- Location: Cairndow, Argyll
- Wood fuel usage: water heating for commercial salmon hatchery
- Installation date: March 2008
Reasons for Changing to Woodfuel
The hatchery process requires consistently heated water tanks. Renewable Devices carried out an initial feasibility study of renewable heat options in the Cairndow area. A wood fuel system was chosen as it offered a constant and controllable heat output at the most competitive cost.
Woodfuel is a carbon lean renewable fuel and significantly reduces the carbon emissions from the hatchery.
System Features and Benefits
The size of the boiler and design of the fuel store allow the system to cope with a large chip size and a moisture content of 40% and more. This gives long-term flexibility in sourcing fuel, with the proviso that the heat output of chips reduces with increased moisture content.
The fuel store has a robust walking floor system that takes the chip from the store directly to the burner plate.
A specialised computer system means Lakeland Smolts can monitor the heat provision throughout the hatchery to ensure each stage of the process is accurately maintained at the required temperature.
Their energy services company (ESCo) also monitors the system remotely via the internet, and will respond to any alarms from the system to ensure continuity of operation and production from the hatchery.
The boiler manufacturer, Mawera, provides regular servicing and maintenance to further ensure continuous operation.
All waste water is recovered on site, with approximately 1-2 MW of waste heat produced annually. Recovering this water to preheat the tanks improves the overall system efficiency, further reducing energy and fuel costs.
Wood Fuel Supply
Renewable Fish & Chips, the energy services company (ESCo), is contracted to provide heat for five years at an agreed rate. The hatchery only purchases the actual quantity of heat used on site. A heat meter measures usage and calculates the total number of kWh supplied.
The ESCo manages the fuel supply contract with Our Power, a community-owned wood chip supply company (part of the Here We Are project), located half a mile from the hatchery.
It is in the supplier’s interest to deliver as dry a fuel as possible, so as much heat per tonne of fuel is obtained. Heat sale contracts, compared to purchasing woodfuel by weight or volume, act to reduce the moisture content of fuel supplied so the number of fuel deliveries are minimised. The customer benefits by knowing exactly how much they are paying for their heat.
Onsite chipping directly into the store occurs twice a week and produces 60-65 tonnes.
The planning requirements for biomass were fairly new to the local authority and technical information, particularly on boiler emissions, was required for planning approval.
The interaction with the Scottish Environment Protection Agency (SEPA) was straightforward, with good correspondence maintained at all times to ensure the standards were achieved.
- For large developments, near residential areas, allow extra time for the planning process to account for queries
- Do not be over optimistic about the speed of construction, always allow time to complete the development
- Co-operative working with the local authority and regulatory bodies will reduce development delays
- Allow a reasonable period for the system to be commissioned
- Time restrictions on grant applications can add extra pressure, so seek advice from grant-awarding bodies at the earliest possible point
- Grant support from the Scottish Biomass Support Scheme was essential to fund the project.
Facts and Figures
Note: figures are approximate
|Maximum boiler output
|70 tonnes (233 m3)
|Oil boiler (1.5 MW)
|Fuel Consumption, Costs and Savings
|Weekly woodfuel use
|100 tonnes (333 m3) max
|Annual woodfuel use
|Annual energy consumption
|Annual CO2 savings
|900 tonnes (compared to oil)
|Annual fuel cost saving at 2008/09 prices
|20% (compared to oil)
|Installation Cost and Funding
|Scottish Biomass Heat Scheme
|Funding support rate
|50% of additional costs of woodfuel system
- Constant source of heat during production season (October to May)
- Carbon emissions reduction
- Brand new reliable system
- Guaranteed energy price for five years through contract
- Reduction in energy costs