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Shining Some Light on Solar Panels
- roz083
- 9 hours ago
- 4 min read
Solar panels, or photovoltaic panels (PVs) have been a growing addition to many UK homes and around 1.6 million households had an array installed as of 2025, with MCS reporting 57,000 small-scale installs in the first half of the year alone. Last season, 55% of our clients expressed interest in solar panels and 49% expressed interest in having batteries to run alongside them, so we felt it was about time to shed some light onto the situation!
Solar panels – an overview
PVs generally come in two forms, poly and monocrystalline versions. Essentially, polycrystalline panels have more layers and are less efficient (around 12-13%) but also cheaper (approx. 20%), so choosing monocrystalline could mean that you will get more from the same physical footprint, though with a bigger upfront cost. Panels are around 23% efficient currently, meaning they will convert 23% of the light energy they receive into electricity for use in your home. Developments are progressing quickly, with a new material called perovskite being used in South Korea to achieve 26-27% - this might not sound particularly high, but bear in mind that photosynthesis achieves around 5-6%! Mostly, individual panels range from 350-450kw, with most homes having 8-14 panels and around 3-4kwh output.
Solar panels create DC electricity which is converted into AC electricity by an inverter, which can be built in or separate to the panels themselves. A battery would store this electricity for use when the panels aren’t generating energy, and can also be charged up directly from the grid. Unless you’ve set your system to work otherwise, the inverter will call for energy from your panels first, then your battery (if you have one) and then the grid. Any electricity which is surplus to requirements can be sold back to the grid via the Smart Exchange Guarantee (SEG), using your smart meter to report volumes. Right now, electricity costs around 27p/kilowatt, and some SEG tariffs will pay 15p/kw, though these vary by provider.
The payback period, which is the time it takes for your system to generate savings equal to the installation cost, is around 10 years for solar panels, meaning they might not be the best option if you are planning to move home before this. However, Solar Energy UK has released a study showing a 2% uplift on purchase prices for homes with solar arrays - using a national average house price of £275,000 for a semi-detached property, that’s an uplift of well over £5,000!
The most common setup of 3-4kwhs with 8-14 panels as mentioned above will cost around £6,000 according to Energy Saving Trust – check out this handy graphic below to see what your annual savings might be. With a battery/PV set up and some behavioural changes, usage of electricity from the grid could be reduced by a sunny 75%. In light of volatility in the energy markets, many solar panel owners take comfort in the opportunity for more energy independence alongside reduced carbon emissions. Thankfully, solar panels can be installed on most properties without planning permission, but homeowners in conservation areas or with graded status should seek advice around planning permission before proceeding.
How do batteries fit in?
Batteries are used to store energy that has not been used in daylight hours instead of selling it back to the grid via SEG. The typical UK household uses 7.4kwh per day, and the average 4kw array will produce up to 15kwh in optimal conditions (though this could drop to around 5kwh in the winter months). Most households opt for a battery with 5kwh capacity, with an indicative cost of around £5,000. You could also use a battery without PVs to take advantage of tariffs with cheaper rates overnight, such as those designed for EVs.
Batteries tend to have a shorter lifespan than PVs at around 10 years, where most solar panels will have guarantees for 25-30 years. This means that the battery and inverter will need replacing at least twice within the lifecycle of your panels, so bear this extra cost in mind. Whilst it is advised to install as many panels as you can at one time due to ancillary costs such as scaffolding and labour, batteries can usually be added/replaced on a modular basis.
What about the emissions generated in manufacturing stages?
The manufacture of solar panels currently generates around 0.15% of total global energy related emissions, and 1 gigawatt of solar energy displaces around 5.1m tonnes of CO2 vs coal-fired electricity, according to the IEA. This means that the offset period, the amount of time it takes for the carbon emissions generated in manufacture to catch up to the emissions saved in energy generation, is around 0.44-1.42 years. Around 3% of the emissions in this phase are due to transport, as the majority of solar panels are manufactured in China which uses coal to power its grid (though this is rapidly decreasing). The emissions intensity of solar panel production fell a whopping 42% between 2011-2021 – pretty impressive stuff!
What about recycling?
Around 95% of the glass used in PVs can be recovered when they have reached the end of their serviceable life, which is guaranteed for 25+ years by most manufacturers but can extend to 40 years in some cases – contrast this with the offset period of 0.5-1.5 years! Panels are collected, broken down into their constituent parts, and resulting material streams are manufactured into new products that use silicon, glass, or precious metals such as silver and copper. Currently, around 85% of the materials on each solar panel are recovered, though there is potential to increase this.
In summary
Renewable energy is a great option for anyone who is seeking to reduce their carbon footprint while futureproofing their home. There is funding available, with low or no interest loans being proposed in the Warm Homes Plan for those households that don’t qualify for grants, but you should always seek professional advice and at least 3 quotes from an MCS installer before proceeding with major works.
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