My uncle installed one, using his local firm - https://www.euroheat.co.uk/ - which has now closed.

Reading their comments, and my uncle's own views, I think there are good reasons. Without the subsidies the burners don't make a lot of sense. His struggle is with delivery costs - he built a large store so he could get a single delivery of pellets each year but the delivery costs still represent a significant part of the total cost of operation.

I get the impression pellets are not easily available and not as cheap as they were. others may be able to tell me i've got the wrong idea on this!

Manninwood - Sorry I can't answer your question about UK manufactured wood pellet boilers but I can certainly concur with the other two contributors. I started off in Nov. 2008 (pre-RHI!) with an OPOP boiler which was made in Denmark. It was a very simple design, relatively cheap, and easy to maintain. However my wife was not able to cope with the cleaning and maintenance and as we are getting on in years we were worried that if she inherited the system she would not be able to manage.

So we changed to an Ekopower boiler (also made in Denmark) which claimed to be virtually maintenance free, self-cleaning etc. This has turned out to be untrue as it has a ridiculous worm drive mechanism which moves the ash plate and this has to be cleaned and greased with a special aluminium paste every month; this is spectacularly filthy stuff to work with too! I am a reasonably competent DIY-er so I give the boiler a complete clean down every month (effectively the equivalent of an annual clean every month!) whilst I'm at it. If I had to pay for this kind of service it would cost me a fortune. So far nothing major has gone wrong thankfully. Spares are available via a company in Cheshire or direct from Denmark. Heating elements vary in quality - some last for years, others barely months. I have invested in a ceramic type now which I will install when the current element dies. I understand these are more reliable but much more expensive of course.

Pellet prices have gone up considerably since 2008. Then I was paying £170 per ton, now nearly £250 per ton so well ahead of inflation. There is no justification as far as I can see for such an increase. The price of heating oil has practically remained the same over the same period (48p per litre in 2008 and 50p per litre today. In fact it reduced to 26p per litre in 2016!). The rising cost of oil was one of the reasons we changed to wood pellets in the first instance, apart from wanting to reduce our CO2 emissions. I have found that the quality of the pellets doesn't vary much at all, so no issues there fair play.

One unforeseen circumstance was that my very well insulated house got a rubbish EPC rating of D because the calculation for the efficiency of the boiler is taken at a generic value of 65% when in reality it is greater than 93%! This is because the manufacturer has not submitted the necessary data to SEDBUK, so beware of that!

I have a 3.3 ton hopper which we fill every summer and that lasts us until the following summer, so we avoid having to buy pellets during the winter months.

Like Artiglio, once the 7 years RHI payments are up, I will probably have to reconsider what to do. I am hoping that there may be some technological breakthrough with ASHP design which would enable us to run the C/H with that (maybe with oversized rads as there is no possibility of UFH). Other than that it will be back to oil or LPG purely based on the ease of use. One idea I have is to keep the wood pellet boiler and fit the LPG or oil boiler in tandem, so as to have the flexibility of using either.

What are you trying to heat?

The pellet market in the UK has been boosted massively by the RHI scheme, not so much in domestic market, but for farms, schools, social housing, council amenities, these have all jumped on the 20 year commercial bandwagon, often the demands are huge in big premises and on site storage is insufficient to cover long periods and many don’t keep a reserve of any great duration.
In addition last winter one of the UK manufacturers had a prolonged shutdown for maintenance, which made for a very tight supplies. Our supplier was asking customers how much they had left and was juggling deliveries to keep everyone going, he has one chicken farm that takes 20 tonnes a week.