Last reviewed: 2026. Figures are indicative and correct as at 2026.
Solar, battery storage and EV charging come with a lot of jargon, so we have gathered the most useful terms in one place. This glossary gives clear, plain-English definitions of the words you will meet when researching solar for a home or business. It is maintained by Cre8 Zero, an MCS-certified solar, battery and EV charging installer based in Brighton, serving Brighton & Hove, East and West Sussex, Kent, Surrey and Hampshire.
Thinking about solar for your home or business? Book a free energy assessment, call us on (020) 3038 4595, or email enquiries@cre8zero.com.
Solar PV (photovoltaics). Technology that converts daylight directly into electricity using semiconductor cells. PV stands for photovoltaic. Solar PV works on daylight rather than heat, so it generates power even on cloudy days.
Solar panel (module). A framed unit made up of many photovoltaic cells that produces direct current (DC) electricity when exposed to daylight. Several panels wired together form a solar array.
Solar array. A group of connected solar panels working together as one system. The size of an array is described in kilowatts-peak (kWp).
kWp (kilowatt-peak). The maximum output of a solar system under standard test conditions. It is the standard measure of system size. A typical UK home system is 3kWp to 6kWp.
kWh (kilowatt-hour). A unit of energy equal to using one kilowatt of power for one hour. Electricity bills and solar generation are measured in kWh, often called units.
Monocrystalline panel. A solar panel made from single-crystal silicon. It is typically more efficient and more space-efficient than polycrystalline, and is the most common choice for UK homes.
Polycrystalline panel. A solar panel made from multiple silicon crystals. It is historically cheaper but slightly less efficient than a monocrystalline panel.
Solar inverter. The device that converts the direct current (DC) produced by solar panels into the alternating current (AC) used by your home, business and the grid. It is the hardest-working component and is usually the first part to need replacement.
String inverter. A single central inverter that converts the combined output of a string of panels. It is cost-effective but more sensitive to shading across the string.
Microinverter. A small inverter fitted to each individual panel, allowing every panel to work independently. It performs better on shaded or complex roofs, at a higher cost.
Power optimiser. A device fitted to each panel that conditions its output before it reaches a central inverter, improving performance on partially shaded roofs.
Hybrid inverter. An inverter that manages solar panels and battery storage together in a single unit, simplifying a system that includes a battery.
Solar irradiance. The amount of solar energy reaching a given surface, usually measured in kWh per square metre. The UK South Coast has some of the highest irradiance in the country.
Diffuse light. Sunlight that has been scattered by cloud and the atmosphere. Solar panels convert diffuse light as well as direct sun, which is why they still generate on overcast days.
Temperature coefficient. A measure of how much a panel’s output falls as it heats up. Because of it, panels can be slightly more efficient on cold, bright days than in extreme heat.
Degradation. The slow, natural decline in a solar panel’s output over time. Modern panels typically degrade at around 0.3% to 0.5% per year.
Self-consumption. The share of your solar generation that you use on site rather than exporting to the grid. Higher self-consumption means bigger savings, because you avoid buying grid electricity at full price.
Peak sun hours. A way of expressing a day’s solar energy as the equivalent number of hours of full-strength sun. It is useful for estimating how much a system will generate.
Solar generation (yield). The electricity a system produces, measured in kWh. As an indicative guide, a well-sited 4kWp UK home system generates around 3,400 to 4,000 kWh a year.
Battery storage (BESS). A battery energy storage system that stores solar or off-peak electricity for use later, raising self-consumption and cutting peak-time grid use. BESS stands for battery energy storage system.
Depth of discharge (DoD). How much of a battery’s capacity can be used, expressed as a percentage. A higher usable depth of discharge means more of the stated capacity is available to you.
Cycle life. The number of charge and discharge cycles a battery is warranted for. It is often used to describe battery lifespan alongside a guaranteed capacity-retention figure.
Time-of-use tariff. An electricity tariff with different rates through the day, including cheap off-peak periods. Batteries and EV charging use these tariffs to shift usage to the cheapest times.
Peak shaving. Using stored energy to reduce the highest points of grid demand. For businesses, this can lower demand or capacity charges.
Backup power (EPS). A battery feature, sometimes called Emergency Power Supply, that keeps essential circuits running during a power cut. Availability depends on the system design.
Smart Export Guarantee (SEG). A scheme requiring larger energy suppliers, those with 150,000 or more domestic customers, to pay you for surplus solar electricity you export. In 2026, rates range from around 1p to 30p or more per kWh. You need an MCS-certified install and a smart meter to claim it.
Feed-in Tariff (FiT). The predecessor to the Smart Export Guarantee, closed to new applicants in 2019. It paid a fixed rate for both generation and export, and existing agreements continue to run.
0% VAT on solar. The zero rate of VAT on solar panels and battery storage installed on homes in Great Britain, in place until 31 March 2027, after which it is expected to rise to at least 5%. Buildings used solely for a charitable purpose may also qualify.
