Hazards of Geothermal Drilling

Hazards of Geothermal Drilling

By Jim Chisholm, P.Eng.
OFM Fire Protection Engineer

Geothermal energy is an important source of renewable energy that uses fluid to exchange heat with the ground or water and provide a green heating and cooling system for buildings. In urban areas where available land is scarce, drilling for vertical closed loop geothermal installations is becoming popular. Because such drilling can go to depths over 100 metres, there is a risk of hitting naturally occurring pockets of natural gas in much of Southern Ontario.

On April 19, 2012, during an installation of a geothermal system in a residential area of Oakville, an under-ground high pressure pocket of hazardous natural gas was punctured. This resulted in the horizontal migration of odourless methane gas into a nearby residential building. The presence of the gas was noticed by the resident as it caused bubbling to occur in their basement sump.

Fortunately, the situation was quickly addressed by emergency response crews to prevent a fire or explosion. As a result of the event, Oakville Mayor Rob Burton, Oakville Fire Chief Lee Grant and the Association of Fire Chiefs of Ontario called on the Province to address the gas hazards associated with geothermal drilling.

On May 18th the Province issued Ontario Regulation 98/12 to strengthen the regulation of this industry. The new regulation requires geothermal installers constructing, altering, replacing and extending vertical closed loop systems that extend more than five metres below the surface to:

  • Obtain an Ministry of the Environment (MOE) Environmental Compliance Approval for vertical closed loop geothermal systems
  • As part of the approval, have a professional engineer or geoscientist develop a work plan to prepare hazardous gas and prevention plans in case hazardous gas was encountered during drilling
  • Notify the occupant of the building, owner of the land, local fire department, MOE’s Spills Action Centre, the municipality, and the geothermal system purchaser if hazardous gas is encountered when drilling for any vertical closed loop geothermal system.

During the Summer and Fall of 2012, geothermal companies made applications to the MOE to obtain the Environmental Compliance Approval. The MOE has issued several approvals over the last few months.

As part of the new geothermal regulatory oversight, the Sector Compliance Branch of the MOE is conducting inspections of geothermal installers during the installers’ drilling operations. The inspection program is designed to ensure that geothermal companies meet the conditions in their approvals and protect public safety and the environment.

The new regulatory scheme allows for geothermal drilling to be done in a safe manner while allowing for the Province to continue its strategy of developing a robust renewable energy sector that can build a strong, green economy for generations.

The Office of the Fire Marshal is monitoring further development of Ontario Regulation 98/12 by the MOE and continues to consider implications of geothermal drilling for the fire services.

Further information is available at the following 3 links: