A Relook at Canada’s Western Canada Sedimentary Basin for Power Generation and Direct-Use Energy Production

The Alberta No. 1 Project, under the terms of Canada’s Federal government’s Emerging Renewable Power Program (ERPP), must produce 5MWe net. The goal of this study was to identify areas where three essential constraining conditions overlap; (1) the temperature gradient is sufficiently high that 120°C brines at depths of 4,500m or less are potentially available, (2) there are formations at the depths targeted with known high fluid flows, and (3) there is adequate existing infrastructure that supports low-cost power grid connection as well as a direct use application. A fluid temperature of at least 120oC is needed to profitably operate the plant. Temperatures below this require increasingly greater amount of fluids to be pumped and injected making them uneconomic. Three hundred liters per second (l/sec) of 120oC water is required to generate 5 MW net of electrical power with an Organic Rankin Cycle (ORC) binary plant. A depth cut off from a project economics perspective is about 4,500m for large diameter geothermal wells. Fortunately, these formations don’t need to be thick to supply these volumes of water to the well bore and thin permeable formations are expected to be laterally extensive in the regional layer cake (Western Canada Sedimentary Basin, WCSB) geology of Alberta. Thus, targeting known high fluid producing geologic units, rather than narrow faults is an important aspect of developing a geothermal project in the WCSB. Alberta No. 1 identified nine study areas to assess for geothermal potential. Of these, the Tri-Municipal Industrial Park (south of Grande Prairie) was determined to be the most suitable for both power production and development, followed by Edson (west-central Alberta). Other areas were identified as being most suitable for basement EGS to produce power, as well as direct use from shallower formations.