Payback period. The time it takes for a system’s savings and income to equal its cost. Home solar typically pays back in roughly 7 to 12 years, while commercial systems often pay back in 3 to 7 years. Figures are indicative.
Return on investment (ROI). The annual return a system delivers relative to its cost. Commercial solar for businesses with high daytime use often returns around 10% to 15% a year. Figures are indicative.
Power Purchase Agreement (PPA). A funding model where a third party funds, owns and maintains a solar system on your roof, and you buy the electricity it generates at an agreed rate, usually below the grid price, with no upfront cost.
Annual Investment Allowance (AIA). A capital allowance giving businesses 100% tax relief on the first £1m of qualifying capital spend in a year. Most commercial solar installations are covered. Confirm the treatment with a qualified accountant.
50% First-Year Allowance. A relief letting companies claim 50% of qualifying special-rate spend, which includes solar, in the first year, above the AIA. Solar is a special-rate asset and does not qualify for full expensing. Confirm the treatment with a qualified accountant.
Business rates exemption. An exemption meaning eligible new rooftop solar does not increase a property’s business rates, currently running until 2035. Confirm eligibility with a qualified adviser.
Smart meter. A meter that records electricity use and export in half-hourly readings. It is required to claim the Smart Export Guarantee and to use time-of-use tariffs.
Not sure which of these applies to your roof? Our team will explain it in plain terms during a free, no-obligation energy assessment. Call (020) 3038 4595.
MCS (Microgeneration Certification Scheme). The recognised UK quality standard for renewable installations. An MCS-certified installation is required to claim the Smart Export Guarantee and the 0% VAT relief.
Insurance-backed workmanship warranty. A guarantee covering the quality of the installation itself, which remains valid even if the installer stops trading. It is separate from the manufacturers’ product warranties.
Product warranty. A manufacturer’s guarantee against defects in a panel, inverter or battery. Panels often carry 25-year product warranties, while inverters and batteries typically carry around 10 years.
Performance warranty. A manufacturer’s guarantee of a minimum output over time, for example at least 87% of original output after 25 years.
DNO (Distribution Network Operator). The company that runs the local electricity network. Your solar system must be notified to, or approved by, the DNO.
G98 and G99. The grid connection standards for small (G98) and larger (G99) generation systems. G98 is usually a notification after installation, while G99 requires approval beforehand.
Permitted development. Planning rules that let most roof-mounted solar be installed without a full planning application, subject to conditions such as projection limits.
Planning permission. Formal consent that may be required for solar on listed buildings, in conservation areas, on some flat-roof or ground-mounted systems, or for larger commercial arrays.
Commercial solar. Solar PV installed on business premises to cut energy costs and carbon emissions. Businesses benefit most when their electricity demand peaks during daylight.
Demand charge (capacity charge). A charge on commercial energy bills linked to your peak grid draw. Battery storage can help reduce it through peak shaving.
Scope 2 emissions. The indirect carbon emissions from the electricity a business buys from the grid. Generating your own solar power directly reduces Scope 2 emissions, which supports carbon reporting.
Grid connection. The link between your system and the local electricity network. Larger systems may require DNO approval and can have managed or limited export.
EV charger (EVSE). Equipment that charges an electric vehicle, sometimes called electric vehicle supply equipment. A typical home charger is 7kW.
Solar diversion (eco charging). A smart-charger feature that sends surplus solar to your electric vehicle instead of exporting it, so you charge from your own generation.
Load balancing. A charger function that manages power draw to protect your electrical supply from overload while an electric vehicle is charging.
For most homes and many businesses, no. Roof-mounted solar is usually permitted development, so no planning application is needed, provided conditions such as projection limits are met. Listed buildings, conservation areas, flat-roof or ground-mounted systems and larger commercial arrays are the main exceptions. Always confirm with your local planning authority.
A typical 4kW home system costs roughly £6,000 to £8,500, with smaller 3kW systems from around £5,000 and larger 6kW systems up to about £12,000. Battery storage adds roughly £3,000 to £6,000. All figures are indicative and depend on the roof and usage.
Yes. Solar panels and battery storage installed on homes in Great Britain carry 0% VAT until 31 March 2027, after which the rate is expected to rise to at least 5%. Buildings used solely for a charitable purpose may also qualify.
No. Solar is classed as a special-rate asset, so it does not qualify for full expensing. The correct reliefs are the Annual Investment Allowance (100% on the first £1m of qualifying spend) and, for companies, a 50% first-year allowance above that. Always confirm with a qualified accountant.
Cre8 Zero is an MCS-certified solar, battery and EV charging installer based in Brighton, serving Brighton & Hove, East and West Sussex, Kent, Surrey and Hampshire. Every installation is carried out by qualified electricians and backed by an insurance-backed workmanship warranty.
Ready to see what solar could do for you? Cre8 Zero designs MCS-certified solar, battery and EV charging systems across Brighton & Hove, Sussex, Kent, Surrey and Hampshire, backed by an insurance-backed workmanship warranty and 5-star Trustpilot and Google reviews. Book your free energy assessment, call (020) 3038 4595, or email enquiries@cre8zero.com.
