+BIOMASS BLACK MOUNTAIN WOODFUELS

INCREASING THE ENERGY DENSITY OF BIOMASS via

IMPROVED PROCESSING TECHNOLOGY.

INTRODUCTION:

I started cutting and preparing my own firewood more than 25 years ago, and in that time I have probably burned more than 150 tonnes of wood on various

domestic appliances, in various properties. That wood has been carried by hand (back!), cut with a small

chainsaw and split with an axe into logs to fit the firebox.

I have calculated that I handle each log 6 times before it enters the firebox, which means that my back has borne around 900 tonnes of wood - more than the average seaside donkey!

Due to the fact that moisture exists in this wood, it is more accurate to suggest that during this time I have carried 400 tonnes of water and 500 tonnes of dry-fibre. Half of the water that I have carried has evaporated into the atmosphere during the “seasoning” process and what remained has been burned - taking up more than 40tonnes of the dry-fibre to get rid of this water before I have achieved a reasonably warm fire! And then I have sat in front of my fire and watched about 30% of the heat generated being sucked out my chimney, while depositing tars on its journey to the atmosphere!

The exercise has kept me out of the obesity ratings and there have been times when I know that I have been warmer in winter than the majority of people living in the northern hemisphere, but I cannot ignore

that fact that the way that wood is currently being burned at both domestic and industrial levels is inefficient. The truth is that unless consumers have access to bone-dry wood, they will always waste precious energy from the early stages of combustion by having to get rid of the water in the fuel. And by the time the stove/boiler has reached the point whereby the combustion process is fairly efficient the habit is to feed more fuel (water) on to it! The inefficiency is maintained! This is the quandary that persists to this day: efficiencies are prevented due to issues with the moisture in fuel and thermal storage issues are often ignored in favour of cheap (and inefficient) steel stoves, which

are favoured in the UK above more beneficial designs that have existed in Europe for many centuries.

This document describes one of the most ambitious efforts yet to resolve the inherent inefficiencies that are caused by moisture/water in wood and all other forms of biomass. The companies behind the development of this work range from global corporations, employing more than 100 engineers, to micro-businesses employing fewer than 3 people. Collectively, the experience and knowledge has led to the development of technology that completely removes all water/moisture from wood (and most other forms of biomass) cost-effectively, and a unique range of combustion and gasification technologies that enable users to produce increased levels of renewable energy (both electrical and thermal) from smaller volumes of fuel. Richard Edwards: Business Development Director, Black Mountain Woodfuels.

THE STATISTICAL NIGHTMARE THAT IS WATER.

In 2012, consumers in Europe burned about 153million cubic metres of fuelwood (1). If each cubic metre of wood is taken to weigh 400kg and it had all been dried to an optimistic 25% moisture content, then of that 61.2million tonnes of woodfuel, about 15million tonnes was sold in the form of water/moisture. That

water represents possibly £150million of wasted expenditure.

The “carbon-cost” of moving this volume of woodfuel around Europe, in terms of CO2 vehicle emissions, amounts to around 912,000 tonnes annually*. At 25% moisture content, that woodfuel has an energy density (calorific value) of about 14 megajoules per kilogram, and a transport density of 400kg per cubic metre. When you remove water from the equation, via a process promoted here called TORREFACTION, you eliminate the cost of transporting it, you stop selling it to consumers, you increase the energy value of woodfuel by at least 40% and, perhaps most importantly, you achieve gains in efficiency, which ultimately reduce the cost of producing renewable heat and energy from wood and many other forms of biomass. The transport density of torrefied woodfuel can reach as high as 750kg per cubic metre and the energy density increases to around 25 megajoules per kilogram.

* based on diesel-fuel at 400grams of CO2 per tonne per kilometre.

LOGS/CHIP PELLETS TORREFIED

LOWER HEATING VALUE 10-12 mj/kg

15-17 mj/kg

23-25 mj/kg

ENERGY DENSITY (CV) 2-3.2 kWh/kg 4.7-5 kWh/kg 6 – 6.95 kWh/kg

MOISTURE CONTENT 30-50% < 10% < 1%

TRANSPORT DENSITY 250-400 kg/m3 600 kg/m3 750 kg/m3

TORREFACTION – THE KINDLE TO SPARK THE REVOLUTION.

A detailed description of the torrefaction process, when applied to increasing the energy value of wood is provided as “Torrefied wood is completely desiccated biomass, with devolatilised hemicellulose, which has not yet reached the point of ‘char’. That is to say – that pyrolysis, in any form, has not yet commenced. When the critical surface moisture content of the particle is reached, the evaporation is assumed to take place inside the particle in the moving front between dry and moist regions. In the next stage the surface temperature of the particle never exceeds the pyrolysis temperature. In this case, it means that the drying

isotherm reaches the centre of the particle and vanishes before the pyrolysis isotherm appears at the particle surface. In the above context - the drying isotherm is meant to be the torrefaction temperature

(from surface to core) that initiates and completes the devolatilisation of hemicellulose.” (2)

Put simply, torrefaction is a very efficient process of slow-roasting biomass, in an atmosphere with zero oxygen concentrations, to remove all moisture and low energy volatiles to create a combustible product with an increased energy density.

The energy contained in the released volatiles is equal to the heating requirements of the process so that a thermal efficiency exceeding approx. 95% is achieved.

TORREFACTION IN A GLOBAL PERSPECTIVE.

Torrefied fuels have already been successfully test-fired at several power plants in the U.S., Europe and Japan. They have demonstrated the potential to displace coal in largely un-modified utility-scale power

plants at high co-firing percentages and at minimal capital cost to the generator.

One of the main advantages for industrial-scale users of torrefied fuel is that its higher energy density reduces sensitivity to the cost of transport. Each shipment of torrefied fuel carries about 40% more energy

(by volume) than conventional white pellets and well over three times that of wood chips. The carbon footprint of torrefied biomass is also significantly smaller than that of conventional wood pellets. This is

due to reduced electricity consumption in the manufacturing process and to the lower transport emissions per unit of energy.

TORREFACTION IN A UK PERSPECTIVE.

The increased demand for ‘biomass’, driven by Govt subsidies, EU action plans and a desire from consumers to feed their energy demand from “renewable” fuels, has been encouraging for landowners,

managers and woodfuel supply businesses alike, however, because of the fact that water persists in this fuel, efficiencies are not being maximised.

Black Mountain Woodfuels has long seen torrefaction as the answer to the many problems associated with marketing ‘low-value’ hardwoods and softwood thinnings in the UK. In May of 2013 we forged a strategic partnership with TSI Inc., (www.tsi-inc.net.org) the Seattle-based specialists in dryer systems, finishing lines, and heat energy systems, to work together to design, manufacture and market a range of small-scale, static and mobile torrefaction reactors in the UK. Around $1million has been invested in the development of this patented process.

THE AVAILABLE RESOURCE:

“The woodfuel market could represent the single most important economic activity to reinvigorate our woodland wildlife.” Plantlife (2011) Bringing England’s woodlands back to life.

In 2012, 9.3 million green tonnes of wood was harvested across the UK, of which 95 per cent was softwood. A total of 8.6 million green tonnes were delivered to industry, including 5.2 million tonnes to sawmills, 1 million tonnes to the wood-based panel industry and 0.5 million tonnes to integrated pulp and paper mills. A further 1.6 million green tonnes went into fencing, woodfuel, shavings and exports .

A total of 1 million green tonnes of stem-wood was reported by the Forestry Commission (FC) to have been

delivered as woodfuel (600,000 tonnes of softwood and 400,000 tonnes of hardwood) (3). In the same year, about 4million tonnes of wood entered the UK waste stream from construction, packaging and

municipal waste (4).

The FC estimates that the UK’s under‐managed woodlands could provide an additional 2 million green tonnes of woodfuel material in England alone. There are also more than 450,000 kilometres of hedgerow in the UK which could produce more than 150,000 tonnes of wood annually if the whole resource was cut over a 15yr cycle. Furthermore, in recent years, the UK has experienced outbreaks of pathogenic fungi (the most recent being Phytophthora ramorum and Chalara fraxinea), which have threatened the loss of up to 15% of its tree cover. During the next 10-15 years, more than 4million tonnes of infected Larch could be felled in the UK (5).

