise have gone to a landfill. The gas is burned to heat water, which is then piped to all the buildings. Architect Peter Busby explains: “Dockside Green, at just over a million square feet, is about the smallest [project] size for which you can get the gasification equipment at the moment.” No electricity is generated in this scheme, and he comments that piping hot water to radiant heating systems is easier and more efficient than creating and distributing electricity and then converting it to heat.

Busby emphasizes the importance of project density, to minimize the distances the hot water has to travel. Dockside Green’s density was one reason it was chosen as a case study for the USGBC’s pilot program for LEED for Neighborhood Development. Although this is not the case at Dockside, additional efficiencies can be obtained from ground-source cooling or solar water heating. Busby explains: “There’s a threecornered opportunity that’s extremely efficient: in-slab radiant systems in buildings, ground-source heat pumps, and a small district utility. They’re all intermixed, and they work well together.”

To explain why district heating has received so little attention in the North American professional community, Busby cites several factors. One is the shortage of engineers knowledgeable in green-building design. Also, he says, there’s a cultural bias toward large, centralized power plants. “We have a tradition of big engineering,” he comments. “We’ve gone for generations thinking ‘the bigger the cheaper.’ But if you look at power systems in which up to a third of the electricity is lost in transmission, that’s where the inefficiencies creep in.”

A POWER PLANT NEXT DOOR
Local, renewable generation of electricity is on the rise. The nine-campus, 190,000-student Los Angeles Community College District (LACCD) has launched a sustainablebuilding program that includes LEED certification for new and existing buildings and, eventually, enough photovoltaic arrays to supply all the needed electricity. On each campus, arrays are cropping up on building rooftops and as parking lot covers. The goal for these systems, planned to reach 200,000 panels, creating 40 megawatts, is not only to save on utility costs and reduce carbon emissions, but to provide green-career training for students.

In Gainesville, Florida, photovoltaic collection is being planned to be even more distributed than at LACCD. The municipal Gainesville Regional Utilities (GRU) has adopted a program to buy renewably generated electricity from its customers. This differs from the more familiar “net metering,” in which customers’ meters run backward when excess power is being produced, thus lowering utility bills. In contrast, GRU’s “feed-in-tariff” program, borrowed from highly successful programs in Germany, pays above-market rates for customer electricity. Calculating the cost of installation and 20 years of maintenance, the program guarantees a profit to participants. This provides a safer investment climate than tax incentives, which can be withdrawn and which often limit system size even when vast rooftops could be productive. Moreover, easily managed by the utility, and using off-theshelf technology, the feed-in tariff is an investment option available to anyone, unlike large-scale solar farms, which are accessible only to deep-pocketed corporations. Electricity flows through existing, small-scale distribution lines, making high-voltage transmission lines unnecessary. It’s been estimated that GRU’s program could grow to 80 megawatts.

In Germany, the goal was to get 12 percent of the nation’s electri city from renewable sources by 2010. They passed that goal three years early and are now at 15 percent. Other countries in Europe and around the world are following Germany’s example, just as other locales in the United States will soon be following Gainesville. The cost of the feed-in tariff system is paid for by utility rate increases, but these have proved acceptable in countries where the program succeeds: The rate increases are less than if the utility invested in new, conventional power plants, and individuals have the option to put profitable panels on their own roofs to offset the rate hikes.

Natural Resources Defense Council environmentalist Robert Kennedy, who spoke at the National Clean Energy Project forum, cited benefits of feed-in tariffs over net metering. “If we [offer market rates], we will make every American into an energy entrepreneur, every home into a power plant, and we can power this country from American initiative and entrepreneurship and energy rather than Saudi oil.” Hopefully, other policymakers at the forum were listening. Whether it’s sunshine in Florida, wind in Minnesota, or chilled water in upstate New York, innovations are being fueled by thinking small and local.

Source: Originally published in the July/August 2009 issue of GreenSource