Solar PV systems are generally very low maintenance.
There seems to be a difference of opinion on whether it is necessary to clean panels and you can find advocates for annual cleaning (this could cost £100 – £200) while others say that this isn’t needed in UK conditions (but check more carefully if pigeons roost nearby!). Investigate further before getting this done or trying to do it yourself.
The amount of time it takes for you to recoup the initial cost of the solar panel system (the payback time) depends on:
If you can optimise these variables (i.e. a reasonably priced system, good generation, good self-consumption, low rate for buying electricity and high rate for exporting (selling) electricity), your payback could be around 10 years. Once an installer has designed your specific system, payback can be estimated, but will remain difficult to pin down exactly due to the factors that are outside of the installers’ control.
Yes, and you should shop around for the best electricity tariff. The things to look out for are:
At present, Octopus energy seem to be offering the best tariffs, but keep on the look out for others who might catch up.
Any excess, over and above what you are using at any time gets automatically exported to the national electricity grid. Conversely, if your panels are not producing enough electricity to power your home the extra needed comes automatically from the grid. You only have to pay for what you take from the grid.
Solar panels produce most of their electricity in summer and much less in winter, whereas most homes use more electricity in winter and less in summer. On a sunny day in summer your panels could produce 30kWh and not many houses use this amount in a single day. On a dull winter’s day they may produce less than 1kWh.
Typically, for solar panel systems without a battery, you will use about 30% of the electricity that you generate, and the rest will be exported back to the national grid.
If you add a battery, your self-consumption can increase to around 60% as you can store excess electricity generated during the day to use at other times.
Solar panels can be fitted on a variety of different roof coverings. Newer systems can actually replace your tiles or slates and be in-line with the rest of your roof.
It’s important to think about your roof condition before you install solar. It needs to be able to take the weight of the panels, and you need to be confident that you won’t have to remove the panels after a few years to maintain or replace your roof covering. You can seek an independent roof survey or ask your installer for advice.
Also do consider whether you have a sufficiently clear space on your roof. If you have lots of dormer windows or chimneys or other features, they can cast shadows and reduce the amount of space available for the panels. An average panel is approximately 1.7m long by 1m wide (although a variety of different sized panels is emerging) and you need to be able install enough in one area to make it worth the cost of scaffolding.
Yes. For the same total number of panels you will get about 15% less energy over the year from an east-west facing roof, compared to a south-facing one. For other orientations you will get a different percentage, e.g. for a south-west facing roof you will get about 5% less.
However, in summer you will get more electricity from an east-west facing roof early in the morning or late in the evening and you could well find this an advantage. Also, east-west oriented houses (assuming they have a simple pitched roof) have twice the viable roof space of a comparable north-south oriented house.
The amount of electricity that you will be able to generate from your panels depends on:
Electricity generation is not constant – it varies dramatically both across the day and across the year, to reflect the changing levels of light.
This depends on where you live and the orientation of your roof. There is standard data table for the UK that provides one single factor for Cumbria.
The power of typical solar panels is currently around 400Wp (the p stands for ‘peak’ and 400W is the power of the panel in standardised laboratory tests). For a 12 panel system, the total power is therefore 4.8kWp. Using the standard Cumbrian factor, this will result in an estimate that the system on a south-facing roof, will generate around 4,000 kWh per year.
However, there is a variance across Cumbria since some places are sunnier or cloudier than average. So be mindful that the quote you receive might be an over- or under-estimate of what your system will produce. You can explore the differences across Cumbria on this map.
This depends on the size of the system, the manufacturer and spec of the equipment, how easy the panels are to install and whether you need any work to your roof or electrical system. It also depends on whether you add a battery.
A typical solar PV system for a family home, consisting of about 12 panels with a battery would cost around £11,000, of which the battery would be about £3,000.
The major components of panels that are mined and processed are quartz, copper and aluminium. Various attempts to calculate how much greenhouse gas is produced in the mining of these materials and the manufacture of panels suggest that this is recovered by production of carbon-free electricity in about two years. This is regarded as a good return on investment, particularly as panels are expected to be used for well over 25 years. So from a global warming perspective they have a positive environmental impact.
However, there can be negative social and environmental impacts from the mining process, which depend upon where the minerals are sourced and how well the mines are managed. Panels made from ethically sourced materials do exist, so it is worth asking your supplier about this (even if just to get them thinking about it). Ethical Consumer rank different panel manufacturers, but you do need to subscribe to them to access the rationale behind their scoring. Recycling at the end of their lifetime is yet to be fully solved, but once well-established, this should reduce the need for new raw materials.
There are more serious social and environmental issues around the mining of the materials used in electrical batteries, which are mainly lithium, cobalt, nickel and manganese. Again, there is significant work to be done to up systems and facilities for recycling these batteries, as well as research and development of alternative battery technology that avoids lithium in particular.