BIOMASS FUEL TYPE FACTS

ABOUT WOOD FUEL Wood is emerging as an important fuel as part of the Government's drive for increasing the proportion of our energy produced from sustainable biofuels. Trees grow every summer using the energy of the sun to fix carbon from the atmosphere. Every wood land has a sustainable yield of timber, which can be harvested indefinitely without depleting the resource in any way. Wood is carbon neutral and does not contribute to greenhouse gasses. Burning wood gives off carbon dioxide just like fossil fuels, but this is balanced by the carbon absorbed by the growing trees. Un-harvested wood will give off the same amount of carbon dioxide when it eventually decomposes as it would have done if burnt in a boiler. Wood is an age old fuel which fell out of use in Britain with the industrial revolution and advent of cheap fossil fuels. However, wood is still the primary fuel for people in many countries around the world, both developing and developed. In Britain, with increasing concern about climate change, wood is now an increasingly attractive energy source along with other forms of biomass. Wood burning has always played a central role in our lives and even more so now when the energy prices are increasingly rising. Step by step the wood burning technology has improved and more and more of the heat value is being used within the fuel. Today, the energy content of the wood has been able to be utilized even more with today's modern combustion technology, combined with modern accumulator technology. Today, we even see environmentally certified wood boilers on the market which typically now provide added oxygen with the help of a fan. This then makes the combustion even more stable compared to the old natural draught principle. With today’s technology wood burning is a very practical and economic heating form for our buildings and industrial processes.

ABOUT WOOD CHIP

Wood chip is a processed form of wood fuel that can be used in automatic boiler equipment without the high degree of processing required to manufacture pellets. Within biomass heating, wood chip is often used in boilers, ranging from 25 kilowatts to many megawatts for Combined Heat and Power (CHP) and district heating plants. Wood chip boilers are available for all scales of operation. As with wood pellets, modern wood chip boilers can provide a high level of automation and convenience for wood fuelled space heating. Due to oil and gas price rises over the last three years, wood chip is a very cost-competitive fuel, with the less processed forms such as logs and chips typically undercutting all other domestic fuels. The equipment to burn chip must be rather heavy-duty and tends therefore to be a little more expensive and space extensive than its pellet burning counter-parts. However, with the recent introduction of various grant schemes such as the RHI to help with the capital costs the scales are more balanced, particularly as the variable costs are lower and more predictable. Wood chips present no risk if accidentally released into the environment, unlike oil which is a serious pollutant and gas which can explode. There are no harmful by-products. The flue gas is smoke-free and the ash content of between 0.5% and 3% by volume (depending on material), is minimal. Unlike coal ash, wood ash is an excellent fertiliser and can be used in the garden or returned to the forest as bio-char. Modern appliances burn very cleanly with minimal smoke. The majority of woodchip boilers currently being installed in the UK require fuel to comply with the Austrian ONORM M 7133 specification. This wood should then be carefully stacked allowing good airflow and kept covered on top (typically with a breathable membrane sheet) allowing natural air to flow and moisture to evaporate through the membrane. After being left in situ in log form in this way for approximately 9 months to one year after felling, the wood will typically dry naturally to around 20-25% moisture content and will then produce a good, high quality chip.

Woodchip can then be stored under cover ready for use, but again it is advisable to store in a well-ventilated, yet reasonably weather proof enclosure to help avoid stagnation and moisture absorption. If wood chip is turned occasionally in this situation, this will help create the ideal chip. SUITABLE WOOD CHIP SPECIFICATION:

Woodchips used in smaller installations should have a homogeneous particle size. Avoid pieces of width less than 8mm or length greater than 50mm.

Ideally wood chip shall be sized: 10mm width x 30 (G30)-40mm length (in the direction of the wood fibre).

Moisture Content: between 20 – 30% (W30), ideally 20-25%.

Limits: no less than 15% moisture content ideally (W20) (the moisture actually assists in improving combustion efficiency.

No greater than 35% moisture content (W35) (excess moisture leads to product clumping, insufficient combustion chamber temperatures, excessive boiler condensation and overall poor energy value for a given volume of product.

Unknown objects: Every effort should be made to avoid the introduction of foreign bodies such as sand or metal. Sand and grit can become embedded within bark if logs are dragged prior to stacking (and can in some instances where exposure to sand, dust or grit is possible) grow within the bark . De-barking is therefore a practice that should be considered for ideal chip production.

The moisture content determines the choice of equipment used.

