More district heat produced than ever before
Westenergy’s WtE plant is a link between municipal waste management and the energy sector as the non-recyclable waste is refined into electricity and district heat in the plant.
Year 2020 was very significant as the flue gas scrubber increased our district heat production by 55 gigawatt-hours.
Westenergy’s role as the district heat producer in the Vaasa area has become more important year after year – our district heat production has increased by 53 percent since 2013 when the plant started operation. The production target for electricity was not achieved in 2020 due to the relatively low price of electricity in the market and district heat energy optimisation, but the production targets regarding energy production as a whole were, however, achieved. The availability rate of the plant was very good (94,1 %) although the goal was slightly missed because of three separate disturbances in the plant and repair work that followed.
In 2020, we produced 402 gigawatt-hours of district heat which is about 60 percent of the district heating in the Vaasa region.
Energy production became more climate-friendly in 2020.
Our aim is to develop the plant operation continuously, making it cleaner and more efficient. Because of the flue gas scrubber, the levels of impurities in the air emissions have lowered significantly. In addition, we produce 15–20 % more energy with the scrubber without increasing the amount of waste which means that the specific emissions of the plant have decreased, respectively. With the scrubber, even moisture in the waste can be utilised: water vapour is condensed and after purification, the condensate is used in the plant processes. In 2021, we will take the utilisation of the condensate further as it will be used to produce make up-water to the district heating network.
Last year, the energy storage owned by Vaasan Sähkö and EPV Energia was taken into use. This means that in the future, additional thermal energy that Westenergy’s plant produces in the summertime can be stored in the energy storage and used when the demand of district heating is greater. The energy storage will also help schedule the annual service stop to a more opportune time regarding energy production.
In 2021, the infrastructure of the plant area will be developed when the new road to the plant site and a new storage area will be constructed. The new road and scale unit will improve the overall logistics in the plant area, and waste can be moved into the tipping hall more quickly as the new storage area will be located nearer the plant. In addition, the current storage area will be returned to Stormossen’s own use.
Maintenance creates the prerequisites for high availability
No cases of coronavirus occurred during the service stop.
Westenergy’s waste-to-energy plant is maintained systematically, and different investments are car-ried out to ensure the reliability of the plant also in the future. Cost-efficiency is an important part of planning maintenance, and the scope of the plant maintenance is specified in the preventive maintenance plan. The annual service stop forms the culmination of the year as a massive amount of service and repair tasks are carried out during the service stop. In 2020, the largest single maintenance work was the partial replacement of the grate. The pressure equipment of the plant was also inspected during the service stop.
The corona pandemic had its effects also on the annual service stop of the plant. Physical contacts were kept at minimum by carefully scheduling the work and dividing people into small teams, lunch and coffee breaks were organised in a large tent on the parking lot to make sure that the employees could keep social distance, hand sanitation posts were added to the plant area, and everyone was obliged to use a face mask at the plant site. Informing all the approximately 100 workers about the special arrangements and rules posed a challenge, but no cases of coronavirus occurred during the service stop. The pandemic affected the availability of workers and spare parts as many production facilities decided to organise their service stop in the fall instead of the spring when the pandemic began. We were, however, able to carry out all the critical repair and maintenance work in time.
Quality inspections give information on the consistency of the raw material
The raw material refined into energy in Westenergy’s waste-to-energy plant is source-separated community waste that consists of different types of materials. The inconsistent quality of the fuel can be stabilised by mixing it thoroughly and crushing larger items. This pre-treatment is essential for the entire production process to operate smoothly and efficiently.
We carry out random inspections for the waste deliveries to get a better idea of the consistency of the raw material. The waste types that can be used in energy recovery are listed in detail in the environmental permit which also compels us to carry out inspections.
In 2020, we carried out 84 waste quality inspections.
The amount of metal and hazardous waste has remained quite stable during the years that the company has been in operation but the amount of construction waste such as PVC plastics, plaster boards and insulation wool in the combustible waste has unfortunately increased. The raw gas analysis that provides information on the consistency of the flue gases before purification, has indicated the same trend. Construction waste cannot be used in waste-to-energy plants as incinerating them causes acidic impurities that slowly cause corrosion in the boiler pipes. In addition, construction waste can melt and jam mechanic equipment of the plant. Although energy recovery has decreased landfilling significantly, there are still various materials that cannot be recycled or refined into energy and remain, therefore, challenges for circular economy.
In 2021, a new place for carrying out waste quality inspections will be constructed, and this brings new possibilities for developing waste quality inspection.