A guide to Biomass Boilers for Educational Establishments.

Constant Energy Ltd Magnetic HouseMedia VillageThe QuaysManchester, M50 3XW

Philip R.Smith-LawrenceOffice: +44 (0)161 813-1760Mobile: 07748443805Website: www.constantenergy.co.ukEmail: psl@constantenergy.co.uk

CONTENTS PAGE

BIOMASS OVERVIEW

HOW DO MODERN BIOMASS BOILERS WORK?

WHY INSTALL A BIOMASS BOILER?

HEAT LOAD

MAINTENANCE

EDUCATIONAL BENEFITS

WHICH FUELS SHOULD BE USED?

FUEL DELIVERIES AND ACCESS

SPACE REQUIREMENTS

BIOMASS CABIN SCHEMATICS

ABOUT US.

BIOMASS OVERVIEW

Biomass is a renewable energy source that is obtained from living or once living material includingwood, grass, wheat or suitable waste materials. Biomass is mostly used in the production of heat andthe generation of electricity. When burnt, biomass sources release CO2, equivalent to the amount thata plant would release when it dies and decomposes.

Hence, the carbon released has a limited effect on the environment as it is a part of the naturalcarbon cycle. This is unlike fossil fuels which continually increase the carbon levels in the environmentwhen burnt. The history of biomass heating is mainly based on basic biomass log stoves which werevery high maintenance and not very energy efficient for the amount of warmth that they generated.Technological advancements have seen major improvements to these biomass devices which are nowcapable of operating at efficiency levels of over 95% which is comparable to modern oil-fired and gas-fired boilers.

If oil is currently used to fire a central heating boiler, biomass is the closest alternative renewabletechnology as the appliances operate in a very similar way but with lower CO2 emissions and residues.Biomass for heating can take many forms but the main ones are likely to be wood chip or wood pellet.People have been producing energy from biomass for centuries, and in many parts of the world it isstill the principle source of heat. However modern technologies are far more efficient and cleanerthan the traditional open fire and there are an increasing number of fuels are being used namely logs,wood chips, wood pellets and wood briquettes.

Energy from biomass refers to energy produced from organic matter of recent origin. This excludesfossil fuels which have taken millions of years to evolve. Biomass is also referred to as ‘Bio-energy’ or‘bio fuels’ (in terms of renewable energy).

‘The Definition of Biomass’“Any solid, liquid or gaseous fuels produced from organic materials either directly

from plants or indirectly from industrial, commercial, domestic or agricultural wastes”

However, we are only concerned with woody biomass. Producing energy from wood bringsenvironmental and economic advantages both nationally and locally and has considerable potentialwithin the UK. Biomass heating systems, unlike other renewable energy sources, do emit carbondioxide. However, it is the carbon dioxide (CO2) taken from the atmosphere by trees forphotosynthesis that is released during burning. This closed CO2 cycle means that biomass heating isconsidered a renewable energy source, and therefore eligible for the Renewable Heat Incentive (RHI).

For sustainably managed woodland, or energy crops, the process is similar. Wood is never removedfaster than it is added by new growth, therefore the CO2 released when the wood fuel is burned isnever more than the CO2 absorbed by new tree growth. Biomass heating systems in reality createsmall net emissions of CO2 to the atmosphere through operations including harvesting, transport,processing and the construction and commissioning of the boiler. Wood fuel emits 25 grams of CO2

per kilowatt-hour (g/kWh); Wind Energy emits 8g/kWh; gas emits 194g/kWh; oil emits 265g/kWh andcoal emits 291g/kWh.

THE CARBON CYCLE

When grown sustainably, wood pellets are a carbon neutral energy source.

When trees grow, they absorb atmospheric carbon dioxide (CO2). During the burning of wood, carbondioxide which was initially absorbed, is release back in to the atmosphere. In essence, this provides nooverall increase in the level of atmospheric CO2. If the tree was to die naturally, it would still breakdown and thus eventually release the same amount of CO2 back into the atmosphere. The burning ofwood pellets just speeds up this process. This process is often referred to as the Carbon Cycle.

HOW DO MODERN BIOMASS BOILERS WORK?

In the case of wood chip and wood pellet boilers, the fuel is fed automatically into the boiler from thefuel store using an auger screw system (see below). The fuel then burns in the combustion chamber,where a regulated flow of oxygen ensures a clean and efficient combustion process. The resulting hotgases then heat water in a heat exchanger which feeds the hot water storage tank, or for smallerstoves a back boiler, and ultimately the heating circuit (radiators in most cases).

