The carbon-neutral way to heat your property
Clean, Green, Convenient, Efficient & Economical
Wood
pellets are the convenient, renewable alternative, both to fossil fuels
for heating your property, and to straw and shavings for animal
bedding.
This site has been created as a resource for information and
discussion on wood pellets. For Wood Pellet Supplies, see Forever Fuels, who have taken over the wood-pellet supply activities in the UK of Lantmännen Renewable Fuels. For Heat Logs, see the Renewable Wood Fuels website. For SRC/Wood Chips, see Coppice Resources Ltd.
What are wood pellets?
Wood
pellets are made from wood that has been dried, ground and compressed to
create an easy-to-handle, high-energy wood-fuel, typically 6 or 8mm in
diameter and between 5 and 40mm long.
How are wood pellets used?
Wood
pellets are burnt in heating appliances, just like gas, oil and LPG,
e.g. pellet boilers for central heating and hot water, and pellet stoves
for space heating. They are also highly absorbent, and are therefore
popular as a substitute for straw or shavings for animal bedding.
How are wood pellets delivered?
Wood
pellets can be blown into the boiler's fuel-store by a pneumatic
delivery lorry, like deliveries of heating oil and LPG, or delivered in
bags for manual handling.
Are wood pellets as convenient as other heating fuels?
Wood
pellets have a high energy-content and low moisture-content compared to
other wood fuels. Consequently, they need less storage-space and burn
easily throughout the year.
Wood pellets flow well, so they can be
handled easily by automated systems that adjust the heat production to
your needs, just like fossil-fueled boilers.
Are wood pellets clean to use?
High-grade
pellets are made with fresh, clean wood (“virgin fibre”), either direct
from the forest, or using by-products from saw-mills.
Wood
pellets from a quality supplier are consistent and clean. Good,
automated heating systems burning consistent, high-grade fuel produce
low emissions. Several pellet boilers and stoves are suitable for use
in Clean Air Zones. DEFRA publish a long list of appliances, including many pellet stoves and boilers, which are exempt appliances (when using the specified fuels) for the purposes of the Clean Air Act.
High-grade wood pellets have a very low
ash-content, less than 0.7%. A typical property needing 20 MWh of heat
per year would need just over 4 tonnes of wood pellets and produce
around 25 kg of ash (the weight of a typical bag of compost or cement).
Ash from virgin-fibre pellets may provide useful nutrients if spread on
the land.
Are wood pellets sustainable?
The wood for
high-grade pellets usually comes from sustainable sources (ask for "FSC
or equivalent"). Wood pellets are generally produced from conifers.
Rainforests are not cut, and agricultural land is not diverted, for the
purposes of producing wood pellets.
Sustainably-harvested wood is
part of the carbon cycle – the carbon dioxide from combustion is
absorbed by growing trees. Compared to their energy content, wood
pellets require little fossil-fuel to produce and distribute. They have a
very low carbon footprint, even when transported over long distances.
Is there plenty of wood to go around?
There
is a lot of wood, and a lot of uses for the wood. Even if we used all
the forests for energy, it wouldn't be enough to meet all our energy
needs sustainably. In any case, a lot of the forest is needed for
environmental services, and for producing timber and pulp (for paper).
But
the pulp industry is in decline, hopefully permanently, as we stop
printing stuff that modern technology makes it unnecessary to print. And
you can't use the whole of a tree for timber unless we invent square
trees.
So there's a substantial resource of wood that is best
used for energy. It may not be able to meet all our energy needs, but no
energy-resource can. It can make a substantial contribution,
particularly if we use it as efficiently as possible (i.e. for heat) and
get it as efficiently as possible from where the trees are plentiful to
where the people are plentiful.
Because they are dense and dry,
wood pellets can be transported efficiently and economically over long
distances. Wood pellets are an international commodity, allowing regions
with more wood than people to sell to regions with more people than
wood.
Can I depend on wood pellets?
As a solid fuel, wood
pellets are easier to store in large quantities for long periods than
gaseous or liquid fuels (like gas, oil and LPG), let alone electricity.
Serious wood-pellet suppliers build up stocks in the summer to ensure
that they have plenty in hand when demand peaks in the winter. This is
what makes it such a good heating fuel, and why it is such a waste to
burn it at low efficiency in massive power stations throughout the year.
We consume much more heat than electricity, and very few fuels (and no
other renewables) can match biomass's suitability for seasonal
energy-demands.
The UK has the potential to produce significantly
more wood pellets than at present, and current production is many times
higher than the current demand for pellets for heating. Most of the
countries that produce a lot of wood pellets are friendly countries
(e.g. Sweden, Finland, Austria, Germany, Canada, USA, etc.).
There
is little risk that a hostile country with a substantial resource could
cause price-spikes or interruptions, as there is for gas and oil.
Pellet prices have remained pretty stable when suppliers of gas,
electricity and heating oil have pushed up their prices in recent
winters.
