Case study

St Audries Bay Holiday Club

130 kW Wood Chip Heating System

Key facts


February 2011


Supply of heating and hot water to St Audries Bay Holiday Park, which comprises chalets, communal buildings, a restaurant, and a swimming pool.

Boiler and plant

130 kW ETA Hack woodchip boiler installed in an adapted outbuilding, with a 3,000 litre accumulator tank.


The boiler is expected to use about 100 tonnes of G30 woodchip per annum, producing around 350,000 kWh of heat. Seasoned woodchip fuel is bought in from local suppliers.

Wood chip storage

An 80m3 fuel store was created by installing a second-hand galvanised grain silo adjacent to the boiler. Woodchip is transferred direct from the grain silo to the boiler by auger and rotary arm agitator. The fuel store is loaded with woodchip by use of an adapted 8m potato elevator, allowing fuel deliveries to be made using a standard tipping trailer. Replenishment of the woodchip store occurs approximately every 2 weeks, with standard loads of 25m3. Nevertheless, the store is of sufficient size that larger deliveries could easily be accepted less frequently. An additional benefit of this system is an integral drying floor, which allows a fan to blow air through the chips if moisture content exceeds 30%.

Grant / Funding

The system received a 40% grant under the Bio-Energy Capital Grants Scheme. The installation is also now eligible for RHI scheme income.

Savings / Investments

Fuel savings are still being determined, since the boiler has replaced a range of oil, gas and electric systems. However, the reduced fuel bills have already had a substantial impact on the financial viability of many of the club’s activities.

CO2 saving

Estimated at 110 tonnes per annum.

The owner of St Audries Bay Holiday Club decided to install a woodchip system to replace an aging and inefficient oil-fired boiler that serviced the main communal buildings at the site. At the same time, it was decided to extend the system to provide hot water to 12 chalets and heating to the indoor swimming pool. The existing gas fired boilers were retained as a back-up for the swimming pool, with smaller oil-fired boilers installed for the remainder. These were used briefly when an experiment with a different fuel type proved unsuccessful, but otherwise have not been required.

Fuel supply and wood chip handling

Dunster designed and implemented the conversion of an existing outbuilding in order to house the boiler and accumulator tank. Dunster sourced a second-hand grain silo and potato handler for the loading system and woodchip store. The mechanism was adapted to make deliveries by using a standard tipping trailer. This has been a great success. There is no requirement for extra equipment or any woodchip handling by St Audries staff.

Wood chip silo and conveyor

System design and installation

The system was designed with a base load woodchip boiler that provides 90%+ of heat and hot water, this is combined with oil and gas boilers to deal with peak loads. Thus far, the 3,000 litre primary thermal store and 2,ooo litre satellite thermal store have had sufficient reserve to mean that the back-up boilers have not been required.

ETA 130Kw wood chip boiler


In addition to the major financial benefit of becoming independent of oil and gas prices, the installation has further enhanced St Audries’ environmental credentials.

Download St Audries case study

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