Biomass boilers are as controllable as modern gas condensing systems; heating controls allow theuser to adjust all personal parameters for the central heating and domestic hot water. Some controlseven allow the user to switch on the boiler remotely via text messaging.

Basic operation of a wood pellet and wood chip boiler

HOW DO MODERN BIOMASS BOILERS WORK?

It is important to realise that biomass boilers are very different from their fossil fuel counterparts.They prefer to run at their maximum capacity, primarily as a result of limited ability to react to spikesin demand. Most installations are optimised to provide around 50-60% of peak load in order tomaximise plant running hours, minimise the capital outlay and increase both the efficiency of theboiler and carbon reductions. This would then be teamed with either an accumulator tank or a backup supplied from fossil fuel sources. Hence, a school currently heated with a 300kW oil boiler willprobably opt for a biomass boiler in the range of 150 -180kW; the actual size will also depend on theage and efficiency of the current boiler.

A Biomass Boiler housed in an Energy Cabin

Many biomass boiler systems are now specified with an accumulator tank (a large hot water storagetank) which is integrated into the heating system. It collects and stores heat energy from the systemto allow its flexible use at all times and to smooth out daily demand profiles. The boiler works flat outto heat the water contained in the tank until it reaches 75-80OC. Once this temperature is achievedthe boiler reverts to slumber mode and only starts up again when the water in the accumulator fallsbelow a certain threshold (perhaps 70OC). In this way, repeated starts and shut-downs which can leadto inefficiencies and running problems are substantially reduced, increasing the boiler’s lifetime andminimising emissions. Tanks are normally sized in litres corresponding to 20-30 times the boiler ratedkW capacity.

WHY INSTALL A BIOMASS BOILER?

Many schools, colleges, universities and other educational organisations could make savings on theirheating fuel costs by replacing their current fossil fuelled system with a biomass boiler fuelled withwood. As mentioned, as long as wood is obtained from sustainable sources it is extremely ‘carbonlean’ leading to large savings in carbon dioxide emissions. In addition, housing a boiler at aneducational establishment provides the opportunity for wider curriculum benefits giving a practicaldemonstration of a low carbon technology.

It is also important to think about the age of the current fossil fuel boiler and whether it is due forreplacement. It is easier to make the financial case for replacing a 15 year old boiler than a 5 year oldboiler. If older boilers are still in good condition they can often be retained to back up a new biomassboiler to meet peak loads.

Heat Load

Where schools have swimming pools or are located adjacent to leisure centres the cost efficiencycan be improved due to the significant demand for heating and hot water provision throughout theyear. For instance, a school without a swimming pool might have a capacity factor of 16% (i.e. 1,400full load hours) whilst one with a swimming pool might have a capacity factor of 30% (2,600 hours).In recent years many schools have been designed to be ‘learning centres’, with the intention thatthey are used by the wider community in the evenings and at weekends for adult education andother purposes. This increase in operational time makes Biomass Boilers an ideal solution for power& heat production.

Maintenance

Whilst biomass requires more maintenance than fossil fuelled heating systems the activities are notparticularly onerous. It is important that each school has a caretaker or other member of staff whocan take on the regular inspections, routine maintenance checks and activities such as de-ashing.With highly automated systems the day to day activities required should be minimal. For instancesome machines have in built ash bins on wheels. The efficiency is such that they only need to be de-ashed every four weeks.

Educational benefits

The boiler room should, where possible, be accessible for educational purposes as it can provide aninteresting demonstration of renewable energy at work as well providing a real life installation onwhich students could base mathematics, sustainability and climate change projects. The QueenElizabeth School in Wimborne, Dorset is building a sustainability centre to showcase its biomassboiler and other on site renewable energy technologies. The boiler installation will include a perspex‘see through’ to allow students to see the woodchip moving through the auger.

WHICH FUEL SHOULD BE USED?

Wood pellets are consistent in size and have low moisture content whereas woodchip can come in arange of specifications. Most modern biomass boilers that are specified for woodchip can also burnwood pellets, although the reverse is not true. In an ideal world most large schools should use woodchip as it is by far the cheapest fuel and there are likely to be local suppliers. However, it is up to threetimes as bulky as pellets and therefore requires either a large fuel storage facility or more frequentdeliveries. Our advice is to use wood pellets for practical storage reasons.

