Woodburning Stoves

What can we do in the South East to help global warming?

There is much debate in the press as to what should be done about global warming, with the world population approaching 10 billion there is a limit to what governments can do nationally and it is up to every individual to do their bit.

So what can we do? Most heating in Kent and Sussex is fossil fuel natural gas oil fired central heating. But we have a vast natural source of energy on our doorstep, biofuel.

We are blessed with an abundance of woodlands, in Kent for example there are around 100,000 acres mostly medieval style coppice. This type of woodland is grown on a 14-to-16-year cycle, or at least should be. It is then cropped and will regrow, to long straight poles which in the past we have used for fencing, hop poles, and building. These traditional uses have virtually ended, and the coppice is being left uncropped to fall and rot. This reduces biodiversity killing the flora and fauna at the base of the trees. To see the bluebells the year after a coppice has been cropped must rate as one of the wonders of the world.

Should every house have a wood burning stove and reduce their fossil fuel usage by 40 – 60%? And is this renewable energy source clean and green? As with all these things there is no simple straight answer. Let’s first look at whether it is green or not.

With any crop, carbon dioxide is absorbed from the atmosphere and with the sun’s energy can be turned into various more complex molecules containing energy, which we use for food, or to burn in a wood stove (you can also burn wheat, barley and other grain crops in a pellet burner). When burnt, the crop (wood or grain) releases the carbon dioxide back into the atmosphere and the energy is released into the room. A perfect cycle? Well not quite as we will use energy to cut, transport, chop to length, split the road, stack the wood and finally bring it into the home.

But with coppice wood the cycle is approximately every fifteen years so every person should get five to six cycles in their lifetime. Good coppice will produce around fifty tonnes an acre every fifteen years. Therefore, a home that wanted to reduce its carbon footprint by 50% would need to burn about two tonnes of wood a year, fifteen acres could supply enough for 25 homes forever. In Kent we have enough for over 150,000 homes to be 50% green (and with improved insulation and electric water heating 100% carbon neutral).

Some people may say ‘you must just leave the trees to grow and not cut them down’, but this does not work completely either. Trees have a lifespan like everything on the earth. Some trees last between 6 to 800 years or more, while some humans live to 110 years. But, after forty years the coppice starts to fall and collapse in the wind and rotting wood releases some of the carbon back into the atmosphere as carbon dioxide. Yes, you do need some rotting vegetation and wood for invertebrates and other life in our complex ecosystem, but there can be too much. Some estimates give the amount of CO2 released into the atmosphere by rotting vegetation each year at around 80% of the total!

There is much debate about whether Europe importing vast quantities of biomass from North America to burn in power stations is green. This discussion and calculation revolves around the life cycle of trees and there is a good argument that it is not as green as first appears, when the life cycle is 80 to 120 years.

The second problem with burning anything is by-products in the exhaust, commonly known as smoke. If we could achieve perfect combustion there would be no smoke and no exhaust, but this is impossible. New EC rules will come into force in 2022, however they are not a very high standard and some manufactures achieved higher standards than the new rules ten years ago, but the standards are at least a step in the right direction – a stove with the EC rules, produces less than one-hundredth of the particulates of an open coal fire, which produced the smog of the early 1950s found in cities throughout the UK.

Should we in the southeast be trying to do our bit for global warming, by reducing our fossil fuel burning, and partially heating our home with local wood? A resounding yes, with certain provisos:

Only use a good, properly installed, closed wood burning stove. It should preferably meet the new standards or at least be over 80 – 85% efficient.
Only burn dry wood, not ‘seasoned’. Wood must be kiln dried or stored chopped, split and stacked under cover for two years and used on the third year.
Light the stove with good kindling as fast as you can, most of the pollution is generated lighting the stove, and then run it fairly hard.

If you want to avoid pollution and carcinogens, then:

Do not burn house coal, bituminous coal, plastics, wet wood and other rubbish on an open fire.
Do not burn wet wood (wood over 20% moisture in the middle) on an open fire or wood stove.
Do not shut an old stove down over night to try to keep it smouldering all night long, just relight it in the morning.

There are many woodstove showrooms in Kent and Sussex offering sales and installation services so you can do your bit for global warming, the local economy and local biodiversity.

What are you waiting for? Make a start at being carbon neutral in your home.

Written by Graham Thornhill. C.Eng. Eur. Ing.
Engineering Designer and Inventor of the Patented T3 system of clean wood burning. As used by Burley Wood stove & Thornhill Range Cookers.

www.thornhillrangecookers.co.uk