September 2022 update:

Thank you to those who helped with the September walk around.

If you missed our walk around then there will be a STEM practical activity for children and parents at St Mary’s Church on Saturday 15th October from 9am until midday.

The St Mary’s site has 3 buildings: the church, the presbytery and the parish centre.

Church

The church is a listed building and as such would be potentially complicated to cover in solar panels. Irrespective of this complication, we still assessed its potential. It has an East-facing side and West-facing side to the nave roof with shading coming from the Pugin tower. It also has a an East-facing side aisle roof and a West-facing side aisle roof that theoretically could have solar potential. The West-facing aisle roof is actually hidden from view. It may be that the church would benefit from solar tiles rather than solar panels and this would be best done in the future when it next needs to be re-roofed. The panels used in the assessment process are thus indicative of solar potential rather than a preferred approach.

The East-facing nave roof is around 7° North of East but is shaded by the tower. The solar tile area would be equivalent to 60 panels. The roof pitch angle is around 42°. The West-facing nave roof is around 7° South of West and is shaded by the tower.

The East-facing side aisle roof is shaded by the tower and church and has a pitch angle of 24°. It could accommodate a solar tile area equivalent to 48 panels. The West-facing side aisle roof is similar.

The East-facing lady chapel roof is heavily shaded by the church and is not suitable for solar generation. The West-facing lady chapel roof could be covered by solar tiles equivalent to 54 panels. It has a steep pitch angle of 56°.

Roof	Equivalent Number of Panels	kWp (assume equivalent to 300W panels)	kWh/year (unshaded)*
Nave East	60	18	12807
Nave West	60	18	13542
Aisle East	48	14.4	9516
Aisle West	48	14.4	10210
Lady Chapel East	(54)	(16.2)	(10659)
Lady Chapel West	54	16.2	11420
Total	270	81	57495

* Estimate from europa.eu, Aisle East and West have had modified horizons to account for the nave blocking light but the tower shading is not included.

Presbytery

The presbytery is set down to the East of the church and has an East-facing largely unobscured roof and a West-facing roof that is partially shaded by the church and tower. It also has three chimneys that create partial shading that sweep round the roof. The East-facing roof has a cross gable which reduces the area for panels slightly.

The East-facing side is around 22° North of East and has a small chimney close to the ridge at the Southern end and a larger central chimney. The maximum number of panels that can be accommodated is 28 (it may be preferable to remove panels around the central chimney). The roof pitch angle is 40°.

The West-facing side is around 22° South of West and has a large chimney that shades the Northern section. The Southern section could accommodate 13 panels (10 comfortably) and the Northern section 18 panels. The roof pitch angle is 40°.

Roof	Number of Panels	kWp (assume 300W panels)	kWh/year (unshaded)*
East (Northern section)	16 (12 better)	4.8	3156
East (Southern section)	12	3.6	2367
West (Southern section)	13	3.9	3162
West (Northern section)	18	5.4	4378
Total	59	17.7	13063

* Estimate from europa.eu

Parish Centre

The parish centre is the most obvious building for adding solar panels on. It has one large East-facing roof with little shading, a small South-facing roof with some shading and one extensive West-facing roof with significant shading mainly from the tall church building to the South. The flush windows in the roof mean that the solar panel array would need to fit around them. It appears that it would be possible to fit a large number of panels on the roof but due to shading some on the South and West sides will be in shade some of the time.

The East-facing side is around 18° North of East and is split into a Southern section (maximum 12 panels) and a larger Northern section (19 panels in the example above although more are possible) both with roof pitch angle of 25°.

The South-facing side is 18° East of South and has a pitch of 37° and could fit five or six panels.

The West-facing side is 18° South of West and has a pitch of 25°. The arrangement in the example has 33 panels. It is possible to put a fourth layer of panels at the bottom of the roof although this lowest layer would be shaded more than the layers above.

Roof	Number of Panels	kWp (assume 300W panels)	kWh/year (unshaded)*
East (Northern section)	19	5.7	4104
East (Southern section)	12	3.6	2592
South	6	1.8	1685
West	33	9.9	8031
Total	70	21	16412

* Estimate from europa.eu

Project Background:

We are looking into the feasibility of solar panels at St Mary’s. As part of this we will start with a practical walk around at 09:00 on Saturday 3rd September. This is a STEM (Science, Technology, Engineering and Mathematics) activity which may be of interest to children and parents as well as parishioners keen to help with this exciting project! We will try and measure building dimensions, roof angles and orientation (if you happen to have a long tape measure or large protractor or a North locating compass then please bring them along – if not then don’t worry as we will have some we can share). We will talk about the solar angles from the position of the sun in the sky, consider what happens in different seasons and look at shading. This event is a local event during the Season of Creation. Look at some of the global events too here.

Can’t make the day? Get in contact using our contact form with your availability and we will try and organize a repeat in September or early October.

Keep an eye on this page for project updates!

If you are keen you are very welcome to start preparing…

Look at Google Maps to understand the position of the church buildings

Make a sketch of the buildings noting North and ready to write down the measurements on the day:

Many thanks.