|dc.description.abstract||Bioenergy with carbon capture and storage (BECCS), as a negative emission technology, has been assigned a key role for achieving ambitious mitigation targets in several climate models.
BECCS is a multifaceted complex system which consists of a range of variables such as type of biomass resource, conversion technology, carbon dioxide capture process and storage options. Each of the pathways to connect these options has its own environmental, economic and social impacts and needs to be assessed through a holistic sustainability framework. Too often, however, the sole focus of assessment models is on techno-economics of BECCS to produce energy and deliver negative emissions. This study proposes an integrated adaptive management approach to model technical, economic, environmental, social and political aspects of BECCS systems. The adaptive management system employs a multi-criteria decision-making tool to rank BECCS systems against a set of key sustainability criteria. The aim of such adaptive management systems is to facilitate the decision-making process by evaluating the sustainability of the BECCS systems and introducing a systematic methodology to analyse the synergies and trade-offs between different criteria and mitigation scenarios.
The technical and economic impact values of the BECCS systems were calculated using a techno-economic assessment model based on published technical data. Environmental impacts were calculated using SimaPro software. With only very limited practical experience on BECCS deployment available, scoring qualitative social and policy criteria was based on prior literature associated with bioenergy systems and carbon capture and storage systems separately, for which social and policy experience is available.
It is crucial to adapt the objectives and criteria of an adaptive management system used for implementing a BECCS system according to the regional parameters. To this end, opportunities for application of BECCS in the Australian power sector, using the adaptive management principals, were investigated. Having significant resources of organic waste for bioenergy production and the accumulated practical knowledge through ongoing carbon capture and storage projects, makes Australia a good candidate for deployment of BECCS. A feasibility assessment conducted in this study found that, based on the quantity of biomass resources available, BECCS options in Australia have the potential to remove a total of 25 Mt CO2 per year from the atmosphere as negative emissions and supply up to 13.7 TWh of renewable power.
Co-firing in existing power plants equipped with carbon capture and storage could be an effective near-term mitigation option and provides a bridging technology to deliver secure energy for a growing population while cost-effectively lowering CO2 emissions. In this study, the global technical potential and challenges of co-firing biomass with carbon capture and storage to achieve zero or negative emissions was assessed. The results show that direct co-firing of up to 20 per cent biomass in a modern pulverised coal combustion plant equipped with CO2 capture and storage could deliver negative emissions of up to -26 kg CO2 per MWh.
One of the main challenges to deploy BECCS at the level required in the stringent emission scenarios is expanding sustainable bioenergy production. Intensification of bioenergy production could result in severe pressure on natural resources, especially land and water, and competition between food, feed, and energy. Thus, it potentially could lead to controversial economic, ethical, and environmental issues. To avoid the social uncertainties and environmental impacts resulting from dedicated energy crop production, this study focuses on BECCS potential restricted to the presumption of no land-use expansion and no increase in water consumption. Hence, it is recommended that any projection of the potential of BECCS to deliver negative emissions in the future should be limited to bioenergy using organic residue and waste.
A sensitivity analysis using scenarios with different sustainability paradigms for mitigation was conducted. Selection of a scenario determines the objective of the decision-making analysis. The scenarios examined in this study reflect the effect of socio-economic, technical and environmental drivers on the sustainability ranking of BECCS systems. Water-use, and land-use change, levelised cost of electricity production, and global technical capacity to deliver negative emission were used to demonstrate the trade-off between environmental, economic and technical performance of the BECCS systems using municipal solid waste and residues from agricultural and forestry sectors. The priority was assigned to the technical potential of BECCS to deliver negative emission with minimum environmental ramifications and economic cost. The results endorse BECCS systems using municipal solid wastes under all scenarios and trade-offs.
The results of this study show that sustainable agricultural residues have the potential to deliver global negative emissions of 1.7 Gt CO2/year, forestry residues can deliver global negative emissions of 1.1 Gt CO2/year, and organic municipal solid waste can provide global negative emissions of 2 Gt CO2/year. Therefore, globally, the total sustainable BECCS potential is 4.8 Gt CO2/year, with the total energy produced (through sustainable BECCS pathways) is around 50 EJ. It should be noted that 4.8 Gt CO2 is considered to be the maximum amount of negative emission that could be delivered under the holistic sustainability criteria used here. This compares with a value of 20 Gt CO2/year negative emissions used in many global models. Even the annual 4.8 Gt contribution may be constrained further by technical, economic and policy challenge, although advances in biotechnology for example, might conceivably lead to new opportunities for BECCS. However, it would be dangerous to base a global mitigation strategy on as-yet-undiscovered biotechnologies.
Lack of integrated governmental and public support has made investment in BECCS a high political and financial risk. Therefore, a more certain way forward to underpin BECCS deployment, is to ensure that there is strong social support and integrated policy schemes that recognise, support and reward negative emission, for without negative emissions delivered through BECCS and perhaps other technologies, there is little prospect of the global targets agreed to at Paris, being met.||en_US