Carbon capture in the waste-to-energy sector

Posted on 27/01/20.

Waste to Energy incineration plants have been ranked the 18th largest direct CO2 emitters to the atmosphere. Although not quite at the incomparable scales as steel and cement industries or large power plants, the waste to energy companies have an equal role in CO2 emission mitigation.

According to the International Energy Agency, carbon capture is considered one of the most important single reduction measures and requires the development of highly effcient and cost-effective capture technologies. Carbon capture from waste incineration can remove 90 million tons CO2 annually only from the existing plants in Europe. Cognisant of the fact, a number of waste-to-energy plants have begun to look for ways to tackle their carbon emissions both by setting ambitious goals and looking into the existing technologies to achieve this goal.

Westenergy, (a waste to energy operator located in the Vaasa area) for example, has set a goal to be a carbon-neutral energy producer by 2030, which implies that significant investments in carbon capture, storage and utilization technologies, as well as the right partners, are needed to achieve the goal. Westenergy and VEBIC, a research platform on energy and sustainable development at the University of Vaasa, have begun firstly, to identify and evaluate suitable carbon capture technologies suitable for Westenergy’s utilisation and secondly, to identify and network with key players and solution providers in the industry.

Recently, a team from VEBIC and Westenergy, led by the company’s CEO Olli Alhoniemi visited key waste to energy companies in the Nordic countries with an aim to learn, share knowledge, challenges, progress and experiences with respect to curbing CO2 emissions. At Renova group (Gothenburg, Sweden) studies have begun on examining the energy balance on using different solvents i.e. MEA and chilled ammonia in the carbon dioxide capture process and its effect on energy production revenues. Fortum Oslo Varme (Oslo, Norway) has made substantial progress in deploying a pilot-scale carbon-capture technology in their waste to energy plant in Klemetsrud. The Klemetsrud facility processes over 400,000 tonnes of non-recyclable waste per year, generating 700 GWh of heat and 150 GWh of electricity annually. At the Klemetsrud facility, a pilot-scale CO2 capture plant has been tested, which removes climate-warming carbon dioxide from the flue gases generated from industrial and household waste.

The flue gases after combustion are passed through a solvent (amine-based solvent) that preferentially absorbs carbon dioxide. The CO2 is stripped off the CO2-rich stream, then cooled and compressed to where it can be efficiently transported for storage in the seabed. The transportation by ship and storage in the seabed in the Klementsrud project is covered by the Northern lights consortium. The pilot project deployed captured 90-95% of the CO2 from a small flue gas stream. Full-scale carbon capture is projected to capture up to 400,000 tonnes of CO2 every year with an amine-based absorption capture plant. 50% of the captured CO2 is biogenic, making this a partial bio-energy with carbon capture and storage (BECCS) facility; a CO2-negative project.

It is noteworthy that municipal waste in particular contains materials of plant-based (biogenic) and fossil fuel (non-biogenic) origin. When burnt, the biogenic waste produces CO2 that does not lead to an increase in atmospheric CO2 levels. However, the non-biogenic component of waste has been rising over time as e.g. more paper and food waste is recycled. Although the waste incineration companies are considered among the CO2 emitters, they do not produce but instead dispose of the waste. Which begs the question, who should be footing the bill for CO2 emitted? The plastic producer, the consumer or the waste management companies?

On a positive note, CO2 capture from a WtE plant is relatively simpler than for a coal-fired power station. This is because waste contains much less sulphur and produces less particulate matter than coal, which could imply smaller capital investment requirements for further gas cleaning. WtE plants operate at a smaller scale in comparison to conventional coal or gas-fired power stations, therefore, the CO2 capture volumes are also smaller. Thus, successful Carbon Capture and Storage (CCS) installations will need to be able to deliver low-cost abatement without the economies of scale available at larger power plants.

In addition to the techno-economical considerations on a micro-level, the future of CCS in the industrial context depends heavily on the different considerations on the system level. For example in Norway, the long-term financial support from the state as well as the other ecosystem members’ willingness to jointly share the costs seem to play an important role for the realization of the CCS aspirations. Furthermore, the imposition of the favourable policy mechanisms, regulation, and the compatibility with existing carbon-related regulations (e.g. emission trading system and taxes) are critical for large scale CCS developments. VEBIC explores the aspirations of the Finnish waste-to-energy producers towards CCS technologies in the CEE4WES project (funded by Business Finland) during the spring of 2020..

Text: Dr Joel Songok

Further information

Researcher Joel Songok: joel.songok@univaasa.fi, tel. + 358 29 449 8114

Project Manager Karita Luokkanen-Rabetino: klr@univaasa.fi, tel. +358 29 449 8183

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