Decentralized energy in flexible energy system: Life cycle environmental impacts in Belgium

Abstract

Decentralized energy systems enable a higher integration of electricity generation by renewable energy sources supported by electric storage and may significantly reduce greenhouse gas emissions for electricity generation. While the environmental impact of single technologies has received great attention in recent years, the environmental impacts of decentralized energy generation and storage technologies remain unaddressed. This study presents a cradle-to-grave life cycle assessment of those technologies in Belgium for 2030 and 2050. The system technologies comprise single-Si photovoltaic installations combined with lithium-ion and second-life batteries. To compile the life cycle inventory (LCI), energy balances are built based on a Belgian impact energy model. The flexibility of the energy system is introduced by different EV charging strategies and distinct modes of stationary battery storage with the Belgium electricity grid, represented by four different scenarios: i) low flexibility, ii) medium flexibility, iii) high flexibility, and iv) high flexibility with high prosumer potential (PPH). The midpoint impact categories climate change, land use, mineral resource scarcity and terrestrial ecotoxicity of ReCiPe life cycle impact assessment method are analyzed. The decentralized energy generation and storage technologies in Belgium in 2050 result in 64.51 gCO₂eq/kWh of consumed electricity for the medium flexibility scenario, representing a 72 % decrease compared to 2014. However, these reductions are driven by changes in the national electricity mix. Land use impacts are also reduced, up to 72 % for the high flexibility PPH scenario. In contrast, mineral resource scarcity and terrestrial ecotoxicity rise over time in the high flexibility PPH scenario in 2050 to 46 % and 66 %, respectively. A perturbation analysis is conducted to assess the sensitivity of the results, showing solar irradiation as the most sensitive parameter. One way to further reduce the environmental impacts of decentralized energy systems could be to investigate new strategies for the end-of-life of photovoltaic installations and batteries.

Keywords: Decentralized energy systems; Energy model; Life cycle assessment; Photovoltaic installations; Second-life battery; lithium-ion battery.