Exploring Battery Storage Options for Solar Energy
For homeowners and businesses adopting solar PV, adding energy storage can maximize self-consumption of solar power and provide backup during grid outages. With the UK targeting net-zero emissions by 2050, interest in solar batteries is rising. But what are the battery options for storing solar energy? This article provides an overview.
Why Add Batteries to Solar?
The intermittent nature of solar PV generation means surplus power is often produced when not immediately needed onsite. Batteries allow capturing this excess generation for use at night or during cloudy spells.
Key benefits batteries provide for solar systems include:
- Storing surplus solar power for later self-use, reducing grid imports
- Supplying backup power during grid failures
- Enabling off-grid solar system capabilities
- Unlocking revenue from grid demand response services in some markets
Integrating lithium-ion batteries with smart solar inverters can optimize onsite usage and storage of PV generation.
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Main Types of Solar Batteries
Lithium-ion (Li-ion) – Currently the dominant battery chemistry used with solar due to high efficiency, long cycle life and declining costs. Can be formulated with different cathode materials.
Lead-acid – Traditional rechargeable battery providing a low-cost but heavy and less efficient alternative to Li-ion. Shorter-lived but can suit smaller solar needs.
Saltwater – Innovative saltwater flow batteries are long-lasting and non-flammable but have low energy density. High costs presently limit adoption.
Redox flow – Flow batteries utilizing liquid electrolytes in tanks can offer long durations but have complex maintenance and size requirements.
Key Considerations for Selection
Discharge duration – Daily cycles or multi-day backup during prolonged bad weather? Shorter discharge spans enable smaller, cheaper batteries.
Lifespan – Premium lithium-ion batteries can achieve 4,000-5,000 cycles and beyond. Lead-acid’s lifespan is typically 500-800 cycles.
Depth of discharge – How deeply will batteries be discharged each cycle? Partial discharges extend battery lifetimes.
Efficiency – Lithium-ion batteries approach 90-95% efficiency while lead-acid is around 80%. Flow batteries can see substantial parasitic losses.
Safety – Lithium-ion requires dedicated battery management systems. Lead-acid, saltwater and flow batteries generally safer by chemistry.
Size – Energy density impacts footprint. Lithium-ion requires around one-third the space of an equivalent lead-acid system.
Key Players in the UK Storage Market
Major international battery suppliers like LG Chem and BYD operate in the UK along with domestic providers such as Powervault and Moixa. Sonnen and Tesla also deliver integrated solar+storage solutions.
Leading inverter brands including SolarEdge, Fronius and SMA offer battery interfaces and optimized solar storage packages.
Continued technology advances and cost declines expected in coming years will likely expand integration of solar power and lithium-ion storage across UK homes, businesses and the grid.