For a domestic stoker boiler, the moisture content should not be higher than 20-25%. For ceramic lined retort or heavy-duty stepped grate boilers the maximum moisture content should be no higher than 35%. Purpose made ‘wet fuel’ boilers (where combustion chambers are lined with refractory bricks for example) can typically handle moisture contents between 35% and 55%. These types of boilers are not usually then able to fire ‘dry’ fuels as their combustion chamber temperatures become excessive on dry fuel. Please see Table 3 within the “Biomass Energy Content & Price” section of the website for further details on wood chips.

BIO-NORDICS FAVOURITE WOOD CHIP BOILER SYSTEMS INCLUDE:

1) LARGE DOMESTIC & SMALL COMMERCIAL: GOTFire Wood chip Heating Systems

GOTFire 40kW Wood Chip Boiler GOTFire produce woodchip heating systems in outputs of 25, 40, 60 and 100kW and multiples thereof, including containerised versions and with optional and bespoke walking floor fuel stores and fuel transport systems.

2) SMALL TO MEDIUM MULTI-FUEL:

FUMO Multi-Fuel Heating Systems

FUMO FBR 25kW MULTI-FUEL BOILER

FUMO are one of Denmark’s leading manufacturers of multi-fuel biomass boilers and fuel feed and storage systems in outputs of 12, 25, 45, 60, 90, 280 and 500kW.

3) MEDIUM TO LARGE SCALE COMMERCIAL: OSBY PARCA BIOMASS HEATING SYSTEMS

OSBY PARCA PB2 (2MW) BOILER Osby Parca offers an extensive range of biomass boiler solutions ranging from 200kW – 7MW, manufactured within their own factory in Osby, Southern Sweden, able to be fired on wood chips, wood pellets and / or wood briquettes.

Bio-Nordic are also able to supply a wood chip drying system solution. Please contact us if you wish to find out more.

Bio-Nordic can provide a list of national and regional wood-chip suppliers:

To be added to this list or to enquire about deliveries and/or costs of fuel in your area, please contact us.

ABOUT WOOD PELLETS

Pellets – The Fuel: Basic facts about fuel pellets

A fuel pellet is as per definition a "short cylindrical piece of wood" intended for combustion. Fuel pellets are produced by pressing a finely powdered dry fuel from waste products typically derived from the forest industry. The diameter of the fuel pellets within the European Union today varies between 6-12 mm, with a standard length in the range 5 mm to 30 mm.

The overall effect on the environment using pellets is very low when burning pellets. Combustion is typically carried out in a pellet fired system such as for example a pellet boiler or stove. Upon combustion the stored sun energy inside the raw material is then released. The emissions of unburned hydrocarbons as well as dust are in most cases way under the limited values of most local authorities throughout the EU. Please see Table 3 within the “Biomass Energy Content & Price” section of the website for further details on wood pellets.

Pellets can be transported on a large-scale via bulk loaded lorries for example, either for domestic use or for use in district heating plants close to a harbour, where transportation from the boat already exists. For distribution to home-owners there are also developed alternatives such as pellets in bags (typically in 10-15kg bags), on pallets, bigger bags or bulk loads for example. Note: Please contact us for further information on your local wood pellet supplier.

BIO-NORDICS FAVOURITE WOOD PELLET/STOVE BOILER SYSTEMS INCLUDE:

1) SMALL / LARGE DOMESTIC & SMALL COMMERCIAL EFFECTA ENERGY SOLUTIONS AB

EFFECTA ‘COMPLETE’ 20KW WOOD PELLET BOILER The Effecta biomass boiler range comes in outputs of 20kw and 30kW (wood pellets) and 35kW and 60kW (wood log gasification).

2) SMALL TO MEDIUM MULTI-FUEL:

FUMO Multi-Fuel Heating Systems

FUMO FBR 45KW MULTI-FUEL BOILER

FUMO are one of Denmark’s leading manufacturers of multi-fuel biomass boilers and fuel feed and storage systems in outputs of 12, 25, 45, 60, 90, 280 and 500kW.

3) MEDIUM TO LARGE SCALE COMMERCIAL: OSBY PARCA BIOMASS HEATING SYSTEMS

OSBY PARCA PB2 (3MW LPHW) BOILER Osby Parca offers an extensive range of biomass boiler solutions ranging from 200kW – 7MW, manufactured within their own factory in Osby, Southern Sweden, able to be fired on wood chips, wood pellets and / or wood briquettes.

