Harvesting Energy Wood to Warmth: Opportunities and practicalities 22 nd February 2013 Matthew Woodcock Partnerships & Expertise Manager South East England Forestry Commission

Wood to Warmth: Opportunities

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February South east England Woodland - Background Undermanaged mixed (conifer/broadleaf) woodland planted in the 1950s Typical broadleaved woodland of south east England – overstood coppice last cut > 40 years ago Also ancient woodland with high ecological value – declining through under-management

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Future vision for SE woods Active management of coppice with standards woodland Impacts of management

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Potential for sustainable production? Traditional broadleaved trees like beech and oak can grow at 4m 3 per ha per year Conifers like Scots pine can grow at > 8m 3 per ha per year Traditional coppice species like sweet chestnut and ash can grow at > 6m 3 per ha per year

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Potential from New Forest LA District Private Woods haEst YC m3 per ha per yr Yield from 75% Sawlogs Woodfuel Slabwood MWh/yr Conifer89687,1685,376 3,2262,1501,6133,871 Broadleaved5,483421,93216,449 1,64514, ,010 Mixed (* 3 )1,25967,5545,666 3,3992,2661,7004,986 Coppice (* 8 ) Coppice with standards (* 8 ) Windblow (* 4 ) Felled (* 4 ) Open space TOTAL8,890 37,29827,9748,31819,6554,159 46,649 FC Woods haEst YC m3 per ha per yr All managed Sawlogs Woodfuel Slabwood MWh/yr Conifer4, ,140 25,88417,25612,94231,061 Broadleaved5,613422,452 2,24520,2071,12350,517 Mixed2,151612,906 7,7445,1623,87211,357 Coppice Coppice with standards Windblow Felled33441, ,202672,164 Open space1, TOTAL (* 2 )13,566 79,834 36,00643,82818,003 95,099

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Assumptions * 1 Based on latest IFOS dataset which having utilised much more sophisticated systems than NIWT1 reveals that the total area of woodland in SE&L is 323,152 ha (NIWT1 was 270,079). Breakdown into Forest Types is based on proportions identified in NIWT1 as IFOS data isnt broken down to that detail yet. * 2 Area of FC woodland will have been reduced by sales during this period so area of non FC woods could be slightly greater. * 3 Assume 60% broadleaves by area and 40% conifer by area – on basis that most mixed crops will be > 40 years old and well into their thinning regime to establish a final crop of broadleaves * 4 Assume windblown and felled areas will be restocked with broadleaves *5 Estimate that 25% of all woods will not be actively harvested due to owners preference or site difficulties *6 Estimate that 60% of conifer and mixed crops, and 10% of broadleaf growing resource could be used as sawlogs *7 Estimate that there is a 50% conversion rate of saw logs into sawn timber, hence 50% of the sawlog volume will be slabwood or sawdust and hence potential woodfuel *8 Traditionally many of the broadleaved woods in SEE would have been managed as coppice, or as coppice with standards, whereby the stems were felled every 7 (hazel) to 15 (sweet chestnut) years and then allowed to regrow from the cut stump. Having the well established root stock effectively supporting regrowth the growth rates of coppiced woods are significantly higher in their early years than would be possible from newly planted trees. Our ancestors found that this was the most effective way to produce the fuel and building material they needed. I have used an estimated growth rate of 6 m3 per ha per year to balance between hazel where the volumetric growth rates appear to be lower (no-one to my knowledge has done any research on this as hazel has traditionally been used for the hurdle and thatching market) and where we break the estimate down to counties I have dropped the estimated growth rate for Hampshire coppice to 2 m3 per ha per year as a good proportion of Hampshire coppice is hazel). At the other end of the spectrum sweet chestnut on a 15 year rotation will deliver 8 m3 per ha per year BUT if the rotation is extended to years this increases to up to 12 m3 per ha per year. However, we should also remember that sweet chestnut coppice can be converted into a whole range of products - spile fencing, cleft fencing, even faggots for flood defence but having a use for the lower quality elements and offcuts is essential to make the whole business work. This principle of increased average growth rates by extending coppice rotations to years is likely to hold true for all major broadleaved coppice species such as ash and hornbeam. Overall traditional coppice management appears to offer considerable opportunites for woodfuel production - just as our ancestors found! *9 Assumes wood is seasoned to 30% moisture content (as a proportion of overall weight), broadleaves deliver 2,500kWhrs per m 3, conifers 1,800kWh per m 3 and mixed crops 2,200kWh's per m 3. Again figures are conservative as oak and beech will manage 2,800 and 2,700kWh per m 3 respectively but poplar and willow will deliver about 1,800kWh's per m 3

