Quality of Wood Pellets, Boilers & Other Equipment

It is important to use the right quality of wood pellet and equipment for your purpose. You get what you pay for. Generally, if you save in the short term by buying poor-quality equipment and wood pellets, you will pay more in the long run from the resulting problems.

In some non-essential situations, or where robust industrial systems can be used, the cost-savings from using lower quality fuel may justify the lower efficiency and higher operating and/or capital costs. Likewise, a low-cost heating system may be able to operate tolerably well with a high-grade fuel and delivery.

In most situations, high quality is essential to a positive outcome. The efficiency and reliability of the heating system will depend on the quality of the equipment and of the wood pellets. Poor quality wood pellets used for bedding and litter may have an impact on the health of animals.

Quality depends not only on the standard of the product as it leaves the factory, but also on the way the product is utilised. Bad design and/or installation can make good quality equipment perform badly. Poor quality handling and delivery can wreck good quality wood pellets. Quality is a chain. It is only as strong as the weakest link in the chain. You must ensure that all aspects of your wood pellet use are to a quality that meets your requirements.

You should take care of the quality in all aspects of your use of wood pellets, including:

Wood Pellet Quality

Standards, specifications, analysis, quality management systems and accreditation schemes help the buyer to identify producers and suppliers of wood pellets of a suitable quality for their purpose. There is a lot of confusion in the market about the meaning of these terms. We have put together a set of pages to explain the terminology of wood pellet quality, to help you avoid being hoodwinked by a poor quality supplier.

EN 14961: European standard for solid biofuels

Logo of CEN, European Committee for StandardisationWood pellets are commonly described according to European standard EN 14961-2. Most qualities of wood pellet can be described according to EN 14961-2, so avoid suppliers who claim to supply pellets that "conform with EN 14961-2" or similar meaningless claims.

EN 14961-2 sets out three specifications that may be used to describe different grades of wood pellets.

  • A1 is the highest grade, composed solely of virgin fibre with low ash content.
  • A2 is also a pure virgin-fibre pellet, but with higher ash.
  • B grade may contain some types of untreated recovered wood, and may have a higher ash content still.

Many small and medium boilers nowadays require wood pellets that meet the A1 specification in EN 14961-2.

ENplus: European wood pellet accreditation scheme

ENplus stamp plus wood pellets, DEPI imageENplus provides independent assurance that wood pellet producers and suppliers are operating in such a way that the quality of their product and service is reliable.

ENplus certifies producers and traders (i.e. suppliers) separately to ensure that the wood pellets are in a good condition not just when they leave the factory, but when they arrive in the customer's fuel store.

For blown deliveries you should buy from an ENplus accredited trader, who will have to have sourced wood pellets from an ENplus accredited producer.

ENplus bagged wood pellets are identified by the ENplus stamp and the producer's ENplus ID on each bag. National wood pellet associations (such as the UK Pellet Council) may list the bagged wood pellets that meet the ENplus standard. You can buy bagged ENplus wood pellets from unaccredited traders, but you should take care that the bags have been stored in suitable conditions to avoid degradation.

ENplus has three grades - ENplus-A1, ENplus-A2 and EN-B - based on EN 14961-2, but with an important refinement with regard to ash fusion temperature.

National assurance schemes

Most national schemes are being gradually supplanted by ENplus. Wood pellets are an internationally tradable commodity, so an international accreditation scheme is important to maintain standards across borders.

DINplus logoDINplus (the German wood pellet standard) has an element of accreditation of the whole chain, although not as complete as ENplus. Many wood pellet producers still offer DINplus wood pellets. There are subtle differences between DINplus and ENplus-A1 wood pellets, but generally a boiler that requires one of these standards will work OK with the other.

WoodSure logoWoodSure is the British accreditation scheme for woodfuel. It covers all wood fuels (e.g. chip and log), not just wood pellets. It is more commonly adopted by wood chip and log suppliers, for whom it is the best option. In the UK wood pellet industry, ENplus is generally preferred, but WoodSure has some strengths (e.g. more rigorous auditing) and some companies may offer both or even WoodSure alone.

WoodSure are also one of the few organisations eligible to carry out ENplus audits in the UK.

WoodSure Plus is under development as a scheme to incorporate sustainability accreditation into wood fuel accreditation.

Pellet Boiler Quality

The consequences of buying a poor-quality wood pellet boiler or stove may include:

  • Poor emissions quality: high emissions of NOx and particulates (i.e. smoke)
  • Low efficiency
  • Unreliability

Unfortunately, there are fewer standards and accreditation schemes for wood pellet heating systems than there are for the wood pellets themselves.

MCS Assurance

MCS logoThe Micro-generation Certification Scheme (MCS) certifies (a) biomass boilers under 45 kW, and (b) the companies that install them. There is no equivalent scheme for boilers over 45 kW and their installers.

MCS is not as rigorous as the wood pellet accreditation schemes. It is largely a test of whether you can fill out the necessary forms. MCS lists hundreds of installers who claim expertise at installing biomass boilers. As of summer 2013, there are not so many pellet boilers in the country that hundreds of installers can all have substantial experience of installing pellet boilers. The number of mistakes that are found in pellet heating systems indicates that plenty of installers are less competent than their accreditation would suggest.

RECC (formerly REAL Assurance)

RECC logoThe Renewable Energy Consumer Code (RECC) provides some assurance and recourse for small customers. Again, there is nothing equivalent for medium and large systems.

HETAS approval and training

HETAS approved appliance logoHETAS provide training courses for installers of pellet boilers, and certify the participants' competence. The focus is also on smaller systems, but HETAS do take account of larger systems in the training.

HETAS also offer assessment and approval of heating appliances.

Quality of Other Wood Pellet Equipment

If standards and accreditation are somewhat lacking for boilers and stoves, they are almost completely absent for other wood pellet equipment and the design and installation of the whole system. Most problems with pellet heating systems relate to the fuel handling components, yet there are almost no standards and assurance. Indeed, many members of the industry treat the equipment around the boiler as an afterthought.

As things stand in summer 2013, you will have to rely on reputation and your own judgment as to how much an installer seems to know. You should look for an installer to demonstrate a long track record of installing pellet boilers, as you will be relying on their experience to avoid the common mistakes.

UKPC Storage Guide

UK Pellet Council logoThe UK Pellet Council publishes a Storage and Handling Guide. If you have a problem with your wood pellet heating system and your system does not comply with the advice in this guide, you will be unlikely to succeed in any complaint under the ENplus assurance scheme, because it will be hard to show that the problem resulted from the quality of the fuel or delivery rather than from the failings of your system. You should require your installer to confirm in writing that their installation will conform in all regards with the UKPC's Storage and Handling Guide, and you should follow the operation and maintenance advice in that guide.

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