A Typical pellet fuel delivery

Fuel Deliveries & Access

For fuel deliveries, good access to the fuel store is required and the impact of any noise or otherdisturbance on the surrounding area should be considered. There are a number of storage methodsavailable and the option chosen depends largely on the quantity of fuel required, the space availableand the delivery vehicle used by your fuel supplier. Where space is an issue subterranean fuel storesmay be specified. This involves using standard tipping vehicles to deliver woodchip into pits excavatedunder ground level. This kind of storage provides more flexibility but will cost more to install unlessthere is an existing height difference to work with.

Above ground fuel stores include permanent containerised fuel store or pre-filled hook-bindeliveries. Using a containerised fuel store would require fuel to be blown in usingspecialised equipment. Pellets flow more easily than chips and are frequently delivered bythe blown method - as above.

SPACE REQUIREMENTS

Biomass boilers have a significantly larger footprint than their fossil fuel equivalents and allowanceshould therefore be factored in. Firstly, the size of a biomass boiler itself is about double that of a gasor oil system.

Secondly, wood fuel has a much lower energy density than fossil fuels so much higher volumes ofstorage are needed. However, these problems have been addressed with the construction ofcontainerised 20ft or 40ft Energy Cabins. The Energy Cabins house both the biomass boiler and thefuel store all in one complete unit. They are constructed off-site and installed with the minimuminterruption to the educational establishment, as any grounds works are completed prior to thedelivery, installation and commissioning of the biomass boiler housed in the Energy Cabin.

A 40ft Energy Cabin with fuel store

Of course a school currently with mains gas heating will have no need to store fuel in the first place sothis would also need to be factored in. Also, in most situations, the existing fossil fuel boiler will beretained as back up. Even if there is room, installing the system into the existing boiler house could beproblematic as the boilers are not always modular and can rarely be taken apart.

ENERGY CABIN SCHEMATICS

A single 20ft Energy Cabin

OUR INSTALLATION PARTNER

Our installation partner are plumbing and heating engineers that have been established for over 60 years and have been chosen due to their longstanding experience in the heating sector. They provide heating services for home and industrial purposes with a strong emphasis on wood burning heating systems.

‘Our partner is Gas Safe, Oftec and Hetas registered, so all modifications and improvements to the existing system can be done internally.’

‘Our partner consists of building services engineers which provide full biomass system packages including installation and servicing.’

Our installation partner has undertaken a number of biomass projects recently including;• Q Hotels (Norton Park – 200kW – Biomass Energy Cabin), • Cosmopolitan housing (Liverpool – Twin 80kw Pellet Boilers to heat a social housing project), • Mersey Forest Trust (50kW log boiler and full central heating system) ,• Peak Oak (Onecote – 60kW log boiler to heat farm buildings and showroom),• Galliford Try (Warrington – 50kW pellet boiler for a block of flats).

ABOUT US

Constant Energy Limited provides a complete and expert turnkey service in the commissioning, design,finance, installation, management and maintenance of biomass boilers, to the public and privatesectors. We bring together commercial experience, expertise and a unique funding model to biomassboiler installations, a proven, clean technology fuel, which has been used successfully in the Nordiccountries for many years.

Constant Energy Limitedʼs project management includes the full design of your biomass boiler system,supply and installation of the boiler(s), buffer vessel, fuel store, controls and heat meters, flue andconnection to your existing hot water flow return system. Constant Energy Limitedʼs also includesongoing monitoring and maintenance of the system, and fuel supply under our long term fuel supplycontracts.

We also finance packages that are tailored to our clients circumstances, be it 100% financing or ourtruly Free to Fit model, backed by our investment partners. This enables us to deliver to our clients astructured and immediate cash flow saving on the biomass boiler system and clients will also benefitfrom reduced fuel costs.

Our service takes care of every aspect of biomass boilers from initial consultation through design,installation, commissioning, ongoing operation and fuelling. Our state of the art systems will monitorthe day to day operation of the system, and will even tell us when fuel levels need replenishing. Ouraim is to make saving money with biomass very straightforward.

Constant Energy Limited only works with experienced market leading partners and sub-contractors who have completed many biomass boiler installations throughout the UK, including;

Q Hotels - Norton Park Hotel. 200kW Biomass energy cabin.Cosmopolitan Housing - Liverpool. Twin 80kW pellet boilers to heat a social housing project.Mersey Forest Trust -‐ 50kW Log boiler and full central heating system.

Constant Energy Ltd, Magnetic House, Media Village, Salford Quays, Manchester, M50 3XW

Philip R.Smith-LawrenceOffice: +44 (0)161 813 1760Mobile: 07748443805.

Website: www.constantenergy.co.ukEmail: psl@constantenergy.co.uk