Solar panel systems use the sun’s energy to power homes and businesses, reducing reliance on fossil-fuel powered electricity sources. These renewable energy systems are made up of several key components that work together to capture, convert and store solar energy efficiently.
Investing in a full solar system can lead to significant long-term savings on electricity bills and a reduced carbon footprint. Here we’ll take a look at what a typical solar set-up includes and some other good-to-have components.
Why go with solar?
Solar energy offers a much greener, cleaner alternative to generating energy than fossil fuels. There are significant benefits for both homeowners and the environment.
First of all, solar panels produce no greenhouse gas emissions during operation. Zero. Yes, there are embedded carbon costs involved in creating the panels, including the use of silicon and other metals, but there are no on-going costs that you get with the burning of gas, oil and coal.
Solar panels also have a long lifespan. They often last for 25-30 years with minimal maintenance. At the end of their life, solar panels can, and should, be recycled. Standard solar panel recycling facilities can recover around 95% of the materials, with advanced facilities hitting 98% recovery.
For homeowners, solar energy can significantly reduce electricity bills. Even smaller sized systems can knock hundreds of pounds off your annual bill. In fact, the International Energy Agency called in the cheapest form of electricity in history. Solar power also increases energy independence, protecting against rising supplier costs.
Components of a solar power system
A complete solar power system consists of several vital elements. Each component plays a key role in converting sunlight into usable electricity for homes and businesses. Let’s take a look.
Solar panels
As you may have guessed, the solar panels themselves form the foundation of any solar power system.
Solar panels contain photovoltaic cells made of semiconductor materials, usually silicon. When sunlight hits these cells, it excites electrons and creates an electric field. This process generates direct current (DC) electricity.
Most residential systems use monocrystalline or polycrystalline silicon panels. You can also get thin-film panels, which are flexible and lightweight, and a better option for places such as canal boats. These are often not as efficient though.
Solar cell efficiency varies based on material quality and design, but modern solar panels can convert 17-22% of sunlight into usable energy. Monocrystalline panels are the most efficient but researchers continually work to improve this efficiency, with some experimental cells achieving over 40% conversion rates.
Solar panels are generally powered between 300W to 500W per panel. The number of panels needed depends on the energy requirements of a home and roof space available. To make sure panels are operating at their maximum, you’ll want to make sure the orientation and tilt angle are optimised and the panels aren’t in shade. Regular cleaning can help maximise panel efficiency over their 25-30 year lifespan.
Inverters
Although solar panels produce DC electricity, this isn’t actually used by our homes or by the national grid. What we need is AC electricity. And to get this, you need an inverter.
Inverters are a vital piece of kit that convert the DC electricity into AC so it can be used around the home. There are a few types of inverters:
- String inverters – These connect multiple panels in series. They’re cost-effective and work well when all panels have similar exposure to sunlight.
- Microinverters – Attached to individual panels for optimised performance. These combine features of string and microinverters. They’re attached to individual panels like microinverters but work in conjunction with a string inverter. These are becoming the more preferred option for solar panel installations.
- Power optimisers – These combine features of string and microinverters. They’re attached to individual panels like microinverters but work alongside a string inverter.
- Hybrid inverters – These can manage electricity flow between solar panels, batteries and the grid. They’re essential for systems with battery storage and offer greater energy management flexibility.
The size of the inverter plays a significant role in overall electricity production and how much power can be used around your home at any given time. Usually, the inverter size is similar to the DC solar panel power or slightly smaller. This sizing strategy can optimise system performance and cost-effectiveness.
For example, if you have a 5kW solar panel array, you might use a 3.5-4.5kW inverter. Whilst this means some potential energy production is ‘clipped’ during peak sunlight hours, it allows for more efficient operation during the majority of the day when the panels aren’t producing at their maximum capacity.
