They are the future of farming, according to some in the industry.
Anaerobic Digesters, or AD plants, use waste product to produce electricity. On a dairy farm they use slurry to keep it running.
Iain Service is building a dairy farm near Newton Stewart, and the AD plant was built into the design from the start.
"When we were designing the new dairy complex we decided that AD should be an integral part of it, I mean it uses the cow slurry to produce electricity which we can use on the farm and we can sell the surplus, it also gives us a much better fertiliser for the fields so we're winning that way, and it also reduces the smell of the slurry, which helps all our neighbours, we thought when we were designing something that was going to last a long time into the future, the AD was something that we should include in it."
The AD plant works like a stomach, using bacteria to break down the slurry to produce methane gas, that is then burned to produce electricity.
It is green energy on a constant basis, unlike wind turbines the digester should not be shut down.
Feed in tariffs to help famers install the plants have now been reduced by the UK Government by 20 per cent. NFU Scotland are worried that is likely to stall the positive impact that AD plants could have on Scottish farms.
"Because this is still a new technology and it produces less energy and less power than the traditional type of digester, we were hoping that the feed-in tariffs, the support for this renewable energy, could be maintained at a level, you know a plateau for some time to allow us to catch up, unfortunately the feed-in tariffs have been cut, and although we have appealed to the Government that cut remains in place."
Iain integrated the AD plant into his new farm because he is resolute that the technology should be given a chance.
"The feed-in tariffs are designed to strike a balance between the support paid to the industry and the cost of that support ...we cannot consider any changes to the cost-reduction measures until we conduct a full review of FiTs in 2015."
Anaerobic Digesters are still a very new technology but NFU Scotland are determined that they could play a massive part in the industry's future.