Howard Mustoe

Solar batteries can store surplus daytime solar electricity for evening use, reduce grid dependence and provide backup power, but typically cost £2,500–£6,000 plus around £3,000 for installation. Their financial value depends on household consumption, solar-system size, electricity and export tariffs, battery degradation and how frequently the system is cycled. A Duracell Dura5 example produces a theoretical storage cost of about 5p per kilowatt-hour before fitting, though lower-than-expected usage can substantially increase the effective cost. Batteries are most suitable for households with high evening demand, heat pumps, electric vehicles, large solar arrays or access to cheap time-of-use tariffs; households with low usage or attractive export rates should be more cautious. Typical payback periods are estimated at eight to 12 years, and professional, MCS-certified installation is recommended.

Modern solar panels typically last 25 to 30 years and often continue generating electricity well beyond their warranty period, though output gradually declines. Degradation rates of 0.3 to 0.5 percent per year mean most panels still produce 85 to 90 percent of their original capacity after 25 years. Inverters usually need replacing sooner, often after 10 to 15 years, making them the main long-term maintenance cost. Replacement of panels is only necessary when faults, roof work or significant performance drops occur, as many older systems remain safe and useful. Panels can be recycled under UK waste regulations, and home insurance should cover external damage. Factors such as poor installation, extreme weather and overheating can shorten lifespan. Panels typically remain effective after both 10 and 25 years, though with reduced efficiency.