Domestic solar electric frequently asked questions.
I want to reduce my bills, but is Solar PV still a good investment?
Most Solar PV systems are grid-connected, enabling solar-generated electricity to be fed directly into a building's existing mains supply. Power generated from a Solar PV system reduces the electricity your household imports from the grid, subsequently cutting the cost of your bills. Any excess 'green' electricity not used by your household is fed back into the grid and, in effect, purchased by your energy supplier in the form of Smart Export Guarantee (SEG) payments. Some benefits of installing solar:
- You'll be paid under the SEG scheme for the electricity you export to the national grid.
- The electricity you generate and use in your home saves money on your electric bill. With our systems lasting 25+ years, this is thousands of £'s in electricity.
- It's green energy which reduces your household's carbon footprint and helps the environment.
- It adds value to your home.
Solar PV system's consist of three main elements:
- - an array of Solar PV modules
- - an inverter(s)
- - cables, display and switchgear
Image taken from: http://www.caplor.co.uk/talk-to-us/how-works/how-solar-pv-works/.
The inverter is an electronic device that converts solar panels' solar electricity (DC) into AC electricity with the same voltage and frequency as the mains supply. The inverter is also outfitted with various safety features, constantly monitoring the grid and switching off in the event of a fault in the mains supply.
The output of the inverter goes directly into the building's fuse box - feeding solar electricity into the building's electricity supply. This means you will not have to purchase as much electricity from your supplier, making your household more energy efficient whilst cutting bills.
Do PV systems work in the UK?
Absolutely! Solar PV systems are very effective in the UK. The government's new 0% VAT policy starting from April 2022 for the next five years makes it an ideal time for UK homeowners to install solar panels, reaping the benefits of the solar electric system and significantly lowering energy bills.
How is the solar electricity used?
The grid-connected PV system output is fed directly into the households existing circuits, usually through the main distribution board. Apart from lower electric bills, there is no difference between the electricity generated by the solar panels and the electricity bought from your supplier.
What happens if the system generates more than the building is using?
If the Solar PV system generates more electricity than your household currently uses, all excess is exported to the grid. Export occurs automatically and can be measured (and income collected) using an 'export meter'.
How long will my PV system last?
Most solar panels come with a 25-30 year guarantee, and inverters generally have a 5-20 year guarantee depending on the manufacturer. Sustainable Energy Engineering provides a 10-year customer workmanship warranty on all its installations. There are PV systems still working after 40 years, so systems should last much longer than the stated 20 or 25 years.
What range of roof pitch is acceptable?
The ideal roof pitch is between 30 and 45 degrees from horizontal. However, pitches between 5 and 60 degrees will still function well with less than 10% efficiency loss for a south-facing roof. Given the current 0% VAT policy, installing solar panels has become more affordable, making it a great time to invest and have a free survey by Sustainable Energy. We can provide specific output and return-on-investment estimates.
We would like a PV system, but have heard they are costly and will take years to repay?
We install systems to suit our customers' needs; we will design a system for your budget. The UK Government has significantly eased the cost burden by reducing VAT on solar panels to 0%. This and the substantial savings on your energy bill could see your investment pay off in less than ten years.
| Size of System in kW | Orientation and Pitch | Shading | Electric Generated Per Year |
|---|---|---|---|
| kW | Kk | SF | kWh |
| 4.35 | 900 | 1 | 3915 |
* Typical panel April 2024, is 435W and 10 x 435W = 4.35 kWp.
| kWs Produced | |||||
|---|---|---|---|---|---|
| 3915 | 0.5 | 0.15 | Additional | £293.63 | Payments from energy company for energy sent back to them. |
| 3915 | 0.5 | 0.29 | Average Electricity | £567.68 | savings from electricity by not buying it from the energy company. |
| Total | £861.30 | Annual payback. | |||
| Cost of system exc VAT: | £5,300.00 |
| Return on investment: | 16.25% |
| Payback period in years: | 6.15 |
| CO2 saved from PV's: (kg) | 1683 |
| Cost of system inc VAT: | £5,300.00 |
| VAT at 0%: | £0.00 |
Do I need planning permission?
Generally, PV systems are classed as a permitted development. Listed buildings and sites in AONB would need to seek advice; however, planners look very favourably on PV systems and are under pressure to accept them.
Do PV systems need regular maintenance or servicing?
Solar PV systems have few moving parts, so there's little that can wear out. However, the MCS guide and manufacturers recommend that systems are serviced to ensure that connections are sound and roof fixings are secure. Also, in some locations, a build of dirt on the panels can reduce output, so we recommend cleaning them. Keep in mind that maintenance costs are part of your overall investment. With the new 0% VAT scheme, the initial cost of installing your PV system will be significantly lower, making now a great time to invest.
What is a Solar PV panel?
Photovoltaic panels are made up of a large group of PV cells that convert light into electricity. A standard PV cell contains a wafer of silicon that has been manufactured with a 'p-n junction' inside. This junction creates a border between the 'p type' and the 'n type' silicon. Light frees these electrons inside the silicon, and the electric field of the p-n junction then picks them up. Small metal contacts running through the cell will then take the electric current that has been produced to a central point on the back of the panel. The cells are compressed between a sheet of glass and a laminated backing sheet, which is generally fixed within a rigid aluminium frame. The frames were traditionally silver but are increasingly anodised black to give a more aesthetically pleasing look.
What's the life expectancy of a PV system?
A typical Solar PV system can last between 25-40 years. Furthermore, the 0% VAT incentive on energy efficient systems such as Solar PV is a wise long-term investment for your home. Not only will you significantly reduce your energy bill, but you'll also be contributing to a more sustainable future.
What if my roof is shaded?
Shading can impact the efficiency of solar panels. However, modern systems can minimise these effects. Considering the newly reduced 0% VAT on solar panels, investing in top-quality, high-efficiency solar panels that can mitigate the effects of shading has become even more affordable. Also, hiring a professional solar panel company can make all of the difference, so please don't hesitate to contact Sustainable Energy today.
Do I need to inform my electricity supplier if I have a PV system installed?
You must inform your electricity supplier once a PV system is installed.
Can I heat my water with a PV system?
Absolutely! You can heat your water using solar energy with the correct system setup.
What are monocrystalline and polycrystalline cells?
Monocrystalline and Polycrystalline describe the type of silicon used to create the PV cell. Polycrystalline cells use multi-crystalline silicon, which is cheaper to produce as it is created from a patchwork of individual crystals. Consequently, this makes it slightly less efficient than the monocrystalline cell. The Monocrystalline cells use a wafer cut from single-crystal silicon, usually cut from an ingot. Monocrystalline cells are usually identical in appearance; however, polycrystalline cells look slightly different because of the patchwork of individual crystals.
How is a system sized?
Solar PV systems are modular; they can be almost any size necessary. The size of the PV system usually depends on the available roof space and the customer's budget or is designed to hit a certain percentage of a building's electricity needs.
