Biomass district heating

Today we will explore the large costs and CO₂ savings biomass delivers when compared to fossil fuels as well as the opportunity for installations heating more than a single building with one biomass boiler in a district heating scheme. Social housing providers and housing developers are easily able to magnify these cost savings across multiple units of housing stock.

Biomass district heating 

Where more than a single building is heated by a single biomass boiler, this is called biomass district heating. The boiler is programmed to maintain a target temperature in a thermal heat store and automatically 'turns down', or 'modulates', to below full capacity when this is achieved. When the temperature drops in the thermal heat store, the boiler is automatically fed from its fuel store and runs at full 100% capacity, until the target temperature in the thermal heat store is reached.

From the thermal store, a series of insulated pipes distribute hot water underground to each individual building in the district heating scheme. The flow and return within each pipe is usually connected to a heat exchanger in each property. Space heating for radiators, under floor heating or domestic hot water temperatures is then controlled in the same way that a traditional boiler would be.

To measure the usage in each building within the district heating scheme, a heat meter is fitted in each property and individual central heating bills can be easily calculated.

District heating – safety in numbers

Biomass district heating delivers scale economies, fuel cost savings and is eligible for RHI payments. This makes the capital cost per building lower than those with a single boiler serving a single property.

The biomass boiler can also be housed in its own dedicated boiler room and a heat exchanger installed in each property. This means that space is freed up and interior layouts have more flexibility. From a maintenance point of view, a single biomass boiler requires less time in servicing and so is far more cost effective, per unit, than having one boiler in each property.

Biomass boilers at the higher end of the quality scale, the likes of Guntamatic and Frӧling, have high heating efficiencies of up to 96% along with CO₂ savings of up to 96%. A larger and more sophisticated combustion chamber and the simultaneous production of heat for multiple housing units also delivers better pollution control than would be possible with a series of localised boilers. This is a real plus for developers who are aiming to meet the efficiency standards set out in the Code for Sustainable Homes.

The lower cost per unit is a great way to pass on the savings to tenants and homeowners, protecting entire communities from fuel poverty, shortages and increasing fuel costs. With the forecasts of the UK being hit by below-freezing temperatures and burried in snow, this would certainly be great news for more than a million oil-reliant families!

Money for green heat

Not only will a biomass district heating scheme deliver up to 50% fuel savings an 96% reductions in CO₂, but with the government-led incentive, the Renewable Heat Incentive (RHI) further ensures a district heating scheme is both financially as well as environmentally rewarding.

Case studies

Since we were established in 2006, Treco’s own installers have now fitted in excess of 700 biomass boiler systems nationally so we’ve seen the benefits of several district schemes for ourselves. A development of new-build housing in the West Country involved three 100kW boilers providing heating and hot water to 66 units of privately-owned and social housing properties.

Three high specification, custom-built boiler houses were located in key areas across the site. In each house, there is a customer interface unit with a heat meter, heat exchanger and radio link for heating and two heat exchangers where domestic hot water is also supplied.

The housing developer met the requirements for emissions and efficiencies against the Code for Sustainable Homes and other stringent planning requirements. This enables them to save on cost in the long term as well as gaining fuel cost savings and RHI payments.

Conclusion

To conclude, where there are multiple units in social housing developments, a biomass district heating scheme can achieve up to 50% savings over heating oil. Landlords or management companies can use the RHI payments to fund the long-term provision of front-line services to the most vulnerable.

Fuel poverty can be eased through offering cost-effective heating to homeowners and tenants living in district schemes. Capital costs per unit of housing stock and the bill for ongoing maintenance can be reduced, making sustainability viable and a win-win for all involved.