The Hub carried out an exploratory feasibility study and option appraisal for a Tees Valley authority to assess opportunities for optimising local solar generation.

A council depot currently operates two solar PV systems totalling 165 kWp, spread across three separate electricity meters. While the generation assets perform well, the site cannot share solar electricity across the different meters, meaning:

• Surplus solar is exported at ~5p/kWh,
• Imported grid electricity costs 23–25p/kWh,

This resulted in a ~£5k/year commercial loss.

The authority is considering constructing a full physical microgrid linking all buildings and EV chargers. This, however, would require a costly new substation, extensive cabling, and external grant support.

The council shifted focus from infrastructure delivery to commercial optimisation, exploring options maximising the value of existing solar assets without major construction. The solution identified was an Aggregator Power Purchase Agreement (PPA), allowing solar electricity to be “sold internally” at 15–18p/kWh, improving returns by £7k–£10k/year with minimal site changes.

The Hub enabled the exploration of this option, aiming to overcome challenges, including:

• Structural Grid Constraints
• The physical microgrid option not representing value for money without external funding.
• High cost and risk (and disruption) of infrastructure works – such as a microgrid requiring a new substation, trenching and cabling.

The council required a low‑risk, nor regrets solution, including a pathway that improved financial performance without committing to irreversible capital spend. Any solution also needed to mantain flexibility for future electrification of depot buildings.

With the Hub’s support, the council identified a clear preferred option, an Aggregator PPA covering both solar arrays — offers the best commercial return with minimal complexity.

This option is expected to:

• Deliver a £7k–£10k/year uplift through better monetisation of solar generation and lower‑cost EV charging.
• Maintain existing carbon savings of 38.1 tCO₂e/year
• Avoid major capital expenditure and construction risks by focusing on commercial mechanisms instead of physical infrastructure.
• Leave open the option to electrify heating in depot buildings.

The final decision regarding the progression of either a new substation or this proposed option is subject to internal and external stakeholder input and agreement.