4) SMALL TO MEDIUM SCALE DOMESTIC: WOOD PELLET BOILER STOVES:

Wood pellet boiler stoves tick all the boxes: they are very efficient, the internal pellet hopper has a good capacity and they have a high enough output for most houses. Additionally many wood pellet boiler stoves look good and so can be installed inside the house where you can watch the flames through the window as the wood pellets burn. When combined with a correctly sized hot water tank the wood pellet boiler stove can provide all the hot water and run the central heating for a large house.

5) SMALL SCALE DOMESTIC: WOOD PELLET STOVES:

ARITERM LILLA FRÖ 2-5KW WOOD PELLET STOVE

Ariterm is of one of Scandinavian’s leading manufacturers of wood pellet stoves. Ariterm has a century of tradition but bubbles with creativeness and the will to be in the lead in environmental, effective and functionally-safe heating techniques. The pellet stove can cover the heating requirements for living accommodation, an entire low energy one-family house or indeed small office or hall and can be installed as either a primary heating source or as a supplement to a central heating system. Pellet stoves typically feature automatic ignition and modulation via thermostat heat is spread throughout the house by an integral, low watt, quiet running fan. The only manual intervention required is the occasional filling of pellets (via small bag) into the integral hopper typically necessary between 2 –3 times per week depending on hopper size and heat setting chosen. Some more interesting facts about wood pellet fuel

1) The compactness of the wood pellet material comes from the lignin which is contained in the wood itself, and allows the production of pellets without the use of glues or binders.

2) Good quality pellets have a density which varies between 600 kg/m3 and 750 kg/m3, with a moisture content which varies from 5% to 8% by weight.

3) Pellets also have technical advantages. While good-quality timber has a typical calorific energy content around 4.4 kW/kg (with 15% moisture, i.e: after about 18 months' seasoning), the equivalent figure for wood pellets is around 4.9 kW/kg.

5) To ensure they burn well, the pellets must be stored in an area that is free from humidity and protected from dirt.

6) The poorer the quality of the fuel, the less well it will burn and the more frequently you will need to clean the internal parts, such as the grate and the combustion chamber.

7) The main certifications of quality for pellets in the European market are DINplus and Ö-Norm M7135; these ensure the following qualities: • Calorific power: 4.9 kW/kg • Water content: max 10% of weight • Percentage of ashes: max 0.5% of weight • Diameter: 5 to 8 mm

• Length: max 30mm • Contents: 100% untreated wood, with no added bonding substances (bark percentage 5% max). We strongly recommend using certified fuel in pellet stoves to European standards (DINplus and Ö-Norm M7135).

8) If you use fuel of inferior quality, or not conforming to the specification given above, it compromises the running of your boiler/stove and can lead to the termination of the guarantee and of the manufacturer's responsibility for the product.

9) Recently the supply of pellets from distributors has become very good throughout Europe. The number of manufacturers & distributors coming on line is increasing all the time. This will hopefully mean the price of pellets will get cheaper, become more competitive and they will become more readily available.

ABOUT WOOD LOGS

WOOD LOG SPECIFICATION:

There are typically three different types of wood logs that can be used for burning within wood boilers, being unseasoned logs , seasoned logs and kiln dried logs.

A seasoned log is one that has been cut and dry stored (i.e. under cover) for a long period of time, usually over 12 months. These are very suitable for burning. The moisture content after seasoning is typically around 30%.

Unseasoned logs are just that, unseasoned and recently cut. They are likely to have high moisture content - i.e. above 50%. Whilst it is possible to burn unseasoned logs on an open fire, it is not really advised to burn unseasoned logs within wood log boilers because the temperature is not sufficient to burn off the sap contained in the wood, which can then build up on the inside of the boiler as a tar condensate and lead to severe damage.

Lastly, Kiln Dried Logs are logs that have been put through a large kiln chamber that controls the temperature and humidity. Moisture content is then typically around 20%. The result is a wood log that burns hotter and for longer, due to the lower moisture content, resulting in even greater efficiency of your boiler.

Scoring or partial removal of bark may help to accelerate drying of wood logs. For logs over 15 cm diameter splitting is recommended to assist drying.

The optimum size for wood logs should be around 25-30 cm long to be used within a wood log boiler.

Please see Table 3 within the “Biomass Energy Content & Price” section of the website for further details on wood logs. BIO-CHAR: Finally, it should also be noted that the intentional and controlled charring of wood and its incorporation into the soil is an effective method for carbon sequestration as well as an important technique to improve soil conditions for agriculture, particularly in heavily forested regions. It forms the basis of the rich soils known as “Terra preta”.

