Utilizing geothermal heat and membrane distillation for sustainable greenhouse horticulture in Alberta, Canada: a multi-criteria analysis

Sammanfattning: Growing populations are contributing to resource scarcity, making it ever more important for governments to address resource challenges in a holistic and integrated manner. Energy, water and food are examples of these critical resources, and the province of Alberta in Canada faces an interesting opportunity to tackle all three in tandem. Alberta struggles with food insecurity, with one in ten households affected on an annual basis. The province has the additional issue of an abating fossil fuel-based energy sector. Retrofitting oil and gas wells to harness geothermal heat is a possible initiative that encourages an energy transition and boasts lesser environmental impacts. Further, combining geothermal heat with agricultural greenhouse production and thermally driven water filtration systems has the potential to reduce food insecurity and water scarcity in the province. The system thus handles all three food, energy and water security at once. As such, this report compares the overall sustainability of a conventional, natural gas-burning greenhouse against a novel, geothermally-heated greenhouse featuring thermally driven water filtration (membrane distillation) technology. The area of study is constrained to the greenhouse-rich region in Alberta between Edmonton and Red Deer that also has a high accessibility to geothermal heat. The comparison is conducted through a multi-criteria analysis following economic, social and environmental objectives, and is analyzed using quantitative data, scientific literature and surveys. The results indicate that the novel greenhouse exhibits a higher score as compared to the conventional greenhouse, implying that it is the preferred option on economic, social and environmental bases. The results are in keeping with economic and technical feasibility reports, though they shed new light on the social and environmental aspects – which were under-studied in the province. The geothermally-heated greenhouse system with membrane distillation acts as a holistic solution that targets energy, water and food issues in tandem, while contributing to Canada’s Sustainable Development Goals. The novel greenhouse is an avenue of exploration and development by policy-makers, greenhouse operators and researchers interested in attaining sustainable agriculture in Alberta, Canada.