Combined Heat and Power (CHP) plants fuelled by natural gas as a power generation solution for the energy transition ::impact on the hourly carbon footprint of the electricity consumed in Switzerland

Having started the phasing-out of nuclear process, Switzerland will have to face the challenge of replacing nearly 30% of its domestic power generation in the medium run. Currently, imports from the European Union are used when indigenous production is unable to meet demand. However, growing import dependency in winter represents not only a potential threat to the security of supply but also electricity import with a heavy GHG content. The development of decentralized power generation through natural gas-fired combined heat and power (CHP) plants could be a short-medium run solution allowing to produce electricity on the Swiss territory during winter. In this work, we evaluate how the replacement of a part of the inflows from neighbouring countries by decentralized CHP plants fueled by natural gas impacts the hourly carbon footprint of the electricity consumed in Switzerland. We developed a four-step methodology to answer this question. Firstly, we assess, for the years 2016 to 2019, the GHG content of the electricity consumed in Switzerland in accordance with the consumption principle and applying the attributional Life Cycle Analysis (LCA) approach. Secondly, based on natural gas delivery data, we modelled hourly gas consumption for heating purposes by means of the heating degree-hour method. Then, based on the previous part, we simulated hourly electricity production with natural gas CHP plants. Finally, we assessed the hourly GHG emission from electricity consumption with the new solution. The results show that, actually, imports impact strongly and negatively the GHG footprint of the electricity consumed in Switzerland. The results of the last part show that the development of decentralized power generation through natural gas-fired CHP plants can lower the GHG footprint of the electricity consumed in Switzerland. Indeed, in nearly all the scenarios, the naturalgas CHP solution is a less-GHG-emitting alternative to imports