How Cardiff's Lamby Way Solar Farm Uses a Private Wire
Cardiff's 9 MW Lamby Way solar farm supplies a neighbour over a 2 km private wire. The 20-year contract, the design, and lessons for nearby businesses.
Most explanations of private wires stay theoretical. Cardiff Council's Lamby Way solar farm is a working one, and the Welsh Government's 2026 guidance on private wire energy systems uses it as its case study. Here is what the published facts show, and what a business near a generator can learn from them.
The project
- A 9 MW solar farm built on a former landfill site in Cardiff.
- A dedicated 2 km private wire to a nearby large commercial consumer.
- The council funded the private wire as part of a £9 million project.
- Two connections, each with 5 MW of export capacity: one to the consumer, one to the public grid.
Source: Welsh Government — Private wire energy systems: guidance (29 June 2026) (case study). Verified 28 Sep 2026.
The contract
The consumer signed a 20-year PPA on a take-and-pay basis, with no minimum power supply commitment. The price is index-linked and updated monthly. That is unusual: many long-term PPAs fix a minimum volume, and the guidance itself notes that take-or-pay clauses are common in private wire deals. Lamby Way can offer flexible terms because the council never depends on the consumer alone.
Why the design works
An automated system decides whether the farm's output earns more going down the private wire or out to the grid, and it can be overridden manually. An export PPA with Octopus Energy covers the power sold to the grid. So the council can always sell what it generates, and it chooses the better price between the two outlets. The guidance calls this a blended export model.
Lessons for a business near a generator
- Ask who funds the cable. Where the generator pays for the private wire, you have more leverage to avoid a minimum-volume commitment.
- Look for a generator with a second outlet. A farm that can also export to the grid can give you flexible volume terms.
- Expect an index-linked price. Flexible pricing that tracks the market is common in private wire deals; decide in advance whether you prefer that or a fixed rate.
- Plan for a long relationship. Twenty years is in line with the guidance, which puts agreements at 15 years or more.
The full mechanics, including the licence exemptions and the costs a private wire avoids, are in our guide to the private wire PPA.
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