Bénéfices environnementaux de la cogénération d'énergie en milieu hospitalier et cas de l'Hôpital de Moncton

Abstract

The present study aimed at assessing the environmental benefits of power management practices based on cogeneration in the particular industrial sector of hospitals and healthcare. Cogeneration power systems, also known as "Combined Heat and Power" (CHP) or Cogen, supply on-site electricity and heat from a single fuel source (natural gas in general). While the efficiency of conventional plants to produce power and heat separately is limited to about 30%, the efficiency of a CHP plant is close to 80% and can reach up to 90% in some applications (Borbely et Kreider, 2001). One of the distinctive features of hospitals is their continuous demand for both type of energy (electricity and heat), which makes them good candidate for cogeneration. However, in North America at the present time, less than 5% of hospitals run on CHP. Most are being supplied with electricity by conventional power plants, run by specialized companies, and use on-site boiler(s) to generate heat. Energy spending can reach up to 3% of an hospital's annual operational budget. There are also environmental impacts related to current energy supply and use in hospitals. For instance, the burning of fossil fuels releases greenhouse gases (GHG), which contribute to human health problems and climate change. The first objective of the study was to outline the main benefits and challenges faced by hospitals that aim at becoming their own energy co-generator, in comparison to having power and heat produced separately. Our second objective was to assess prospectively (proactively) the environmental impacts of a cogeneration plant that is being planned, but not yet operated, in a Canadian hospital. The methodology was based on literature reviews and on a case study, namely that of The Moncton Hospital (TMH)/L'Hôpital de Moncton, Moncton, New Brunswick, Canada. This hospital is considered a large hospital with 375 beds and a major and expanding ambulatory care service. It is also in the process of developing a 1.06 MW cogeneration plant, to be run on natural gas, to meet about 30% of the facility's current demand for electricity and heat. In order to anticipate the environmental consequences of this CHP project, an environmental impact assessment (EIA) was conducted, according to the principles that apply in New Brunswick (Regulation 87-83 on EIA). A literature review was conducted and a matrix approach (matrix of impacts) was used to identify and assess the anticipated environmental impacts.