Solar vs Grid Electricity Cost Comparison

Electricity prices in the UK have gone up a lot in recent years, and many homeowners are now looking for ways to spend less. The average unit rate for grid electricity is now around 25.73 pence per kWh, according to Ofgem.

That adds up fast for a typical household. Solar panels work differently; your roof generates the power, and you use it yourself instead of buying it. The big question most people have is whether the upfront cost is actually worth it.

The short answer is that for most UK homes, it is. You will find a breakdown of the real costs on both sides, how much you could save, and what the Smart Export Guarantee means for your pocket.

What Does Grid Electricity Cost in the UK Right Now?

Most UK homes get their electricity from the national grid. You pay for it by the unit, which is called a kilowatt-hour or kWh. The price you pay is set by Ofgem, the UK's energy regulator, which reviews the price cap every three months.

Right now, the average unit rate for grid electricity sits at around 25 to 27 pence per kWh, depending on the quarter. On top of that, there is a daily standing charge of around 50 to 54 pence, which you pay every single day just to stay connected.

That means before you switch on a single light, you are already spending roughly £15 to £16 a month. For a typical home using around 2,700 kWh a year, the electricity part of the bill easily comes to over £600 a year before standing charges.

Why Do Grid Prices Keep Changing?

Grid prices go up and down based on several things:

• Wholesale energy costs — what suppliers pay to buy electricity in bulk

• Grid maintenance — the cost of keeping the national network running

• Government levies — charges added to support green energy projects and low-income households

Grid prices have been much higher than normal since the energy crisis in 2022. While they have come down from their peak, they are still around 26 per cent higher than they were before the crisis, according to the House of Commons Library. That is a big reason why so many UK homeowners are now looking at solar as an alternative.

The solar vs grid electricity cost gap is growing. Every year that grid prices stay high, the case for generating your own electricity at home gets stronger. If you want to explore what a solar setup could look like for your property, Natural Spark's solar photovoltaic installations are a good place to start.

How Much Does Solar Electricity Actually Cost Per Unit?

With solar panels, you make your own electricity using sunlight. Instead of paying your supplier for every unit you use, you generate it yourself from your roof. The cost of that electricity is worked out by spreading the price of installing the system across its full working life.

A typical 4kW system for a UK home costs between £5,000 and £8,000 to install. Most systems come with a 25-year performance guarantee, and they need very little maintenance because there are no moving parts.

If you spend £6,500 on a system that generates around 3,400 kWh a year, you produce roughly 85,000 kWh over 25 years. That works out at around 7 to 8 pence per kWh, compared to the 25 to 27 pence you pay when buying from the grid.

What Affects How Much Your System Generates?

Not every home will generate the same amount of power. Here are the main things that make a difference:

• Roof direction — a south-facing roof gets the most sunlight throughout the day

• Location — homes in Cornwall, Devon, and the south of England tend to generate more than those in northern regions

• Shading — trees, chimneys, and nearby buildings can reduce output

• System size — a larger system generates more, but costs more upfront

Even on cloudy days, solar panels still generate electricity, just less of it. The Energy Saving Trust confirms that solar panels work year-round in the UK and are a practical option for most homes, not just those in sunny areas.

If you are thinking about adding battery storage alongside your panels to get the most from what you generate, Natural Spark's battery storage solutions explain how that works in more detail.

How Do Solar Panels Reduce Your Electricity Bills?

When your solar panels are producing power, your home uses that first before drawing anything from the grid. This means every unit of solar electricity you use is a unit you do not have to pay your supplier for. That is where most of the savings come from.

According to the UK Government's clean energy campaign, homeowners can save an average of over £500 a year on their energy bills by going solar. Some homes save significantly more. Research from the MCS Foundation found that a semi-detached new build with solar panels alone could save over £1,000 a year on energy bills, depending on usage and system size.

Where Do the Savings Actually Come From?

The savings stack up in three main ways:

• Lower grid imports — every unit you generate and use at home is one you do not buy at 25p or more

• Export payments — any leftover electricity goes back to the grid and you get paid for it through the Smart Export Guarantee

• Protection from price rises — once your panels are installed, the cost of the electricity they make does not go up the way grid prices do

Getting the Most From Your System

The more electricity you use during the day while the panels are generating, the more you save. Simple changes can make a real difference:

• Run the washing machine or dishwasher during the day

• Charge your electric vehicle while the sun is shining

• Set your hot water immersion heater to run at midday rather than overnight

These small shifts mean more of your solar electricity is used at home rather than sent to the grid. The Energy Saving Trust has useful guidance on how to get the most from a solar setup at home, including tips for different household types.

What Is the Smart Export Guarantee, and Can You Earn From It?

The Smart Export Guarantee, or SEG, is a UK government scheme that pays homeowners for the extra electricity their solar panels send back to the national grid. If your system generates more than you need, that surplus does not go to waste. It goes to the grid, and you get paid for it.

The SEG replaced the old Feed-in Tariff scheme in January 2020. Under the current rules, any energy supplier with over 150,000 domestic customers must offer at least one export tariff to eligible solar panel owners. Suppliers set their own rates, which typically range from 4 to 15 pence per kWh. Some variable tariffs can go higher during peak demand periods.

