Comparative life cycle GHG emissions from local electricity generation using heavy oil, natural gas, and MSW incineration in Macau

The electricity generation processes represent a large contribution to the potential greenhouse gases (GHG) emissions. Macau, a Special Administrative Region of China, is not of exception. Macau has multiple electricity generation modes, including heavy oil, natural gas, and municipal solid waste (MSW) incineration, and coal-dominated mode which is directly imported from China mainland. On the basis of first-hand data from two power plants and one MSW incineration facility, this study performed a Life Cycle Assessment (LCA) process for three kinds of local electricity generation (heavy oil, natural gas, and MSW incineration) to estimate the greenhouse gas (GHG) emissions under the operating practices used from 2010 to 2014. Results indicate that the mean GHG emissions of electricity production from heavy oil, natural gas, and MSW incineration were 0.71, 0.42, 0.95 kg CO2 eq per kW h, respectively. The mean value for aggregated GHG emissions of the local power grid (imported electricity excluded) was 0.69 kg CO2 per kW h, noticeably lower than many neighboring countries and regions, such as mainland China, Taiwan, and Japan. Our scenario analysis indicated that the development of natural gas-fired electricity would be more effective for a short-term GHG emission reduction target, while the utilization of more solar energy for electricity is the better choice in the long term, for Macau. In term of influence factors for GHG emissions, energy transformation efficiency (ETE) is the most sensitive one, for changing GHG emissions, and should be allocated to the highest priority for GHG reduction. All the obtained results could be useful for decisions makers, with providing a robust support for assessing the environmental performance and drawing up the appropriate improvement planning of power systems.