Feature : Distri ct energy Croatia turns to biomass heat and power Bioenergy International No 81, 5-2015 13 the two croatian projects are for Hrvatska Elektroprivreda (HEP Group), a national heat and power generator and distributor. Though the latest Eurostat figures suggest Croatia is well on track to meet its EU 2020 renewable energy target of 20 percent, having reached 18 percent in 2013, the country is still heavily dependent on electricity, gas and oil imports. – The projects in Sisak and Osijek in Croatia are special because they not only supply district heating but also supply steam to factories. This makes the system and the optimal operation load more complex but at the same time assures a high base load during the summer too, a period that is difficult for heating plants that supply space heating only, said Herman Klein Teeselink, Project Manager with HoSt. The total investment is around EUR 35 million for the two projects together. This relative high investment includes infrastructure like new district heating piping, road changes and high-voltage lines. The projects will be finished in 2nd quarter of 2017. Flexi-fuel and high efficiency The plants in Croatia are relatively small with a 14 MWth boiler and 3 MW electric generator output. Both projects are being built in a consortium with Duro-Dakovic Holding (DDH), one of the largest industrial groups in the country. DDH will carry out local work like civil engineering, grid connection and the district heating system. – The plants all have a very high total efficiency due to the flue-gas condenser, boosting efficiency by 20 percent or 2.4 MW thermal. This low temperature heat, 60°C, can be used for district heating but also for other purposes, said Teeselink. However, some district heating systems have a higher return than 60°C. – We have a concept with an electrical-driven heat pump. This system can be attractive, depending on price differentials, when natural gas is saved and power from the grid is used, Teeselink explained. A feature of the HoSt biomass CHP plants is fuel flexibility in terms of biomass quality. According to HoSt its moving grate furnace can use particle sizes up to 15 cm pieces and moisture content from 10 to 55 percent. – The furnace is also flexible for the type of fuel. In the Netherlands we have very bad quality wood from composting installations and about six years ago we modified the firing system. The firing temperature on the grate is very low, about 800 °C. In fact the biomass is gasifying on the grate. The temperature above the grate is increased to 950 °C by injecting air and additional combustion of the biomass gas. In this way, difficult fuels can be added to the woodchips like wood from composting installations and straw without having problematic agglomerates, said Teeselink. In Croatia the plants will be use forestry residues and woodchips from sawmills. – The advantage of the low grate temperature for this customer is the long lifetime of the grate elements resulting in high availability and low maintenance, remarked Teeselink. Combining with solar and biogas – For the Croatian customer, the combination of a wood CHP and solar photovoltaic (PV) is very interesting. The solar PV systems will produce very cheap daytime electricity in the summer. The wood CHP generates more in the winter because of the higher heat demand, Teeselink said. He added that a biogas plant complete with gas engines and large biogas storage would be a very good third technology to complete the ideal renewable base- and peak load CHP facility. It is also a technology sector HoSt is well versed in as suppliers. – These biogas plants could store the gas during daytime and when the solar PV goes down, these units can increase the output, concluded Herman Klein Teeselink without revealing if this may become a reality in any of the Croatian projects. Text: Alan Sherrard BI81/4975/AS Abengoa and Toshiba selected for major UK biomass CHP project Spanish environmental and renewable energy technology major Abengoa and Japanese global conglomerate Toshiba Corporation have been selected as preferred bidders by UK company MGT Power via its subsidiary MGT Teesside to build its 299 MW Tees Renewable Energy Plant (Tees REP). According to a statement Abengoa will be responsible for carrying out the engineering, design and construction of the plant, a contract worth in excess of EUR 600 million. To be built on a 14 ha site in an Economic Zone in the Port of Teesside, Middlesbrough, the biomass combined heat and power (CHP) plant will have an electrical capacity of 299 MW that, according to MGT Teesside, makes it one of the world’s largest purposebuilt biomass CHP plants of its type. Several existing heat users are within economic distance of the power station site and it is also within “economic supply distance” from another Economic Zone. Construction is expected to be- Celebrating two decades of peace and its second anniversary of European Union membership, the Republic of Croatia has wasted little time in rebuilding its society and energy infrastructure while reducing its dependence on imported fossil fuels. Dutch biomass combustion technology specialists HoSt has revealed it already has three contracts for biomass-fired combined heat and power (CHP) plants for district heat projects this year, two of which are in Croatia. gin 2016 and be fully operational, and supplying electricity to the grid in 2019. The plant will use wood pellets and woodchips sourced from Europe and North America. At full capacity the plant is estimated to use 1.1 million tonnes of wood pellets per annum. BI81/4963/AS Photo courtesy HoSt
Bioenergy no 5 September 2015
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