This Q&A emerged during the visit to Ickworth by Neil Harris, Countryside Manager from National Trust London & Southeast region, who has successfully run and fed a woodchip boiler at Hughenden Manor, near High Wycombe, for the last four years. The feeding part was particularly useful as, like them, we are looking to self-supply our woodchip boiler, a pilot project under the Renewable Energy Investment Programme. Before I move onto that, for those of you who love all the juicy details (and I know there are a few of you out there), they have a Froling Turbomat 220 kW woodchip with a 4000 litre thermal store, all of which is supplied by a 40m3 woodchip store.
Lots of useful, practical information was shared such as how often they sweep the flue (quarterly) and service (annually); how much ash is produced; make sure you have a heat, not a smoke, detector above the boiler; you’ll see a significant increase in the load on the boiler when people leave doors open or there are events (please don’t waste our hard-earned woodchip!); you may get more heat loss per m2 of district pipe than you are expecting (theirs is 80 m long); Corsican Pine is prone to re-wetting after seasoning, so may need a cover especially if it snows; and a good thinning regime can lead to around a third more timber in a woodland. Looking back would they have done anything differently? Having an “idiot’s guide” to running the boiler, with telephone contacts i.e. if this happens, call this number. All really valuable advice.
We went to have a look at the timber which was extracted from the 1979-planted woodland in September.
The first thing that hit you was the delicious aroma – sorry we haven’t got smell-o-vision. After seasoning and chipping, this should be able to keep the Ickworth and regional office boilers for at least 18 months. Very exciting to finally see it.
Whilst we were at Ickworth, we had a look at the Rangers’ office, which has been throughly insulated so that it can be heated by a 1.5 kW woodburning stove. Nice and cosy. In fact, they only need to use it for a few hours in the morning, or it becomes too cosy. With this, a log boiler in Visitor Reception, air source heat pump in plant centre & toilets and, all being well, the woodchip boiler to serve the House, Ickworth is taking a sensible pick ‘n’ mix approach when it comes to renewable technology.