Tuesday, June 26, 2007

Wood residues to heat and electricity


Biomass is the largest renewable energy source in use today. For the future, bioenergy offers cost-effective and sustainable opportunities with the potential to meet up to 50% of world energy demands during the next century, while meeting the requirements of reducing carbon emissions from fossil fuels.

That sounds like big; I try to figure out, how realistic that statement is. Finland is, thanks to its forestry industry, one of the biggest producers of bioenergy. Thirty percent of energy produced by bioenergy is probably a realistic figure for Finland.

Bioenergy projects come in all sizes and types. Biomass can provide heat, power, transport fuels and even alternative material feed stocks. Communities with bioenergy systems (often rural) benefit from the economic activity associated with the biomass production.

We’ve been driving 400 km’s and are approaching our planned bioenergy destination. It’s 4:30 PM and we’ve been on the road for more than five hours. Our destination sawmill is at the right side of the national road.

Bioenergy is stored energy from the sun contained in materials such as plant matter and animal waste, known as biomass. We consider biomass as renewable energy while it is replenished more quickly when compared to the millions of years required to replenish fossil fuels.

Walking towards the brand new 1 MW bioenergy plant, Irja says, “They have specialized in big log dimensions.”

“Yes, that’s right; I think this mill made the decision to go for big dimensions sawing in the early 90’s.” I say, while taking pictures with my digital camera.

The wide variety of biomass fuel sources includes agricultural residue, sawmill, joinery, planning, pulp/paper mill residue, urban wood waste, forest residue, energy crops, landfill methane, and animal waste.

“They have a planing unit here at the sawmill premises,” I say to her. “They use the residues to get the heat for the drying kilns.”

“Are they able to burn a variety of wood based residues, also those from the planing unit?” she asks.

Activities included in the timber processing and semi-finished goods sector are sawmilling and planing of wood and semi-finished products. Energy in the form of electricity, heat, steam, and fuels can be derived from these sources through conversion methods such as direct combustion boiler and steam turbines, anaerobic digestion, co-firing, gasification, and pyrolysis.

The co-firing method mixes biomass with coal, and may be the best near-term economic opportunity for biomass, particularly in combined heat and power applications, which make the most efficient use of biomass. But this is a smaller unit and is using wood based material only.

Although biomass-based energy systems are more common in rural areas, there are more and more examples of large scale use in urban communities, as demonstrated in Vienna (Austria), Stockholm (Sweden) and many other cities around the world. Jyväskylä and Kuopio (Finland).

Small scale biomass applications are also increasingly important for heating individual homes. Biomass is gaining significant profile in the case of re-building or regeneration of urban areas where a greening’ marketing strategy is being embraced by both public and private sector developers. An example of this is the Bracknell development in the UK.

Moreover, an interesting and relatively new category – urban biomass, which is represented by municipal green waste, landfill gas, biogas from organic households

The security of energy supply, together with import/export balance is an important macroeconomic and strategic issue for any country.

The growing import dependence ratio in the European Union (estimated at 70% before 2030, 90% for oil), influenced several legislative initiatives (Directives) intended to facilitate development of the biofuels market in Europe.

The importance of reducing energy dependence is so high that The Ministry of Foreign Affairs of Japan has established a so called ‘energy diplomacy’ initiative working to secure the stable supply of energy (energy security) for Japan.

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