Geothermal Options for Remote Canadian Communities: Golden, BC
The town of Golden has a population of roughly 4600 and is located in southeastern British Columbia, 260 km West of Calgary, in the Rocky Mountain Trench. It is situated where the Columbia River and Kicking Horse Rivers meet, and is surrounded by 3 different mountain ranges and 5 National Parks: Yoho National Park, Banff National Park, Jasper National Park, Glacier National Park, and Kootenay National Park. Golden is also located on the Trans-Canada Highway and at the end of Highway 95, which eventually connects with the United States and passes through some major cities in the East Kootenay region, such as Cranbrook. Golden’s climate is characterized by relatively cold temperatures in the winter, with temperatures dropping below 45°C.
As Golden is a growing city, energy in all its forms is needed, however, the town suffers from frequent electricity blackouts due to its location at the end of a power line. The city also needs heat during the cold season when the average low temperature is below freezing. The heat demand of Golden is presently met by fossil fuels (mostly heating oil and propane) and wood. While wood is considered as carbon neutral (condition to burned wood being replaced by new plantation), it produces significant amounts of air pollution such as carbon monoxide and air-born particles, and for this reason it has been banned in all new buildings and retrofits.
A typical home (not using wood) in Golden spends about $3000/year on heating (based on inquiries from local home owners and the Municipality in August 2010). Due to both economical and environmental reasons, the city has been recently trying to investigate the viability of its renewable energy resources such as hydro and geothermal. While hydro and high-grade geothermal resources can potentially respond to the power demand, the medium grade and low-grade geothermal resources can contribute to the much-needed heat energy.
Because Golden is situated in a valley between two rivers, secure groundwater at a relatively shallow depth is present (at or less than 100 meters below ground). The existing water wells in Golden are all very productive, and assuming that each well can produce 50 to 100 gallons per minute (GPM), each geothermal resource centre can potentially produce 150 to 300 GPM of ground water. This could be sufficient for producing up to 200 to 400 kW of heat steadily; such a system could provide heat to 40 to 50 dwellings (about 150 to 200 people). If a geothermal surge tank is incorporated (to store well water for peak demand), this could mean the supply of heat for up to 60 to 70 dwellings. The downtown of Golden could be divided into heating “blocks” and a separate system could be developed for each, while being managed by the same geothermal utility administration.
The cost of this type of semi-distributed open loop scheme is estimated around $725, 000 for 60 homes, and the heat energy delivery could be as high as 10,000 GJ/ year. Savings on fuel costs and carbon emissions were estimated and for 10,000 GJ per year, the total savings amount to $150,000 per year. If the system services 60 residences, each residence will save $2500 per year with a payback period of 5 years. This means 60% savings in energy costs and 90% to 100% reduction in carbon emissions. Furthermore, the risk for such an investment is minimal to non-existent, as the resource is secure and the technology is off-the-shelf.
As opposed to closed loop, an open loop geothermal system for the Municipal Centre is possible with minimum disturbance to the land and the city activities. A semi-distributed system (as described above) with 2 to 3 production wells can provide heat for the municipal centre and buildings around it. Alternatively, a small system (consisting of one production well and one injection well) can be developed to provide heat only for the city center. In both alternatives, ground water will be brought to the surface, passed through heat pumps, and reinjected to the ground. In summer, heat pumps can dump heat into the ground (providing cooling, if needed) and in winter heat is extracted from the groundwater. Heat pumps would replace 90% of the heating capacity and would be located in the boiler room to allow easy interface with the existing HVAC system.
Link to full article:
Ghomshei, Mory; Hassani, Ferri, Madiseh, Seyed Ali Goreishi; Mousavi, Nima. Oct, 2011.