Today's inhabitants of Denmark's Samsø Island view their world quite differently than they did 10 years ago. Farmers still work the fields, but today they harvest the straw from their grain production to create a renewable-fuel source. Spinning wind turbines on land and at sea are constant reminders that their homes are powered with sustainable energy. Vacationing tourists now mix with visitors from around the globe who flock to Samsø to witness the quintessential model of a society virtually independent of fossil fuels.
Situated off the east coast of the Jutland mainland, Samsø is a 44-square-mile (114-km2) island with 4,100 residents. The island once imported nearly all its electricity from Jutland’s coal-based power plants via an undersea cable, but this practice became destined to change when Samsø won a national competition issued by the Copenhagen-based Danish Energy Agency in 1997. The competition’s goal was to select an island that would convert to using 100 percent renewable energy within 10 years.
Samsø’s journey toward energy self-sufficiency and carbon neutrality involved a multi-pronged approach and hinged on a spirit of cooperation from the islanders. Local investors and resident-formed cooperatives purchased land-based wind turbines to produce green power. Allowing Samsø’s population personal ownership in the project increased the acceptance of the turbines’ construction and created local prosperity. In all, 11 land-based wind turbines produce 11 megawatts of energy to serve the island’s electricity needs.
THE HEAT IS ON
Four district heating plants on the island use solar panels, as well as locally grown straw and wood pellets, to produce hot water and pipe it underground to heat area residences. Because the straw comes from crops that remove atmospheric CO2, the process is carbon neutral. By congregating the solar-thermal panels in larger applications at the heating plants rather than on individual homes— the facility at Nordby/Mårup has 27,000 square feet (2508 m2) of solar collectors—the island is able to better leverage its energy production.
Outside the district heating facilities’ range, homeowners and businesses received public subsidies to convert their oil-based furnaces to renewable-energy alternatives, such as wood-pellet furnaces, air- and ground-source heat pumps, and solar-thermal panels.
Transportation created a stumbling block in the quest for carbon neutrality. Fossil-fuel alternatives aren’t available for all the island’s vehicles, so Samsø decided to build 10 wind turbines at sea to offset the carbon footprint created by vehicular use. The offshore turbines have a total production capacity of 23 mW— more than enough to offset the CO2 the island generates—and the excess energy they produce is sent to Denmark’s main power grid. Although the Danish Energy Authority contributed money for initial studies and materials, the turbines are owned by an array of public and private sources.
Meanwhile, the effort to find renewable-fuel sources for transport continues. Several farmers are growing rapeseed and transforming this crop into biofuel with rapeseed presses. The future plan is for all ferries and tractors to be converted to accept this local form of biodiesel. In addition, discussions are underway to develop a wind-powered hydrogen plant to fuel automobiles on the island. A small demonstration 30-kilowatt hydrogen plant will be installed on the island this summer.
SPREADING THE WORD
Samsø succeeded in meeting 100 percent of its electricity demand with wind turbines and 70 percent of its heating needs through renewable energy. With the wealth of knowledge gained about renewable-energy initiatives, it made sense to create a central source for information. A combination of public funds, private sponsors and loans raised 13 million Danish Kroner (about $2.7 million) to create the Samsø Energy Academy, which officially opened in May 2007.
Architects at Aarhus, Denmark-based Arkitema designed the academy as two overlapping forms—a concept based on the single-winged farmhouse style typical on the island. The buildings were raised above ground to account for high groundwater levels and future increases in sea level.
“We created two juxtaposed, metal-clad ‘floating’ building volumes with a layout and orientation that interplays with the site's natural conditions and makes optimal use of the sun,” explains Lars Kvist, Arkitema’s environmental manager.
The 6,700 square-foot (622-m2) academy serves as office space for eight employees of the Samsø Energy Agency; Samsø Energy and Environment Office; and Energy Service Denmark, which is headquartered in Aarhus. The center includes a 2,152-square-foot (200-m2) exhibition hall and conference spaces. In addition, the Energy Academy provides education for local and visiting school groups and offers an energy summer school for tourists.
The academy obtains its heat from the district plant and uses electricity from the island’s wind turbines and solar power. Photovoltaic cells integrated into 1,000 square feet (93 m2) of the building’s roof provide approximately 8,000 kW of power per year. Estimates predict this will meet 40 to 50 percent of the building’s electrical needs.
To maximize the efficiency of the PV cells, the roof panels are angled at 52 degrees and face south. On the backside of the 144 solar crystalline power cells, the system includes eight solar hot-water-generating panels that provide domestic hot water to the facility’s buildings.
A critical part of the academy’s energy performance is conservation. The buildings’ slender volumes and equal window distribution on each side capture daylight to supply a bright interior space and deliver optimum views. External sunscreens provide shade when the weather warms. Electrical appliances are rated A-class energy savers by Denmark’s Elsparefonden, the Copenhagen-based Danish Electricity Saving Trust. Heavy brick cores help stabilize the academy’s interior temperature, and prefabricated low-energy, high-insulating building components were used to achieve Darmstadt, Germany-based Passivhaus Institut’s Passivhaus insulation standards with U-values near 0.1. The building’s heat loss is rated at a mere 3.9 watts per m².
Locally sourced spruce makes up the structure and zinc is the primary outdoor cladding for roofs, gables and façade frames. The designers chose zinc because it is a long-lasting, maintenance-free, fire-resistant product that can stand up to rainfall and be reused in the future. A 70-cubic-foot (2-m3) underground storage tank collects rainwater, which is transferred to a small indoor cistern for use in the academy’s toilets. The cistern is supplemented by a fresh-water system during dry periods.
“By exemplifying green-building practices, the Samsø Energy Academy is more than a place to simply collect information about Samsø’s renewable-energy efforts,” Kvist says. “It points the way to a sustainable future.”
K.J. Fields writes about architecture and sustainability from Portland, Ore.