New Energy From Old Gas Wells is 100% Renewable

September 28, 2017 – A Calgary-based energy company is teaming up with Hinton, Alberta in what may become a common new practice in places where fossil fuels were extracted in the past. Epoch Energy Development has completed feasibility studies to reopen an abandoned gas well to convert it to produce geothermal energy. The technology involves pumping hot water from the old gas reservoir to the surface and using the heat from it as a resource in a network of buildings in the town.

The well in question is more than 3,000 meters deep. The temperature of the water in the well exceeds 120 Celsius (almost 250 Fahrenheit) degrees. When the water reaches the surface the heat is exchanged with a parallel set of pipes containing water or another liquid that then circulates through the system. And with Hinton having more than 100 old gas and oil wells in its immediate vicinity, what may start as a one-well project could soon expand to eventually provide energy for the entire town.

The water from the wells would remain contained in a closed-loop system. It would recirculate back to the bottom of the well and then be pumped to the surface. Keeping it self-contained ensures that any chemicals or heavy metals contained in the fluid would be kept safely away from Hinton residents.

Geothermal heating is an underutilized energy source in much of North America. And in places where oil and gas production is on the wane, the repurposing of old wells to take advantage of the internal heat of the planet represents a renewable energy source with zero emissions.

For Hinton, this initial project is expected to cut the town’s carbon dioxide emissions by 3,795 tons in the first year. The savings will come from not using power purchased from one of Alberta’s coal-fired thermal power plants. And since Alberta is planning to phase out these plants over the next 10 years, and has instituted a price on carbon, the timing to repurpose the neighbourhood wells makes a lot of sense. The project should be up and running in 2019.

Geothermal heat and power technology works when the temperature gradient is sufficiently large between the two fluids during the heat exchange. In the Hinton project, the pipes that will provide the town energy contain water. But they could contain liquid carbon dioxide (CO2) which can be captured from industrial, power plant, and fossil fuel sources. The CO2 would be a better medium with higher heat retention than water. And if Alberta is serious about reducing its carbon footprint, capturing and using CO2 to generate heat and electricity while sequestering the greenhouse gas would kill two birds with one stone.

In California where geothermal heating from abandoned wells is also under consideration, well depths in one recent study were considerably less than those at Hinton. Near Santa Barbara, we are talking about 1,000 meters deep with temperatures reaching 70 Celsius (158 Fahrenheit). Even at less than the boiling point, the heat transfer can be harvested effectively.

Other operational considerations relate to consistency over time. In testing well heat integrity over a ten year period, it was noted in one project that temperatures remained fairly consistent showing only a small drop 0f 2 Celsius (3.6 Fahrenheit).

For Alberta, geothermal heat could mean a raft of new economic opportunity. The province has thousands of abandoned wells and the industry faces a considerable cost to clean them up. But if many of these wells can be repurposed to produce zero-emission renewable energy the revenue generated from them would offset cleanup costs for the balance deemed unsuitable for geothermal energy production.

In addition, geothermal heat could launch a greenhouse agriculture industry in the province.

There’s a lot of upside to this project. It would seem a “no-brainer.”

 

Hinton, Alberta hopes to convert abandoned gas wells into a source of geothermal energy to power the town beginning in 2019. Photo credit: Canadian Press


Len Rosen lives in Toronto, Ontario, Canada. He is a researcher and writer who has a fascination with science and technology. He is married with a daughter who works in radio, and a miniature red poodle who is his daily companion on walks of discovery.
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