Solar PV on UK Homes: A new build requirement

In 2018, I have been running a petition on the UK Parliament website asking for a Parliamentary Debate that every new home in the UK should be installed with solar panels. I still believe that solar on all new build homes should be mandatory through building regulations to ensure that all new homes save money from day one on their energy bills. As a new build home, the costs of installation of solar are minimised and the payback would be short for most UK homes. Building firms follow regulations and this would be the correct way to implement the policy. Having worked myself with the Microgeneration Certification Scheme (MCS) on their standards and calculators, I know that the savings are real and significant.

You can find the petition here.
https://petition.parliament.uk/petitions/218223

And my press release is here:

Petition for Solar on all New Homes


Why should solar be mandatory on all new build homes?

The reasons for doing so are threefold:

  1. Through my years working with solar and batteries I know that they can save people money and the economics of solar and batteries gets better every year.
  2. Installing solar on a new home is cheaper than retrofitting them because it reduces the cost of sale, allows components to be bought in bulk and there is already safe roof access with scaffolding. Reducing the cost offers the best value for home owners and renters, both rich and poor.
  3. As shown with the EPC standards for homes, building companies need to be regulated if they are to install any energy saving equipment which benefits householders.

To make the case for this, I thought it best to share some insights from my PhD on solar PV pricing and the returns it could bring over 25 years (the duration of the manufacturers warranty for solar panels).

Saving people money

A simple calculation for Sheffield would be as follows:

  • An average system (3.6kWh or 12 panels) will generate 2,875 kWh per year in Sheffield according to calculations from the UK certification scheme for microgeneration (the MCS). A link to their calculator is in my assumptions below.
  • According to research conducted by Loughborough University, 47% of this will be consumed by the house (for a family home half of the day). This consumption reduces the homes electricity bill and the rest is exported to the grid to reduce national carbon emissions.
  • All of my price and modelling assumptions are given at the end of the blog. The calculation is based on average values and publically available information.

If we do a quick calculation over 25 years to give a return and a payback period, we find some pretty impressive results due to the savings brought about by installing solar on a new build home. I’ve done this for four cities in the UK.

Cornwall: 9 year payback, 13% return
Sheffield: 10 year payback, 11% return
Edinburgh: 10 year payback, 11% return
Lerwick: 13 year payback, 9% return

The Building Industry Needs Regulation

With tens of thousands of homes being built in Britain, there will always be variations which mean the economics above are better for some and worse for others:

  • To ensure value for money for all: I would like to see the policy implemented in such a way that each new home has to undergo a cost-benefit analysis using a nationally recognised and enforced calculator. If the returns of that analysis are above a threshold return (9%) and a 10 year payback then the house builder should be mandated to add solar panels. This shall be submitted as part of the planning process. Homes that don’t meet that criteria won’t have to have solar installed.
  • To ensure meaningful system sizes, builders would be mandated to install 3.6kW or within 20% of the maximum number of panels that can be installed within the national returns model (whichever is lowest).
  • The installs shall be completed in accordance with the Microgeneration Scheme and the calculator administered by MCS or Ofgem.
  • The calculator will of course account for shading and local weather (as is standard for all UK installs completed under MCS) and use a standard price model.

There are already recognised and well managed calculators for energy saving in homes (e.g. the SAP calculation) with mechanisms to assure compliance. This is just an extension of the above.

Cheaper than Retrofitting

Ultimately, installing solar on a new home is usually cheaper than retrofitting it after a family moves in. It’s a great opportunity to save money on the installation cost and to start saving money from the day the home is occupied.

Conclusions

I think this result is quite clear:

  1. The payback period is good and the internal rate of return is strong
  2. Over 25 years, this saves a family over £8,000 of electricity.
  3. The system adds less than 1.4% (£3,000) to the price of a UK home before savings in roofing are considered.

What you can do to help

If you believe in this petition, I ask that you share it widely and gain support. This petition will work with grass roots support, from people like you using their networks to spread the message and from you making the case to others (if you agree with me).

