Case study

Dalraddy Holiday Park, Inverness-Shire, Scotland

70 kW Wood Chip Heating Scheme

Key facts


July 2009


Supply of hot water and heating to shower block, toilets and laundry at Dalraddy Holiday Park, Inverness-Shire.

Boiler and Plant

70 kW ETA Hack woodchip boiler installed in a purpose built boiler house with a 2000 litre accumulator tank.


The boiler uses approximately 160 m³ of G30/50 woodchip per annum, producing around 110,000 kWh of heat. Seasoned woodchip fuel is produced by the estate.

Wood chip storage

A 20m3 fuel store with an opening roof was built as part of a combined woodchip store and woodchip boiler house, adjacent to the existing shower and toilet block. Woodchip is transferred direct from this to the boiler by auger and rotary arm agitator. Refilling of the fuel store is achieved by the estate’s own high-lift tipping trailer at intervals, ranging from every 2 months in low season, to every 2 weeks in peak season.

Grant / Funding

The system was funded by the estate, who expect to apply for support from the RHI scheme.

Savings / Investments

The woodchip heating system replaced electrical heating, which had been costing in the region of £15,000 per year. Heating bills have been reduced to an annual woodchip cost of under £2,000, making an excellent return on the capital invested.

CO2 saving

Estimated at 66 tonnes per annum.

As part of an overall strategy to increase the use of renewable energy at the Dalraddy Holiday Park, the estate decided to install a woodchip heating system to provide underfloor heating and hot water to the shower, toilet and laundry block.

Fuel supply and wood chip handling

Woodchip is delivered from the estate’s existing woodchip supply business. A 15m³ high-lift tipping trailer drops woodchip directly into the feed hopper.  The purpose-built boiler house and feed store has an opening roof, which facilitates loading and keep the scale of the construction to a minimum.  Due to the proximity of the woodchip supply, no bulk store is required and refilling occurs when required.  Replenishment of the woodchip store occurs fortnightly when the holiday park (which comprises around 1000 beds) is operating at full capacity, and bi-monthly in the low season.  Timber for chipping is sourced from both the estate and the open market.  It is stored outside for around 12-18 months, before chipping to ensure a moisture content of below 30%.

Wood chip boiler room and chip store

System design and installation

The system was designed so that 100% of heat and hot water would be provided by biomass fuel.  A 2,000 litre accumulator tank was installed to assist with peak heating requirements, to avoid inefficient short cycling of the boiler, and to allow possible expansion of the shower block in future.  The existing electrical heating systems were retained as back-up but have not yet been required.

Wood chip boiler room and wood pile


This project has produced substantial costs savings. In reducing the annual heating bill by £13,000 per annum, it has cut heating costs by over 85%. The system has also contributed to the estate’s policy of self-sufficiency; it demonstrates the Dalaraddy Holiday Park’s green credentials: to both customers and a wider audience.


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