Energy industry - growing back to its roots
Bioenergy, a diverse array of renewable energies derived from plant or animal matter, first used by the forebears of Homo sapiens at least one and a half million years ago, is making a comeback as a highly sophisticated solution to our energy problems. Not only that, but bioenergy is also proving to be a solution to one of our other burning environmental issues – that of waste and how best to dispose of it.
Bioenergy sources can be waste materials, such as forestry waste, poultry litter, livestock slurry, or bagasse – the husk around sugarcane, or can be grown specially for the purpose, such as short rotation tree crops and elephant grass (Miscanthus giganteus). The form which the fuel takes can be very flexible. Biofuels can be solid, either naturally, such as with wood, or can be processed into briquettes, chips or pellets, which can be burnt in order to produce heat alone, or used to produce steam to generate electricity.
Advantages of bioenergy
The advantages of bioenergy are as numerous as the forms that the energy sources take. As a sustainable form of waste disposal, Bioenergy generating companies regard organic waste not as the end of the line for resources, but as a source for power generation. Forestry and arable wastes can be burnt, as can other resources such as poultry litter, and manure, and other compostable organic wastes can be used to produce biogas, a mixture of carbon dioxide, methane and small amounts of other gases, which can be used for energy generation. By cutting the amount of organic waste going to landfill, there will be less need for new waste dump sites, which will also cut down on fugitive emissions of the powerful greenhouse gas, methane.
Bienergy generation is also independent of the vagaries of the British weather, unlike other renewable sources such as wind and solar power, which means, primarily, that the source is constant and dependable, but also that bioenergy power plants can be situated in any part of the country. The carbon neutral nature of energy produced from vegetation also makes it an attractive piece for the climate change jigsaw puzzle, and if used as British BioGen suggests, to replace coal power, it could substantially cut greenhouse gas emissions. According to the organisation, a 10 MegaWatt (MW) bioenergy power plant emits 50,000 tonnes less carbon dioxide per year than an equivalent sized coal powered plant. “A sustainably managed woodland or energy crop follows the natural carbon cycle,” says British BioGen Managing Director Peter Billins. “On balance, wood is never removed faster than it is added by new growth. Therefore the CO2 released when the wood fuel is burnt is never more than the CO2 being taken up by new growth.” Short rotation coppice, the energy crop closest to market realisation, also has substantial biodiversity and habitat benefits, he says. Billins does admit, however, that there are some emissions involved in the harvesting and transport of wood energy, but these are still far less than those emitted by fossil fuels.
Finally, the ever-shrinking UK rural economy, with a lower proportion of agricultural
workers than even Hong Kong, and which in recent years has been hit by
a plethora of high-profile animal-related diseases, could be given a boost
with an increased demand for biofuel crops. Compared to the traditionally-fuelled,
large centralised power plants, bioenergy plants provide energy for local
customers, using local fuels, and providing incomes and profits to local
people. That same 10 MW bioenergy power plant will create 50 full time
jobs, put an estimated £2 million back into the local economy, and provide
electricity for 20,000 homes, says British BioGen. According to Washington-based
environmental think-tank, the Worldwatch Institute, such small localised
power stations are the future for the energy industry, cutting down on
leaks in transmission, increasing stability of supply, and doing away
with the need for the vast investments required by large generators (see
British BioGen agrees, adding that local power generation also reduces
or avoids the costs of reinforcing or upgrading electricity distribution
|So much for the advantages, but what of the dioxins of which we have heard so much in recent months, particularly in the plumes from the foot and mouth burning pyres which, though distasteful, are as biological as one can get? It’s not a problem, says Kirsten Chambers, Project Manager at British BioGen. “As long as the wood fuel is burned in a suitable biomass combustion unit the emissions can be controlled and are well below limits set by the Environment Agency,” she said.||
bioenergy...is the forgotten renewable, little known or understood outside the energy industry
Poultry litter power
One example of a successful bioenergy plant is Europe’s largest generator of electricity from biomass, Fibrothetford, a 38.5 MegaWatt (MW) facility in Norfolk, burning poultry litter - which consists of a mixture of wood shavings, straw and other bedding materials, and poultry droppings, of which the UK produces 1.5 million tonnes per year. The resulting ash is rich in potash and phosphate, and is sold as an environmentally friendly fertiliser, completing the biological cycle. The emissions resulting from burning poultry litter are very low, and could be reduced even further in order to meet the statutory requirements of different countries, claims Fibrowatt, the power plant’s parent company. Further to this, Fibrowatt is also raising the company’s environmental profile by cutting down on its visual impact. The plant is screened on all sides by forest, with the boiler house sunk into the ground to ensure that it does not exceed the height of the trees, and the buildings have been painted dark brown to match the forest background. The plant has been very well received by Thetford locals, especially since they have seen the benefits of the plant, says Nina Butcher, now Assistant Vice President of Fibrowatt in the US. “The people who were protesting the loudest now speak out very favourably for us,” she said.
Biogas which can be used in much the same way as a fossil fuel gas, can be produced either through gasification – where biomass is partially oxidised in temperatures of the order of 800-900°C – or through anaerobic digestion of liquid biomass such as animal slurry or vegetable waste. Not only is this a sustainable method of waste utilisation, but it is also a positive form of agricultural diversification, increasing farm revenues, such as in the case of the new biogas generator using cow manure from a Wisconsin dairy farm which is providing electricity for 250 local homes (see related story).
|Biomass can also be used to produce hydrogen, methanol and ethanol, the first of which is essential for powering fuel cells, probably the most potentially sustainable form of energy generation for the future, from which the only emission is water vapour (see related story).||
"... the CO2 released when the wood fuel is burnt is never more than the CO2 being taken up by the new growth."
