Linstock Castle AD

Alistair Wannop, Managing Director of Linstock Castle AD, medium scale, North Cumbria

The plant:

1200ac mixed dairy and arable farm operating a 1.1MW plant. The feedstock mix includes: muck and slurry from the dairy heifer rearing operation; grass silage; maize silage; and whole crop hybrid rye.

Why AD:

We were at a point where we need to make a decision. Expanding our herd of 400 milking cows to around 600-800 required a considerable financial investment, not just for the livestock but also farm buildings equipment. Having investigated a range of options, we found AD and thought the stability this could bring was attractive, volatility in milk and cereal prices was a real consideration. We visited Germany and Austria and thought that it looked achievable, that they weren’t doing anything that we couldn’t do. Thought it was a good fit for our farm.


When we looked into AD, the key barriers include: capital costs; access to finance; planning restrictions; and grid connection limitations.

The lack of familiarity with the technology was a real barrier in accessing funds, we had to do a lot of educating, and there was a feeling that the technology was risky because it wasn’t proven in the UK – despite evidence to the contrary. Understanding has improved since we first built our plant in March 2012, and we have seen some improvements in access to finance.

The spectre of degression is, however, a big issue now. Realistically if you are considering AD on farm you have to think about establishing a use for the heat.

There are still significant barriers that need to be overcome, especially from the point of view of a congenital farmer. With the right business model, however, AD can prove a worthwhile investment.

Making AD work:

By structuring the farm business around the plant, you can ensure that you maximise the potential returns from AD. 

There are, however, more options now available for farmers to incorporate small-scale AD plants alongside existing farming operations with 100kW and 125 kW plants. The same applies for 500kW plants provided that they find an outlet for the heat they produce.

Advice to farmers considering AD:

It’s important not to approach AD with a preconceived notion about the size a plant - bigger is not always better. Think instead about what you can offer: what feedstock you produce; what heat you could use; and the practicalities of any grid connections.

Choosing the right technology for your farm is essential. Every AD plant is effectively bespoke in terms of what feedstock it has readily available and how much time you have to operate it.

It’s important to be persistent and to plan ahead – try to anticipate any potential hurdles like planning and finance.

What would we have done differently:

Had we known that smaller scale digesters were an option then we would have explored that option. We have no regrets having sold our cows, however, putting a 100kW or 250kW plant alongside an existing livestock business is a real business opportunity now. 

The opportunity for smaller scales, in terms of supporting existing livestock and dairy operations, is really valuable, however, degression is really squeezing this opportunity which is a real shame

The idealistic part of me says why shouldn’t every dairy and livestock farmer have an AD plant? The green credentials of AD at this scale are strong; supporting farmers to manage farm wastes, including slurries and manure. AD can be an ideal fit for farming businesses – especially where they can use the heat and electricity generated on site.