This report investigates the feasibility of installing Photovoltaic (PV) panels into the UK private housing stock to achieve the Government’s CO2 reduction targets (34% reduction in carbon emission by 2020 and 80% reduction by 2050) (Carbon Trust, 2008). Furthermore, this report studies whether PV installation is financially viable to the average homeowner in the UK.
Analysing the data from the case studies and the results from the Ecotect computer modelling, it is not feasible to achieve the targets set out by the Government by solely installing PV panels onto all of the suitable roofs into the UK private domestic building stock (Table 6.5). However, the results display that PV technology could play an important part in the UK’s energy system as part of a Government strategy that involves other renewable technologies such as offshore wind turbines in order to increase future energy security and achieve the CO2 emissions targets.
It was financially viable to the average homeowner to install a PV array on the old tariff of 43.3p as a potential profit of £35,111 over 25 years could be generated. However, the revised tariff of 21p means that the average homeowner is better off investing the capital cost of the installation into an ISA account paying an interest 1% (Graph 8.1: How a decrease in the Feed in Tariff will affect the financial rewards of an average domestic PV array).
Case Study map with colour coded roofs to show which houses would be suitable for a Photovoltaic array:
Ecotect Computer modelling allowed me to analyse the annual solar radiation penetrating the domestic roofs which were being investigated:
For further information or to see the full report, please email wtaholley@hotmail.com
PV installation in Camden
The following information displays the practical experience I gained by installing Photovoltaic panels in a residential site in Camden with GreenCap Energy http://www.greencapenergy.co.uk.
The site for the PV panel installation was three flat roofs in Camden, London. First of all, planning permission had to be carried out as the panels would sit above the roof. The planning permission was granted thanks to the Government's Planning Policy on Renewable energy, particularly part (vi) on Small scale projects.
Planning Policy Statement 22: Renewable Energy
National Planning Policies: Key Principles
1. Regional planning bodies and local planning authorities should adhere to the following key principles in their approach to planning for renewable energy:
(i) Renewable energy developments should be capable of being accommodated throughout England in locations where the technology is viable and environmental, economic, and social impacts can be addressed satisfactorily.
(vi) Small-scale projects can provide a limited but valuable contribution to overall outputs of renewable energy and to meeting energy needs both locally and nationally. Planning authorities should not therefore reject planning applications simply because the level of output is small.
As the survey was carried out, there were three possible problems for the installations:
1) The three roofs are completely flat. The optimum efficiency of panels can be achieved when they are installed at an angle of 35 degrees. Therefore, steel brackets were sourced from Belgium to allow the panels to sit at an angle of 10 degrees. An angle of 35 degrees wasn't possible as the higher angle would put the panels in danger of lifting off the roof in high winds and the angle of 10 degrees only decreases the efficiency of the panels by a few percent.
2) Roof lights and vents are positioned on the roof. The panels were therefore arranged to avoid shading.
3) Fitting the desired amount of panels on the available roof space. There has to be a 300mm clearance from the edge of the roof to allow water to run off into the gutter. If this clearance isn't achieved, water will bounce off the panels and straight into the garden which could cause drainage issues.
3) Fitting the desired amount of panels on the available roof space. There has to be a 300mm clearance from the edge of the roof to allow water to run off into the gutter. If this clearance isn't achieved, water will bounce off the panels and straight into the garden which could cause drainage issues.
After solving the possible problems, a roof plan of how the panels would be arranged was drawn up:
The first roof decided to install 10 panels which gives a power capacity of 2.5 kW.
First day on site
The panels ordered were 250 W Mono crystalline Hyundai panels with an efficiency of 15.5%.
The panels arrived in boxes of 25, securely packaged as they are very fragile.
Scaffolding was assembled to allow the team to work on top of the roof safely
Transporting the panels and tools to the top of the roof:
The brackets were assembled from flat pack and allowed the panels to be installed at an angle on the flat roof. Building Regulations ensure that panels cannot be drilled onto a flat roof to avoid water leaking into the upper floors. Therefore, the brackets were weighed down, placed on recycled foam strips which were melted on to the roof felt. This will ensure that the panels are secured to the roof and there is no danger of them lifting off in high winds.
The brackets were kept in line and secured by screwing them on to long steel beams. They were arranged on the roof following the roof plan which was drawn up after carrying out the survey.
The panel was attached to the steel base by specially designed plastic brackets:
Once it was connected, the panel needs to be tested to see if it was functioning properly. This was achieved by connecting a voltmeter / ammeter to the output wires of the panel to record the voltage and amps produced. At the same time, a light meter was used to record the light levels. This allows you to see if the panel is producing a reasonable voltage for the lighting conditions
Once the panels had been tested, they were connected in series. A hole was then drilled into the roof to allow cables to be sent down to the:
1) Isolator - prevent high voltages or rapidly changing voltages from damaging components or distorting transmissions on the other side
2) Transformer - converts Direct Current which is generated from the panels into Alternating Current (AC) which is more readily used in a domestic situation
3) Fuse box - prevents very high currents from damaging components in the house.
Panorama of the roof:
