What is biomass?

Biomass is all non-fossil organic materials that have an intrinsic chemical energy content. This includes all water and land-based vegetation and trees or virgin biomass, such as log wood or thinnings from local forests, prunings from roadsides or parks, grasses and energy crops and in some countries residues from agriculture or food processing e.g. nutshells or olive pits, wood chips, recycled untreated wood or pelletising residues from wood processing.  Also all waste biomass such as municipal solid waste (MSW), municipal bio solids (sewage) and animal wastes (manures), forestry and agricultural residues, and certain types of industrial wastes.  Through using these resources a possible disposal problem can be turned into a high quality fuel and local suppliers of wood fuels will gain extra income and enhance local economic turnover.

What are energy crops?

Perennial crops such as deciduous trees and grasses are grown for use as fuel to be used in biomass power plants to provide heat and power.  The most commonly used is willow, grown on a rotation of 2-4 years and known as short rotation coppice.  Grasses such as miscanthus give a bigger harvest per hectare than willow and can be harvested annually, and are better suited to the more temperate regions of the UK.  Straw and grain can also be used, as well as a variety of oliferous crops suitable for extracting oilseed .

How is biomass used?

Biomass can be used on a domestic or industrial scale.  For a biomass power plant, the chipped, shredded and dried fuel is fed into a boiler or gasifier, from where the gas is collected and used to produce electricity and heat.  Biomass can also be used at a more basic level to produce heat for the home - this is done most efficiently using a wood burning stove which can also be an attractive feature in any home.  It is possible with larger stoves to use a back boiler to provide all of the water heating and central heating for a house.  Alternatively, a biomass boiler can be used for the same purpose.

What are the benefits of biomass?

Biomass is a renewable resource as it can be grown year on year and therefore offers sustainability.  It is less polluting and displacing consumption of fossil fuels by wood fuels helps to counter the impacts of climate change.  Biomass generates about the same amount of carbon dioxide as fossil fuels, but every time a new plant grows, carbon dioxide is actually removed from the atmosphere. The net emission of carbon dioxide will therefore be zero as long as plants continue to be replenished for biomass energy purposes. 

With energy crops, very little is required in the way of pesticides and herbicides and apart from the visual impact of growing coppice, it is generally regarded as very environmentally friendly.  It can improve the biodiversity of an area, as there is an increase in the number of plants and wildlife compared to existing farmland, and it also contributes to better management of woodland.  There are few environmental issues related to forestry and straw although after a forestry site has been cleared there could be more water run-off but this is manageable with good forestry practice.  Using industrial wood waste avoids land filling and the use of woodland residues can make forests more accessible through better management.

How much does it cost?

Modern biomass boilers can be an expensive investment compared to domestic gas or oil fired systems and the cost of wood pellets tends to follow the cost of oil (as a tracker price). 

Sundance can supply gasifying log boilers from the Czech Republic as a cost effective biomass system that uses logs and small round wood which are often cheaply available in rural areas, where they can be locally sourced (See www.atmos.cz for more information).

Sundance offers 15-25kW domestic sized systems for around £2,500 plus the cost of the flue pipe and installation.  There are grants available for around £1,500 of this cost, regardless of system size - please see www.clear-skies.org for more information.

Are there many projects in Britain?

There are many examples of energy crop/wood waste heating systems in Britain:

• In Ely, Cambridgeshire, a 31MW straw burning plant, the biggest and most effective plant in the world, was commissioned recently.

• A 350kW wood-fired boiler was installed at Weobley school in 1997.  Using locally grown wood, it heats the school itself as well as the secondary school on the adjoining site.

• The National Botanic Garden of Wales and Singleton Park Botanic Gardens in Swansea are heated using energy crops/wood waste.

• An increasing number of farms are using straw-fires boilers for on site heating requirements in buildings and polytunnels.

• The Centre for Alternative Technology in Machynlleth, North Wales, are currently undertaking a project to build a Welsh Institute for Sustainable Education, which will include an innovative biomass combined heat and power micro turbine system from Talbott's linked to the district heating system and grid.