Biomass can be sustainable
Notwithstanding that reducing energy consumption is the most pressing requirement for us all, We (Green Building Press) believe the take-up of biomass heating in the UK and the wider world is, and will continue to be, an essential part of the 'move' towards a more sustainable and safe world. Biomass is a natural, easy to grow and harvest fuel that, contrary to the authors' claims, need not be at the 'expense' of other uses for wood. In fact, anyone with a reasonable knowledge of wood and forestry - how it is grown, thinned, harvested etc, would not have written much of what they have included in this paper.
Early in the paper, the authors chose to dismiss many of the very important factors that make biomass perhaps the most environmentally friendly and sustainable choice for heating (where heating is required). They chose instead to simplify the matter to just CO2
calculations. To do this is to over-simplify the complex nature of the earth's ecosystems and processes. And their proposal that people should happily plant trees to just offset gas consumption is naive at best and foolhardy at worst.
Putting aside the discussion regarding whether or not we should still be erecting new buildings that require heating at all, it is clear that we still need heat in some form and will continue to do so for some time, in most new, and certainly almost all, existing building stock. In my opinion, a key fuel for meeting this need 'sustainably' is biomass, for five fundamental reasons:
1. Biomass is a renewable fuel (within human timescales).
2. Biomass can be grown locally, close to the point where it is needed.
3. Biomass is energy secure - no need to rely on supplies from other countries.
4. Biomass requires relatively simple technology and equipment to enable it to be grown, harvested and burnt efficiently.
5. Biomass can provide employment, environmental protection of habitat and improved lumber production, all for use in the UK.
Whereas on the other hand, mined natural gas, the fuel which the report seems to lean towards as they regularly compare it with biomass, is unacceptable for five fundamental reasons:
1. Gas is not a renewable fuel (in human timescales).
2. Gas cannot be sourced locally, or even easily for that matter.
3. Gas is not energy secure and forces us to rely on imports from other countries and can be implicated in recent conflicts with other nations and the oppression of third world countries.
4 Gas requires complex and increasingly sophisticated technology to extract, transport, store and burn efficiently.
5. Gas provides for very little UK employment or for any habitat protection.Note 1: The carbon released from fossil fuels has been long separated from the global carbon cycle and adds to the total amount of carbon in active circulation between the atmosphere and biosphere. In contrast, the CO2 released from burning woody biomass was absorbed as part of the “biogenic” carbon cycle where plants absorb CO2 as they grow (through photosynthesis), and release carbon dioxide as they decay or are burned (see www.safnet.org/documents/biomass_science_letter_SENATE7-20-10.pdf).
Note 2: Biogas from anaerobic digestion could quite safely be excluded in the above statements about gas.
Note 3: A study by Cornell University environmental professor Robert W. Howarth in 2010 (see: http://tiny.cc/tzi0j) finds that once methane leak impacts are included, the life-cycle greenhouse gas (GHG) footprint of shale gas would be worse than those of coal and fuel oil. He highlights. "A complete consideration of all emissions from using natural gas seems likely to make natural gas far less attractive than other fossil fuels in terms of the consequences for global warming." Methane is by far the major component of natural gas, and it is a powerful greenhouse gas: 25-times more powerful than is CO2 per molecule in the atmosphere (see: http://tiny.cc/tiv9y)Wood Biomass and forestry - both help to keep us in harmony with nature (in a UK context)
Contrary to the authors' suggestion that forestry cover is on the decline, the opposite is probably true, certainly in the UK. Since 1965, UK forestry cover has grown by 4.3% and 2.7% since 1980. Biomass is now a valued resource from many sectors. In fact trees, per-se, nowadays have an intrinsically high value in the eye of the general public, partly due to their multiple benefits - including as a fuel. A growth in forest cover has many many benefits which the authors seem to have chosen to overlook.
Extensive research over the years has revealed that woodland ownership in the UK is now much more diverse and there has been a large increase in the planting of native, broadleaved trees on land taken out of farming for a variety of reasons - including for fuel security. For instance, the total area of new planting and restocking in the UK was 21.8 thousand hectares in 2008-09. Although restocking accounted for 73% of this total, broadleaved species accounted for the majority (80%). As for new planting (on land not previously used for forestry), since 2004-05, 45 thousand hectares of the UK was put down to new forestry and again, most was broadleaved trees. This increased interest in woodlands and timber as a fuel is more likely attributable to a growing awareness that all nature is interconnected, and forests, woodland, trees and timber are part of what makes us human beings, rather than just robots (see Forestry Commission website for facts and figures).
Forestry is an old profession, therefore much data is available and history proves that when value for forestry is increased, then there is more interest in managing it carefully. UK woodlands will, we believe, benefit from increased extraction of wood for fuel. Forestry is as much a skilled art as any other professional trade and until recently, UK woodlands had suffered from desperate undervaluation because little use could be found for thinnings, which is an essential step in the growing of quality lumber for building. For instance, when planting a woodland for commercial timber purposes, one would plant trees at a maximum of 1 metre apart. Then over the following 25-30 years as the saplings grow and compete with each other for light, they force each other to grow straight and true but eventually need thinning out. Thinning out would be carried out at least once when the trunks are about 125 - 200mm diameter as the woodland matures. The best, most straight and clean trees would be left to mature and grow on for high quality timber. The thinnings, especially in broadleaved woodland have little value other than as firewood (for which they are perfectly sized) or perhaps for making charcoal, (they also used to be used for pit props in the early days of coal mining).
In an ever-shrinking world we need to choose what we do with our land wisely. Growing wood for both biomass and lumber is far more cost-effective and likely to succeed than growing trees for just lumber. Further notes on the collective phrase "biomass"
Of course, not all biomass that is currently burned or planned to be burned will be from forestry sourced wood. Therefore, for a proper analysis to be carried out to conclusion each source fuel would need to be examined in isolation for a number of factors before any findings and/or recommendations can be drawn. Notwithstanding that, it seems to be quite commonly agreed that where and when variable origin/quality biomass feedstock is involved, the combustion plant will need to be ever-more technically advanced in order to keep localised pollution to a minimum. It would seem that when sort of activity is carried out, the plant in question becomes a suspected polluter. Perhaps this is an area where more detailed work is needed.With grateful thanks to the multiple users on the Green Building Forum and others by e-mail and telephone who took the time to discuss this with me on the Green Building Forum in two notable threads:
'Why biomass is better than gas': http://tiny.cc/flwkl
'Natural gas - is it hydrogen or carbon': http://tiny.cc/8qc93wk54e