Investment appraisal of PV and energy storage on Irish dairy farms

Dairy farms are increasingly adopting renewable energy systems to reduce emissions and energy costs, yet comprehensive economic evaluations are lacking. The objective of this study was to conduct an investment appraisal of PV, a hot water diverter (HWD), and battery energy storage (BES) on dairy farms, using three farms of varying scale, assessing economic and environmental performance. Four scenarios were evaluated (1: PV, 2: PV with HWD, 3: PV with BES, 4: PV with HWD and BES) and compared to a baseline without investment in these technologies. Three farms were simulated (Farm 1: 99 cows, Farm 2: 191 cows, Farm 3: 329 cows). Three electricity tariffs were considered (flat rate, day/night, time-of-use (TOU)). PV generation, self-consumption, electricity cost, additional profit (AP), return on investment (ROI), and electricity-related CO 2 emissions were quantified over 10 years. The flat rate tariff resulted in the highest electricity costs, while the day/night tariff resulted in the lowest for all farms and scenarios. PV with BES (scenario 3) yielded the lowest electricity costs for all farms when day/night or TOU tariffs were applied. With a day/night tariff, scenario 1 resulted in the largest ROI for Farm 1 (15.67 %), scenario 3 resulted in the largest ROI for Farm 2 (16.99 %), and scenarios 1 and 3 resulted in the largest ROI (17.23 %) for Farm 3. • Investment appraisal of PV, battery, and hot water diverter on dairy farms. • Realistic scenarios modelled using the validated FESS model. • Battery storage improved ROI and reduced costs under time of use tariffs. • Hot water diverter added limited value when feed-in tariffs were available.