Optimal economic and environmental design of multi-energy systems
Tom Terlouw, Paolo Gabrielli, Tarek AlSkaif, Christian Bauer, Russell McKenna, Marco Mazzotti
Abstract
Designing decentralized energy systems in an optimal way can substantially reduce costs and environmental burdens. However, most models for the optimal design of multi-energy systems (MESs) exclude a comprehensive environmental assessment and consider limited technology options for relevant energy-intensive sectors, such as the industrial and mobility sectors. This paper presents a multi-objective optimization framework for designing MESs, which includes life cycle environmental burdens and considers a wide portfolio of technology options for residential, mobility, and industrial sectors. The optimization problem is formulated as a mixed integer linear program that minimizes costs and greenhouse gas (GHG) emissions while meeting the energy demands of given end-users. Whereas our MESs optimization framework can be applied for a large range of boundary conditions, the geographical island Eigerøy (Norway) is used as a showcase as it includes substantial industrial activities. Results demonstrate that, when properly designed, MESs are already cost-competitive with incumbent energy systems, and significant reductions in the amount of natural gas (92%) and GHG emissions (73%) can be obtained with a marginal cost increase (18%). Stricter decarbonization targets incur larger costs. A broad portfolio of technologies is deployed when minimizing GHG emissions and integrating the industrial sector. Environmental trade-offs are identified when considering the construction phase of energy technologies. Therefore, we argue that (i) MES designs and assessments require a thorough life cycle assessment beyond GHG emissions, and (ii) the entire life cycle should be considered when designing MESs, with the construction phase contributing up to 80% of specific environmental impact categories.