1. September 2010 1 Wood to Warmth – Fuel Delivery and Storage Michael Beech TV Energy

2. September 2010 2 Fuel Delivery & Storage Pellets – delivery and storage Domestic systems: 10 or 15 kg bags of pellets can be loaded manually into an integral hopper attached to boiler Larger systems: 15tonne pellet tanker or larger for bulk delivery – concept similar to oil Size store for boiler consumption at full load and largest volume practical to allow lowest £/tonne as a bulk delivery Pellets can be blown into an above ground store via flexible tube, up to 30m if necessary – but the shorter the better Minimise bends in delivery tube to reduce pellet damage Fuel transfer to boiler by lightweight or flexible auger feed

3. September 2010 3 Fuel Delivery & Storage Pellets

4. September 2010 4 Fuel Delivery & Storage Woodchip – delivery and storage Consider carefully: Delivery vehicle access to fuel store Types & sizes of delivery vehicle Method of transfer of woodchip from delivery vehicle into store Storage capacity sized for boiler consumption at full load and lowest £/tonne of woodchip (largest delivery volume practical) Maintenance access to fuel store and boiler feed auger in case of fuel quality problems Ventilation within fuel store to prevent condensation causing saturated chip

5. September 2010 5 Fuel Delivery & Storage Type and arrangement can be determined by method of woodchip delivery. Common arrangements are: Woodchip Store - 1 Above ground, walking floor transfer, open at one end. Vehicle can drive into storage area and tip (or offload using moving floor) onto walking floor ladders, which transfer chip to one end towards auger feed to boiler. Can also accept deliveries from front loader vehicle, or direct from chipper. Walking floor mechanism requires significant civil works & hydraulics, therefore expensive Robust system if designed and installed correctly

6. September 2010 6 Fuel Delivery & Storage Above ground store, walking floor transfer

7. September 2010 7 Fuel Delivery & Storage Above ground store, walking floor transfer

8. September 2010 8 Fuel Delivery & Storage Above ground store, walking floor transfer

9. September 2010 9 Fuel Delivery & Storage Woodchip Store - 2 Above ground store, rotary arm agitator feed to boiler, fully enclosed or part open on one side. Vehicle will offload from above, in through hinged/ sliding opening or hatch. Requires chip volume to be raised and tipped, front loader or scissor lift trailer are suitable. Use of a chip blower (trough type or integral to container vehicle) is a further alternative, though relatively slow, noisy and energy intensive. A vehicle ramp or bank up to one side of store can allow use of standard tipping vehicle.

10. September 2010 10 Fuel Delivery & Storage Above ground store, rotary agitator

11. September 2010 11 Fuel Delivery & Storage Above ground store, chip blowers

12. September 2010 12 Fuel Delivery & Storage Above ground store, delivery methods

13. September 2010 13 Fuel Delivery & Storage Woodchip Store – 3 Containerised storage (Roll on roll off/ hook lift bins). A fuel store and transport container in one. Bins are specially designed with walking floors and connection to feed auger, part of docking station. Usually 3 docking stations required, bins ~30m3 each. An expensive system, requires good a deal of space, but affords clean woodfuel delivery Mechanisms and connections prone to damage

14. September 2010 14 Fuel Delivery & Storage Containerised Storage

15. September 2010 15 Fuel Delivery & Storage Woodchip Store - 4 Below ground store: Both walking floor and rotary arm agitator systems can be designed to be below ground, allowing standard tipping vehicles/ trailers or moving floor container vehicles to be used to transfer chip into store under gravity. Allows simplest and quickest delivery method, wide range of vehicles and hence fuel suppliers can be used High excavation costs, pit needs to be waterproof. If plant room is at ground level then woodchip feed auger must route upwards with maximum 30deg. angle from horizontal, to connect to boiler.

16. September 2010 16 Fuel Delivery & Storage Below ground storage

17. September 2010 17 Fuel Delivery & Storage Below ground storage

18. September 2010 18 Fuel Delivery & Storage Example calculation

19. September 2010 19 Fuel Delivery & Storage Common problems Storage capacity too small - requires frequent deliveries Difficult access to fuel store – increases delivery times, smaller than optimal capacity vehicles used Poor design of access opening into fuel store – chip spillage Inadequate ventilation within fuel store – condensation from chip causes drips from roof onto top layer causing wet chip Double handling of chip (offloading then delivering into store) Inadequate provision made for maintenance access to fuel store, woodchip agitator/ transfer equipment, feed augers Fuel delivery and storage are most likely areas for failure of biomass systems, due to poor planning and design

20. September 2010 20 Thank you michael.beech@tvenergy.org