Most modern inverters operate at 95-98% efficiency. Higher efficiency means more of the DC electricity from your panels is converted into usable AC power. In terms of their lifespan, inverters might not last quite as long as the accompanying solar panels. String inverters have a life expectancy of 10-15 years and microinverters can last for 20-25 years, so it’s likely you may have to upgrade once during the solar array lifetime.
Mounting systems
Mounting systems secure solar panels to roofs or ground-based structures. They make sure panels remain stable in all weather conditions and are exposed to maximum sunlight.
There are a few different types of mounting systems including:
- Roof mounts – Attached directly to roof structures. Metal brackets are drilled directly into the roof, which need to be properly sealed against any water ingress. You can also get cheaper ballasted systems. Rather than drilling into the roof, ballasted mounts are packed down with solid, heavy materials to make sure they don’t move anywhere. They’re quicker to install but require roof assessment to ensure the structure can bear the additional weight.
- Ground mounts – Freestanding structures for large arrays and ground mounted residential panels.
- Tracking systems – Adjust panel angles to follow the sun’s path. There are currently expensive but could become more common in the future.
Management system
A solar management system monitors and controls the performance of the entire solar power setup. It provides real-time data on energy production, consumption and system health. You can also get historical data on system performance. Most solar panel management systems can be controlled with a mobile app.
There are varying degrees of management system sophistication. A standard system will just assess solar panel performance, but the most comprehensive are known as home energy management systems (HEMS).
HEMS allows an all-round approach to energy management across multiple smart devices and sources. These systems can optimise energy use patterns, adjust device operation and even choose when to sell energy to the grid depending on dynamic pricing.
Storage battery
Although not essential in a full solar panel system, battery storage is increasingly becoming a wise addition. This is especially true for larger arrays that produce large amounts of extra electricity during the day.
Battery storage is a fantastic way to improve the overall system efficiency of your solar array. By storing excess daytime energy for use in the evening, storage batteries maximise the use of your own solar-generated electricity. This way you also reduce your reliance on expensive grid electricity. Check out this article on the full benefits of solar battery storage.
There are a few types of storage batteries, but lithium-ion is currently the gold standard. Lithium-ion batteries have emerged as the preferred choice for solar energy storage due to their high efficiency and long lifespan. There are two main types of lithium-ion batteries used in solar applications – Nickel Manganese Cobalt (NMC) and Lithium Iron Phosphate (LiFePO4).
When choosing a battery storage system, consider the following:
- Capacity (kWh) – This determines how much energy the battery can store. Typical home systems range from 5kWh to 15kWh. Calculate battery storage size here.
- Depth of Discharge (DoD) – This indicates how much of the battery’s capacity can be used. Modern lithium-ion batteries offer 90-100% DoD.
- Round-Trip Efficiency – This measures how efficiently the battery can store and release energy. Most residential storage batteries have a 90-95% round-trip efficiency.
- Cycle life – This is the number of charge/discharge cycles the battery can undergo before significant degradation. Lithium-ion batteries often offer 6000-8000 cycles or more.
- Warranty – Look out for warranties that guarantee performance for 10 years or more.
Battery storage can add anywhere from £1-5,000 to your costs. The long-term benefits often outweigh the initial investment though and help to shorten your payback time. It’s important to size the battery correctly based on your energy consumption patterns and solar production. An oversized battery may not provide additional benefits, whilst an undersized one may not meet your needs.
Site assessment and panel installation
Proper site assessment and installation are key for maximising the performance and longevity of a full solar system. These steps make sure you get optimal placement and efficiency with your set-up.
Central to this is the orientation and angle of solar panels. In the UK, south-facing roofs are ideal for maximising sun exposure. However, southeast and southwest orientations can also be suitable.
The optimal panel angle varies depending on latitude. For most UK locations, a tilt between 30-40 degrees yields the best year-round performance. Adjustable mounting systems allow for seasonal angle optimisation, capturing more energy during winter months when the sun is lower in the sky. However, these are much more expensive.
