The Drake Landing Solar Community of Okotoks, Alta.: Solar panels are mounted on the garages behind the homes.
Saving energy costs wasn't the driving reason for Alberta mechanical engineer Robert Pugh's move into a solar-heated community that was conceived a dozen years ago as the first of its kind in North America, where it remains unique in how it heats an entire subdivision in the winter.
You could say owning one of the 52 homes in the Drake Landing Solar Community (DLSC) in Okotoks, Alta., has proved to be an ethical ray of sunshine for residents, including Mr. Pugh, his wife Dana and their two young children.
Eight years after the completion of the DLSC, which is the brainchild of Natural Resources Canada and was developed in partnership with governmental organizations and private interests, Okotoks remains a shining example of how an entire community living much of the year in freezing weather can use the sun to drastically reduce dependency on fossil fuels.
Mr. Pugh, one of the first owners of a solar-heated home in Okotoks, a town of about 27,000 just south of Calgary, says he bought into the subdivision more for ideological reasons and not for financial reasons.
"I am extremely concerned about our carbon emissions and want to try to adjust my behaviour as much as I can," Mr. Pugh says.
"The house has an extremely small carbon footprint, and in terms of heating and home comfort, it actually does deliver everything they say and they hope for – all year round. It is very similar to a typical Western Canadian home with a gas furnace."
Drake Landing is the first – and according to Natural Resources Canada's Doug McClenahan, still the only – large-scale, master-planned community in North America to use borehole thermal energy storage (BTES). The technology stores solar energy in the ground in the summer to save it for winter, and acts as a large underground heat exchanger.
The 52 homes remain the largest subdivision of R-2000 single-family homes in Canada. And the DLSC project has won numerous awards – last fall, it was recognized by the International Energy Agency for "outstanding achievement in the field of solar heating and cooling." The Pughs paid about $270,000 and moved into their two-storey, 1,600-square-foot home seven years ago, after the March, 2006, completion of the development.
From the street, the homes don't stand out as an example of cutting-edge green technology. Most of the solar magic happens at the back of the properties.
Mounted on the detached double garages located behind the homes are 800 flat-plate solar panels, which were manufactured by Enerworks, a Canadian solar equipment manufacturer. Glycol is used as the heat transfer fluid to move the thermal energy from the solar collectors through a network of insulated pipes to an Energy Centre, a 2,500-square-foot building located in the corner of the community park, that houses short-term storage tanks and mechanical equipment.
The heat exchanger, using 144 boreholes drilled 37 metres into the earth, extracts the thermal energy from the solar collector loop that is stored in two 125,000-litre steel tanks and transfers it to the surrounding soil. Heat is then recovered from the soil during the winter and transferred into a district energy network that is connected to each home, which has a low-temperature air handler that blows air across a warm fan coil.
According to officials with the project, building to a higher energy-efficiency standard and solar heating the homes has helped eliminate 260 tonnes of greenhouse gas emissions a year.
Mr. Pugh says his home's heating costs have risen from about $60 to $75 a month – a bit less than heating a home through conventional gas. He says his home was appraised last year for $380,000, about on par with similar homes in other neighbourhoods, although Okotoks municipal manager Richard Quail says a town analysis shows the solar homes go for a premium "on a square footage basis" and are in a highly desirable neighbourhood.
For its part, the town of Okotoks jumped on the idea of becoming a solar-driven energy showcase when approached by Natural Resources Canada in 2002.
Led by Mr. McClenahan, Natural Resources Canada's solar-thermal research and development manager, a study team including an Okotoks engineer, as well as other government and private interests involved in the original DLSC feasibility study, travelled to Europe more than a decade ago to study communities that were leaders in the use of large-scale solar heat storage.
Mr. McClenahan says it took a lot of research, planning and networking to pull together the DLSC stakeholders – Natural Resources Canada footed $2-million of the $7-million in initial startup capital for the project that would cost a total of $19-million, including the cost of the homes. Others getting on board included the Federation of Canadian Municipalities, ATCO Gas, United Communities and Sterling Homes, which ended up building the 52 homes.
For a project of this magnitude and uniqueness, the partners wanted to ensure they could deliver according to what was expected, says Mr. McClenahan from Ottawa.
"The concept of solar seasonal storage was experimented with on a small scale before and had some flaws."
The first home in Canada to be heated by the sun with seasonal storage – Provident House in King City, Ont., in the late 1970s – used solar collectors (devices or systems that capture and use solar radiation to generate heat) that were imported from Israel because they weren't available in Canada, but the Israeli collectors were not designed for the harsher Canadian climate, so ended up failing over time, Mr. McClenahan notes. Years later, he says, the solar collectors became more common in Canada, so they weren't the issue for a senior citizens' building in Aylmer, Ont., although the concrete tank that stored the heat collected from the sun ended up leaking.
Countries such as Sweden, Germany and Denmark have long been involved in larger-scale use of underground solar heat storage systems that retain heat collected from the sun in the summer for distribution to homes in the winter, but the DLSC was a North American first.
Drake Landing has Europeans beat in another respect – at 90 per cent, and last year reaching a world-record high of 98 per cent, it leads the world in efficiency at space heating through solar means. Mr. McClenahan says that compares with projects in Germany, Sweden and Denmark that have set 50 to 60 per cent as their goal, supplementing with other sources of heat.
ATCO Gas, the natural gas distribution company that manages and runs the Okotoks project, says that, while the average Canadian home produces about six to seven tonnes of greenhouse gases a year for space and water heating, each home in the DLSC produces about one to two tonnes per year.
Keith Paget, manager, sales administration and cost control with Sterling Homes in Calgary, says the early infrastructure pricing of such a solar heating project can be expensive. There were also some engineering and building hurdles to overcome with the DLSC project, but it all came together.
Given the solar success of Drake Landing's community, Mr. McClenahan says Natural Resources is looking into starting other solar-heating storage neighbourhoods in Canada, in areas where natural gas is either too costly or non-existent. One feasibility study has found promise in Whitehorse, while projects in Fort McMurray and Nova Scotia are also being considered.
Other solar-heated communities
Doug McClenahan of Natural Resources Canada gives some other examples of large-scale solar-heated communities using a borehole thermal energy storage system (BTES):
Braedstrup, Denmark: Opened in 2007; 1,400 households.
Anneberg, Sweden: Completed in late 2002; 50 homes.
Attenkirchen, Germany: Operating since spring of 2002.
Crailsheim, Germany: Operating since 2007.