Earth as a heat source and "sink"....geothermal versus geo-exchange

Literally translated, geothermal means heat from the earth. From an energy perspective, the term has historically referred to electrical power generated by tapping into the earth's geothermal reservoirs (molten rock or magma close to the surface) through the use of deep drilling.

For example, geothermal hot water heats almost all homes and buildings for the 85,000 people of Reykjavik, Iceland, and geothermal steam just north of San Francisco generates two per cent of the electricity for the state of California.

More recently, however, the term has been used -- somewhat erroneously -- to refer to the process of converting the earth's stored solar radiation into heating and/or cooling energy at the building level.

Unlike the large power stations described above, this "geo-exchange'' technology utilizes a geothermal heat-pump system -- pipes buried in relatively shallow ground (from six to more than 300 feet) or a body of water (a lake, for example), and a heat exchanger -- to use the earth (or water) as a "heat source" during the winter and "heat sink" during the summer.

GROUNDSWELL

Natural Resources Canada and the U.S. Environmental Protection Agency describe geo-exchange as the most energy efficient, environmentally clean, and cost-effective space-conditioning system available on the market today. According to the World Energy Council, the number of geo-exchange systems in the world has tripled since 2005.

Ruben Arellano, project director for Hemmera's Renewable Energy Division, says it's a challenge to keep up with the demand and interest.

"Five years ago, people said GeoExchange what?" says Arellano. "Now most people have heard about it, and want more information."

Jason McDiarmid, president and CEO of Essential Innovations Technology and Earth Source Energy, describes a similar experience. "When we first started, people said it was too expensive. The next year there was increased interest. Now the phone is ringing off the hook."

DOLLARS AND SENSE

"We knew [the GeoExchange] would cost more, but felt it was the right thing to do," says Vasarajs about the significant capital investment -- approximately $60,000 -- required for their project. While both costs and payback periods for GeoExchange systems can vary considerably depending on the parameters and size of a project, McDiarmid estimates that four to seven years is the average for single-family homes to realize a payback.

"We received quotes ranging from $50,000 to $100,000," says Moh, in talking about the importance of finding the right company to work with. He notes that even these figures may not include additional electrical and/or plumbing upgrading or other site-specific costs. While Arellano estimates that some retrofits -- typically much more expensive than new building installations -- might be done for as little as $20,000, he encourages people to contact local, qualified service providers, who have done similar work in their areas to get more accurate figures specific to their situations.

GEO WHAT?

While some municipalities require an engineer to sign off on GeoExchange systems, many others simply have no provisions for the technology

"Our system was a non-issue for the city of Vancouver," says Ravkov.

While better informed city officials could encourage more installations, along with development variances that reward people for implementing such forward-thinking systems, Arellano believes the biggest challenge to more widespread GeoExchange systems is the perceived price barrier.

"Historically, people in North America haven't looked at the operating costs of a home. People won't hesitate to put $20,000 into a driveway or other visible elements, but are just now beginning to think more seriously about investments into 'green' features like GeoExchange that create cost savings and increase resale value."

On the up side, there is a growing number of incentive and/or rebate programs, such as the federal government's EcoEnergy Retrofit and BC Hydro's PowerSmart program, to help those interested in exploring GeoExchange.

On the down side, the diverse funding options can be confusing, says Arellano, but help from service providers can make a real difference in the financial support people ultimately receive.

A list of financial assistance programs and opportunities can be found at www.geoexchangebc.ca.

INTEGRATED RESPONSIBILITIES

GeoExchange systems are thought to have the longest life expectancy -- 25 years -- among heating and cooling systems, and require very little maintenance. But the suppliers and developers of the project at Blenheim and West 2nd stress that since it is an integrated design technology -- incorporating plumbing, electrical, mechanical, etc. -- it is important to work with people, including certified dealers, installers, and knowledgeable trades people, who understand all of the components of the system, and how they operate together.

"With so many different sub-trades involved, should something go wrong it could be a challenge," points out Moh.

While companies like Earth Source often base their warranties on having systems installed by company-approved -- or GeoExchange-certified -- trades, it is important for consumers to know who to contact in the event of a problem, and who is ultimately responsible.

DIGGING DEEPER

Want more info? You are not alone, and also in luck. According to Arellano, a growing number of educational institutions are looking to develop course materials and/or offer lectures on the topic.

For more information, visit:

www.geo-exchange.ca

www.Hemmera.com

www.earthsource.ca

www3.telus.net/blenheim

(prepared by Kim Davis/Vancouver Sun)