What will it cost me?
It depends, of course. You can lookup what a delivery of wood pellets would cost to your
property by entering your postcode and the quantity and type of pellets
you would require into Forever Fuels' wood-pellet Price Calculator.
Blown
deliveries of high-grade pellets generally cost between £160 and
£250/tonne delivered, depending where you are and how much you can take
in one go. £40/MWh (£192/tonne) would be a reasonably-typical price.
Bagged
pellets can be bought by the individual bag or by the pallet-load. A
1-tonne pallet of high-grade pellets will probably cost between £200 and
£300 delivered. £52/MWh (£250/tonne) would be a fairly-competitive
price. By the bag, wood pellets may cost between 30 and 50 pence per kg.
£80/MWh (e.g. £4.80 for a 12.5kg bag) would not be unusual.
You
will need a boiler or stove to convert the wood pellets into heat. When
looking at prices online, make sure that the price includes all the
necessary equipment, such as the flue and the fuel-store (for boilers),
and the cost of installation, and not just the boiler or stove alone.
A
rough rule of thumb would be £5,000 plus £500 per kW of capacity, for
the cost of a pellet boiler including all necessary ancillaries and
installation at a site with no special requirements. You will find
prices that are significantly higher and lower than this. If the price
is much lower, be careful that the equipment and installation will be of
good quality.
Pellet stoves may cost from £2,500 upwards installed.
The
forthcoming Renewable Heat Incentive (RHI) will reward the
carbon-savings from heating with wood pellets (amongst other
technologies). It was originally proposed at the levels of £90/MWh for
boilers up to 45 kW, £65/MWh for boilers between 45 and 500 kW, and
£16-25/MWh for larger boilers. It is likely to be reduced somewhat in
the light of the economic situation, perhaps by around 20%. The
Government has promised to introduce it in June 2011, although that is
also likely to slip a little as they are several months overdue
publishing their proposals. Nevertheless, for small-to-medium pellet
boilers, the RHI is likely to result in a negative net cost of running
in the not-too-distant future (i.e. the value per MWh of the mechanism
is likely to be higher than the cost per MWh of the fuel).
Unfortunately, wood-burning stoves, including pellet stoves, looked likely to be excluded from the RHI under the original proposals.
How does that compare with other heating fuels?
| High-grade wood pellets at £192/tonne = | £40/MWh |
| Heating-oil at 60p/litre = | £57/MWh |
| LPG at 50p/litre = | £77/MWh |
| Natural gas at 3.5p/kWh = | £35/MWh |
| Electricity at 13p/kWh = | £130/MWh |
| Ground-source heat-pump at 13p/kWh and seasonal efficiency of 2.6 = | £50/MWh |
| Air-source heat-pump at 13p/kWh and seasonal efficiency of 2.4 = | £54/MWh |
| Wood chip at 33% moisture and £90/tonne | £28/MWh |
A condensing gas boiler may cost (depending on size and quality) upwards of £1,000 installed, a condensing LPG boiler maybe £4,000, an oil-fired boiler maybe £6,500, ground-source heat-pump £9,000 (plus secondary heat-source), air-source heat-pump £6,000 (plus secondary heat-source), a wood-chip boiler around a couple of thousand pounds more than a wood-pellet boiler.
It is difficult to compare a direct electric heating system with these options, because electric heating requires significant differences in the wider central heating and hot water systems, but in any case, direct electric heating is the most expensive and carbon-intensive option available, to be used only as a last resort. Just because you can't see them doesn't mean that fossil fuels aren't being burnt for electric heating - they are, and at 40% rather than 90% efficiency, plus transmission losses.
To compare the cost of wood-pellet heating with other comparable options, you need to weigh the differences in the capital costs and the running costs. If you have a working boiler, the capital cost is simply the cost of a pellet-boiler. If you need a new boiler, the capital cost is the difference between the cost of a pellet boiler and the alternatives. The running costs can be calculated as the difference between the alternative fuels and the cost of pellets, multiplied by the amount of energy used, plus the value of the RHI.
For example, let's take a new property that is off the gas grid and expected to need 25 MWh of heat each year. An oil-fired boiler costing £6,500 might consume £1,425 of oil each year. A pellet boiler costing £12,500 installed might consume £1,125 of pellets each year (a small consumer like this will pay an above-average price), and receive £1,500 from the RHI - a negative running cost of £375 per year. The extra £6,000 it costs to buy a pellet boiler has to be set against the difference of £1,800 in the annual running costs, i.e. a payback of around 3½ years - a compelling proposition.
If, on the other hand, you already had a serviceable oil-fired boiler, you would have to compare that difference in the annual running cost (£1,800) with the full cost of a new pellet boiler (£12,500) - a longer-term investment. In practice, the gains may be greater than this suggests, as old boilers tend to be inefficient, so the savings from a new boiler of any description are likely to be greater than a like-for-like replacement.