Bio-fuelled plant soon opened
On the plains of Skåne north of Lund, some distance from the large sugar refinery in Örtofta, the Kraftringen energy group (formerly Lunds Energikoncernen) is building its new bio-fuelled power plant. LTH News was there in August when a number of experts from LTH were invited to view the site and hear all the details.
The investment amounts to approximately SEK 1.8 billion, the largest in the group’s history. The municipalities of Lund, Eslöv, Hörby and Lomma are behind the enterprise.
In order to convert to a sustainable society, which does not continuously increase the temperature in the atmosphere, for example, we have to replace energy production from fossil fuels with biofuels. But this is not so easy to achieve in practice.
The Örtofta plant is to run on wood and other biofuels from Skåne and Southern Småland and will be inaugurated in March 2014 – but test-runs have already begun.
The new plant is to cover half the group’s district heating production (equivalent to 50 000 households) and in addition, will produce electrical power equivalent to that of the entire city of Eslöv. The reduction in CO2 emissions is estimated to be 205 000 tonnes per year and will contribute to the achievement of Region Skåne’s environmental goals for 2020.
The idea is to burn substandard wood fuel including tree stumps, branches and tops, along with recycled wood from households and construction work in a specially constructed furnace. Some peat is also to be added and everything will be mixed into an optimal combination with regard to humidity, etc. The heat is to be converted into electrical power and will also be added to the district heating network.
“Thanks to this combination and to the flue gas purification, the efficiency levels will be close to 100 per cent, double the rate of a conventional power station”, explains Lars Hammar, who is the project manager for the furnace construction.
CEO Richard Bengtsson welcomed the guests from LTH. Liisa Fransson from Kraftringen, who also has a position as an adjunct senior lecturer at LTH spoke of the group’s need to increase cooperation with research at LTH. Kraftringen about 10 LTH engineering students working on their degree projects addressing various sub-problems within the enterprise. Summer jobs were arranged for engineering students on the power plant programme. Curiosity from researchers was noted with regard to both technology and sustainability issues.
“Lecturers and researchers have a desire to access real data and test hypotheses in a real facility. And Kraftringen is happy to help them achieve this”, said Lisa.
“I wanted to consider the study visit as a starting point for this type of cooperation. LTH and Kraftringen may need to get to know one another to create added value together”. There are joint projects via Vinnova and LU innovation and several more research projects and applications are in the pipeline.
There was a great deal of interest in the opportunity for researchers to use the facility in their teaching. Professor Pål Börjesson, Division of Environmental and Energy Systems Studies, pointed out how the plant can illustrate teaching in energy studies with great breadth, addressing fuel, technology, Swedish regulations, etc. He asked whether it would not be possible to return the ashes to the forest, and got the answare that today nobody is willing to accept the ashes but that it is an important question for the future. A straw furnace is another such question, he was told.
Professor Olof Samuelsson, expert on electrical networks, is already running a co-authored degree project but would like to use the power plant also in teaching.
Around 50 trucks per day will come and dump biofuel on the large plot around the Örtofta plant once it is up and running. The fuel supply is reported to be good. After 2016, one third of deliveries could arrive via rail on a new short siding.
Loaders will drive around taking wood from the 12 hectare storage area to a crusher where everything will be reduced to chips. These are then transferred by enormous screws to a conveyor belt. In a sorting shed, a large magnet will pick out metal objects and any other non-combustible material will be removed. The chips are stored on trays and fed by a conveyor belt up to the furnace.
The used steam is condensed into water fed at approximately 100 degrees into the district heating network. The heat is then used in approximately 50 000 households in Lund, Lomma and Eslöv. The flue gases are purified in a bag filter and in principle there will be only water vapour in the exhaust from the 80 metre high chimney.
The furnace is 50 metres high and the foundations are enormous. A lot of expertise has gone into optimising all the processes. The fuel is mixed in order to maintain a constant humidity level. The white building offers a sweeping view over the Lund plain and can be seen from afar. The control room is also at the top.
It takes a long time to get permission for energy production. Six years in this case, because of an appeal and a rejection in the Land and Environment Court of Appeal, which forced a new application. The emissions into the air are now promised to be well under the limits set in the environmental permit and the plant will purify its water on site before releasing it into the Kävlinge river. There the effects on local fish life will be monitored. The noise is to be kept under 40 dB at night where there are homes and 45 dB during daytime. A sound-absorbing bank will also be planted with trees.
Since August, one activity after another has gradually started to undergo testing. The fuel crusher was test-driven in September. On 23 October, the furnace was fired up in a test for the first time. In November solid fuel was run through the furnace and tests will begin on the steam system. In November also the first delivery of district heating is to take place. On 13 December the first electrical current is to be delivered. On 31 March, the entire process is to be tuned and the plant is to be in continuous use.
TEXT AND PHOTO: MATS NYGREN
Find plenty more information on http://www.kraftringen.se/ortoftaverket