Year 8 pupils at West Bridgford School look into their boiler converted to run on wood-fuel.

Nottinghamshire has a history of coal mining, and many schools have traditionally used coal-fired heating systems.

Fortunately Nottinghamshire has a significant area of forest and land to grow energy crops that can provide a sustainable alternative fuel. The County Council has converted old boilers in its schools from coal to wood pellets.

Summary

As part of its Local Public Service Agreement (PSA) to reduce CO2 emissions, Nottinghamshire County Council started a programme of replacing coal with wood-fuel in schools throughout the county, either by installing new boilers or converting existing coal-fired boilers to handle wood pellets. The conversions have been particularly cost-effective, increasing efficiency while making use of much of the existing equipment. The Council has worked hard to build up the infrastructure for the supply and use of wood-fuel, which includes local manufacturers and installers, and also a not-for-profit company dedicated to developing renewable energy solutions and supplying sustainable fuels.

Pupils from Mornington primary school with wood pellets for their wood burning stove.

A total of 21 boilers have already been installed at 17 schools, with a combined heat capacity of 7MW. CO2 savings are 2,400 tonnes/year, and have helped the Council meet its 3,500 tonnes/year PSA target. The schools have benefited from a reduction in pollution and soot, and from the knowledge that they are helping to reduce the county’s CO2 emissions. The Council has a strategy to achieve zero net emissions by 2050, and converting more schools to wood-fuel is part of this. A further 27 schools will have been converted by the end of 2008, and funding is currently being sourced to cover a further 35.

The organisation

Nottinghamshire County Council has around 25,000 employees, of whom 5,000 work in the Communities Department. This was established in October 2006 as an amalgamation of the Environment Department and Culture and Communities. Within the Communities Department is the Sustainability Team, which has been the driving force behind the Woodheat Programme.

Context

The County of Nottinghamshire has a historical tradition of coal mining, so was hit hard by the pit closures of the past few decades. Service industries have created new employment opportunities, but there are still some areas with significant unemployment. The people of Nottinghamshire feel an allegiance to the coal industry, and are keen to protect jobs and businesses that depend on the use of solid fuel. Although very few coal mines are now operating, there is a significant local wood resource. Nottinghamshire is famous for its forests, and has over 16,000 hectares of woodland. There is also in excess of 1,000 hectares of short-rotation-coppice already planted, and more is planned to meet this growing local demand for woodfuel.

Children from West Bridgeford School school are shown the boiler conversion.

Nottinghamshire County Council recognised the potential for using local wood as a fuel and in 2001, in partnership with the Forestry Commission, the Countryside Agency, the Government Office for the East Midlands and the East Midlands Development Agency, set up the Nottinghamshire Wood Heat Partnership. This aims to save CO2 emissions by using wood rather than fossil fuels to heat buildings, and to generate a local market for wood and wood products.

Nottinghamshire County Council was the first council in the UK to set up a Local Public Service Agreement (PSA) which included a requirement to reduce emissions of CO2 from the council building stock. The Council’s PSA commitment was to reduce CO2 emissions by 3,500 tonnes/year. With the mining history of Nottinghamshire, it is not surprising that local schools had traditionally used coal-fired heating systems. However, with concerns over climate change and CO2 emissions, many schools were keen to change to more sustainable forms of heating, and a significant part of the PSA work was to help schools convert to using wood-fuel.

Technology and use

Two approaches have been taken in converting Nottinghamshire schools from coal to woodheating. Some schools had old boilers that had reached the end of their lifetimes, and these were replaced with new wood-fuelled boilers. However, other schools had more modern coal-fired boilers and in these cases the boilers were modified to allow them to burn wood and to improve their efficiency.

Pupil from West Bridgeford School looking inside their wood fuel converted boiler.

The conversions carried out so far by the local company Instatherm have typically involved modifications to the fuel bunker and the control system. The fuel bunker and feed mechanism are modified to allow them to use wood pellets instead of coal, while the control system is upgraded to measure the oxygen content of the flue gases and vary the air flow and pellet feed rate accordingly. The results are typically an increase in boiler efficiency from 55% to 87%, and more reliable operation.

The new boilers have an expected lifetime of 15-20 years and run at efficiencies of over 90% at their design output. The efficiency is still high when they are running at only 30% of design capacity in mild conditions or to supply hot water. This is important because the demand on the boiler varies greatly throughout the year. All installations are in locked boiler houses, and access is controlled very carefully.

By April 2007, the Woodheat Programme had resulted in the installation of:

  • Nine new wood-pellet-fuelled boilers at seven schools, totalling over 2 MW of heat capacity.
  • Four conversions of conventional coal-fuelled boilers at two schools to wood-pellet use, totalling just under 4 MW.
  • Eight conversions of boilers using coalflow pearls, a manufactured product similar to anthracite which has now been phased out, at eight schools to wood-pellet use, totalling over 1 MW.

