14 kW Solar on Grade II South London Parish — 74% Self-Consumption via Daily Food Bank

The parish

A Grade II listed Victorian parish church in Peckham, built 1874, in the Diocese of Southwark. The church occupies a corner site on a busy residential street and operates some of the most intensive community use of any parish church we have worked with: a daily food bank (open six days per week, serving approximately 180 households per week), a registered nursery (Monday to Friday, 25 children), a Thursday evening youth club, and a weekly Saturday evening community dinner. The church building also hosts three rehearsal groups and runs a debt counselling service with Citizens Advice.

Electricity spend in 2023: £7,400. Gas: £4,200. Total: £11,600.

The self-consumption opportunity

Sunday-only church sites typically self-consume 25–35% of generation — the majority is exported to the grid at wholesale SEG rates. Peckham was different. The food bank’s refrigeration, the nursery’s heating and cooking, and the evening youth club represent near-continuous electrical load from 7am to 10pm on six days a week. Our initial modelling forecast 72–76% self-consumption — meaning most of the generation would offset retail electricity at 22p/kWh rather than be exported at 10p.

This fundamentally changes the economics. At 74% self-consumption on a 14kW system:

• On-site consumption value: 8,450 kWh × 22p = £1,859/year
• SEG export value: 2,950 kWh × 10.5p = £310/year
• Total annual benefit: £2,169 in year 1

The PCC noted that the food bank had been their largest single worry regarding energy costs. Keeping the food bank’s freezers and fridges running through the winter accounted for a significant proportion of the electricity bill. Solar with battery storage directly offset this cost.

The faculty application

Faculty application submitted to the Diocese of Southwark in September 2024. The Diocese of Southwark DAC has processed several dozen solar applications since 2019 and has a clear guidance note for applicants. The Southwark DAC is generally supportive of solar on Grade II listed parish churches where the panel placement is on non-prominent slopes with appropriate heritage care.

For this church, the only suitable roof face was the north transept south slope — an awkward geometry that required custom panel layout to avoid the existing roof lights. The diocesan architect reviewed at design stage and suggested reducing the array from 16kW to 14kW to avoid the roof lights and maintain a clear 1-metre perimeter setback from all valley gutters.

Application package:

• Statement of Significance (1,100 words, referencing the 2021 quinquennial)
• Statement of Needs (950 words, emphasising food bank and nursery community benefit)
• Detailed drawings including plan view of proposed array
• Conservation impact assessment
• Structural engineer’s certificate (the 1874 structure has traditional rafter/purlin roof — load confirmed adequate at 14kW with appropriate spreader plates)

DAC review: October 2024. Recommendation: Recommended with conditions (black-on-black panels, non-penetrative fixings, no cabling visible on south elevation). 28-day public notice: November 2024 — one letter of support received from the food bank coordinator, no objections. Faculty granted: December 2024, 13 weeks from submission.

Funding

The parish had previously been unsuccessful with a Buildings for Mission application in 2022 — the application had been submitted without diocesan Net Zero endorsement, and the grant panel had scored the mission narrative as insufficient. In 2024 we drafted a revised BfM application with full engagement from the Southwark Diocese Net Zero Officer and a much stronger community impact quantification (180 food bank households per week, 25 nursery children, debt counselling clients).

Simultaneously, we identified an additional source: the Southwark Borough’s community energy grant fund — a capital grant available to registered charities operating in the borough for energy efficiency works.

Source	Amount	% of capex
Buildings for Mission (national CofE fund)	£9,500	50%
Listed Places of Worship VAT scheme	£2,333	12%
Southwark Community Energy Grant	£2,000	11%
Diocese of Southwark capital grant	£2,500	13%
Parish reserves	£2,667	14%
Total funding	£19,000	100%
Total capex	£19,000	—

Net cost to parish: zero.

System specification

• 28 panels on north transept south slope
• Total: 14 kWp (Panasonic EverVolt, 500W, black-on-black HIT panels)
• 1 × SolarEdge 10kW three-phase inverter with HD-Wave optimisers
• 7.5kWh battery (SENEC Home 4.0) — sized for evening and overnight food bank freezer load
• All cabling run internally through roof void to inverter in church boiler room
• No visible external cabling on any elevation

DNO (UK Power Networks): G99 approval, 6 weeks. No reinforcement required — three-phase supply already in situ from the nursery’s cooker and large refrigerators. Final commissioning: 3 March 2025.

First-year results (March 2025 – March 2026)

• Annual generation: 11,420 kWh (modelled: 11,400)
• Self-consumption: 74.4% (modelled: 72–76% range — hit midpoint)
• Cost avoidance: £1,865 (8,500 kWh on-site consumption at 21.9p blended tariff)
• SEG export income: £311 (2,920 kWh × 10.65p Octopus Flux)
• Total first-year benefit: £2,176

Battery utilisation: 6.1 kWh average discharge per day. The battery’s primary function was absorbing food bank refrigeration load overnight and during the early morning shift before solar generation began. The food bank coordinator estimated a saving of approximately £800 per year in food bank operational electricity costs specifically attributable to the battery.

Parish and community impact

The nursery’s parents’ committee featured the solar installation in their newsletter. The food bank manager noted that the project had removed a source of financial anxiety — the food bank had been looking at reducing opening hours in 2024 partly due to energy costs, which the solar income has now reversed. The Thursday youth club added a secondary benefit from the battery: the church hall stayed warm into the evening, previously a source of complaints in winter when the gas boiler was switched off at 6pm.

The parish was featured in the Diocese of Southwark’s 2025 Net Zero report. The vicar gave a presentation at the Southwark Archdeacons’ Conference in May 2025 on the community-energy model.

Eco Church assessment: Silver achieved in May 2025. The Buildings category moved from 39% to 78%.

Key lessons for London urban parishes

Urban London parishes offer some of the best self-consumption economics in the country — but also some of the most complex roof geometries and constrained access logistics (narrow streets, no crane access, scaffold permit requirements). Key lessons from this project:

• Southwark DAC is well-aligned with solar: properly-prepared applications with black-on-black panels and a clear conservation rationale are now well-handled
• Three-phase supply is common in active London parishes: nurseries, large kitchens and community halls often already have three-phase. This simplifies the DNO G99 process significantly
• Previous failed grant applications can succeed with better drafting: this parish had been rejected by BfM in 2022. The key change was: (a) securing diocesan Net Zero Officer endorsement first, and (b) quantifying community impact in specific numbers rather than general narrative
• Borough community energy grants are underused: Southwark, Lambeth, Haringey, Lewisham, Tower Hamlets all have capital grants available to charities for energy works. These are poorly publicised and most parish enquirers are unaware of them

Could we deliver a similar project for your London parish?

If your parish is in any London diocese — Southwark, London, Chelmsford (Essex), Rochester (Kent) — we’d be happy to provide a free feasibility. Request your free feasibility here.