The most visible component of solar power plants is the solar panels on the roof or ground. It is also the most important part of the whole system. Well like most of the northern hemisphere, in the UK solar panels are placed facing south to get maximum sunlight. In the southern hemisphere of the Earth, the solar panels are placed facing north for the same reason. The tilt angle of the panels to the ground is calculated based on the latitude of that location and in most general scenarios; the tilt angle is the latitude degree of that location.

Well, to get the maximum out of the solar panels, design and system installation has to be perfect. From the tilt of your roof to the type of inverter you choose and install, it is all a play of efficiency. The solar panels do not convert all of the sunlight or photons of light to electricity or direct current, they have a particular efficiency of doing this. From the solar panels to wiring and Inverter to transmission or storage, the efficiency drops with each component.

Installation of solar panels is a process to be carried out by trained and professional installers but the person spending money on the solar generator should be aware of all the aspects of installation and working. So let us look at the process of installing solar panels or the whole solar photovoltaic system in the UK.

Get your location assessed is always recommended to get the location assessed by a certified surveyor to check the viability of a solar power plant at that location. For a typical UK home, an EPC assessment is carried out to rate the energy efficiency of the building. Here EPC stands for “energy performance certificate” and it is required to know the energy behaviour of the building.

To qualify for the latest SEG or smart export guarantee scheme, EPC is required.
Similarly, a solar surveyor can check the inclination of your roof, its orientation and do shade analysis. Based on these factors, solar PV system output can be assessed and a rough idea on savings from solar investment can be calculated. Also, the roof strength to bear solar PV system weight and electrical connections are checked to finalise the design and recommend amendments if required.

1. Finalise a solar system with detailed finances

For a layman, all the solar panels will look the same and work as same to generate electricity. All the components from solar panels to inverter and wiring etc are standard equipment with specific ratings and outputs. Now, solar PV system design based on specific location is calculated by a certified engineer whom we need to trust. It is the awareness and duty of the homeowner to get the details of the investment noted.

The person who is getting a solar power plant installed on the roof of his home should know the total investment and expected return from the investment. It is good if the solar power plant pays for itself within 5 years of installation. This will give at least 20 years of free electricity and reduced bills. The solar investment and return should be understood in detail to get the best results.

2. Define roof access

Most of the UK’s typical homes have slanted roofs and all do not have clear roof access. To install the solar structure on the roof, scaffoldings are installed first. These are temporary structures that are installed according to the requirement. Whole system installation can be made easy with proper scaffolding installation.

It is desirable to have access identified even after the solar system is installed on the roof. As the only maintenance required with solar panels is cleaning them for better efficiency, so reaching them is essential. So at the time of defining roof access for solar panel installation, it is advisable to also identify roof access to clean the solar panels. Safety of personnel working to install solar panels and of the person to clean solar panels should be a priority and setup should be adequately designed.

3. Installation of the mounting structure

The mounting structures vary in design depending on the placement of the power plant. For ground mount and flat roof locations, the mounting structure base is fixed with concrete. These flat surfaces give the ability to tilt the panel at a specific location for maximum sunlight exposure.

For tilted roofs of homes, the mounting structure frame is hooked with the rafters of the roof on which tiles or slates are fixed. The earlier survey is very important in the respect of ensuring the load-bearing capacity of the roof. If additional support is required to fix solar panels on domestic roofs, for which additional expense is required. Solar system installer or surveyor should figure this out as a priority. For industrial and commercial roofs with slanted metal sheets, the mounting structure is fixed with iron beams and roof sheets.

The strength of the roof, strength of the mounting structure, leakproof fixing of structure, the orientation of the structure and most importantly the angle of the mounting structure should be very adequate for successful solar installation.

4. Fix and connect panels on the mounting structure

Once the mounting structure is fixed to the roof or to the ground, the panels are fixed to it with clamps. The mounting structure holds the heavy panels at a particular inclination. Domestic solar panels weigh 15kg per sq. meter and add additional weight to the roof[1].

