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The Ministry of the Environment moved swiftly this spring to increase regulation of geothermal (ground-sourced) heat pump installations, because of an urgent risk of releasing hazardous underground gases. Ontario revoked the old regulation governing Ground Source Heat Pumps and replaced it with O. Reg. 98/12.

A “geothermal” or “ground source heat pump” heats and/or cools a building by using a heat-transfer fluid to exchange heat with the ground or ground water, rather like a giant refrigerator.  Ground source heat pumps are, in principle, highly desirable; they are much more energy efficient than conventional HVAC systems, and can moderate peak electrical demand.

However, like all energy sources, ground source heat pumps can have their drawbacks, including the risk of releasing hazardous underground gases. Heat pump installers were not being sufficiently careful about this risk; now they are required to.

There are two basic types of earth energy heat pump systems: open loop systems and closed loop systems.

In an open loop system, groundwater is pumped from a well or series of wells and circulated through a heat pump located inside a building. A heat pump extracts the heat and distributes it throughout the building.  The system then injects the water back into the aquifer through a well or discharges it to a stream, river, lake or pond.

In a vertical, closed loop heat pump system, vertical holes are drilled into the ground and a U-shaped loop of pipe is installed in each hole. A heat transfer fluid circulates through the system of pipes connected to the heat pump inside the building. A horizontal system works much the same way, but the heat transfer fluid circulates through network of buried pipes in trenches.

Under the new regulation, anyone constructing new or altering, replacing or extending existing vertical closed loop geothermal systems that extend more than 5 meters below the ground must obtain an Environmental Compliance Approval (ECA) from the MOE. As part of the ECA application, the installer must also submit a work plan that:

  1. is prepared by a licensed engineering practitioner or professional geoscientist;
  2. identifies equipment and procedures to be used to monitor for the presence and migration of hazardous gas;
  3. identifies measures to be taken to prevent or reduce the likelihood of the migration of hazardous gas, whether through the hole or otherwise, during construction, alteration, extension or replacement of the vertical closed loop ground source heat pump, including detailed requirements for,
    1. ensuring that any space around the underground heat exchanger is sealed to prevent any movement of hazardous gas between subsurface formations or between a subsurface formation and the ground surface, or otherwise managing the gas in a way that removes any potential hazard, and
    2. decommissioning the heat pump if measures under subclause (i) are not taken, or are taken but do not remove all potential hazard;
  4. identifies measures to be taken to prevent an adverse effect if hazardous gas is encountered;
  5. identifies a standard of protection that is at least equal to what is required in similar circumstances by “Oil, Gas and Salt Resources of Ontario – Provincial Operating Standards”, version 2.0, dated January 24, 2002 and published by the Ministry of Natural Resources, as amended from time to time; and
  6. includes a health and safety plan. O. Reg. 98/12, s. 3 (3).

Open loop and horizontal geothermal systems are not subject to the new Regulation. As explained in the Environmental Registry Notice:

  • Horizontal geothermal systems are not at risk of encountering natural gas as they are not installed deep enough to encounter natural gas.
  • Open loop systems are regulated by the Wells Regulation (Regulation 903) and the Ontario Water Resources Act. A sewage works Environmental Compliance Approval is also required for open loop geothermal systems.

The prohibition against using or operating ground source heat pumps that use methanol as a heat-transfer fluid (except for those in operation before June 1, 1998) continues under the new regulation.

The changes were made without notice or consultation. The MOE exercised its power  to do so under s. 29(1) of the Environmental Bill of Rights, on the ground that the delay caused by public notice and public consultation would result in (a) danger to the health or safety of any person; (b) harm or serious risk of harm to the environment, or; (c) injury or damage or serious risk of injury or damage to any property he or she can simply post a notice of the changes. In this case, the Ministry was concerned about delay in “making of regulations that would help reduce the risk that deep boreholes that are drilled for vertical closed loop geothermal systems could encounter explosive or flammable gases and pose a risk to public health and safety.”

by Meredith James and Dianne Saxe

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