Delivering a full 11 kV contestable grid connection for Tamar Energy’s first operational AD facility
Project Snapshot
| Client | Tamar Energy |
| Location | Farleigh Wallop, Basingstoke, Hampshire |
| Project Value | Confidential |
| Duration | 2013 (Grid connection works delivered on time and on budget) |
| Market Sector | Renewable Energy — Anaerobic Digestion |
| Services Delivered | 11 kV Contestable Connection & Substation Works |
| Powersystems Fact | Powersystems was selected as Tamar Energy’s preferred grid‑connection partner for their first operational AD facility in Basingstoke. |
Farleigh Wallop 1.5 MW Anaerobic Digestion Case Study
Download the full Farleigh Wallop Anaerobic Digestion Plant Case Study to learn how Powersystems delivered the complete 11 kV contestable grid connection for Tamar Energy’s first operational AD facility in Basingstoke. The PDF highlights our 3 km fully‑ducted cable installation, directional drilling beneath Farleigh Lane, substation construction, switchgear installation and G59/2 commissioning. As Tamar Energy launched its nationwide AD programme aimed at building 40 plants generating 100 MW of renewable power, Farleigh Wallop became their first commissioned site, processing 30,000 tonnes of food waste annually and producing 1.5 MW of electricity—enough for more than 3,000 homes.
Client & Site Background
Tamar Energy, founded in 2012 and backed by major UK investors, launched a national strategy to build around 40 anaerobic digestion plants by 2018, targeting 100 MW of renewable electricity — enough to power more than 200,000 homes.
The Farleigh Wallop facility was Tamar Energy’s first operational AD plant, designed to generate 1.5 MW of renewable energy — enough to power more than 3,000 homes.
The plant processes around 30,000 tonnes of food waste per year, diverting organic waste from landfill and producing nutrient‑rich digestate for local agricultural use.
Powersystems was appointed by FLI Energy (EPC contractor) as Tamar Energy’s preferred grid‑connection partner, responsible for delivering the complete 11 kV contestable connection.
The Challenge
The Farleigh Wallop connection required Powersystems to:
- Construct a 3 km 11 kV grid route from the SSE point of connection
- Route cabling through Farleigh Estates agricultural land
- Avoid major disruption to the local community and road network
- Overcome a complex Farleigh Lane and woodland crossing, where open‑cut trenching was impossible due to trees and narrow roadway
- Deliver a fast‑track installation to meet Tamar Energy’s commissioning programme
Additionally, the project had to accommodate the needs of a live rural environment, sensitive residents, and strict environmental planning conditions.
Our Engineering Solution
Powersystems delivered a complete turnkey 11 kV contestable connection, including civil, electrical, testing and commissioning works.
11 kV Grid Route (3 km)
- Fully ducted grid route agreed with SSE designers to accelerate installation and reduce excavation time.
- Joint bays installed at 350 m intervals along the route.
Farleigh Lane / Woodland Crossing
Open‑cut trenching was impossible due to:
- Dense tree network
- Narrow roadway
- Risk of road closure and major resident disruption
Solution: Powersystems employed a specialist directional drilling contractor to carry out a trenchless crossing beneath the lane and woodland. This enabled installation of a 75 m duct, through which 11 kV cables were installed and jointed to the existing grid route.
Substation Development
At the AD facility substation, Powersystems delivered:
- Connection design
- Construction of substation building infrastructure
- Installation of 11 kV switchgear
- Metering unit with Neutral Voltage Displacement (NVD) protection
- 11 kV terminations and commissioning
All works were reviewed and signed‑off by SSE engineers prior to energisation.
Testing & Commissioning
- Full G59/2 testing completed successfully
- Grid connection energised on schedule
- Tamar Energy’s first plant began exporting renewable electricity to the National Grid in early December
Project Facts & Figures
- 1.5 MW renewable energy generation capacity
- 3 km of 11 kV cabling
- 30,000 t per year food‑waste processing
- Power for 3,000+ homes (renewable)
- Serving Tamar Energy’s first UK AD plant
- Facility part of first wave of Tamar Energy plants entering commissioning in 2013 (6 MW total)
Public Context — Tamar Energy’s AD Strategy
Tamar Energy’s national rollout of AD plants gained significant momentum:
- First three sites (including Basingstoke) produced 6 MW combined capacity and entered commissioning with seeding feedstock in 2013.
- Plants in Basingstoke, Holbeach and Retford were all brought online as part of Tamar’s commitment to a 40‑site AD network.
- Farleigh Wallop’s early completion was celebrated publicly as a major milestone.
This demonstrates the strategic significance of Powersystems’ work delivering the first grid‑connected Tamar Energy AD facility in the UK.
Partnerships
- Tamar Energy — Renewable energy developer
- FLI Energy — EPC contractor
- Powersystems — Grid connection and electrical infrastructure
- SSE — Distribution Network Operator (DNO)
- Directional drilling specialist — 75 m trenchless crossing
Key Risks & Mitigations
- Woodland and narrow‑lane constraints – Mitigation: Directional drilling solved environmental and logistical issues, avoiding full road closure.
- Tight programme – Mitigation: Fully ducted grid route accelerated installation and reduced ground disruption.
- Resident impact – Mitigation: Minimised road closures, controlled construction and clear communication.
- DNO adoption requirements -Mitigation: Close liaison with SSE throughout design, build and commissioning.
Environmental Considerations
- AD plant processes ~30,000 tonnes of food waste annually instead of landfill.
- Produces renewable electricity and heat
- Digestate reused as organic fertiliser on Farleigh Estates farmland
- Supports UK food‑waste recovery and circular‑economy goals
Economic & Social Value
- Renewable energy supporting 3,000+ local households
- Aligns with Tamar Energy’s plan for a 100 MW national AD network
- Job creation at plant and supply‑chain level
- Avoided landfill costs and CO₂ emissions
- Community benefits through improved waste management and local employment
Results
- Grid connection successfully delivered on time and on budget
- First Tamar Energy AD facility connected to National Grid
- G59/2 commissioning completed
- Plant now generating green energy from food waste
- Delivered with minimal environmental or community disruption
Related Projects
- Poundbury Plant AD Facility – The first AD Gas to Grid plant connected by Powersystems
- Piddlehinton Anaerobic Digestion Plant
- Black Dog Biogas Isle of White
- UK Food‑Waste to Energy Projects
- Waste to Energy – Parc Adfor
Developing or upgrading an Anaerobic Digestion facility?
Powersystems delivers complete HV/LV electrical and grid‑connection solutions, including contestable works, cable installation, protection engineering, directional drilling interfaces and full commissioning.