Solar PV panels

Yes, and you should shop around for the best electricity tariff. The things to look out for are:  Who is charging the lowest unit cost for the electricity that you need to buy from the grid;  Who is offering the highest rate for the electricity that you export into the grid? This payment is known as the Smart Export Guarantee (SEG) payment. As of September 2023 best rate is around 15p per kWh. You do not have to sign up for SEG from your current supplier. You can find SEG rates for different electricity suppliers here; and  If you have [...]

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 [...]

Old style meters don’t, they run backwards if you are exporting to the grid. While this may sound good for you, your electricity supplier will detect this as soon as one of your meter readings is less than the previous one. If you are planning to install solar PV and don’t have an operational Smart Meter you should let your supplier know and they will change it. Smart Meters only record electricity coming into the house from the grid. See advice from Which?. 

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. 

Unfortunately not. 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. 

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 [...]

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 [...]

The p stands for “peak” and 370W is the power of the panel in standardised laboratory tests. It is useful as a comparison between different panels (higher rated panels may be a little more expensive, but you’ll need fewer of them), but what you need to know is the total amount of electricity in kWh that your system will generate in a year.  

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 [...]