I will be releasing a series of blogs over the next few weeks, responding to questions and answering any criticisms that come up plus some work on storage too. Having studied and worked on this issue for 6 years now, I felt wrong not to share my knowledge with you.

Share this link: https://petition.parliament.uk/petitions/218223


Assumptions

In the above, I made the following assumptions

  • Homes pay 12p/kWh for electricity and electricity price inflation is 5% per annum
  • Solar electricity not consumed in the home is automatically sold to the grid at 5p/kWh at a 2.3% inflation rate via a smart meter or deemed export rate.
  • The solar panels are unshaded 95% of the time
  • I have not accounted any savings of using solar roof tiles etc. which replace actual roof tiles and reduce the cost of the build BUT I have included an estimate of the engineer to install the panels.
  • I’ve carried out a survey of retailers to get an average install price for solar PV on a UK home. I then estimated that 30% of this price is lost on a new build home due to the cost of sale, the margins of the retailers and that a house builder can buy in bulk with a big solar company to reduce the cost of key components.
  • I have included replacement of the solar inverter at the end of it’s warranty (10 years). I don’t include any other maintenance costs, because there are hardly any.
  • Economic benefits of carbon saving are not calculated, although these can be found at https://www.gov.uk/government/collections/carbon-valuation–2
  • I don’t include any subsidy in the form of a generation tariff.
  • My homes don’t have electric heating or air conditioning – either of which improve the savings.
  • I use a model from Loughborough University to assess the amount of solar consumed on site each year. The amount increases by 0.5% per year as customers get better at using solar and electrify heat and transport.
  • Solar PV generation is calculated for a 30degree roof using MCS standard performance calculations https://www.microgenerationcertification.org/mcs-standards/installer-standards/solar-pv/

Further Reading

http://www.lse.ac.uk/GranthamInstitute/news/do-green-mortgages-work/

https://www.solarpowerportal.co.uk/news/e.on_throws_weight_behind_uk_solar_as_policy_cliff_edge_looms

Author

  • I am an electrical engineer, using energy storage to reduce electricity costs around the world. This was the focus of my PhD. I now work on projects in the UK, East Africa and South America integrating energy storage into the electricity system. The content of this website only represents my own analysis and not necessarily that of any of my employers.

17 thoughts on “Solar PV on UK Homes: A new build requirement”

  1. Solar and Battery Storage would be a better solution than just PV on new houses as the home can produce and store energy for use during the night.

  2. Its a pity this could not be directed to GB, we dont want to know about the UK!
    Solar panels on new homes sounds a good idea,well to the utility companies who will give a pittance for the energy, and then charge consumers extra. Solar panels consume energy to make and create more CO2, and the extra problem with the glass and silicon used for the manufacture. We are already being ripped off now!

  3. There is no need for additional PV in the UK

    Over the next 5 years the UK grid will be very low fossil fuel usage thanks to the infrastructure already under construction or planned to be built in the next 5 years. For instance 3.4 GW links to France and 1.4 GW link to Norway are under construction. That alone will reduce UK gas fired generation by upto 40TWh (but more likely ~25TWh) An additional 2GW link to France is under investigation and if built could import another 16TWh but more likely ~10TWh

    If 10 GW of offshore wind capacity comes online over the same 5 year period that is another 35 TWh in annual non fossil generation

    So some 70 TWh of non fossil fuel energy will displace gas fired generation leaving the UK grid very green

    Any additional PV from now on is likely to be a waste of money and importantly just additional waste generation (in the manufacture transport and instillation pf PV)

    Just take a look at this weekend for example
    No Coal fired Generation
    Gas fired only averaged about 5GW over the weekend
    With 5.4 GW links to 1.4 GW link to Norway and 10 GW of additional offshore wind power the result would likely have been 100% green power this weekend. So any additional PV generation would have just been a waste of resources

  4. On new build homes, are there any issues with the home owner being tied into a contract with the energy/solar company and causing problems when they wish to sell and move home?
    I know this is a problem for many people who have had solar panels fitted.

