Assessing renewable energy installations in pig farms from a financial and environmental perspective: a case study in the EU

Livestock farms rely heavily on fossil fuels to achieve a suitable indoor climate. Only 4 % of this on-farm energy demand is currently provided by renewable energy sources (RES). In order to reach the European Union's ambitious Fit-for-55 climate goals, a higher renewable energy integration is crucial. This work aims to assess the financial and environmental effects of RES integration on an individual livestock farm. Therefore, a methodology is presented that allows the selection of different combinations of RES technologies and sizes, based on technical, financial and environmental considerations, accompanied by a sensitivity analysis on the implemented assumptions. As a case study, 92,650 different scenarios containing various renewable energy sources and different sizes are simulated on a pig barn in Belgium. The RES technologies selected are (thermal) photovoltaic panels, solar collectors, small wind turbines, heat pumps, electrochemical batteries and a thermal storage tank. Within the explored solution space, 84 % of the scenarios have a lower life cycle cost (LCC) and all of them result in lower – down to 85 % – fuel-related greenhouse gas (GHG) emissions. If the investment cost is, for example, limited to five times the cost of the reference scenario – a natural gas boiler for € 5500 – an installation of 100 m2 photovoltaic (PV) panels in combination with a 60 kWth boiler is most effective at reducing the LCC (10 % reduction in LCC, 6 % fuel-related GHG emission reduction) while a combination of two heat pumps of (12 + 48 kWth) and 25 m2 PV reduce the most fuel-related GHG emissions (46 % GHG reduction, but increasing the LCC by 5 %). For a limitation of 10 times the investment cost, a minimum LCC is obtained with 500 m2 PV and 60 kWth boiler (24 % reduction in LCC, 15 % fuel-related GHG emission reduction), while fuel-related GHG emissions are most effectively reduced by an installation of 200 m2 PV, two heat pumps (12 + 48 kWth), a 5000 L thermal storage tank, and 5 kWh battery (56 % fuel-related GHG reduction, 11 % reduction in LCC). Sensitivity analyses indicate that these optima are highly dependent on the emission factor of the electricity grid, as well as the (projected) electricity and gas prices.