The Gas City, Medicine Hat, goes green

Associated Engineering’s Barry Way investigates a PRV Station in the City

Located in southeastern Alberta, Medicine Hat is a growing city of 60,000. Associated Engineering has provided engineering services to the City for many years, including a number of water supply and treatment projects. The City’s water distribution system is characterized by many pressure zones resulting from elevation changes across the City. Booster pump stations throughout Medicine Hat increase pressures for distribution. When water enters one of the City’s four, treated-water, storage reservoirs or 15 pressure reducing valve (PRV) stations, the water’s excess energy is dissipated.

To increase the sustainability of their water utility, rather than dissipate this energy, the City of Medicine Hat is looking for opportunities to “recover” and generate electricity. The City commissioned Associated Engineering to evaluate suitable locations for energy recovery from Medicine Hat’s reservoirs and PRV stations.

The feasibility of small-scale hydro projects depends on flow and pressure conditions at the site, as well as the location’s piping and equipment layout. External factors, including electricity prices, also determine whether energy recovery opportunities are worth pursuing. Following a review of site hydraulic power potentials and visits to the most promising locations, we identified Medicine Hat’s Southview Reservoir as the City’s best candidate for energy recovery.

Using a standard turbine-generator system, the Southview Reservoir is expected to generate 28 kilowatts of electricity, or approximately 95 megawatt hours per year, from energy recovery. This is equivalent to the annual electricity consumption of thirteen singlefamily homes in Alberta. The project would reduce Medicine Hat’s total greenhouse gas emissions by about 51 tonnes per year - roughly equivalent to the annual emissions of eight Honda Civics or four Hummers.

The challenge of many renewable energy schemes, including hydroelectric energy recovery, is making the project economically viable. This is especially true in Medicine Hat, which has one of the lowest electricity rates in North America. According to Sean Bolongaro, P.Eng., Practice Leader - Renewable Energy, “These types of projects have a significant environmental benefit, but are not always big enough to pay for themselves. If they are going to pay for themselves, the utility market needs to market them creatively.” This includes coordinating energy recovery projects with necessary system upgrades and applying for funding opportunities through such organizations as the Federation of Canadian Municipalities, Natural Resources Canada, and Alberta Environment, for example.

The City of Medicine Hat has demonstrated a progressive and innovative approach to sustainability. In 2006, Medicine Hat implemented a 1 kilowatt solar demonstration project on the roof of the public library, and the City is currently developing plans for a wind farm and aquifer thermal energy storage system.

Staff involved on the hydro project include Bill Chisholm, Sean Bolongaro, Barry Way, and Roseanne Warren. For more information on this project and/or renewable energy, contact Sean Bolongaro at bolongaros@ae.ca

Southview Reservoir Fill Line