Worcestershire uses new biomass boiler for their primary school

Worcestershire County Council is aiming to reduce CO2 by 25 per cent over the next five years. Biomass is a big part of effort - the council has installed 10 biomass boilers since 1996, saving about 1,300kW and 800 tonnes of carbon a year. It has now developed its own internal funding mechanism to allow schools to take advantage of the Renewable Heat Initiative.

Project

Inside a boiler house in Worcester

 

 

 

 

 

 

 

Worcestershire County Council has installed 10 biomass boilers since 1996, saving about 1,300kW and 800 tonnes of carbon a year. This case study looks at one of the most recent biomass projects - installing a new boiler house at Sutton Park Community Primary School in 2010.

Roles

About 45 per cent of Worcestershire's biomass projects have been designed and managed in-house. When capacity is limited, projects are outsourced to consulting engineers. All projects work to common engineering standards drawn up by the council.

Sutton Park Community Primary School was rebuilt in 2010 with a new boiler house - including new boilers, one woodchip and one gas. This project was managed in-house.

Funding

The project was mainly funded by the council's own capital programme. A £17,000 grant from the Low Carbon Buildings programme subsidised the cost of boiler house, which was £50,000. This included the wood fuel boiler, wood store, wood fuel systems and the gas boiler.

Under the Renewable Heat Initiative (RHI) schools will be likely to borrow more money from the council to buy wood boilers. But they will get an income stream from RHI.

Worcestershire has an internal mechanism to enable that to happen - effectively by providing its own grant funding from council reserves. Schools will repay this from energy savings.

Motivation

Worcestershire has a target in its Carbon Management Plan to reduce CO2 by 25 per cent over the next five years.

The council also wanted to achieve Building Regulations carbon emission targets cost-effectively. Worcestershire is currently aiming to achieve the Building Research Establishment Environmental Assessment Method (BREEAM) 'very good' target.

Under the Carbon Reduction Commitment (CRC) Energy Efficiency Scheme, the cost of carbon has to be paid in full at about £12 a tonne of CO2. This will cost Worcestershire £500,000 to £600,000 per year. About three-quarters of that is from the schools estate.

Barriers

The children's services department thought installing a wood boiler was an expensive way to save the school money and carbon.

At the time there was a Department for Children Schools and Families (DCSF) policy to cut school carbon emissions by 60 per cent. The engineering team pointed out that the most cost-effective way to achieve that was to fit a wood boiler (among other measures).

Lessons learned

There's an optimum size range where the boilers pay for themselves and make economic sense. This is around about the 100 to 150kW range, which is the ideal size for most primary schools.

Fuel stores need to:

  • look nice and blend in with surroundings
  • keep out rain water
  • be easy to refill with fuel.

Blown delivery works well at schools. It takes about three quarters of an hour to fill the tank and this must be done every three to four weeks. But the noise of a lorry engine and the blower delivering fuel can cause a problem in residential areas. This has to be taken into consideration.

Benefits

Without the RHI, a 100kW woodchip boiler would pay back in 17 years. With RHI, Worcestershire estimated that this would be reduced to six years.

The heating bill at Sutton Park Primary has gone down to less than half the price. This is in part because it replaced an old school that was not energy efficient. The new school has good insulation and much higher energy efficiency.

Jim Cronin, Caretaker at Sutton Park Primary School, says:

"We were using gas before. I used to have trouble with the pilot lights blowing out and I was forever looking after the boiler and trying to get it going. Now, all I have to do is empty the ashes out of the bin every three to four weeks.

"It's been excellent on woodchip. It's cleaner and more efficient than anything. And of course it's working out a lot cheaper."

Worcestershire does not manage any local woodland. The wood fuel provider manages the supply chain and encourages people to bring woodland into harvesting for fuel. Bringing unmanaged woodland into proper management also improves biodiversity.

Councillor Anthony Blagg, Cabinet Member with Responsibility for Waste and Sustainability, says:

"We have a biomass boiler at County Hall. It's still significantly cheaper than using gas and obviously it's less carbon. Reduction in carbon is necessary for the environment as well as saving money in terms of using less energy. So biomass is, I think, a major way forward, particularly in places like Worcestershire where there is a significant number of trees."

Contact

Phil Harris, Chief Engineer
Worcestershire County Council
Telephone: 01905 766406
Email: pnharris@worcestershire.gov.uk

 

14 January 2016