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Cornwall Council – Solar PV review and upgrade

Project Summary

The South West Net Zero Hub carried out a review of the performance of existing solar photovoltaic (PV) arrays on the roof of New County Hall in Cornwall. As a result the existing PVs were re-powered and additional on-site renewable energy generation was provided, to reduce carbon emissions, operational costs, and support local supply chains.


Cornwall Council has an ambition to deliver 2MW of renewable energy generation across their portfolio per annum. 

New County Hall is Cornwall Council’s HQ. As part of planned maintenance to replace its roof covering, The South West Net Zero Hub reviewed the performance of existing PV arrays (c.60kW). 

It was found that these legacy PV arrays were inefficient and required remedial works as part of their removal and reinstatement. The Hub conducted a cost-benefit analysis of reinstating the legacy systems vs re-powering them with new equipment in addition to maximising PV capacity across all roof areas. The latter proved most appealing, and the Hub worked with Cornwall Council and to develop and deploy a c.150kW roof-mounted scheme. 

The scheme will provide renewable energy generation direct to the site to reduce the building’s operational costs by (at time of writing) >£30k p.a. A 230kW solar canopy is also planned for installation Autumn 2023 to further supplement this. 

Our Role

The Hub supported the scheme as follows: 

  • Options Appraisal (reinstate vs repower) 
  • Confirming continuation of FIT payments 
  • Engaging with Council and third-party stakeholders 
  • Securing grid connection 
  • Supporting preparation of the business case 
  • Supporting preparation of the planning application 
  • Identifying procurement routes 
  • Creating a technical specification 
  • Evaluating supplier bids 
  • Providing ad-hoc technical support 


The rooftop of New County Hall, Truro, Cornwall.


Solar photovoltaic (PV) – 150kW roof-mounted system installed on the flat roof of and connected to New County Hall. 

Financing and Ownership

The scheme is funded by Cornwall Council’s £30m Renewable Energy and Low Carbon Technology Fund. It will be owned and operated by Cornwall Council. 


The scheme is estimated to generate c.150MWh p.a. of renewable energy and save 33tCO2 p.a (equivalent to powering 52 homes) and reduce the building’s operational costs by (at time of writing) >£30k p.a. 

Key Facts

ClientCornwall Council 
Strategic priority Renewable Energy Generation 
Energy generation/savingc.150MWh p.a. (>90% utilised on site) 
TimelineProject completed June 2023 
Carbon saving c. 29tCO2 p.a.