Solar Photovoltaics (PV)

20 photovoltaic panels with a peak output of 3.7 kW

The principle in the case of this technology is to directly convert the Sun’s energy into electricity using silicon semi-conductor technology. Panels can by quite small (1 metre square) but are modular, such that a very large system of several tens of square metres could be developed. The average system on a house in the UK would be about 4 square metres. The PV panel would normally be connected to the local electricity network and the energy sold to an electricity company to maximise the use of the energy from the panel although you could have a system which allowed you to use all of the energy in your home. An average costing panel will produce about 75 W per square metre on a bright day. PV panels like solar thermal panels should be oriented to the south and should not be overshadowed by buildings or trees as this will have a detrimental impact on the output of the system.

When information on PV systems was first published on the website of the Esk Valley Community Energy Group in 2011 Government incentives made them both practical and economic in North Yorkshire. Modular solar panels are put together in arrays, with £10,000 of panels producing 3 kW in strong sunlight and providing a return of £670 per year as estimated by the Energy Savings Trust.  Electricity not used can be sold to an electricity company.

Incentives have been reduced many times since 2011, sometimes drastically and sometimes more gradually.  Although panels have increased their efficiency and have become considerably cheaper the savings in electricity bills and Feed-in Tariff or Smart Energy Guarantee returns will no longer allow recovery of the financial investment required within a few years as was possible in the past.  But if you are prepared to take a long view and do not factor in the cost of the capital required the savings and returns over the life of the system will be more than the costs.  Very approximate costs and returns for PV panels in the North of England (based on Manchester) are available from the Energy Saving Trust web page Solar Panels.  More precise figures for your own location can be found by using the Energy Saving Trust’s Solar Energy Calculator.

Even though the economic returns are not as good as they were there certainly will continue to be a return in terms of carbon saving.  Approximate estimates and more precise predictions are available by using the Energy Saving Trust’s web pages Solar Panels and Solar Energy Calculator.

See our page on Financial support for energy saving and generation.   The section on that page relevant to this technology was the one on the Feed-in Tariff but for a new system you need to know about the Smart Energy Guarantee that first became available in 2019.  The Green Deal may also be relevant as a possible source of loan funding for domestic  installations.

Now that the Feed-in Tariff has been replaced by the Smart Energy Guarantee payments for export to the grid are less than the cost of importing electricity it is important to use the system to cut down on imports as much as possible.  For example electric appliances such as washing machines are best used on sunny days.Electricity may be used for heating domestic hot water.  If there is a large hot water requirement surplus electricity generation can automatically be diverted to water heating instead of export with appropriate equipment as in the GOH 2015 Case Study Guisborough 1980’s home.

With the new system of financial support it may be more worthwhile considering battery storage.  There is an introduction to the topic with some external links our page on Financial support for energy saving and generation.   We do not have any experience ourselves nor do we know of local examples or experience so cannot give any further advice.

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Have a look at our information on choosing an installer if you plan to install this technology.

For local case studies that generate photovoltaic electricity follow the links below

1. GOH_2014_Case_Study_1900_End_of_terrace_home

2. GOH_2014_Case_Study_Victorian_Eco_Renovation and the article A Local Eco House Renovation part 2: Generating green energy with a solar photovoltaic (PV) array

3. GOH_2014_Case_Study_Maisonette

4. GOH_2014_Case_Study_1991 Stone built house

5. GOH_2014_Case_Study_Home_by_the_moor

6.  GOH_2014_Case_Study_1860s stone built house

7.  GOH_2014_Case_Study_Farm in Glaisdale

8. Green Open Farm Case Study Dunsley

9.  GOH 2015 Case Study ‘Heatherley’

10. GOH 2015 Case Study Guisborough 1980’s home

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