Wood Pellet Specification | Forever Fuels

Forever Fuels is an ENplus accredited wood pellet supplier, mainly supplying A1-grade pellets. The specifications in the current (v3) ENplus Handbook are shown below.

A specification is not a description of the product. It is a minimum that the pellets are guaranteed to exceed. If a supplier shows you a certificate of analysis and tries to tell you that their wood pellets are superior because the analysis exceeds the spec, remember that every other analysis of pellets of that spec would also have exceeded the spec.

In most regards the ENplus specs are practical for their purpose, and variations from one load to another or one supplier to another will be insignificant. For example, the Calorific Value (i.e. energy content) of softwood pellets will depend largely on the moisture content, and as most ENplus A1 pellets are likely to have a moisture content within a narrow range of around 5% to 8%, the variations in the CV will be marginal, whatever some disreputable suppliers may claim about the "high energy content" of their wood pellets.

The key factor that (a) may vary significantly and (b) will affect the operation of your boiler is the fines content. There are many factors in the fines that reach your boiler, not all of which are within the fuel-supplier's control (for instance, the blowing distance, the number of bends in the pipe, and how often you clean your store). But your pellet supplier can play an important role in reducing the delivered fines, within the constraints of the installation.

Notice that the Fines limit in the table below applies to the proportion loaded onto the truck, not to the proportion delivered. Additional fines will be generated during the delivery. ENplus permits upto 4% delivered fines.

The actual amount will depend on the characteristics of the installation, the technology used for the delivery, the skill of the driver, and the "strength" of the pellets. The propensity for pellets to disintegrate under stress is described as the Mechanical Durability. The standard PDI test for Durability is not a reliable guide to real-world behaviour, but it is the best we've got. In general, the higher the Durability, the fewer fines should be generated during delivery (all other things being equal).

For wood pellets that are delivered straight from the factory to your store, the extent to which the Durability exceeds the spec is not critical, unless the delivery conditions are difficult. But for wood pellets that are handled multiple times, such as imports, a high Durability is important to cope with the stresses that the pellets go through without shedding large amounts of fines and dramatically reducing the average length of the remaining pellets.

Consequently, we have ensured that our main contracts for imported wood pellets specify a higher Durability limit than the ENplus A1 spec. Combined with:

  • our screening and sampling systems to ensure that the pellets are genuinely loaded with <1% fines,

  • our pressurised tankers and

  • our expert delivery drivers,

we offer the gentlest deliveries of the hardest, cleanest pellets, to minimise the amount of fines delivered to you.

That doesn't absolve you of the responsibility of designing your installation to cause as little degradation as possible. But within the constraints of your installation, we will deliver as few fines as possible.

ENplus Quality Specifications

Property

Unit

ENplus A1

ENplus A2

ENplus B

Testing standard 11)

Diameter

mm

6 ± 1 or 8 ± 1

ISO 17829

Length

mm

3.15 < L ≤ 40 4)

ISO 17829

Moisture

w-% 2)

≤ 10

ISO 18134

Ash

w-% 3)

≤ 0.7

≤ 1.2

≤ 2.0

ISO 18122

Mechanical Durability

w-% 2)

≥ 98.0 5)

≥ 97.5 5)

ISO 17831-1

Fines (< 3,15 mm)

w-% 2)

≤ 1.0 6) (≤ 0.5 7))

ISO 18846

Temperature of pellets

°C

≤ 40 8)

Net Calorific Value

kWh/kg 2)

≥ 4.6 9)

ISO 18125

Bulk Density

kg/m3 2)

600 ≤ BD ≤ 750

ISO 17828

Additives

w-% 2)

≤ 2 10)

-

Nitrogen

w-% 3)

≤ 0.3

≤ 0.5

≤ 1.0

ISO 16948

Sulfur

w-% 3)

≤ 0.04

≤ 0.05

ISO 16994

Chlorine

w-% 3)

≤ 0.02

≤0.03

ISO 16994

Ash Deformation Temperature1)

°C

≥ 1200

≥ 1100

CEN/TC 15370-1

Arsenic

mg/kg 3)

≤1

ISO 16968

Cadmium

mg/kg 3)

≤ 0.5

ISO 16968

Chromium

mg/kg 3)

≤10

ISO 16968

Copper

mg/kg 3)

≤10

ISO 16968

Lead

mg/kg 3)

≤10

ISO 16968

Mercury

mg/kg 3)

≤0.1

ISO 16968

Nickel

mg/kg 3)

≤10

ISO 16968

Zinc

mg/kg 3)

≤100

ISO 16968

  1. ash is produced at 815 °C
  2. as received
  3. dry basis
  4. a maximum of 1% of the pellets may be longer than 40mm, no pellets longer than 45mm are allowed.
  5. at the loading point of the transport unit (truck, vessel) at the production site
  6. at factory gate or when loading truck for deliveries to end-users (Part Load Delivery and Full Load Delivery)
  7. at factory gate, when filling pellet bags or sealed Big Bags.
  8. at the last loading point for truck deliveries to end-users (Part Load Delivery and Full Load Delivery)
  9. equal ≥ 16,5 MJ/kg as received
  10. the amount of additives in production shall be limited to 1,8 w-%, the amount of post-production additives (e.g. coating oils) shall be limited to 0,2 w-% of the pellets.
  11. As long as the mentioned ISO standards are not published, analyses shall be performed according to related CEN standards

Sustainable wood pellets, authorised by the Biomass Suppliers List (ID:BSL0037716-*) From sustainably-sourced virgin fibre, certified by the FSC (Cert.No. C130395) ENplus A1 accredited wood pellet trader (ID:UK302) Operating to ISO 9001 standard, audited by ACS Operating to ISO 14001 standard, audited by ACS Wood Heat Association member UK Pellet Council member REA Awards Winner 2015: Company of the Year