Wednesday, 1 September 2010

carbon for the winter last

are you getting ready for a cold winter?

no! for the last!

No, I won't discuss this stupid "wood is carbon neutral again" while my nose is still full of those fossil fumes from the chainsaw, the tractor and the hydraulic splitter from yesterday's workout in the forest.

Last Winter we ran out of gas (LPG) which fires our CHP Island solution (i.e. off-grid); producing electricity and thermal energy (i.e. heat). The gas tanker - a high-tech-one-wheel-drive (1WD) with no locks but on Formula 1 slick-like tyres, what else would you expect North of Loch Ness - wouldn't make it up for weeks. So we installed two 48kg bottles and had the complex of 22,000 sqft run on bottled gas, one lasting two days! Hard to believe it worked, electricity-wise and for some of the thermal energy we need; for the additional heat we started up the good old 110kW wood-chip boiler which we hadn't used for three or four years. Worked so-so and we had to chip more wood to fill the hopper; at minus five feeling rather like -18°, a solidly frozen chipper and horizontal snowstorms not really my favourite amusement; but again, and lucky us it worked.

This year, surprise, we want to be prepared and with this crazy weather all around the globe who knows what this coming Winter or the next will have in mind for us.

So we cut about 30 stacked cubic metres of wood; that's more than what 4 to 5 hectare of matured woodland reproduce every year. 0.7 kg CO2 are stored per square meter and year, so, once fired we will have emitted what CO2 the 45,000m² have not stored in one year, i.e. 31,5 tonnes! That's a load - and a nice plot of land, isn't it?

I don't know in detail how long it will last us; in theory this depends very much on the quality of the wood, humidity and how old it is and in practice, how cold it will be; as we cleaned up wind fallen trees as well the moisture content and quality defer very much. I will monitor the figures - however, theory would calculate about 1 cubic metre spruce weighing app. 350 kg, the equivalent of 1.400 kw/h, so we stacked 42,000 kWh.

So far so easy; but we are replacing LPG; 1 kg LPG equals 12.4kw/h, so in theory we will then not burn about 3,390 kg of LPG which are about 6,600 litres and not emit about 9.3 tonnes of CO2 but then, surprise, surprise, 31.5 tonnes while burning that wood will not be stored.

Understood? It just tells us how difficult and complicated the process of replacing fossil fuels with any renewables is and will be... it also tells us all that every single step, theory, material and technology will have to be thoroughly analysed and it tells you that burning wood emits more CO2 than using gas! Why?

... and still the forest needs replanting, managing, protecting, harvesting...

The proof is in the pudding - and in lots of muscles.

Carpe diem!