  5. Despite massive Residential new building in our town and area I haven’t seen a single built in solar panel.

  6. Money better spent on low Gwp heat pumps. If they can also heat water for domestic use, and supplemental heating. Induction cooking reducing domestic gas consumption pollution in your nose,co2 for whatever. Your new well sealed and insulated house will require a large exhaust fan . How many CFM? Pryic victory design at its best ! Non flamable insulation,,,, however you say it in the U.K., or GB. Rock wool is my favorite. Better wiring standards reduce the loses in household wiring to as close to 2% as you can get. Pay back is slow but fire risk decreases also. Ban PVC insulation on electric wires. Go to XLPE insulation or what ever you like . The wire required for you solar instillation will be this or similar specification. The IEC spec refrigerators use in many countries are a disaster. UL spec did something right. The use of fire proof insulation or intumescent paint between the compressor, and storage area of the frig should also help. The fires reported by the London fire bragade, and their videos of frig fires is quite striking. From looking at data on your site energy conservation is still ahead of solar. Where I am 5.5 hours of sun per day. Many similar problems.

  7. The petition is now closed. Please could you start a new one.. Let’s get solar panels compulsory on all new builds

  8. pease start a new petition
    I am sure that this time it would be shared and signed by many more

  9. Why not a petition to mandate all boilers/cookers to be hydrogen ready. This is going to be the hardest sector to replace unless the infrastructure is ready. By starting now then in 20-30 years time there will hopefully be very little re-medial work necessary to fully switch to hydrogen supply.

  10. The first bullet point in the Petition begins “An average system (3.6kWh or 12 panels)…”
    Do you not mean 3.6kW rather than 3.6kWh ?

  11. New build should have pvs and where a number of houses built should enable battery storage and also rainwater harvesting

  12. I think this is a good idea but making it mandatory is not always the best solution. If the assumption was that new build would have a minimum level of green energy generation and storage or the builder would need to obtain a license for the build to be excluded in circumstances where installation is not advantageous. I assume your calculations are based on south facing non-shaded roof space which is not always practical to achieve.
    We are now I believe in a position where occasionally the retail price of electricity goes negative, if we are going to add generation capacity of this type it needs to come with storage capacity, used automotive batteries of the type fitted to PHEV and BEV vehicles are ideal for this, I used to work for a manufacturer of these vehicles, our batteries had to deliver 127 amps at maximum draw and had to except fast charging both lead to loss of battery performance, when the batteries no-longer give the required output for automotive use they are still excellent for domestic purposes where the maximum output is never required and the rate of deterioration is negligible.

    I thoroughly agree with Bryan Lewens above rainwater harvesting should be included in this assumption, flushing toilets etc. with potable water is an environmental disaster

  13. I think your petition for solar PV needs to be run annually. People have short memories and not all look where & when these are submitted.

    I thoroughly agree with Bryan Lewens above, rainwater harvesting should also be mandatory.

  14. “John Hopkinson
    May 24, 2020 at 11:18
    The first bullet point in the Petition begins “An average system (3.6kWh or 12 panels)…”
    Do you not mean 3.6kW rather than 3.6kWh ?”
    John is correct and I am somewhat concerned this error has not been corrected over a year later.

  15. The Peak District National Park still has a policy of refusing planning permission for air source heat pumps. I know this as I retrospectively applied having installed a system to replace a solid fuel heating system and was refused permission. There were no objections.
    So it needs to be taken out to comply with their policies.
    Is this mad or what???.
    It was three times the capital cost of a Gas boiler, but I would have had to install gas so I seemed it a greener alternative. Is it back to solid fuel??
    By the way they also do not allow solar panels on houses in conservation areas or Listed buildings. So it is hard to save the planet in this area.

  16. Could we have a different colour for storage in mygrid pie chart ? As it currently looks identical to off shore wind!

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