The County Council helped to set up Renewable Nottinghamshire Utilities Limited (ReNU) a notfor-profit company dedicated to developing renewable energy solutions, including supplying woodfuel in Nottinghamshire. ReNU had the initial contract for supplying wood pellets to schools. ReNU have two pellet mills located in Nottinghamshire. By 2007 the wood pellet contract had grown to a value where it was subject to EU procurement regulations, and a new pellet supplier has now been awarded the contract. They have been involved in a partnership with local energy crop growers to establish a new 10,000 tonnes/year pellet mill in Nottinghamshire that will source all its material locally.

Pupils from West Bridgeford School look at the wood pellets for their wood fuel converted boiler.

How users pay

Schools in Nottinghamshire pay one third of the cost of replacing a boiler, no matter what type of fuel it burns, and the Council pays the remainder. The Council has access to Bioenergy Capital Grant funding to reduce the cost of installing wood-fuelled heating systems. This enables schools to have a new wood-fuelled boiler at no additional capital cost to a gas-fuelled boiler. The costs of new installations range from about £400/kW for 150 kW boilers in small primary schools down to less than £300/kW for an 800 kW boiler in a secondary school. Conversions are considerably cheaper, typically £50/kW for small boilers and as low as £20/kW for the 2 MW schemes in very large secondary schools.

Each school is responsible for paying for fuel and boiler maintenance from its own budget. Wood pellets currently cost £130/tonne delivered, and work out more expensive than coal. However, operational and maintenance costs are lower, and most schools have been willing to absorb a small increase in overall cost because they believe that the environmental benefits are worth it.

Training, support and quality control

When a boiler is converted or a new one installed, the school site manager is trained by the company doing the installation.

The school will normally have a maintenance contract with the installation company, who will provide advice over the telephone and come to visit if a problem requires their attention. The company will also handle communications with any third parties for spare parts when they are required. Using local manufacturers and installers is therefore a significant advantage for maintenance and support, as they are able to respond quickly and are keen to maintain their reputation.

Deputy head of West Bridgeford School in the playground with the boiler room chimney in the background.

In the larger schools there are usually multiple independent boilers so that there is some backup capacity in the event of one boiler failing. In smaller schools with a single boiler there is provision to use portable heaters if the boiler fails. The Council also has a portable oil-fired boiler that is used to maintain supply during conversions, and is also available as a backup boiler should this ever be required.

The experience of using wood pellets as a fuel has generally been very positive. Nottinghamshire County Council keeps records of all installations and monitors performance.

Benefits

The schools are enthusiastic about using wood-fuel for a variety of reasons, most importantly the environmental benefit of using a sustainable fuel. They also appreciate the lack of smoke and soot when using wood-fuel – one site manager commented that the old coal-fuelled boiler sometimes looked like a ship setting off from the docks! The schools’ neighbours are also pleased with the reduction in local pollution – there had been several complaints in the past, but these have stopped completely since the switch from coal to wood-fuel.

The schools and the Council are also pleased to be able to use local manufacturers, installers and infrastructure. For example, the businesses and drivers that used to deliver coal to the schools are now delivering wood pellets, so jobs in the region have been protected. As the fuel supply becomes increasingly localised, further employment opportunities will be created in the county, especially in rural areas.

Primary schools in particular have been able to use their new wood-fuel boiler as an educational resource, in lessons on sustainability and climate change. The use of wood pellet boilers in schools has resulted in a significant reduction in CO2 emissions of 2,400 tonnes/year. This has helped the Council meet its PSA target reduction of 3,500 tonnes/year, resulting in a reward grant that covered the costs of the wood heating programme.

Pupils from Mornington primary school with the council climate change display van. 

The county as a whole has also benefited, as the Council’s work has helped create an infrastructure for the supply and use of wood-fuel, in particular wood pellets. About seven jobs have been created or secured through the programme to date. New suppliers and users will be able to enter an established and growing market.

Potential for growth and replication

Nottinghamshire County Council now has a strategy for zero net emissions from all council activities by 2050. The council is also to pilot a scheme which puts a strict requirement on emissions from any buildings which are constructed on land which it sells. Extending the use of wood for heat in schools is an important part of this strategy. To ensure continued support from the schools, the council is actively promoting the programme, and communicating the benefits to the schools. The result is that schools are choosing wood-fuel over the alternatives, even if it is not always the cheapest option, because of the environmental benefits and the resulting local employment that is generated.

Nottinghamshire County Council was named as one of the Beacon Councils for sustainable energy in 2005, giving it the opportunity to pass on its lessons to other councils in the UK. The council also established the Nottinghamshire and Derbyshire Local Authorities Energy Partnership which has been successful in recently obtaining almost £400,000 funding from the government Climate Challenge Fund. This has been used to set up a Climate Change campaign including a vehicle which will travel to schools and other locations to promote the “Everybody’s talking about climate change” campaign by providing advice and information.