According to Ofgem's SEG Annual Report for Year 5, by the end of March 2025, 270,395 UK solar installations were registered to an SEG tariff. That is a 63 per cent rise on the year before, with total payments of £56.97 million paid out to registered generators.

How Do You Qualify for SEG Payments?

To get paid through the SEG, your installation must meet a few conditions:

• Your system must be installed by an MCS-certified installer

• You need a smart meter or an export meter to measure what you send to the grid

• Your system must be no larger than 5MW in total capacity

You do not have to use the same energy supplier for your export tariff as you do for your regular bills. It is worth comparing rates before signing up, as they vary quite a lot between suppliers. The Energy Saving Trust's SEG guidance explains the sign-up process clearly and points to the list of licensed SEG suppliers on the Ofgem website.

Is Solar Worth It for a Typical UK Home?

For most UK homeowners, the numbers make sense over the long term. The big question is how quickly the upfront cost pays itself back through savings and export income.

A 4kW system costs between £5,000 and £8,000 installed and can save a household anywhere from £500 to over £1,000 a year. That puts the payback period at around six to twelve years. Since most panels carry a 25-year guarantee, there are still thirteen or more years of very low-cost electricity generation after the system has paid for itself.

A Real-World Example

Think about a homeowner in Cornwall or Devon with a south-facing roof. Their 4kW system might generate 4,000 kWh or more a year thanks to the region's above-average sunshine. At current grid prices, using just half of that directly would save them around £500 a year in grid electricity costs. Add export payments on top of that, and the total return over ten years would more than cover the original installation.

Solar also makes good sense for:

• Landlords — solar panels can improve a property's Energy Performance Certificate rating, which is becoming more important under UK rental rules

• Property developers — new builds with solar already fitted can command higher prices and attract eco-conscious buyers

• Small business owners — daytime energy use means more of the solar generation gets used directly, improving the return

The Energy Saving Trust consistently supports solar as one of the most effective ways for UK homeowners to cut their bills and reduce their carbon footprint. Natural Spark's solar photovoltaic installations service covers homes and businesses across the UK, with systems sized to match your energy use and roof.

What About Battery Storage?

Solar panels only generate electricity when the sun is shining. If you are out at work during the day, a lot of that generation can go to waste unless your home finds a way to use or store it. A solar battery solves that problem.

A battery stores the electricity your panels generate during the day so you can use it in the evening or overnight, when grid rates apply. Without a battery, most homes use around 30 per cent of the solar electricity they generate. With a battery, the Energy Saving Trust notes that for every unit stored and used at night, you save around 14 pence compared to buying from the grid. Battery storage typically costs between £5,000 and £8,000.

Who Benefits Most From a Battery?

A battery is especially useful for:

• Households where most energy is used in the evenings

• Homes with an electric vehicle that charges overnight

• Anyone who wants more protection against future grid price rises

• People on time-of-use tariffs who want to avoid peak-rate electricity

The MCS notes that a battery can raise your self-consumption rate to 80 per cent or higher, which significantly improves the overall return from a solar system.

Battery storage also works well alongside an EV charge point. You can charge your car using stored solar electricity, meaning your vehicle runs on power your roof generated rather than power you bought from the grid. Natural Spark offers both battery storage solutions and EV charge point installations, so the two can be planned and fitted together.

Do Solar Panels Need Planning Permission in the UK?

For most UK homes, the answer is no. Solar panels on a standard pitched roof are classed as permitted development, which means you do not need to apply to your local council for planning permission. This makes the process much simpler than many people expect.

According to the Planning Portal, the official government resource for planning guidance, solar panel installations on residential buildings may be carried out without planning permission, provided they meet certain conditions. The panels must not stick out more than 200mm from the roof surface and must not go above the highest point of the roof.

When Might You Need Permission?

There are some situations where the rules are different:

• Listed buildings — you will need listed building consent before any work begins

• Conservation areas — panels on the principal elevation facing a road may need prior approval from your local council

• Flat roofs — panels can extend up to 0.6 metres above the roofline without permission under updated 2023 rules

• Ground-mounted panels — separate rules apply and planning permission may be required depending on size

If you are unsure, it is always worth checking with your local planning authority before going ahead. An MCS-certified installer will also be familiar with local requirements and can help you understand what applies to your property.

Under UK Building Regulations, electrical work connected to a solar installation must meet safety standards and may require a completion certificate, which a qualified installer will provide as standard.

Find Out How Much You Could Save With Solar

Switching from grid electricity to solar is one of the best things a UK homeowner can do right now. Bills are high, and solar gives you a way to take back some control. The first step is finding out what is possible for your home.

Natural Spark installs solar panels for homes and businesses across the UK. Every system is designed around your roof, your energy use, and your budget. We are MCS-certified, so your installation will meet the standards needed to earn Smart Export Guarantee payments.

If you want to store what you generate, Natural Spark also fits battery storage systems. And if you drive an electric vehicle, you can add an EV charge point and charge your car using your own solar power.

Get in touch with Natural Spark today to find out what solar could do for you.