The introduction of torrefaction technology to the UK will mean that the neglected resource of more than 1million acres of broadleaved woodland and miles of neglected hedgerows can now be managed effectively and profitably, and the waste-wood resource can be processed to produce a high-grade woodfuel. Similarly, the use of torrefaction to treat infected species can limit the spread of pathogens,

while encouraging the use of woodfuel locally.

Chalara fraxinea on Ash

EFFICIENT GENERATION OF BIOMASS-BASED RENEWABLE ENERGY. While feeding electrical energy back to the national grid is attractive, due to the existence of subsidies paid for production, more than 60% of that energy is lost to network inefficiencies, which cause losses during distribution (6). The current trend with biomass is the generation of heat and electricity via district heating

systems. Often, large woodchip/pellet boilers replace fossil-fuel systems, which usually result in a net reduction of greenhouse gases (CO2) and reduced energy costs for consumers.

The “golden egg” for energy production from biomass is a system which can be installed in individual

households that can generate both thermal and electrical energy from technologies built specifically to run on improved biomass.

The development of small-scale torrefaction technology has helped advance the design of new, smarter

forms of biomass combustion units, which are not only more efficient than district-scale systems, but allow individuals to set the levels of both thermal and electrical energy production from within an

individual household.

THE BLACK MOUNTAIN WOODFUELS MODEL FOR BIOMASS: The initial option for the market-placement of torrefaction technology would be to target large biomass businesses with a turnover to justify the level of expenditure. This would enable these suppliers to make gains by reducing transport costs and increasing the value of their product. This is seen as an efficie nt way

to introduce larger volumes of torrefied fuel to the market in a relatively short period of time.

Pursuing this as the sole option, however, would exclude more than 75% of businesses involved in supplying biomass across the UK and the wider EC. Given that the technology offers possible solutions to

the problems associated with the management of smaller woodlands in the UK, and may contribute toward the effort to alleviate fuel-poverty, other models/options need to be pursued. One possible solution, detailed below, would be to offer these reactors on the basis that the greatest number of small, localised biomass suppliers can benefit from the collective ownership, and this may be best achieved by establishing a network of private/public sector co-operatives, which will facilitate the use of the torrefied fuel in a greater number of locations. The following model describes this principle:

Private sector

biomass/woodfuel

business

Public sector

woodland owners

councils, Govt., etc.

Land-owning

charities Biomass users Communities

Supply existing

and new markets

at domestic and

commercial-scale.

Provide fuel for

own buildings.

Provide fuel for

own buildings and

sales to local

businesses.

Provide fuel for

own use.

Provide fuel from

community

woodland to

community.

THE TORREFACTION BUSINESS MODEL: 500KG/HR MOBILE UNIT/ANNUAL PRODUCTION

The operational process of a torrefaction reactor needs to be sustained at very precise temperatures over prolonged periods of production - 24 hours a day, up to 7 days a week. The very high levels of engineering and operational precision are reflected in the price of the technology: the 500kg/hr. torrefaction reactor costs £750,000 and the 1.5tonne/hr. (static) reactor costs £1.5million.

At a production rate of 500kg/hr., the small, mobile torrefaction reactor has a maximum output capacity of 4380 tonnes per year: in reality, this figure is likely to be closer to 3600 tonnes (300days @ 24/7).

COST: £750,000 (ex VAT)

ANNUAL PRODUCTION CAPACITY (300 X 24HR DAYS): 3600 TONNES

RETAIL VALUE OF FINISHED PRODUCT (AT £200 PER TONNE): £720,000

RAW MATERIAL COST (5000 TONNE AT £40 PER TONNE PRESENTED AT SITE): £200,000

LABOUR COSTS (BASED ON TWO-PERSON OPERATING): £70,000

Figures provided as an example only. Raw material cost based on 1 tonne at 20% MC producing 700kg torrefied at 0-2% MC.

Given the energy-value of the fuel, there is a belief that the retail price to consumers will settle at around

£200 per tonne, which is similar to the retail price of wood-pellets (10% moisture) in the UK. The gross value of the product over this period would sit close to £700,000.

As suggested previously, allowing for down-time, travel to and from sites, set-up, etc., the minimum operational limit of a 12-month period will be 3600 tonne: this figure is taken to be 100% in the following

example:

Private business 1 supplying 360 tonnes of woodfuel locally – 10% of annual reactor capacity (£75,000). Private business 2 supplying 1080 tonnes of woodfuel locally – 30% (£225,000).

