April 4, 2005

Large-scale solar heating project to take advantage of seasonal storage

Atco Gas, in Calgary, will serve as project manager for construction of North America's first large-scale solar heating system using seasonal storage. The first-of-its-kind project will capture the sun's rays in the summer and store them to heat 52 homes in winter--reducing greenhouse gas emissions by as much as five tonnes annually at every residence (260 tonnes total) and by 80% for the overall residential development. Atco Gas will initially act as project manager and will later become owner and operator of the innovative system.

The Drake Landing solar community will be built in the town of Okotoks, just south of Calgary. The town is ranked as a "top ten" Canadian location in terms of sunny days per year, receiving almost as much solar energy as Italy and Greece.

The demonstration project will collect thermal energy through approximately 800 solar panels mounted on the roofs of interconnected garages and breezeways. These collectors will generate up to 1.5 megawatts of thermal power, which will be stored underground during the summer in a "borehole field" under the neighbourhood park. The subsurface temperature in the field will reach 80*C by the end of each summer. To enhance insulation, the borehole system will be covered with sand, high-density R-40 insulation, a waterproof membrane, clay and other landscaping materials.

In the winter, heat will be extracted from the field and distributed to the houses as hot water through underground insulated pipes in a central district heating system. On sunny days, solar energy will be collected and delivered directly to the homes. The system will supply more than 90% of the space heating requirements for the 52 houses.

Each house will have an "air handler" instead of a furnace. The hot water from the district heating system will warm the air, which will circulate through the house by means of conventional forced-air ducts. Homeowners will be charged a favourable long-term fixed monthly rate.

Although the system's cost will be higher than that of current prices for fossil fuels such as natural gas, the scale of the demonstration will be large enough to make it competitive with higher-priced conventional heating sources such as electricity. In the longer term, as the size of such projects increases and fossil fuel prices rise, the cost of this type of system will become more competitive. Moreover, the operating costs will be lower than those of a combustion furnace.

Atco Gas will act as project manager for system construction, and will be responsible for operating the three component parts of the system: the collection system, including the solar panels; the energy storage system, including the energy centre building and storage field; and the district heating delivery system. This will give the company first-hand knowledge of the technology, potentially enabling Atco to offer other customers in its service territory new options to meet their energy needs in the future.

The project is being supported by governments and various private sector groups and companies. The federal government's Technology Early Action Measures program and Natural Resources Canada have contributed $2 million to this project. Through the Green Municipal Funds, the Federation of Canadian Municipalities has invested $2.9 million. The Alberta government has provided $625,000 in funding through its Innovation Program.

Sterling Homes, the builder for the project, has designed each of the houses to meet both R-2000 criteria for energy efficiency and the highest-level standards under the Built Green Alberta program. This will make Drake Landing the first R-2000 subdivision in Alberta. The solar equipment is being supplied by EnerWorks, based in London, Ontario. More information is available from Atco Gas president Jerome Engler, 780/420-7276, or Lucille Hodgins at FCM, 613/241-5221, ext 299.

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