Feasibility of battery storage in solar photovoltaic (PV) installations in Ireland: A case study

Nations are working to cut greenhouse gas emissions and switch to sustainable, low-carbon energy sources. Because of its scalability, adaptability, increasing efficiency and continually declining cost, solar photovoltaic (PV) technology has become one of the most promising renewable energy sources. In Ireland, interest in renewable energy, particularly PV, has grown rapidly in the last decade even though the climate, often marked by significant cloud cover, poses difficulties for PV system efficiency. The remarkable growth in the PV sector in Ireland can be attributed in many ways to the savings achievable for electricity consumers due to current Government policies and incentives. One of the most effective policies in recent years was the introduction of a feed-in-tariff (FIT) in 2022 for electricity consumers. Prior to this, excess electricity generated by solar PV was lost, if not self-consumed. Batteries can be utilised to store extra electricity produced during the day to supply it back to the system during peak periods or in the evening when solar production is at a minimum. This strategy encourages load shifting, peak shaving, and increased energy self-sufficiency in general. This case study looks at the financial feasibility of combining battery storage with solar PV installations. It uses electricity consumption and PV production data from an educational building located in Ireland. Using solar irradiance figures for the case study location along with day-night tariffs and FIT data, the authors found that the Simple Payback Period for investment in batteries is 11 years, only 1 year more than without batteries. This is despite the case study building being recognised as one of the most sustainable buildings in Ireland and the UK, characterised by inherently low electricity consumption levels. In addition to the financial justification for installing batteries, there is a strong argument for their potential to reduce carbon emissions. To illustrate their environmental value, carbon modelling calculations are conducted in parallel with financial analyses.