Workers backfill the trenches while making sure that the supply and return lines stay separated. Otherwise lines will draw heat away from each other and risk freezing. (Charles Milne)"My home energy source? It's my field out front," says Charles Milne.

Milne, a government relations consultant for the agri-food sector, and his wife are the proud proprietors of what they say could be one of the largest residential geothermal installations (of the closed-horizontal-loop variety) in the country.

The term "geothermal" simply means "heat from the earth." Just six feet under the ground at Milne's home is a 3.2-kilometre network of plastic piping that delivers heat to the 160-year-old frame house with the help of geothermal heat pumps.

When it comes to sizeable geothermal installations, Manitoba Hydro's new corporate office in Winnipeg is an equally impressive site. About 122 metres beneath the ultra-energy efficient, 22-storey building is a vast network of pipes and underground wells, or bore holes, (280 to be exact) that provide most of the energy needed to heat and cool the building year round. The facility has received a gold rating under the LEED (Leadership in Energy and Environmental Design) certification program for green construction.

Tom Gouldsborough, division manager for corporate planning and business development, claims that the installation is the largest high-rise application of geothermal heating in Canada, and "very close" to being the largest in North America.

"Basically, we're using the whole city block to store energy 400 feet [122 metres] below the surface," says Tom Ackerstream, energy co-ordinator for Manitoba Hydro.

"In winter mode, we take heat out of the ground and put it into the system for bringing up the building temperature. Summer mode reverses the process, where heat/energy is taken from the air conditioning system and put back in the ground for the colder seasons, making it very sustainable."

Ancient thinking

These examples might be considered groundbreaking projects in Canada, but the idea of using the earth's natural heat resources for space and water heating is a well-tried concept.

The ancient Romans often used hot water and steam resources near the earth's surface for heating buildings and spas, for example.

In Iceland, which sits squarely on top of an area of old volcanic activity, geothermal energy has been used for centuries as a source of district heating. According to the Canadian Geothermal Energy Association, Iceland today generates 17 per cent of its electricity and 87 per cent of its heating from geothermal energy.

Running hot and cold

Many rural residents in Canada are familiar with the concept of drawing from a warm resource to heat a cooler one. A number have been using what's known as an open-loop system for decades.

This heat pump is one of two systems in the Milne home that take heat from the closed loops in the ground and distributes it through the house. (Charles Milne)This type of system takes advantage of subsurface ground water by drawing water from a supply well, running it through a geothermal heat pump where heat is either pulled from it or transferred to it to help heat or cool a building, and then returning the water to a second well.

However, closed-loop systems are now increasing in popularity as heat-exchanger technology has become more reliable and affordable. Rather than hot water or steam being transferred from one well to another, in closed-loop applications, water (or a water and antifreeze solution) is circulated through a continuous, buried pipe. A heat exchanger transfers the heat absorbed from the ground to the air distribution or hydronic floor heating unit in the building.

According to the Canadian GeoExchange Coalition in Montreal, the technology can save a developer or consumer from 40 per cent to 60 per cent on their current energy bills. A typical two bedroom house-sized installation is equivalent to taking two cars off the road or planting one acre of trees.

Cost versus comfort

While it all seems simple enough, uptake on geothermal solutions for commercial installations has been slow.

One problem is that it's not economically an easy sell in a country where electricity and oil and gas resources abound and policy is keen to support them, Craig Dunn, outreach director for the Canadian Geothermal Energy Association in Calgary explains.

"We are cursed with an abundance of resources," he says. "Between having hydro for electricity, natural gas and oil resources, we have a number of options available to us."

Dunn adds that drilling can account for up to 40 per cent to 50 per cent of a project's capital costs, which is a deterrent to those who don't apply long-term thinking to the equation. "When doing the ROI [return on investment calculation] for geothermal, however, look at the costs over the next 100 years — not just what you're paying out up front," says Dunn.

"Commercial developers tend to want to lower their capital costs and pass operating costs on to the tenant, which makes [geothermal] a difficult sell," Manitoba Hydro's Goldsbourough admits. "But once you've paid off the initial capital, you get the savings for the rest of the building's life. And we expect this one to last 100 years or more."

He notes that geothermal is a great option for buildings with long-term ownership such as schools, commercial buildings, rural community centres and greenhouse operations. "There, you're focusing on lifecycle costs, not the initial capital. Average payback for geothermal is 10 to 15 years for a commercial building."

On the home front, Milne says that with drilling and trenching costs, the up-front investment was high. "When we contracted for this back in the summer, so was oil!"

With the savings on heating costs, however, he still anticipates a four- to six-year payback on the investment. And whatever the cost of oil, he and his wife maintain it would have been irresponsible to put in another fossil-fuel heating system.

"Why heat a house of this size with fossil fuel when you can take heat out of the ground?" he asks. "The reality is, [with geothermal], we save about 19 tonnes of greenhouse gases every year."

The learning curve

Another challenge is getting the right contractors to handle a geothermal project.

The Milne’s closed loop system is made up of six 300 foot trenches with two loops in each. A 600 foot loop produces one ton of heating and cooling capacity. (Charles Milne)"A lot [of suppliers] are coming to the party right now, so it's easy to find someone to do it," says Dunn. "But it's finding one with the right expertise."

Barrie, Ont.-based Peter Archer is an architect who has been working on geothermal projects for more than a decade. "I love it, because it's a renewable energy for eternity. I'd say almost half the projects we do now are geothermal," he says.

He stresses that when you're thinking geothermal, "You need to understand that it may be more expensive up front, but the maintenance and operating costs are a lot lower. I've learned that the real key to making it work is having a really good practical engineer who knows what he is doing."

More power to the people

While heating with geothermal continues to gain traction, Dunn says, "we haven't even touched on using it to generate electricity in Canada."

One exception of note, he adds, is Western GeoPower, which is working on a large-scale geothermal power project at a site in South Meager, near Vancouver. When operational, it will be one of the first geothermal electrical-generation projects in Canada.

"The beauty of it is, a geothermal power plant can run indefinitely if engineered correctly," Dunn says. "There is a geothermal power project in Lardarello, Italy, for example, that has been operating more than 100 years. In California, 4.8 per cent of its power supply is now geothermal. However, Canada — unlike Europe and the U.S. — has one of the lowest incentive programs [for geothermal energy]."

That's unfortunate, as far as Dunn is concerned.

"The genius of geothermal is in the simplicity and that it is available indefinitely," he says. "In terms of baseload capacity, the sheer amount of energy in our planet dwarfs anything any other source can offer, including oil and gas or solar. It's the king of renewables."