Case History of Aquifer Thermal Energy Storage (ATES)

Aquifer Thermal Energy storage (ATES) is a relatively new energy conserving technology which enables subsurface seasonal storage of freely available cold of winters and heat of summers for re-use in the opposite season. Thermal energy is stored in aquifers, groundwater serving as the medium of energy transfer. This case history describes an ATES installation for an office building in Ontario. Groundwater from a 10 m thick sandy aquifer at the 60 m depth is pumped from one pair of wells and re-injected, after extraction or addition of heat, into an opposing pair of wells. ATES technology not only conserves non-renewable oil and coal based energy resources used in the production of electrical energy, but also minimizes atmospheric pollution from thermal power plant emissions. The payback on investment is generally less than five years, for optimum weather and building combinations. The chemical and environmental impacts of ATES, however, must be fully understood, in addition to geothermal and hydrogeological aspects, to ensure a successful and cost-effective application