BECCUS and flexible bioenergy – finding the balance

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Given that flexibility – in terms of inputs, shifting between different outputs and varying outputs over time and place – and the ability to capture and store (or utilize) biogenic CO₂ (BECCUS) are expected to be two of the more important characteristics for bioenergy systems of the future it is important to see how these two aspects interact and find strategies for how these interactions can come in the form of benefits rather than trade-offs.

The research questions in this study were:

• How could a more flexible operation of the BECCUS value chains of the various sectors look like?
• Where and how do BECCUS and flexible bioenergy interact in biobased value chains and what are the implications for the (bio)energy system?
• How can the implementation of BECCUS solutions in different sectors be combined with flexible bioenergy in terms of existing modi of operandi, technologically, business models and value chain configurations?

For the analysis, available case studies on the application of BECCS and BECCU were taken into account. Thereby mainly combustion technologies for renewable energy generation were considered, with a focus on the post-combustion technology to capture the carbon. This system study is part of a series of studies carried out under the IEA Bioenergy inter-task project Deployment of BECCUS value chains with the aim to highlight these system-specific characteristics.

Flexible bioenergy and BECCS (bioenergy with carbon capture and storage) are important technologies that are expected to play a crucial role in mitigating climate change (see IEA Net Zero by 2050 roadmap, IEA 2021). Flexible bioenergy involves the use of biomass to produce energy, such as heat and electricity, and can be used to replace fossil fuels in various applications. The flexibility of this technology lies in its ability to adjust its output according to the demand for energy, inter alia, making it a valuable complement to intermittent renewable energy sources like wind and solar power (operational flexibility) and also allowing the use of different feedstocks and intermediates (flexibility in input) as well as providing different energy carriers and products and services (flexibility in output).

On the other hand, BECCS is a negative emissions technology (NET) that involves the use of bioenergy to produce electricity or other forms of energy while capturing and storing the resulting carbon dioxide (CO₂) emissions underground and thus preventing it from entering the atmosphere. This process not only reduces emissions from the energy sector but can also remove CO₂ from the atmosphere, thus contributing to negative emissions. With carbon utilization (BECCU) the resulting CO₂ emissions are captured and further utilized and thus kept for some longer time in use. However, CO₂ emissions are not permanently stored and prevented from entering the atmosphere. Negative emissions won’t result from this technology.

Key conclusions of the study:

• Combining CCU and CCS with a flexible operation of bioenergy facilities is possible from a technological point of view. Different types and levels of flexibility measures (flexibility in input, operations and output) can be applied to the various BECCS/U case studies with post-combustion. However, not all of the BECCS/U case studies and thus (bioenergy) facilities are suitable for flexible operation.
• A flexible operation, with regular ramping up and down, does not allow for a constant CO₂ capture rate what could be specifically a drawback for certain CO₂-utilization concepts and business models where this is a requirement. A flexible operation leads to a lower level of carbon captured what in turn results in a lower level of negative emissions for the installation.
• The current core business model for operating CCU is the market price realized for selling the carbon for use in other applications. Here, a constant CO₂ capture rate could be required to run reliable CO₂-utilization concepts and business models. For developing a business model for BECCS a reward system needs yet to be established first, potentially it is a revenue generated due to carbon dioxide removal – one could think of a mechanism that rewards CO₂ removal, i.e. negative emissions, like a premium payment (financial instrument) or emission certificates.
• The current business models for a flexible operation are mainly based on electricity market prices and/or possible incentive schemes supporting a flexible operation. Broader climate policy instruments and corresponding incentive schemes, however, are not in place (yet).

As the business models for the provision of flexible bioenergy and BECCS/U are of different nature, it has to be governed which role each of the technologies is going to play within the energy system and further within climate policy making.

For better describing the implications of Flexible BECCUS for the energy system we see a need for a profound energy system modelling, and thereby raising the awareness among energy system modelers and policy makers that possible trade-offs for the energy system may occur when bioenergy installations provide flexibility and CCS/U at the same time. This will also support the understanding on the level of carbon dioxide removals from the atmosphere when a bioenergy installation provides flexibility and carbon capture and storage at the same time.

This report was delivered in the frame of the project ‘Deployment of BECCUS value chains’.

The full set of reports is available here