Situation
Castle Mill Equity Partners identified Manor Renewable Energy as a potential platform investment within the offshore wind supply chain.
Manor provides specialist temporary power solutions to offshore wind construction and early-stage operations projects. In 2020, while offshore wind fundamentals were strong, the temporary power segment remained relatively immature. Contracting models were evolving, long-term O&M demand was still forming, and visibility on contract lengths and recurring revenue potential was limited.
Castle Mill required independent commercial validation of the addressable market, competitive positioning, and the sustainability of Manor’s differentiator, particularly as the market transitioned from construction-led activity to longer-term operations and maintenance.
What Does Manor Renewable Energy Do?
Manor delivers rental and service-based temporary power solutions to the offshore wind sector, including:
• Generator rental for construction and commissioning campaigns
• Electrical testing and fault-finding services
• Maintenance and rapid-response support for installed temporary power assets
The business supports projects during construction, cable installation and commissioning phases, and increasingly within O&M scopes. Mobilisation is often coordinated with offshore logistics and crew transfer vessels (CTVs), where technician deployment, equipment movement and vessel availability directly influence utilisation and contract economics.
Contract lengths vary significantly, from short construction windows to longer O&M frameworks, making visibility on utilisation and renewal dynamics central to the investment case.
Calash’s Role: Commercial Due Diligence
Calash delivered focused commercial due diligence to support Castle Mill’s investment decision.
Our work included:
• Independent market assessment of offshore wind temporary power demand across construction and O&M phases
• Review of customer procurement behaviour, contractor selection criteria and outsourcing trends
• Competitive mapping of specialist providers and adjacent electrical and industrial service contractors
• Assessment of contract structures, typical contract lengths and implications for fleet utilisation and revenue stability
• Validation of growth opportunities across service expansion, geography and adjacent onshore markets
The work provided Castle Mill with clarity on the market trajectory, the defensibility of Manor’s positioning, and the operational requirements for scaling.
Results
The diligence confirmed a credible pathway from construction-driven revenue towards more recurring O&M activity, supported by improving contract visibility and fleet utilisation.
Calash’s findings helped derisk the market opportunity and refine the post-investment growth strategy. Manor subsequently delivered accelerated growth during the investment period, with Castle Mill exiting successfully in 2022 following three years of value creation.
About Castle Mill Equity Partners
Castle Mill Equity Partners is a UK-based family office investor focused on energy transition and asset-backed industrial service businesses.
About Manor Renewable Energy
Manor Renewable Energy provides temporary power rental, electrical testing and maintenance services to the offshore wind sector, supporting both construction and operational windfarm activity.
