How big is the solar system installed at Marsden Building Society?
Alliant Energy installed a 61.6kWp solar PV system using 140 panels paired with a Solis inverter. The installation took 2 weeks from arrival on site to commissioning.
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Financial Services
Marsden Building Society
61.6kWp system saving £10,663 a year for Marsden Building Society.
Project overview
As part of Marsden Building Society’s commitment to sustainability and strong ESG principles, a 61.6kWp commercial solar PV system was installed at their central Nelson branch. The project, designed to reduce grid reliance by 46%, utilised SolarEdge technology paired with JA Solar panels. Careful coordination ensured zero disruption to business operations, even during roofing works and technical upgrades. The project reflects Marsden’s ongoing commitment to ESG values and sustainable operation. The installation was specifically designed to achieve a 46% reduction in grid electricity consumption, with provision for future battery integration to further enhance energy independence. Installation took place during a planned weekend shutdown to avoid disruption to critical banking services and server systems, with close collaboration between IT and technical teams.
The challenge
Like most financial services operations, Marsden Building Society faced a structural exposure to wholesale electricity prices — a cost line that doubled for many UK businesses between 2021 and 2023 and shows no sign of returning to pre-crisis levels. With significant daytime load and suitable roof space, on-site generation was the obvious lever, but the project needed to stand on its own commercial merits: predictable payback, manufacturer-backed warranties, and zero operational disruption during install.
The solution Alliant Energy designed
Following a structural roof survey and DNO capacity check, Alliant Energy specified a 61.6kWp array using 140 high-efficiency mono-PERC panels, paired with a Solis hybrid inverter. The Solis platform was chosen for its export-management capability and remote firmware updates, allowing the array to be tuned over its life without site visits. Surplus generation is exported to the grid under a Smart Export Guarantee tariff, providing a secondary revenue stream alongside the primary saving on imported electricity.
Install & commissioning
The full installation completed in 2 weeks, scheduled around the customer's operating hours to avoid downtime. Work was carried out by Alliant Energy's directly employed MCS-registered engineers — no subcontracted labour. The system was commissioned to G99 requirements, registered with the Microgeneration Certification Scheme, and handed over with monitoring access, electrical certification, and structural sign-off documents on the day of completion.
Financial outcome
In its first full year of operation the system is on track to save Marsden Building Society approximately £10,663 on electricity costs, with a payback term of 10 Years and a projected total ROI of 250%. Over the 25-year warranted life of the panels, the cumulative saving is forecast at £198,090 — a figure that improves materially if grid prices continue their long-term upward trend, and that benefits from the UK's 100% full-expensing capital allowance for qualifying solar assets.
Environmental impact
The installation displaces roughly 6.9 Tonnes of CO₂ emissions every year compared with grid-sourced electricity. Over the system's 25-year design life that is the equivalent of removing more than Marsden Building Society's entire annual Scope 2 footprint several times over — a material data point for ESG, B-Corp and net-zero reporting frameworks.
Why it matters for the financial services sector
Financial Services businesses typically run daytime electrical loads — refrigeration, machinery, IT, lighting, compressors — that overlap closely with solar generation. That overlap is what drives strong economics: every unit generated and consumed on-site replaces a unit that would otherwise be bought from the grid at full commercial rates. The Marsden Building Society project demonstrates how the model scales for this kind of operation.
System
61.6kWp
Panels
140
Inverter
Solis
Install
2 Weeks
Project FAQ
How much does Marsden Building Society save each year?
Marsden Building Society saves approximately £10,663 per year on electricity, with projected lifetime savings of £198,090 over the system's 25-year guaranteed performance period. The payback term is 10 Years, delivering a total ROI of 250%.
Was the project funded or paid for upfront?
This project was paid for directly by the customer. Under the UK's full-expensing capital allowance, the entire cost can be deducted from corporation tax in year one — improving the effective payback meaningfully for profitable companies.
What's the environmental impact?
The system avoids around 6.9 Tonnes of CO₂ emissions every year compared with grid-sourced electricity. Over a 25-year design life that's a material contribution toward Scope 2 reduction and any ESG or net-zero reporting commitments the business holds.
Could a similar system work for my business?
Probably — the same hardware platform (panels, hybrid inverter, optional battery) scales from roughly 10kW up to 1MW+. The deciding factors are roof area, daytime electricity use, current unit rate, and grid-connection capacity. Alliant Energy carries out a free desktop feasibility study and follow-up site survey before quoting.
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