Energy Audit for St Mary Redcliffe Church, Bristol

The pinnacles along the parapet could cause some shading issues and therefore it is recommended
that any potential array is installed with a solar edge or micro panel mounted inverter which will
reduce any losses if panels are partially shaded. In the calculations below and allowance of 25%
shading has been made in light of this issue.
Having run the various calculations given the area and dimensions of the roof it appears that the
best layout and size of array is to consider two rows of 30 panels giving 60 panels in total. This would
provide a 15kWp system.
Such a system has been estimated to cost in the region of £22,000. (This excludes VAT that the
church may be able to recover).
The system, once shading, orientation and pitch, have been considered, is estimated to generate
9,968kWh per year. As such it would provide 17% of the churches current electrical consumption
although with a low energy lighting scheme this could increase to providing around one third of the
electrical needs of the church.
The PV system would benefit from 20 years income from the governments Feed in Tariff scheme and
if installed in the near future would ‘buy-in’ to this scheme at a rate of 12.57p/kWh for every kWh
generated. In addition the church would gain from any electricity exported at the rate of an
additional 4.64p/kWh. For most of the time the church will, rather than exporting the electricity, use
the electricity on site and therefore avoid purchasing electricity at the current rate of 10.03p/kWh.
For the purposes of calculations it is assumed that a site uses 50% of the energy it generates and
exports 50% of the energy however it is likely that the church will use a greater percentage of the
energy generated and therefore the savings figures are slightly conservative.
Given all the above the system would generate savings and income totalling in the region of £2,000
per year. This would therefore deliver a simple payback of 11 years. Once energy price inflation is
factored in the payback is estimated to be 9.5 years and provide an annual return on investment
(RoI) of 7.9%.
The installation would require a mobile crane to lift the panels and ballast onto the roof and for edge
protection to be temporarily added to the parapets for safe working on the roof. The works would
then be carried out with the contractor gaining access up the tower stairs.
For further details on a potential PV system contact Solar Solutions Malvern Ltd, 01684 893000
David McCann (Managing Director), 07824 832274, david@solarmalvern.com .
Funding in forms of grants, for the installation of renewables mostly stopped with the Feed in Tariff
introduction a few years ago and it is not possible to use money from public sources (which includes
Lottery Grants) to fund renewable installations and gain from the Feed in Tariff (or renewable heat
incentive) as this would be against the European State Aid rules. The use of more local ‘trust’ based
funds can be possible as can the use of some of the Landfill Tax Credit schemes although care needs
to be taken on how these are structured as some allow such schemes and other do not.
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