- Outsourced cost
- £4-10/kWp/year typical
- In-house viable at
- 5+ MW portfolio
- Specialist services
- Always retain
- Sector default
- 95% outsourced
Side-by-side comparison
| Dimension | Outsourced O&M | In-house O&M |
|---|---|---|
| Annual cost (typical 280 kW install) | £1,700-£2,800/year | £800-£1,500 direct cost; ~£8,000-£18,000 internal time + tooling allocation |
| Performance monitoring platform | Included in contract | Separate subscription £400-£1,200/year |
| Capability required | None internal | Electrical competence + MCS commercial + inverter manufacturer certification |
| Response time on faults | Per SLA (typically 24-72h) | Variable; depends on estates team workload |
| Specialist services | Included or coordinated | Must be procured separately (inverter manufacturer service, etc.) |
| Performance guarantee | 92-95% typical | Not applicable (corp carries risk) |
| Annual reporting | Comprehensive report included | Internal reporting effort required |
| AoC/EAUC reporting format | Provider-supplied | Must be authored internally |
| 25-year cost (single 280 kW install) | £45,000-£70,000 | £60,000-£100,000+ all-in including internal time |
When outsourced wins (most cases)
For 95% of UK FE corporations, outsourced O&M wins because:
- Sub-2 MW portfolio scale doesn't justify the internal capability investment
- Specialist solar competence is rare in typical FE estates teams
- Performance guarantees only available from specialist providers
- Single supplier accountability simpler than coordinating multiple specialists
- Performance monitoring platform included in contract
- AoC/EAUC reporting format pre-supplied
When in-house might work (rare)
In-house O&M only makes sense where:
- Portfolio scale above 5 MW — sufficient to justify dedicated solar competence in the estates team
- Existing electrical engineering capability — for group corps with substantial maintenance teams already in place
- Curriculum integration potential — running O&M as a T-Level synoptic project (with supervised student involvement) brings curriculum and operational benefit together
- Existing inverter manufacturer relationship — where the estates team is already trained on the specific inverter family in use
Hybrid model — often the practical answer
For mid-size group corps (1-5 MW portfolio), a hybrid model often wins:
- Outsourced: monitoring platform + reactive callouts + annual inspection + specialist inverter service
- In-house: visual inspection between annual visits + first-line fault triage + curriculum integration + AoC/EAUC reporting
The hybrid model captures the capability + curriculum benefit of in-house engagement without requiring full O&M competence.