Local Council buildings requiring 2160 tonnes of woodfuel – 60% (£375,000).

The total elimination of moisture from the biomass means that private business 1 reduces his/her transport costs (and associated CO2 emissions) by half (from doubling the energy density of the fuel

being transported). It loses a total of 108 tonnes of wood/water from the business, which has a retail value of £10,800 (@£100 per tonne for wet wood), but increases the turnover of the business

from £36,000 (360 tonnes @ £100 per tonne) to £50,400 (252 tonnes @ £200 per tonne). The increase in profit may allow for the payback on the investment in torrefaction technology within 5-

10 years.

Local Council currently paying £324,000 annually for heating council-run properties (average of

£150 per tonne). Develop policy to utilise own woodland portfolio, determine sustainable yield, sell wood to private business 1or2 and buy back at reduced cost to run properties more efficiently.

Extracted from: Plantlife (2011), Forestry Recommissioned: Bringing England’s woodlands back to life. Plantlife: Salisbury.

“There is much debate about the future of England’s [UK’s] woodland. A great deal of it to date has

been about who should own our woods and forests and how extensive they should be. Who owns our woods shouldn’t matter; it is what we do with them that counts. This report shifts the focus to managing our woodlands so that they deliver for us and for our wildlife. Plantl ife’s vision is for a woodland estate where the economic incentives exist for private woodland owners to manage their woods more actively, and where those woodlands in public ownership are managed to the highest standard to deliver the public benefits of beautiful landscapes rich in wildlife. England today has more woodland than 20 years ago. It is not a rare and restricted habitat but a widespread and familiar part of the landscape. We have 5 times more ancient woodland than limestone grassland, 27 times more woodland than lowland meadow, and a staggering 229 times more ancient woodland than upland hay-meadow. Yet, characteristic woodland birds and butterflies continue to decline and woodland plants are vanishing at a greater rate than meadow species. It would seem that the

Government’s ambition to create a further 10,000 hectares of new woodland in England every year until 2020 is perhaps too simplistic.

More woodland is a well-intentioned aim but what we really need is better woodland. So why are England’s woodlands losing their life and vitality? They aren’t being bulldozed, concreted over or burned down – they are still standing and you can still walk through them. The simple answer is that too many of our woods are neglected, mismanaged or under-managed. This is the major threat to their plant life and to the other wildlife that depends upon a rich woodland flora. Overgrazing by a soaring deer population and nutrient enrichment from atmospheric pollution compound the problem. If our native woodland – much of it of international importance – is to be protected and

enjoyed by future generations, then private and public woodland owners need to take a more informed and more active approach to woodland management.

It matters little who owns dull woodlands devoid of natural beauty and nor do we need more of them.

In the International Year of Forests, this report sets out Plantlife’s recommendations to put the life back into England’s woodlands.”

REFERENCES: (1). http://www.aebiom.org/ (2). http://raw-torrefactiontechnology.blogspot.co.uk/ (3). The economic value of the woodfuel industry to the UK economy by 2020. Report for the Forestry Commission June 2010. Centre for Economics and Business Research ltd - Unit 1, 4 Bath Street, London EC1V 9DX. www.cebr.com (4). Wood waste: A short review of recent research. DEFRA, July 2012 (5). http://www.forestry.gov.uk/forestry/INFD-5UBESN (6). http://www.off-grid.net/2010/04/11/60-of-power-is-lost-in-the-grid-exclusive/

PICTURES: Cover: sample box deta i l ing the range of drying s tages of torrefaction reactors . (Copyright BMWF) Introduction: Richard Edwards – Bus iness Development Director, Black Mountain Woodfuels . (Copyright BMWF) Page 2: Inefficient combustion of fi rewood in domestic properties . Page 3: Torrefied woodchip. (Copyright BMWF) Page 4: Torrefaction reactors – 1.5tonne/hr s tatic and 500kg/hr mobi le. (Copyright TSI Inc.)

Page 5: US Forest Service Posters Page 6: District heating diagram, Micro-CHP system. Steam Turbine (copyright Green turbine BV), Woodfuel label (copyright BMWF). Page 9: Al l images copyright BMWF.

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