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

Whilst the existing electric system was retained, it has not been used since commissioning.

Fuel Supply and Chip Handling

Woodchip is delivered from the estate’s existing woodchip supply business by 15m³ high-lift tipping trailer directly into the feed hopper. The purpose-built boiler house and feed store has an opening roof to facilitate loading and minimise the size of the building. Due to the proximity of supply, no bulk store is required and refilling occurs when required. The periodicity varies depending on demand and ranges from fortnightly, when the holiday park is operating at full capacity (around 1000 beds), to 2 monthly in the low season. Due to the size of the supply business, timber for chipping is sourced both from the estate and through the open market. It is stored outside for around 12-18 months before chipping to ensure a moisture content of below 30%.

System Design and Installation

The system was designed for 100% of heat and hot water to be provided by Biomass. A 2,000-litre accumulator tank was installed to assist with peak heating loads, 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 a backup but have not been required.


This project has substantially reduced the heating bills for the holiday park as well as contributing to the estate’s policy of self-sufficiency.


July 2009


Supply of hot water and heating to shower block, toilets and laundry at holiday park (Dalraddy Holiday Park)

Boiler and Plant

70Kw 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 110,000Kwh of heat. Seasoned woodchip fuel is produced by the estate.

Chip Storage

A 20m3 fuel store with an opening roof was built as part of a combined chip store and 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 the low season to every 2 weeks when demand is at its peak.

Grant / Funding

The system was funded by the estate and it is intended to apply for support through the upcoming RHI scheme.

Savings / Investment

The system replaced electrical heating which was not metered separately but was estimated to cost in the region of £15,000 per year to run. This has been reduced to an annual wood chip bill of less than £2000 making this an excellent return on the capital investment.

CO2 Saving

Estimated at 66 tonnes per annum

Our 90kw ETA Hack wood chip boiler suffered water damage in late 2014. Dunster Biomass Heating was the only company that could fix the issues without costing me new components. What we have learned is simple. Experience is key! When there is an unusual problem you need more than a guy with a manual – you need a company with the expertise, ability and willingness to solve the problem!

Nick Hiscox, Director, GSF Livestock Equipment