Carbon capture: How waste incineration can become climate neutral
Incinerating residual waste provides valuable energy for heating, but it also produces emissions of greenhouse gases. Statkraft wants to capture CO2 from its incineration plant in Trondheim and store it under the seabed in the North Sea.
Bjørn Hølaas is Director for CCS in Statkraft District Heating and leads the project for the capture and storage of carbon emissions from the incineration of residual waste in the production at the Heimdal district heating plant in Trondheim.
Industrial processes such as cement production and the burning of residual waste in district heating plants lead to emissions of greenhouse gases. For these processes, the capture and storage of CO2 – often abbreviated to CCS (carbon capture and storage) – is the only option for cutting those emissions.
Norway has several large emitters where carbon capture and storage is a relevant solution. Statkraft's production of district heating in the Heimdal district heating plant in Trondheim is one of them.
Effective use of resources
Burning waste that has no other utility value is the best way to dispose of it. In Trondheim, one third of the city's heating needs are met with district heating, which is produced from, among other things, surplus energy from the incineration of residual waste. But waste incineration emits large volumes of CO2.
Heimdal district heating plant has total emissions of approximately 220,000 tonnes of CO2 per year from incineration of two types of waste; biogenic and fossil.
Emissions from the combustion of biogenic waste such as food waste, paper, wood and wood chips form part of a natural carbon cycle. Emissions from the incineration of waste of fossil origin, such as plastics and synthetic textiles, have no such natural cycle and must be removed. At Heimdal, around a third of the emissions are fossil CO2.
"Our heating plant accounts for 25 per cent of fossil CO2 emissions in Trondheim. The goal is to remove this through carbon capture and storage. Statkraft aims to have its district heating operations climate neutral by 2040," says the Director of CCS in Statkraft Varme, Bjørn Hølaas.
About Statkraft Varme
Statkraft's district heating business, Statkraft Varme, has used surplus energy to supply district heating and cooling since 1982 and has 130 employees in Norway and Sweden. The company annually produces over 1 TWh of district heating, roughly the same as 140,000 flats use for heating in a normal year.
More about Statkraft Varme (in Norwegian only)Opens in new tab or window
How is it done?
In a waste incineration plant, the greenhouse gases are mixed with the smoke that rises from the chimney.
"We plan to use the flue gas CO2 capture technology which is the most efficient and the most mature, namely amine technology," says Hølaas.
This technology uses chemicals that bind to the CO2 found in the flue gas, so that the smoke released from the smokestack is CO2-free. Once the carbon is captured, it can be cooled and pressurised before being shipped away in liquid form.
"This is the same technology that will be used at Norcem's cement factory in Brevik and at the waste incineration plant at Klemetsrud in Oslo," Hølaas points out.
Land-intensive capture plants and long-distance transport, but permanent storage
A carbon capture plant requires a lot of space, which is a challenge on an existing industrial site. The feasibility study carried out by Statkraft shows that there is no space for a carbon capture plant on the existing site of the Heimdal district heating plant, so adjoining areas need to be used.
"Preliminary calculations show a land requirement of around 7,000 square metres. However, we are conducting good dialogue with Trondheim municipality to find the necessary space to be able to realise the project," says Hølaas.
Once the greenhouse gas has been removed from the flue gas, it will be transported from the carbon capture plant in pressurised, liquid form in tanker trucks to an intermediate storage facility.
"The plan is to transport the gas 36 kilometres to an intermediate storage facility in Orkanger. We estimate that 21 trucks will be driven every day, each with 30 tonnes of CO2," says Hølaas.
From the port at Orkanger the carbon dioxide will be shipped to a receiving terminal at Øygarden outside Bergen. From there, it will be transported by pipeline into the North Sea and then pumped into porous rocks at a depth of over 2,500 metres. Denser rocks above the reservoir ensure that the gas does not leak out and end up in the atmosphere.
The price will go down
There are several reasons why carbon capture and storage was not adopted on a large scale a long time ago. The biggest obstacles are high costs and technological challenges.
"Our preliminary calculations show a total cost for capture, transport, intermediate storage and permanent storage of NOK 2,500–3,000 per tonne of CO2. We expect this price will decrease over time. With an expected quota price for fossil emissions of NOK 2,000 per tonne of CO2 in Norway in 2030 and income from biological allowances this will eventually become profitable," says Hølaas.
All the same, he emphasises that the CCS project at Heimdal will need public funding if it is to be realised by 2030. The plan is to carry out a concept study until the autumn of 2024, assessing, among other things, access to available land, zoning, discharge permits, and a final concept for capture, transport, interim storage and permanent storage.
"Assuming positive answers from the concept study, we will continue the development and maturation of the project until the final investment decision in the summer of 2027," says Hølaas.
"Statkraft's district heating operations aim to be climate neutral by 2040."
More about district heating
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District heating: Urban energy
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