1) SMALL / LARGE DOMESTIC & SMALL COMMERCIAL EFFECTA ENERGY SOLUTIONS AB

MODERN WOOD BURNING

EFFECTA “LAMBDA” LOG GASIFICATION BOILER

The Effecta biomass boiler range comes in outputs of 20kw and 30kW (wood pellets) and 35kW and 60kW (wood log gasification). Finally the wood boiler should be connected to an accumulator tank that contains a large enough volume of water to meet the function requirements to keep the heat for 24 hours at the coldest temperature. The fact that the water volume in the boiler should be as little as possible makes the boiler increase to the right temperature faster than in old boilers with larger

water storage. As a result, the efficiency then becomes optimal and even radiation and standstill losses are eliminated.

ABOUT ENERGY CROP COMBUSTION

Firing with grain

Most people react in a negative way the first time they hear about firing grain, but the fact is that within parts of the EU there is a surplus amount of arable acreage. Our surplus of grain does not automatically reach the people that are starving in the world but instead costs the society a large amount of money in different support actions. Today, the price of the fuel is too high to make it profitable to fire it. Maybe, just now, it is only suitable for farmers to fire surplus amounts of grain that has been too damaged to be sold to the food industry. If we should be able to try to reach the global climate goals it is necessary to use the surplus acreage within the agriculture sector for energy production. If we choose to grow crops we might lose our open farm land that we are used to seeing. If we use grain for energy production we keep the option of producing alcohol, vehicle fuel, burning for energy production or for eating, for as long as possible. Grain - and especially oats - can be locally produced over the whole of the EU and provide a valuable occupation for many also in rural areas. For the farmer it is not about any new and expensive investments, instead he can use the existing machinery he has already got. As a fuel, grain is nature's own pellets. It is easy to transport, contains little fine fractions and, during combustion, does not contribute to the greenhouse effect.

By firing grain you can, in the long term, decrease the costs upon society on agricultural support measures, whilst at the same time retain the open landscape. Developed grain firing would also give the farmer an alternative return for grain of bad quality.

To fire with grain

Experience of firing grain so far on a farming level is still quite limited. However, there are still some different technologies to choose from, such as that from the Danish manufacturer, FUMO. Whilst firing grain is still not very common even amongst farmers themselves, the interest to start firing with grain is enormous!. The heat value in grain varies dependent upon its moisture content and cleanliness. Still, generally we can assume that oats are the most suitable fuel if you can choose. Oats have typically a slightly higher fat content and a little better calorific value than other types of energy, and the soft shell makes the grain more flammable, whilst at the same time the melting point of the ash from oats produces a higher combustion temperature before the ash then sinters. If you should cultivate for energy purposes it could be then be favourable to grow oats, growing a type that is easy to thresh and gives an early ripeness. The most economic for your own use otherwise is to cultivate as usual and fire the parts of the crop that for different reasons have a lower market price.

1) SMALL TO MEDIUM MULTI-FUEL: FUMO Multi-Fuel Heating Systems

FUMO FBR MULTI-FUEL BIOMASS BOILER

FUMO are one of Denmark’s leading manufacturers of multi-fuel biomass boilers and fuel feed and storage systems in outputs of 12, 25, 45, 60, 90, 280 and 500kW.

When considering the combustion technology side of things there are no bigger differences between firing with wood chips, pellets and/or grain. The equipment presently available can handle each of these fuels and with a similar performance. However, you cannot fire grain in a traditional pellet burner or woodchip stoker due to the increased ash content and the hardness of the grain causes technological problems with the combustion. However, there are special grain burners that can also operate with pellets, such as that produced by FUMO (above). FUEL SUPPLIERS: Bio-Nordic are able to advise on good, reputable wood fuel suppliers within your local area. Additionally, we would also like to suggest that you look at the Forestry Commission Directory of wood suppliers.

WOOD FUEL STORAGE: The method of wood fuel storage is typically bespoke in nature and dependent on a number of practicalities that are assessed when on site. Here are some examples of methods of fuel storage: Subterranean wood chip fuel storage with integrated hydraulic lid.

Blown wood pellet delivery (Note: Wood chip is also able to be delivered this way). Published by Bio-Nordic Ltd, UK: Please visit www.bio-nordic.co.uk for further details