Bio-energy

bio-enerrgy

An all-round energy source

The utilization of biomass is currently well established, but needs to be developed strategically. The effectiveness of conversion, the access of new areas for biomass production, as well as logistics and the interaction with fluctuating energy prices are challenges that need to be solved by more versatile means than only technological improvements.

Worldwide bioenergy is the most commonly used renewable energy, amounting to 15% of the total energy supply. In the Nordic countries bioenergy makes 20% of the energy consumption in Sweden and Finland, 12% in Denmark and 7% (17 TWh in 2012) in Norway.

The Nordic bioresources are wood from forests and solid and liquid organic wastes from industry, households and agriculture. The biomass is mainly converted to heat used for heating buildings. A minor fraction is converted to electricity and liquid biofuels for transportation.

Technology status

Half of the biomass presently used for energy purpose in Norway is used in wood stoves and pellet stoves for heating homes. The other half is input to district and local heating plants and to wood processing industry.

Today, the wood and pellets stoves perform high energy efficiency, 80-85%, and low particle emissions, about 6 g/kg dry wood. Wood stoves may ensure heating in cold periods when the power is expensive and/or insufficient. They have elegant design creating an attractive atmosphere in the home. The trade of fire wood has so far been without information on cost per unit energy. This may possibly be changed in order for the customer to compare energy sources directly. There are about 100 district heating plants in Norway, producing 5 TWh of heat annually. The particle emissions are low, about 200 mg/m3 fluid gas. Also, technology reducing NOx emissions from non- woody wastes to a minimum have been developed. The energy efficiency is high, about 95% for the combustion process itself, the upstream and downstream chains not included. An intelligent regulation system which takes the weather changes and customer behaviour into consideration can help to avoid downstream waste of energy.

New technology and microbial knowledge has increased the energy efficiency of biogas reactors from about 60 to 70%. Development of new thermal and enzymatic processes has opened for lignocellulosic biomass, which is hard to degrade, to be included in the biogas feedstock. The biogas production in Norway is low. However, during the recent years 15 plants have been constructed or planned, some near big towns where food waste is being converted to fuel for buses.

Challenges

There are three main challenges to overcome to meet the target of doubling the bioenergy production. These are the amount of available biomass, conversion efficiency and profitability.

Increasing the forest biomass supply can lead to higher

logistics costs, if new areas are more difficult to access. More efficient logistics can hardly eliminate the cost increase, and higher feedstock price may be the result. Increasing the municipal waste supply is closely linked to public regulations and political decisions. Here the political power on municipality level is the main driving force.

Improving efficiency means to match the characteristics of the biomass feedstock (fire-wood, wood chips, pellets, wastes) with the characteristics of the technology used for energy conversion, and vice versa, calling for close collaboration between the biological and technological sciences.

The profitability for the district heating industry depends on electricity price, as stated in public regulations. This means that low el-price gives low profit for the bioenergy sector. Persevering low price is a serious problem, especially for new plants with high investment costs.

Realising a medium or large biogas plant involves many stakeholders upstream and downstream, leading to collaborative and contractual challenges. Each stakeholder needs to quantify its profit and see its role in the consortium.

Outlook

The worldwide potential for increasing energy production from forest virgin biomass, agriculture residues and waste is large. In Norway a doubling to about 30 TWh/ year is a realistic target, mainly based on forest feedstock without compromising sustainability.

Europe is short of biomass and Norway, with its large forest biomass reserves, can play a role as supplier. International trade of chips, wood residues and pellets may grow due to the EU RES 2020 target. The highest growth is expected in wood fired CHP mills using logging residues and wood pellets. To obtain best price and minimum transportation costs, the energy density of the biomass products must be high.

The maximum biogas energy production in Norway is calculated to 6 TWh/year. Assumed improved profitability and energy efficiency one third of this potential might be realized, as approved by the Ministry of food and agriculture.

Another interesting possibility is to develop ‘smart energy technology’ for industrial clusters – where energy is utilized by different industries within a local community that may cooperate to provide and share electricity, heating and cooling in a smarter and more efficient way.

R&D recommendations:

• Analyse the profitability for the forestto-heat value chains.

• Analyse the energy efficiency and the profitability for small and medium

biogas reactors.

• Develop bioenergy systems for low

energy house standards.

• Identify links between bioenergy and other energies to ensure sufficient heat supply throughout the year.

• Describe bioenergy climate and environment impacts.