What are the advantages of geothermal energy?

Geothermal energy is renewable, and the energy source itself is currently free. To utilize this energy, however, there are capital and operating costs that must be taken into account. The capital costs are generally somewhat higher than conventional heating systems, but the operating costs are usually much lower.

The environmental benefits of geothermal heating systems depend largely on how the electricity to run the pumps is generated; the benefits are greatest if the electricity is generated from a renewable source such as hydro or wind, lowest if the electricity comes from a coal-fired generating station. With renewable electricity, greenhouse gas emissions can be reduced by up to 75 per cent compared to conventional heating and cooling systems.

Some factors to consider in determining the costs and benefits of geothermal energy include:

• Climate – Heat pumps and thermal energy storage systems provide both heating and cooling, so places with hot summers and large air-conditioning needs find the systems more advantageous.
  
  
• Facility design – Geothermal systems are most economical and effective when incorporated into initial facility design. It can be expensive to retrofit buildings already equipped with conventional hot-water or electric heating systems, or to install collector loops amid established buildings and landscaping.
  
  
• Land area required – Horizontal pipes or coils for a home heating system can be installed in trenches under a typical suburban lot, but a larger building or a smaller lot may require drilling to install vertical loops. If there is a pond or lake nearby, the water itself can be also used as the energy source for a heat pump system.
  
  
• Cost of alternatives – The rising cost of conventional natural gas, fuel oil and electric heating has made earth energy systems more attractive economically, especially where there is also a need for air conditioning.
  
  
• Energy efficiency of the building – Like other heating and cooling systems, heat pumps work best in a well-insulated, well-sealed building. A less-efficient building will require a larger and more expensive heat pump installation that will be more costly to operate.

Natural Resources Canada has published a booklet, “Residential Earth Energy Systems: A Buyer’s Guide,” which provides a worksheet for determining the economics of heat pump systems in a particular location. The Canadian Standards Association has established standards for both residential and commercial earth energy installations. However, it is important to have skilled contractors select and install the appropriate system for a given building and landscape.

The costs of geothermal electric generation in British Columbia are expected to be competitive with other sources of electric power in the Pacific Northwest. By reducing the need to generate power from other sources such as natural gas or coal, geothermal electricity helps to reduce greenhouse gas emissions. The main environmental impacts are from surface disturbance for well sites, the power station and transmission lines.