Life Cycle Assessment of solar energy systems for the provision of heating, cooling and electricity in buildings: A comparative analysis

A detailed Life Cycle Assessment (LCA) "from cradle to grave " is performed to a solar combined cooling, heating and power (S-CCHP) system that provides space heating, cooling, domestic hot water and electricity, following two different methodologies (the ReCiPe 2016 Endpoint (H/A) v1.03 and the carbon footprint IPCC 2013 100 years). The innovative S-CCHP system is currently in operation in an industrial building located in Zaragoza (Spain), and the transient model developed to estimate the annual energy outputs has been validated. The system consists of hybrid photovoltaic-thermal (PV-T) collectors integrated via two parallel thermal storage tanks with an air-to-water reversible heat pump (rev-HP). Another contribution is that the detailed LCA analysis is also performed to a conventional PV-system and a grid-based system, viz building electricity consumption supplied from the grid (baseline configuration). The results show that the proposed S-CCHP system has half of the environmental impact of the grid-based system, according to the ReCiPe 2016 Endpoint (H/A) and the IPCC GWP 100a methods (4.48 kPts vs 8.87 kPts, and 82.4 tons of CO2 eq vs 166.9 tons of CO2 eq, respectively). The PV system has 30% less environmental impact than the grid-based system. Another novelty and contribution are the sensitivity analyses performed to assess the influence of the system lifetime, the solar irradiance and the power generation mix (also known as the electricity mix) on the LCA results. The results show that the proposed S-CCHP system appears as an up-and-coming alternative to reduce the environmental impacts of buildings in all the considered solar irradiance levels and electricity mix scenarios, even in climates with low irradiance levels or in countries with a highly decarbonised electricity supply.