Turning Space into Energy and Revenue
For many owners of commercial property and larger residential buildings across England, the roof has long been treated as a passive necessity, something that keeps the rain out and little more. But in today’s energy landscape, that same roof space represents one of the most underutilised financial and environmental assets available.
With rising electricity prices, ongoing grid uncertainty, and increasing pressure to decarbonise, solar photovoltaic (PV) systems are no longer a “green-thinking extra”, they’re a strategic investment.
And crucially, the economics are far more compelling than many property owners realise. For commercial buildings and high-end homes alike, unused space could be actively generating energy, reducing operational costs, and creating long-term financial value.
With the cutting edge solar technology we advise on and instal, what was once passive infrastructure can now deliver measurable returns, often saving tens, if not hundreds, of thousands of pounds over time.
The conversation is shifting from “Can we install solar?” to “Why wouldn’t we maximise the asset we already own?”
The hidden value sitting above your head
A typical commercial or large residential property roof, offers significant usable surface area. Even allowing for access, shading, and plant equipment, most roofs can accommodate substantial solar capacity.
As a rule of thumb:
- For early feasibility / proposals in the South of the UK:
- South‑facing: 1,050 kWh/kWp/year
- East–West: 950 kWh/kWp/year (south facing would require more space between rear of module and front of next module due to shading from module in front)
- Very conservative assumption: 1,000 kWh/kWp/year
Example: Medium Commercial Building
- Roof space available: 500 m²
- Usable for solar: ~400 m²
- System size: ~~50 kWp (That would typically be ~100 × 500 W modules.)
- Annual generation: ~@950kwh per m²: ~47,500 kWh (47.5 MWh)
That’s not just energy, it’s a hedge against future price volatility and a direct reduction in operating costs.
Turning generation into financial return
The real value of solar is self-generated power, displacing the uncertainties and high costs of grid electricity.
Current commercial electricity costs (Typical Range)
- Grid electricity: £0.20–£0.35 per kWh (often higher under certain contracts)
- Solar generation cost (levelised): ~£0.05–£0.10 per kWh
This creates an immediate margin of savings.
Example Savings
Using the 70 kWp system above:
- Annual generation: 65,000 kWh
- Self-consumption: 70% → 45,500 kWh used onsite
- Grid price: £0.25/kWh
Annual savings
- 45,500 × £0.25 = £11,375 per year
Excess energy (exported to the grid) can still generate income, typically:
- Export rates: £0.05–£0.15 per kWh
- Exported energy (~19,500 kWh): ~£1,000–£2,500 per year
Total annual benefit: ~£12,500–£14,000
Installation costs and payback – it’s shorter than expected
One of the most persistent myths is that solar takes decades to pay back. That may have been true in the past, but certainly not today.
Typical installed costs (Commercial Scale)
- £700–£1,000 per kWp (depending on scale and complexity)
For a 70 kWp system:
- Capital cost: ~£50,000–£70,000
Payback Period
With annual returns of ~£13,000:
- Simple payback: ~4–6 years
Given system lifespans of 25–30 years, that leaves potentially two decades of low-cost electricity after payback.
Larger Roofs, Stronger Returns
The economics improve further at scale.
Example: Large Industrial Unit
- Roof space: 2,000 m²
- System size: ~300 kWp
- Annual generation: ~270,000 kWh
Financials:
- Installation: ~£210,000–£270,000
- Annual savings & revenue: ~£50,000–£70,000
- Payback: ~3.5–5 years
Larger systems benefit from:
- Lower cost per kWp
- Higher on-site consumption (especially for energy-intensive operations)
- Greater protection against future price increases
Beyond the Numbers: Strategic Advantages
While the financial case alone is compelling, solar also delivers broader value:
- Energy price stability: Long-term protection against volatile markets
- Increased asset value: More attractive to tenants and investors
- Regulatory readiness: Future-proofing against tightening carbon regulations
- Sustainability credentials: Supporting ESG targets and reporting
Why many still miss the opportunity
Despite strong returns, adoption is often delayed due to:
- Outdated assumptions about cost and payback
- Lack of awareness of usable roof capacity
- Perceived complexity of installation
- Competing capital priorities
However, with financing options, power purchase agreements (PPAs), and falling technology costs, many of these barriers are now significantly reduced.
A simple way to think about it – Every square metre of unused roof is effectively:
- Generating nothing … or:
- Each square metre of a commercial flat‑roof solar installation typically generates ~110–120 kWh per year, equivalent to ~£28–30 per m² annually at 25p/kWh. ,
- That’s £687.50–£750.00 per m² of potential value, often from space that currently delivers none..
The Bottom Line
Solar is no longer a speculative investment. For commercial and large residential property owners, it is a proven, cash-generating asset with:
- Predictable returns
- Short payback periods
- Long operational life
- With EVERYTHING done for you
The question is no longer “Does solar make sense?”
It’s “Why leave that value sitting unused?”
Learn and talk about money, by downloading our Solar Roof Value Report – HERE.
