The challenges of evaluating carbon emissions in a transitioning energy system: a solar PV case study

The transition to renewable energy is vital for combating climate change, but renewable sources are not net-zero due to embodied emissions from materials, manufacturing, and maintenance. These emissions are often overlooked in energy system models that guide policy decisions. As the UK’s renewable energy penetration increases and grid carbon intensity decreases, renewables will increasingly displace other renewables rather than fossil fuels, making accurate carbon accounting essential. This study examines the effectiveness of solar photovoltaic (PV) technology in reducing net emissions and assess its contribution to the UK’s decarbonisation efforts. Preliminary results indicate that while solar PV’s potential for emissions reduction is significant, it is reliant upon a holistic evaluation that includes not only electricity displacement but also impacts of heating and transport electrification, as well as future reductions in embodied emissions; focusing solely on electricity displacement can misrepresent solar PV’s sustainability. Early-stage net emissions may be high due to embodied emissions from solar PV production, but aggressive decarbonisation of the supply chain could lead to substantial long-term benefits. The study also highlights the critical role of the timing of life cycle decarbonisation and the necessity for improved methods to evaluate the emissions impacts and benefits of future renewable energy sources.