Wood pellets have a very wide range of uses. They can be used in stoves and boilers for fuel, as animal/horse bedding and even for BBQs. With such a wide range of uses, wood pellets are produced to different standards and qualities. For instance, when it comes to burning wood pellets the percentage of ash produced is an important consideration. However, when wood pellets are used for horse bedding how much ash those pellets produce when burnt is relevant. Therefore with this post, I wanted to discuss the different grades of wood pellets and what effects their grade.
Premium Wood Pellets For Fuel Uses
There are various different grades of wood pellets used for fuel. The highest standard of pellets and the most expensive are referred to as ‘premium wood pellets’. These are typically produced from the waste sawdust from timber production. However, to produce premium wood pellets from logs the bark has to be removed.
What is considered to be a Premium Grade Wood Pellet?
To be considered as a premium grade wood pellet generally means the following requirements are met:
- Ash content at or below 0.7%
- Moisture content below 10%
- Good mechanical durability with low fines
So as shown above, a premium grade wood pellet requires ash content below 0.5%. However, it also means the pellets produce very little dust, also known as fines. Finally, it also means the wood pellets were produced to a sufficient density. Wood pellet density is very important, as a low-density wood pellet will produce more fines during transportation and handling. You can easily test for yourself if a wood pellet is produced to a good density by breaking the pellet horizontally as shown in the diagram below.
For premium wood pellets, in fact, any well-made wood pellets you expect a clean snap with very few fines. There are various premium wood pellet certification schemes, below are some examples:
Pellet Fuels Institute Wood Pellet Grading
The Pellet Fuels Institute (PFI) is the predominant wood pellet trade association in the US. The institute works with both pellet fuel manufacturers and pellet stove manufactures. Pellet stoves and boilers can use the PFI Fuel Grade stickers to inform consumers that they should only use a particular grade of wood pellet fuel in that appliance.
The PFI has three grades of wood pellets under its certification scheme. They include Premium, Standard and Utility. The table below from the PFI shows the requirements to meet the certification standard of each grade.
The Difference between Premium, Standard and Utility Wood Pellet Grades
First, it’s important to note that all grades have the same required diameter and length. However, the premium grade has slightly higher durability (>96.5), lowers fines (>0.5%), lower ash content (>1%) and moisture content (>8%). Most pellet stoves sold in the US can only use the PFI Premium grade however some are branded with the PFI Standard. Standard grade wood pellets are cheaper to purchase, but you will have to clean out the ash draw more frequently.
ENplus – European Premium Wood Pellet Standard
ENPlus is a premium wood pellet standard agreed by the European Wood Pellet council back in 2011. The objective was to create a quality standard to make the trade of wood pellets as a commodity simpler with an understood price to a quality relationship. Since then ENPlus has seen the following:
- 911 companies part of the ENPlus certification scheme
- 10 million tonnes of ENPlus wood pellets produced in 2018
However, it’s important to note that this standard is not only used in Europe. There are wood pellet manufactures in North and South America and even Asia who are part of the ENplus premium wood pellet certification scheme.
ENplus Premium Wood Pellet Requirements
So as you can see from the table above, there are three grades of ENplus wood pellets. A1 is the top ‘premium’ grade, then there is A2 and finally, grade B.
You can see that all the wood pellet grades are produced as either a 6mm or 8mm pellet, however, there is also a length requirement of between 30mm and 40mm. The reason for this is some pellet feed system augers are specifically designed to deal with pellets up to s certain length. If the wood pellets are too long they can potentially cause damage to the feed systems on some stoves and boilers.
The ash percentages are below 0.7% for A1, below 1.2% for A2 and below 2% for grade B. You will also notice that grade A1 is produced to slightly mechanical durability than A2 of B grade. Most pellet stoves and boilers could probably run on the A2 grade. However, grade B may produce just too much ash for some pellet stoves and boilers.
What are ENplus Grade B Wood Pellets for?
ENPlus grade B wood pellets can also be referred to by the term ‘standard grade’ or ‘industrial grade’. Now, there are some domestic pellet stoves and boilers which can burn these wood pellets. For instance, my Tatano pellet boiler can burn pretty much any type of biomass pellets. I’ve successfully burnt cardboard pellets up 10% ash content! Therefore ENPlus grade B wood pellets at 2% is not an issue. The main market for grade B wood pellets is larger commercial pellet boilers and even for co-firing in coal power stations.
ENPlus Wood Pellet Certification Fraud
There are some wood pellet manufacturers and resellers falsely claiming their product is manufactured to the ENplus standard. Therefore ENPlus have a fraud investigation team. They also invite customers to contact them over wood pellets carrying the ENplus certificate which they believe are not up to standard. ENplus actually have a blacklist of companies who have misused their trademark.
Wood Pellet Grades for Horse and Animal Bedding
There are no specific grades for wood pellets used for horse or animal bedding. However, as stated above, ash content and durability of horse bedding are not a concern. Therefore, for the best value for money, you could purchase loose wood pellets of either standard/utility grade as per the PFI or ENplus Grade B. Just make sure to store the pellets in a space protected from the elements with low humidity.