After fixing the solar panels to the mounting structure they are connected to each other to form an array of panels. They are wired to each other as per the design, which means the amount of current and voltage required from the solar panel is determined by how they are tied to each other. When panels are wired in series, the voltage of panels adds up and when they are wired in parallel, the current (amperage) adds up. The solar array of panels is connected in a way to get desired voltage and current values. The array of solar panels is basically an electrical circuit where panels are connected with specific connectors (like MC4[2]) to each other in series and parallel connections.

Series connection: When +ve of one panel is connected to –ve of other

Parallel connection: When +ve of one panel is connected to +ve of other.

The circuit connection of the solar panels is under the panels and is not visible from the front of the solar panels.

Solar Panels Quotation

5. Connect solar panels to the inverter

The inverter is the second most important component of the solar PV system after solar panels. The solar panels generate direct current or DC and we use AC or alternating current in our homes and offices etc. The DC from solar panels can directly power DC running appliances, which are seldom now. But solar panels can charge a battery directly with direct current, which we’ll discuss later.

So DC from solar panels is converted to AC with help of an inverter. The inverter is usually connected to an array of solar panels. The design of the system specifies the output from the solar array and adequate inverter for the same. The inverter connected to the solar array is called a string inverter with a running life of 10-15 years with possible extended warranties from some suppliers.

Another type of inverter is the micro-inverter which is placed with each solar panel. Where string inverter converts DC to AC of an array of solar panels, the micro inverter does that with each individual panel. The life of micro-inverter is around 25 years as that of solar panels and are much safe in system design too.

If a string inverter is connected to the solar array, it should be placed near the main electricity panel indoors. The inverter can be placed outdoors but should be in shade and away from direct sun. The electricity from the inverter is supplied to the transmission line of the house or is connected to the grid as required.

6. Connect the inverter to main electrical panel and grid

The inverter is connected to the main electrical panel to supply electricity to household appliances. If it is a grid-tie solar inverter, the AC electricity from the inverter is connected to the grid with help of circuit breakers.

In a UK household, the grid-tied solar inverter will satisfy the electrical demands of the household during the day and any excess electricity is supplied to the electricity grid the supplier. In UK Ofgem[3] approved system and meter are installed to supply electricity to the grid.

It is essential in a grid-tie inverter solar power plant to match the frequency of the grid electricity to that of electricity supplied by the inverter for optimal operation. Also, the installer should install adequate circuit breakers to shut down the solar power plant or create islanding in case of a grid electricity outage.

7. Connect to batteries, if required

In case solar power is to be used at night, energy storage technologies like batteries are required. Solar panels are either connected to batteries with charge controllers or via the inverter. Additional electricity generated during the day can be saved in batteries and the same can be used at night.

This system is good for locations with no access to the electricity grid. Otherwise installing batteries with a grid connection is an expensive choice with additional space required to place batteries.

The inverter in case of excess electricity supplies direct current to the batteries where it is stored. At night or during very less sunlight, DC electricity from batteries is converter to AC with help of an inverter and supplied to household electrical loads.

8. Safety checks and MCS registration

After installing the complete system the installer does safety checks before starting or commissioning the power plant. All the plugs and connectors with their connections are thoroughly checked.

Also to avail of government benefits, a micro generation certificate is to be applied. As the solar power plant is registered, it can supply electricity to the electricity grid under the SEG scheme.

In the End

Solar panel installation in the UK is underway with great zeal and effort from citizens and the government. It is up to the installer to undertake each installation with great precision and design. From understating the site and specifications to guiding profitable solar panels and components and connecting it to make a long-lasting electricity generating system, the solar installers are the key.

[1] https://www.building.co.uk/focus/solar-pv-panels-heavy-loads/5036590.article#:~:text=The%20average%20panel%20weighs%20in,and%2060kg%20per%20square%20metre.
[2] https://www.solar-electric.com/learning-center/how-to-use-mc4-connectors-cables.html/
[3] https://www.ofgem.gov.uk/

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