In a world is overly reliant on coal, oil and gas there is another natural carbon resource known to be a significantly substantial replacement for fossil fuels is biomass
by Martin Frohock
21 February 2008
Earthly alternative
Fossil fuels require millions of years to form in the earth, their reserves are finite and subject to depletion as they are consumed. The only natural, renewable carbon resource known to be a significantly substantial replacement for fossil fuels is biomass. Included in biomass is all land and water based organisms, vegetation, trees, dead and waste biomass, sewage, manure, forestry and agricultural residues, and certain industry wastes. Unlike fossil fuels, biomass is renewable in that a much shorter period of time is required to replace consumed resources.
1 Pros and Cons
Biomass is an attractive energy source. There’s an abundance of waste resources in waste products and agricultural materials; biomass is renewable and not dependant on fossil fuels. Gases produced by biomass energy can be used in combined-cycle plants, or CHP. Biomass is also more evenly distributed over the Earth’s surface than finite energy sources, and may be exploited using less capital-intensive technologies.It helps to reduce climate change and enables local, national and world-wide self-sufficiency.
Disadvantages of biomass include the polluting gases and liquid wastes that biomass applications produce, and the lack of ‘fully autonomous’ bio-fuel production plant currently available. The ecological impact of small biomass plants is not yet proven, and often the economical restraints of biomass technologies can be an impedance due to the expensive nature of the collection, transportation and storage costs. There are also potential air quality impacts of combustion-based bioenergy production.
2 Future
With the growing realisation of climate change’s escalation as a result of our fossil fuel addiction, an interest in wood and fuel is being widely reconsidered. The latest technology that anaerobically digests domestic food waste can actually capture energy from your rotting leftovers. This energy spin-off means that 110,000 tonnes of food waste per year could translate into 17,000 KWhours of electricity – enough to power 1,700 homes.
Possible future developments to enable further widespread integration of biomass technologies include:
Supply - Improvements in agricultural practices could lead to increased biomass yields, reductions in cultivation costs, and improved environmental quality.
Green Power Marketing - This provides choices in restructured electricity markets for consumers to purchase power from renewable or environmentally preferred sources, such as biomass. GP allows customers to support greater levels of investment in renewable energy technologies. Job Creation - Investment in the bioenergy sector could create thousands of jobs, especially in rural communities which need support.
3 Costs
Cost will be as varied as the technologies and forms of biomass available. First of all it is important that you are not integrating a new technology for the sake of it - conduct a Return on Investment analysis to ensure that the project is all together viable. Then consider: do you have the staff / knowledge to maintain the equipment? Do you have the financial contingencies to cover all eventualities? Does the near future offer any more suitable technological developments? Does the new technology offer a long term benefit to the organisation?Does the new technology offer environmental benefits? Does the cost outweigh the value?
4 Legal aspects
Current legislation and controls you need to consider include: Renewables Obligation (RO); Good Quality Combined Heat and Power (GQCHP); The Climate Change Levy; Renewable Electricity Guarantee of Origin (REGO); EU Emissions Trading Scheme (EU ETS)
5 Options
To effectively analyse bio-energy conversion we require a comparison with other energy sources that are displaced by the bio-energy.
Other renewable forms of such power conversion include: direct-fired or conventional steam boiler – most of the bio-power plants in the world use these methods. Both systems burn bio-energy feedstock’s directly to produce steam, which in turn creates electricity.
Co-firing – combining biomass with coal to generate energy is probably the most compatible way to use biomass with the current fossil fuel dependent system. With co-firing, woody and herbaceous biomass such as poplar, willow and switchgrass can fuel a small portion of an existing coal power plant.
Pyrolysis – this is a process where biomass is combusted at high temperatures and decomposed in the absence of oxygen. The burning creates pyrolysis oil, char or syngas which can then be used like petroleum to generate electricity.
Biomass gasification – solid biomass can be converted into a gaseous form, known as syngas. The gas can then be run through a "combined-cycle" gas turbine or another power conversion technology such as a coal power plant.
Anaerobic Digestion (AD) – this is a biological process, where the methane released by the synergistic actions between bacteria and archaea are contained and used to create energy.
Landfill Gas – landfill gas uses a similar technology to anaerobic digestion, It occurs as a by-product of the decomposition of solid waste and consists of 50 percent methane (natural gas), 45 percent carbon dioxide and 4 percent nitrogen.
All of these require different technical skills, ability, and time and resource investment, research them carefully before investing.
Martin Frohock is deputy area FM for the NHS National Blood Service
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