Biofuels can also be used to power vehicles. Biodiesel is made from vegetable oil produced from plants such as rape and mustard. In the UK, one example of successful use of vegetable oil is the curry company, Sharwoods, which uses waste oil from cooking poppadoms to power its entire lorry fleet (see related story). However, according to Swedish car manufacturer, Volvo, one of the companies at the forefront of the new generation of alternatively-fuelled vehicles, biodiesel is 10 times more carcinogenic than low-sulphur diesel, the exhaust fumes smell like oily chips, fuel efficiency is reduced, and running costs are high. Nevertheless, there are many who are enthusiastic about its benefits. Results from emissions tests on a biodiesel powered Dodge four-wheel-drive pickup by researchers at the University of Idaho and the Montana Department of Environmental Quality in the United States have shown that it emitted less smoke, hydrocarbons and carbon monoxide than conventional diesel. “It really eliminated a lot of air toxics with the catalytic converter,” said Howard Haines, one of the researchers. The researchers also found that the vehicle’s engine had not suffered serious wear from using the fuel. One proponent of biodiesel is the US National Parks Service, which now uses biodiesel-powered trucks, buses and boats in 22 national parks around the country, from Florida’s Everglades to California’s Channel Islands.
complaints abound within the industry regarding continued refusal of planning permission for bioenergy power plants
A substance called bio-oil can also be produced through a technique known as pyrolysis, a process by which small particles of dried woody biomass are heated very rapidly to around 900°C (see related story). Canadian-based company, DynaMotive Technologies Ltd, has the world-wide patent for ‘fast pyrolysis’, using waste timber and bagasse, producing bio-oil and combustible briquettes known as char. The bio-oil is both transportable and storable, much in the same way that fossil fuels are, but with considerably lower emissions, says Antony Robson, Managing Director of DynaMotive Europe.
A raft of challenges
However, even fans of the technology admit that bioenergy alone is not the answer to the global power supply. According to the Idaho research team, there is only sufficient agricultural land which can be put aside for growing biodiesel crops in the US to supply 10% of the country’s vehicle fuel demand. Other proponents, such as British BioGen foresee the renewable resource as being part – although, a significant one - of a country’s overall energy package. However, before even this can happen, the bioenergy industry has to face up to a number of challenges.
First and foremost, bioenergy has to become better understood by the wider public. “Experience to date shows that this is not a trivial task,” says British BioGen Chief Executive Peter Billins. “The story is a complex one and challenges many pre-conceptions, particularly about burning trees.” The industry still remains small, and resources are limited, which means that the industry’s approach needs to involve a wide range of stakeholders. Bioenergy already enjoys the support of the environmental NGOs, some regional development agencies, and a variety of local authorities, although complaints abound within the industry regarding continued refusal of planning permission for bioenergy power plants, particularly from Liberal Democrat county councils fearful of what they regard to be new ‘incinerators’.
There also needs to be a concerted effort at building the infrastructure. “At the practical level, the development of fuel supply chains is an immediate and urgent task,” said Billins. There needs to be full involvement from the relevant government ministries, and the forestry and agriculture industries, he says. “Similarly, the development of an indigenous manufacturing capability for a range of bioenergy plant and equipment is required,” said Billins. “The industry must be able to offer ‘complete’ solutions to customer’s equipment and energy needs. Standardisation and modular, automated bioenergy products must enable replication so that the benefits of serial production can ensure long-term competitiveness.”
The good news is that the Government appears to be keen to assist the bioenergy industry, having set up the Renewables Obligation, a requirement on licensed suppliers to provide a specified proportion of their electricity from renewable sources. The New Electricity Trading Arrangements (NETA), which is jointly sponsored by the Department of Trade and Industry (DTI) and the energy regulator Ofgem, is also designed to encourage competition in the industry. On top of this, the Climate Change Levy (see related feature), which was brought in this April, is designed to make industry pay for its greenhouse gas emissions, and consequently reduce them. Good quality CHP plants, and some other renewables, are exempt from the levy, further improving their competitiveness. However, there are still problems within Government, not least the need for greater co-ordination between the variety of Ministries – agriculture, energy and environment - responsible for bioenergy, a problem caused by the industry’s own versitility. However, the recent reshuffling of ministerial responsibilities may be a step in the right direction. “The different government departments are working together better at present,” says Chambers. “It is too early to tell the effects of the establishment of [the Department of the Environment, Food and Rural Affairs].”
Despite being considerably less expensive than conventional large-scale power
plants, bioenergy still needs substantial financial input. The 10MW power
plant mentioned earlier requires a £15 million investment, and an additional
£15 million in developing the fuel supply chain, says British BioGen.
However, DynaMotive is one company to have taken advantage of the Government’s
current generosity towards bioenergy, with a recent £1.2 million grant
for the development of the UK’s largest commercial production facility
(see related story).
“To all intents and purposes it is a new commodity,” said Robson, with
demand being driven primarily at the moment by the targets laid down in
Europe by the Commission and by governments.
|Like DynaMotive, bioenergy companies also need to ensure that their ambitions encompass international energy markets. “The development of strong home markets and demand will be essential to the success of UK businesses in taking a share of very substantial world-markets for bioenergy product packages and associated legal, financial and insurance business,” said Billins. So, if the bioenergy industry plays its cards right, it could have the world at its feet.||
The good news is that the Government appears to be keen to assist the bioenergy industry