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Value of wood as a heat source? As we all appreciate unseasoned wood comprises around 50% water, and water doesnt burn well! When seasoned to 30% wood can deliver about 3,500kWhs per tonne But different species vary in density: Broadleaved wood approx. 2,500 kWhs per m 3 Conifer around 1,800 kWhs per m 3

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Compared to heating oil: Heating oil at 60 pence per litre Provides 10kWhrs per litre Cost = 6 pence per kWhr Seasoned broadleaf wood (30% MC) Provides 2,500 kWhrs per m 3 The cost of heating oil to deliver the same heat = > £150 per m 3 The 28,000m 3 from the New Forest could deliver 46,000MWhs of heat Heating oil to deliver the same would cost > £2,500,000

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Energy value of conifers

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Energy value of broadleaves

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Existing markets: timber and wood VerdoSloughBedmax

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Medium scale CHP BAA – Heathrow T2

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Small scale CCHP Waitrose

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Domestic markets

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Hoathly Hill community

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Hoathly Hill - Woodheat production

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Hoathly Hill – woodheat distribution Energy centre Heat distribution network (underground hot water pipe)

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Hoathly Hill – woodheat management Woodheat distribution pipe Woodheat control centre

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Farm diversification

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Difficult land

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Markets stimulate woodland creation

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Heathland maintenance – New Forest

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Biomass Baler

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Future vision - Mureck SE Austria Two 1 MW Woodfuelled boilers have been running since 2001 Biogas production from slurry

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Mureck - continued Biodiesel Solar voltaic

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February FC Support: Technical information and advice

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February FC Support: English Woodland Grant Scheme: Woodland Management Plans

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February English Woodland Grant Scheme: Woodfuel Woodland Improvement Grant FC Support:

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February FC Support: Supporting access to other elements of the RDPE: - Leader; - Farming & Forestry Improvement Scheme; - Rural Economy Grants; and - Support for training and apprenticeships.

Wood to Warmth: Practicalities

Boiler sizing

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February FC Bucks Horn Oak Average heat demand over design day = 15kW Total energy demand over design day = 370kWh Annual energy demand = 14,000kWh Allowing 88% efficiency for boiler would require about 16,000kWh of energy from the wood pellet fuel = approx 3.5 tonnes per year

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Energy Centre

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February The woodpellet heat system

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Woodpellet delivery

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Accumulator tanks are crucial Woodfuelled boilers tend to work most efficiently when they are working at a high proportion of their maximum capacity; and An accumulator tank is purely a large, highly insulated, hot water tank which stores heat – very like a rechargeable battery. For example: Large accumulator working with a 250kW boiler to heat a large country house Accumulator (left rear) linked to a 100kW boiler (right centre) to provide heat for a community building Domestic accumulator drawing heat from a wood burning stove and solar thermal array, with electric emersion coils for frost protection when owner is away in winter

Fuel bunkerage

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Sizing Heat load: Woodchips need lots of space as loose woodchips may contain as little as 500kWhs per loose cubic meter. Buffer required between deliveries: for instance in winter how long do you need to run between fuel deliveries. Method of delivery: Delivery of a full load of woodchips will be cheaper than part loads and tipper lorry/trailers are cheaper than blower systems. Avoid just in time constraints: The bunker should be large enough to hold at least 1.5 times as much volume as the largest delivery vehicle.

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Usable capacity Access doors for tipping woodchips into bunker are sited in the centre of the bunker Allows the delivery to drop into the centre of the bunker, keeping the unused space to the minimum

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Access Ensure that the delivery vehicles you are likely to use can access the bunker easily. Example: Surrey University Sports Centre: Access is well designed and marked to discourage inadvertent parking, thus allowing easy delivery of woodchips from a local estate using existing farm equipment

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Location Boiler location: the bunker needs to be adjacent to the boiler BUT as it is easier to transport heat through a hot water pipe than woodchips the mode of supply may have a greater influence on the location of the boiler than the property being heated! Landform: Fully sunken woodchip bunkers offer great flexibility but are expensive to construct and maintain (also vulnerable to flooding). Semi-sunken systems taking advantage of sloping ground, or even man made landform, can be more cost effective. Hence if you have landform – use it! Delivery method: The more flexible the system the greater the choice of woodfuel supplier, hence if a bunker can be accessed easily by a tipping articulated lorry then it can also be accessed by tractor trailer etc. However, the capacity of the store needs to be at least 1.5 times the capacity of the biggest delivery vehicle (as delivering part loads from tipping systems doesnt work well!

Woodfuel quality

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Woodchip quality Moisture content Chip size & distribution

Harvesting Energy - Wood to Warmth: Opportunities and practicalities 22 February Thank you