High‑voltage design, installation and commissioning for flexible generation supporting the UK energy transition
Project Snapshot
| Project Detail | Information |
| Client | Conrad Energy Ltd |
| Location | Lower Dunton Road, Basildon, Essex, RM14 3TD |
| Project Value | £318,896.65 |
| Project Duration | Dec 2020 – Apr 2021 |
| Services | Electrical Balance of Plant (EBoP), HV/LV Infrastructure, Testing & Commissioning |
| Market Sector | Flexible Generation |
| Installed Capacity | 7.5 MW (3 × 2.5 MW generators) |
| Connection Voltage | 11 kV |
| Powersystems Role | Full design, supply, installation, testing, commissioning & SAP provision |
| Powersystems Fact | Powersystems have delivered flexible generation and STOR connections for over 20 years. This was the third flexible generation project delivered for Conrad Energy during the year, marking a strong and growing partnership. |
Lower Dunton 7.5 MW Flexible Generation Case Study
Download the full Lower Dunton Flexible Generation Case Study — ideal for engineers, developers and technical stakeholders. This summary outlines the 11 kV grid connection, HV underground circuits, auxiliary transformer systems, switchboard installation and full programme of HV/LV installation, protection, commissioning and G99 compliance delivered by Powersystems for the 7.5 MW flexible generation site. The full document provides detailed insight into the electrical design methodologies, containment systems, civil integration, protection studies and SAP‑managed energisation required to bring a modern flexible‑generation site online.
Client & Site Background
Conrad Energy is a leading UK flexible generation developer, providing quick‑response power to support the electricity network when renewable output fluctuates. Their portfolio supplies power to more than one million homes, helping balance the grid as the UK transitions toward net‑zero by 2050.
Lower Dunton is part of Conrad Energy’s expanding portfolio of distributed energy projects delivering essential generation capacity during periods of peak demand or low renewable output.
The Challenge
Flexible generation sites play a vital role in stabilising the energy system. Conrad Energy required:
- A complete 11 kV grid connection into the UK Power Networks (UKPN) system
- Electrical Balance of Plant for three 2.5 MW natural‑gas generators
- Compound civil and electrical works during national COVID‑19 restrictions
- Efficient installation within a compact site layout
- Full protection studies, earthing, control, signalling and LV infrastructure
- Delivery under a tight programme to meet G99 testing deadlines
Powersystems were appointed as the EBoP contractor for the entire electrical scope.
Our Engineering Solution
Powersystems designed, installed, tested and commissioned the full HV/LV system for the site, including:
- Engineering and construction of a new 11 kV GRP substation
- Installation of a five‑panel Schneider GenieEvo switchboard
- Installation of a 500 kVA auxiliary transformer
- Design and installation of:
- 300 mm² 11 kV incomer cable
- 185 mm² 11 kV generator & transformer circuits
- LV, control, signal & communication cabling
- HV earth grid installation
- LV distribution and compound lighting
- Protection and coordination studies
- SAP switching, G99 compliance and energisation
The 7.5 MW flexible generation platform provides rapid‑response power when renewable output is low.
Project Process
- HV and LV design, substation design and protection studies
- GRP substation, auxiliary transformer and civil groundwork
- Installation of 11 kV and LV cabling routes
- Switchboard installation and commissioning
- LV infrastructure, lighting and control panels
- Full system testing, HV pressure tests and relay commissioning
- SAP‑managed energisation and G99 testing
Project Facts & Figures
- Generators: 3 × 2.5 MW (MTU GS Engines – VPower Ltd)
- Installed Capacity: 7.5 MW
- Voltage: 11 kV
- Altitude: 105 ft
- Onsite 11 kV cabling: 0.15 km
- Onsite 400 V cabling: 0.2 km
- Control & signal cabling: 1.0 km
- NERS Accredited ICP: Yes
Technical Specifications
Major Electrical Installations
- 11 kV GRP substation (design & build)
- Schneider GenieEvo 11 kV switchboard
- 500 kVA auxiliary transformer
- 300 mm² and 185 mm² 11 kV circuits
- LV distribution infrastructure
- Compound lighting and control panels
Design & Engineering Works
- Substation and transformer civil foundations
- 11 kV network design and modelling
- LV network design
- Cable sizing and thermal calculations
- Fault level study and protection coordination
- Control & signal wiring schematics
Commissioning Activities
- Hot & cold commissioning of 11 kV switchboard
- Commissioning of 500 kVA auxiliary transformer
- AC pressure testing of HV cables
- LV installation certification
- Functional testing of all systems
Partnerships
Delivered in close collaboration with:
- Conrad Energy Ltd – Client
- ANTS Civil Engineering Ltd – Civil works partner
- UK Power Networks (UKPN) – Distribution Network Operator
This project was the third in a growing series of flexible generation schemes delivered for Conrad Energy.
Flexible Generation Development
As the UK accelerates toward net‑zero, flexible generation provides:
- Rapid‑response backup during low wind/solar output
- Grid stability during peak demand
- Localised generation that reduces stress on transmission systems
The Lower Dunton site uses natural gas to generate power when the grid calls upon it through market signals or DNO requirement.
Key Risks & Mitigations
- COVID‑19 construction restrictions – Mitigation: Enhanced site protocols ensured safe, uninterrupted progress.
- Tight G99 testing deadlines – Mitigation: Prioritised installation phases secured energisation on 18 March 2021.
- High‑fault‑level DNO environment – Mitigation: Detailed fault studies and protection settings ensured compliance.
- Confined site layout – Mitigation: 3D cable routing and bespoke containment solutions optimised installation.
- Integration with UKPN systems – Mitigation: Early engagement ensured seamless coordination and adoption compliance.
- Multiple contractors on a live site – Mitigation: Strong interface management ensured safe and efficient delivery.
Environmental Consideration
- Supports renewable intermittency
- Fast‑start generation reduces reliance on coal and diesel peakers
- Contributes to national grid resilience and decarbonisation efforts
Economic & Social Value
- Rapid‑response power when renewables are unavailable
- Supports grid stability for local homes and businesses
- Reduces risk of grid shortfalls
- Efficient distributed generation with low operational overheads
Future Prospects
The Lower Dunton Flexible Generation project was completed on time, within budget, and under challenging seasonal and COVID‑19 conditions. The site achieved energisation on 18 March 2021 and G99 approval on 7 April 2021, marking the successful delivery of Powersystems’ third flexible generation project for Conrad Energy that year.
Related Projects
- Brecon Power STOR
- The Cornwall Bakery (CHP)
- Poole Bakery (CHP)
- Principality Stadium Cardiff (DRUPS)
Powersystems deliver specialist high voltage Balance of Plant works for flexible generation, STOR and distributed energy facilities across the UK.
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