For flat roofs, installers use specialised mounting frames to achieve the desired angle. These frames must be securely anchored to withstand wind loads without compromising the roof’s integrity.
Proper installation ensures system longevity and peak performance. Installers should use high-quality, weather-resistant mounting suited to the specific roof type. Careful waterproofing around any roof drill holes is essential to prevent leaks. Wiring should be neatly organised and protected from the elements.
Do you need planning permission for a solar panel system?
In the UK, most domestic solar panel installations are considered ‘permitted development’ and don’t require planning permission. However, certain restrictions apply:
- Panels must not protrude more than 200mm from the roof slope
- Installations on listed buildings or in conservation areas may require approval
- Panels should be positioned to minimise visibility from the ground
For ground-mounted systems, planning permission may be required if the array exceeds certain size limits or is installed in the front garden. It’s advisable to check with the local planning authority before proceeding with any installation.
Solar system sizing
Proper sizing and calculation are a key step for a full solar system. Accurate assessment of your energy needs and system requirements means you’ll get more efficient performance and cost-effectiveness for your outlay.
To size a solar system, start by calculating your daily energy consumption. The average UK household uses around 8-10kWh per day. Energy-intensive appliances like electric heating and EV chargers will increase this figure.
Review your electricity bills for the past 12 months to find the average use. Take a note of seasonal variations and account for future needs. Your installer should perform all of this for you, but it’s always good practice to have a reasonable idea yourself.
With energy needs established, you can now determine the required solar array size. A simple calculation is:
System size (kW) = (Daily energy use (kWh) / Average peak sun hours × 1.2 (safety factor)
For example, a home using 10kWh daily with 3.5 peak sun hours needs:
(10 / 3.5) x 1.2 = 3.4kW system
This equates to roughly 8-10 solar panels, depending on their wattage. This is about right for a medium sized 3 bed or small 4 bed home. It’s always better to oversize a solar panel array than undersize.
There are other more complicated calculations that take into account panel efficiency and watt production per panel per day, but this simple one will give you a good idea.
Costs of a full solar system
The price of a complete solar system can vary widely based on several factors. System size is a primary determinant of cost, with larger systems requiring a higher initial investment.
For a medium-sized home, a 4kW solar panel system is often suitable. This setup usually costs between £5,000 and £9,000 to install in the UK.
The price includes not just the panels, but the other system components, as well as labour costs.
Whilst the initial outlay may seem hefty, solar systems often provide a good return on investment. The break-even point for such a system is estimated at around 8-10 years. After this period, the energy savings continue to accumulate, effectively reducing household electricity costs and providing you with free energy for another 10-20 years. If you sell up before this point, then solar panels can add 4-14% value to your home, so you will recoup your costs here.
Using solar for grid-tied vs off-grid systems
Solar systems come in different configurations to suit different energy needs and locations.
Grid-tied solar systems connect to the national electricity grid. They allow homes to use solar power when available and draw from the grid when needed.
These systems consist of solar panels, an inverter and a bi-directional metre. There’s not a strict need for battery storage and any excess electricity can be sold to the grid. Almost all solar panel installations (until fairly recently), have been grid-tied systems.
What’s becoming more popular now for standard households is hybrid systems.
Hybrid solar systems connect to the grid but also include battery storage to give you more independence and the ability to use your own solar energy during peak rate hours and when the sun isn’t shining.
Hybrid systems provide greater flexibility and energy security. They allow you to optimise their energy usage and reduce electricity bills further. You need a few more components for this system, including a hybrid inverter, battery storage and a smart energy management system.
Finally you have off-grid systems. These are able to operate independently from the electrical grid. They are ideal for remote locations or those wanting complete energy autonomy. These systems require solar panels, energy storage batteries, an inverter and management system.
And there you have it in terms of what you need in a full solar system. With over 1.4 million homes with solar panels in the UK, the country is well on its way to making better use of this renewable energy supply. Still a long way to go, but investing in a full solar system is well worth it and will pay off for you and the environment in the long run.
