Battery Storage Systems

Battery storage systems work by storing excess electricity produced by the solar panels during the day for use at night or during periods of high demand. Here's how they function:

Storage: The energy generated by the solar panels is stored in the battery as DC electricity.

Use: When your solar system isn't producing energy (e.g., at night or on cloudy days), the stored energy can be used to power your home.

Efficiency: Modern systems use advanced lithium-ion or similar batteries, offering high efficiency in energy storage and retrieval. New battery technologies are also coming through to further reduce costs of a system and provide increased grid independence.

Financial Benefits

Reduced Energy Bills: By generating your own electricity, you will reduce your reliance on energy from the grid, lowering your monthly electricity bills. The savings you can achieve from solar PV and battery storage depend on a number of factors, including your home’s energy usage, the size of the system, the amount of sunlight your location receives, and the tariff you're on. The initial cost of installing a solar PV system in the UK typically around £5,000 for a standard 4kWp system, depending on the quality of the panels, inverter, and installation costs. A battery system can cost between £4,000 and £6,000 for typical home installations, depending on the capacity and brand. A typical homeowner can save anywhere from £250 to £500 per year on electricity bills, depending on system size and usage patterns. The payback period for solar PV systems is typically 5-7 years, and with battery storage, the overall payback period may extend slightly but can still result in savings in the long term. However, the availability of off peak tariffs, and selling surplus generation will reduce the payback period.

Energy Independence: Solar PV with battery storage allows you to store energy for later use, reducing dependence on grid electricity, especially during peak price hours.

Export Payments: If you generate more electricity than you need, you may receive payment for exporting this excess energy back to the grid through schemes like the Smart Export Guarantee (SEG).

Increased Property Value: Homes with solar panels and battery storage are increasingly seen as more desirable due to lower running costs and environmental credentials, which could increase their value. Government Incentives: Various government schemes like the Feed-in Tariff (although now closed to new applicants) and the SEG still offer potential financial returns for solar installations. The installation of such systems may also qualify for VAT reduction and other incentives under specific conditions.

Environmental Benefits

Reducing Carbon Footprint: Solar power is a clean, renewable energy source that doesn’t produce any greenhouse gases during generation. By installing solar PV, you are helping to reduce your home's carbon footprint.

Energy Resilience

Backup Power: A battery storage system provides security in the event of power outages, enabling your home to continue running essential appliances even when the grid is down.

How to Correctly Size a Solar PV and Battery Storage System

Correctly sizing a solar PV and battery system is crucial to maximizing your investment and achieving optimal performance. Several factors need to be considered:

1. Energy Usage

Evaluate your energy consumption: Start by assessing your average daily energy consumption (in kWh) from your electricity bill. For example, if you use 10kWh/day, this will guide the size of the system you need. Seasonal variation: Energy usage may vary between summer and winter, so it’s important to consider these variations when determining your energy needs.

2. Solar Panel Output

Solar panel capacity: A typical 4kW solar PV system can generate approximately 3,400 to 4,000 kWh of electricity annually, depending on the amount of sunlight. Location: The amount of sunlight your property receives (based on roof orientation, pitch, and geographic location) will affect solar panel output. In the UK, south-facing roofs tend to generate the most energy.

3. Battery Size

Battery storage: The ideal battery size should store enough energy to cover your consumption when the sun isn’t shining. A common recommendation is to install a battery system that can store between 2 to 6kWh of electricity for daily use. Full charge or partial charge: Consider how much stored energy you will typically need for overnight or low-production periods. This will depend on your household's usage patterns.

4. System Design Considerations

System efficiency: It's important to account for system efficiency losses. Solar panels and batteries will lose a small percentage of energy during conversion and storage. Typically, aim for a system that can meet at least 80% of your annual energy needs. Future expansion: If you plan to increase your energy use (e.g., installing an electric vehicle charger or Heat Pump), factor in extra capacity.

Investing in solar PV and battery storage is a smart decision for homeowners who want to reduce their energy costs, increase energy independence, and contribute to sustainability. By generating and storing your own energy, you can offset your electricity bills and gain protection from rising energy prices. Correctly sizing the system to match your energy needs and using quality components ensures you’ll get the most value from your investment.

When considering a system, it’s essential to consult with a qualified installer to conduct a detailed assessment of your energy needs and ensure the system is optimally sized for maximum efficiency and return on investment.