Newsflashes From Denmark
Aggressive particles in straw removed by simple washing. Research by the Danish utility company Elsam has demonstrated that potassium and chloride in straw can be removed by washing the straw in hot water. The most economical temperature is probably 50 60 C. Alkali and chlorine in straw causes major corrosion problems in straw-fired boilers and make it impossible to use the fly ash for cement production. To wash the straw, Elsam will use a machine currently operated by the sugar industry to extract sugar from sugar canes. Washing removes 2 4% of the organic matter from the straw, but these can be reused in a fermentation plant. It is necessary to dry the wet straw before it can be burned in the boiler. Energy losses through washing and drying amount to about 8% of the calorific value of the straw, meaning the net electrical efficiency will be 43% compared to 47% for a new coal fired power plant. Elsam considers a drop of 4% to be an acceptable trade-off for solving the problems with the fly ash and avoiding corrosion problems in the boilers.
Danish renewable energy island
Samsoe has been selected from five competing islands to become the first Danish island to be powered by renewable energy only. Samsoe covers 11,202 ha and has 4,400 permanent residents. About 100,000 tourists visit the island annually. Excluding the transport sector, renewable energy presently covers 12 15% of the total energy consumption. Within the next decade Samsoe will demonstrate how a local community, including industry, can become self sufficient with renewable energy if the public and the private sectors combine their efforts. The project is widely backed by local organisations and by the local utilities. Energy consumption in the transport sector will be markedly reorganised and reduced. It is planned to initiate a global Renewable Energy Islands' Network at a conference on Samsoe in 1999. A European seminar will be held on Samsoe in May 1998 to find renewable energy islands that qualify.
For more information on these two projects contact the CADDET Danish National Team in Tølløse.
The CADDET Renewable Energy Newsletter is a quarterly magazine published by the CADDET Centre for Renewable Energy at ETSU, UK.