Defining bioenergy system services to accelerate the integration of bioenergy into a low-carbon economy

New open-access paper published in the Journal Biofuels, Bioproducts & Biorefining (BioFPR), developed in the frame of IEA Bioenergy Task 44 (flexible bioenergy and system integration).

Read the full paper: Defining bioenergy system services to accelerate the integration of bioenergy into a low-carbon economy

The global energy system is in transition, aiming to reach net-zero greenhouse gas emissions by 2050. The systemic changes mean that the role of bioenergy will change. The potential of bioenergy to make a flexible contribution to the energy system is key for the achievement of global emission reduction ambitions and the functioning of the low-carbon energy system and economy. As the volume of sustainably available biomass resources is limited, defining the contributions from bioenergy to a low-carbon energy system and finding balances – and ideally synergies – between the different possible energy and climate system services that biomass can provide will be very important. The recognized system services include, among others, the flexible operation of bioenergy plants to integrate variable renewable energy sources and to provide negative carbon dioxide (CO2) emissions. Interest in flexible operation of bioenergy value chains, bioenergy with carbon capture and utilization as well as synergies with renewable hydrogen-based value chains has increased recently. The objective of this paper is to present a holistic definition of flexible bioenergy as a system service based on the work conducted in IEA Bioenergy Task 44 (flexible bioenergy and system integration), and to provide some practical examples. The paper also presents the different bioenergy system services and considers their definitions and interactions, as this is important in energy system design. The definition of flexible bioenergy* shows that the flexibility provision from bioenergy goes far beyond the traditional definition of providing short-term flexibility in the power sector. Indicators to demonstrate the value of services as well as further quantitative assessment of synergies and trade-offs are needed to valorize the different services from bioenergy and create viable business cases.

Conclusions

• While variable renewable energy penetration increases, mainly from wind and solar energy, more efforts for balancing are needed to provide stable and secure power supply. Bioenergy is one option to provide the needed flexibility. However, opportunities to provide flexibility from biobased value chains go beyond the power sector and short-term flexibility, as typically suggested in the literature. Flexible bioenergy has a unique supply-chain character as it can provide flexibility in different dimensions: in inputs as feedstock and intermediates flexibility; in outputs as flexibility through bioenergy carriers and products; and operational flexibility in terms of time and space. Several real-world examples of flexibility provision from bioenergy already exist, showcasing for example feedstock flexibility, and flexibility in production of multiple products according to market demand. In addition to a theoretical background on potential flexible value chains, these concrete examples are needed to support market diffusion of flexible bioenergy solutions.
• Flexible bioenergy value chains are increasingly connecting to renewable hydrogen and CO2-based value chains. These interconnections can bring additional flexibility to the system, for instance, in terms of flexible uptake of renewable hydrogen to the biobased process, or in terms of flexible operation mode between hydrogen uptake and CO2 removal in biofuel production process. From the energy and climate system perspective, these system services embed great potential but also form a complex system with many interactions – some of them maybe still unidentified.
• System services are still hardly valued in terms of their energy and climate system benefits. This is particularly the case when considering synergies between biobased and renewable hydrogen-based value chains. Being able to quantify and having a value assigned for the system services will assist in the design of better public policies for accelerating the integration and deployment of bioenergy concepts. Definitions are needed in order to quantify the values of different services. These include definitions of the system boundaries and reference system, definitions of the key performance indicators (KPIs) to assess the value of the service, and definitions of interactions and synergies between the services. Future work is needed, for example, to define meaningful KPIs to support the quantification of the value of bioenergy system services on system level – instead of showing the additional cost at the plant level.
• Another remaining question is how to optimize between different system services. When considering the national strategy of utilizing different services from bioenergy, it must be noted that energy system design differs from country to country due to different supply and demand profiles, climate strategies, market mechanisms, policy conditions, and of course biomass resource availability. Energy system modeling can support the formulation of national and regional strategies for bioenergy use – for instance with regard to how to balance between different end uses and optimize the value of biobased resources. Thorough assessment from system perspective requires new modeling approaches, for example linking life cycle and integrated assessment modeling to analyze impacts of future technologies on energy system dynamics through a multimetric framework.

* Task 44’s definition for flexible bioenergy: “Flexible bioenergy is defined as a bioenergy system that can provide multiple services and benefits to the energy system under varying operating conditions and/or loads.” This definition includes utilization of biomass feedstocks of varying types and qualities, trade and storage of intermediates and energy carriers, flexible production of power and heat, flexible polygeneration of power, heat, fuels and nonenergy biobased products according to market demand, and negative energy vectors to store surpluses from renewable electricity production.

Figure: Expectations on the role of bioenergy in the renewable energy system and resulting energy and climate system services from bioenergy.

Quotes: Mäki, E., Hennig, C., Thrän, D., Lange, N., Schildhauer, T. and Schipfer, F. (2024), Defining bioenergy system services to accelerate the integration of bioenergy into a low-carbon economy. Biofuels, Bioprod. Bioref.. https://doi.org/10.1002/bbb.2649