This article is a general overview of ‘typical solar’ UK solar requirements. Look for the article on detailed solar estimate calculation – how much solar energy your can generate from your own roof in over the course of a year.
You don’t need to have done a lot of research to deduce that the consistency of solar in the UK over the year is not as good as other parts of the world but there is a school of thought that says all is not lost if you want to be ‘more green’ and or save a little on your bills.
From October to February overcast skies and drizzle are the norm for UK skies. Typically, energy bills go up in winter due to heating needs (According to the Met Office – UK temperature drops from 21degC to 7degC ) . Winter also comes with increased lighting requirements (shorter days in the northern hemisphere). Some typical scenarios that may lead you to consider solar include:
- Heavy user of electricity (e.g. home with no gas heating or household with an Electric Vehicle)
- Increasing electricity market costs
In both the above you will likely need to consider a home storage battery to make it all work. Domestic Solar in the UK can offset (or even payback) electricity costs in a significant way for certain circumstances, this can be checked with a few calculations.
Firstly, perhaps consider what kind of energy user you are:
- Are you away at work during the day? So no energy consumed by the home in the 9am-5pm slot but then heavy use for cooking etc between 5pm and 10pm. If you have solar panels but are away from home most of the day it means when the sun shines a lot of this energy is exported to the grid and your beneficial use of solar is limited because the sun has gone down by the time you return home from work. In this situation, a battery may be the solution you need to ensure that during the day your generated energy is stored for your use latter in the evening. This is perfect in the summer months because depending on the size of your battery you can end up in a position where you are self-sufficient from solar alone. Combine your solar and battery with the SEG (Smart Export Guarantee) and a good tariff you can then export your energy onto the gird and buy it back at the same price or lower (if you search for some of the good tariffs out there).
- Or do you spend most of your time at home? This might be typified by a consistent use of energy across the whole day. This situation means you can probably directly self consume solar energy generated by your panels. However to maximise the benefit you would need to be proactive at switching your equipment on and off at the right time to maximise solar consumption whilst minimising grid imports. If it starts raining heavily in the middle of the day after you’ve just switched your tumble drier on then you may and up drawing energy from the grid only to find it because sunny again after your load has finished. A battery will help smooth your energy availability in this scenario.
- Can you shift your energy use? Does your energy consumption comprise of loads (equipment) that can be flexibly operated at different times?(e.g. washing machine) This scenario means that you can take advantage of the solar when power is being generated but also utilise the competitive ‘time of use’ tariffs to avoid high energy cost periods and take advantage of lower cost. This approach would also benefit from a battery (you might be seeing a pattern).
Some of the early purchasers of solar panels who did not think through their energy use profile may have felt as sense of regret upon realising that their generated energy was being exported onto the grid or simply not being used at all whilst they were away from home during the day (we certainly feel this way when can’t consume it ourselves). Battery technology has advanced greatly in the last 10-15yrs, it is still not cheap but costs have come down and designs have become more domestic user friendly (look out for the blog on batteries!).
If you are a heavy electricity user, you need to calculate what size solar system your need to install to be able get to free use during the summer months such that you offset your winter use and costs (see the Detailed Solar Estimate Calculation blog).
For example, if you spend £1,000 per year on electricity, with £50 spent each month on charging the EV throughout the year and the rest made up of £300 spent in winter (October to February) on home heating + light) and £100 spent during the summer (March to September). Then a big enough solar panel and battery system can mean that you have the potential to save as follows:
- £300 (for EV charging) + £100 (home use) + £50(SEG) = £450 during the summer months.
- Using battery and smart tariffs reduce cost for winter use to 1/3 = £100 (EV charging) + £100 (home use) which saves £200
- Therefore the system overall would save £450 +200 = £650 over the year.
- For a system of £9,000 then payback in this scenario can be 15 years
Final thoughts, 15years for payback sounds like a long time however the following points are relevant:
- if you plan to live (and or retire) in your home for the foreseeable future then 15 years could easily make sense – image no electricity bills.
- if energy prices rice feel like they are a future risk you want to mitigate
- if you think you house price will increase over time then the cost of such a system could be accommodated within that (this is not the same as saying solar will increase your house price!)
- it is not all about payback! We buy and treat ourselves to things all the time that we will never get payback for (e.g. holiday, flashy car, Nandos takeaway!). It can easily be forgetting that this can solar pv systems can just as easily be a feel good purchase.
Good luck with your research.
3nergyTech 