The capture and use of carbon dioxide to create valuable products might lower the net costs of reducing emissions or removing carbon dioxide from the atmosphere. Here we review ten pathways for the ...utilization of carbon dioxide. Pathways that involve chemicals, fuels and microalgae might reduce emissions of carbon dioxide but have limited potential for its removal, whereas pathways that involve construction materials can both utilize and remove carbon dioxide. Land-based pathways can increase agricultural output and remove carbon dioxide. Our assessment suggests that each pathway could scale to over 0.5 gigatonnes of carbon dioxide utilization annually. However, barriers to implementation remain substantial and resource constraints prevent the simultaneous deployment of all pathways.
Global decarbonisation scenarios include Carbon Capture and Storage (CCS) as a key technology to reduce carbon dioxide (CO2) emissions from the power and industrial sectors. However, few large scale ...CCS plants are operating worldwide. This mismatch between expectations and reality is caused by a series of barriers which are preventing this technology from being adopted more widely. The goal of this paper is to identify and review the barriers to CCS development, with a focus on recent cost estimates, and to assess the potential of CCS to enable access to fossil fuels without causing dangerous levels of climate change.
The result of the review shows that no CCS barriers are exclusively technical, with CCS cost being the most significant hurdle in the short to medium term. In the long term, CCS is found to be very cost effective when compared with other mitigation options. Cost estimates exhibit a high range, which depends on process type, separation technology, CO2 transport technique and storage site.
CCS potential has been quantified by comparing the amount of fossil fuels that could be used globally with and without CCS. In modelled energy system transition pathways that limit global warming to less than 2 °C, scenarios without CCS result in 26% of fossil fuel reserves being consumed by 2050, against 37% being consumed when CCS is available. However, by 2100, the scenarios without CCS have only consumed slightly more fossil fuel reserves (33%), whereas scenarios with CCS available end up consuming 65% of reserves. It was also shown that the residual emissions from CCS facilities is the key factor limiting long term uptake, rather than cost. Overall, the results show that worldwide CCS adoption will be critical if fossil fuel reserves are to continue to be substantively accessed whilst still meeting climate targets.
•This paper reviews barriers to global CCS adoption and also considers its potential impact on ‘unburnable’ reserves.•CCS availability has a large bearing on the extent of fossil fuel consumption in climate-constrained scenarios.•In the medium term (up to 2050) scenarios including CCS result in 37% of fossil fuel reserves being consumed.•In the long term (up to 2100) scenarios with CCS available end up consuming 65% of reserves.•Residual emissions from CCS facilities are a key factor limiting long term uptake.
Negative emissions technologies (NETs) in general and bioenergy with CO
2
capture and storage (BECCS) in particular are commonly regarded as vital yet controversial to meeting our climate goals. In ...this contribution we present a whole-systems analysis of the BECCS value chain associated with cultivation, harvesting, transport and conversion in dedicated biomass power stations in conjunction with CCS, of a range of biomass resources - both dedicated energy crops (miscanthus, switchgrass, short rotation coppice willow), and agricultural residues (wheat straw). We explicitly consider the implications of sourcing the biomass from different regions, climates and land types. The water, carbon and energy footprints of each value chain were calculated, and their impact on the overall system water, carbon and power efficiencies was evaluated. An extensive literature review was performed and a statistical analysis of the available data is presented. In order to describe the dynamic greenhouse gas balance of such a system, a yearly accounting of the emissions was performed over the lifetime of a BECCS facility, and the carbon "breakeven time" and lifetime net CO
2
removal from the atmosphere were determined. The effects of direct and indirect land use change were included, and were found to be a key determinant of the viability of a BECCS project. Overall we conclude that, depending on the conditions of its deployment, BECCS could lead to both carbon positive and negative results. The total quantity of CO
2
removed from the atmosphere over the project lifetime and the carbon breakeven time were observed to be highly case specific. This has profound implications for the policy frameworks required to incentivise and regulate the widespread deployment of BECCS technology. The results of a sensitivity analysis on the model combined with the investigation of alternate supply chain scenarios elucidated key levers to improve the sustainability of BECCS: (1) measuring and limiting the impacts of direct and indirect land use change, (2) using carbon neutral power and organic fertilizer, (3) minimising biomass transport, and prioritising sea over road transport, (4) maximising the use of carbon negative fuels, and (5) exploiting alternative biomass processing options,
e.g.
, natural drying or torrefaction. A key conclusion is that, regardless of the biomass and region studied, the sustainability of BECCS relies heavily on intelligent management of the supply chain.
Negative emissions technologies (NETs) in general and bioenergy with CO
2
capture and storage (BECCS) in particular are commonly regarded as vital yet controversial to meeting our climate goals. In this contribution we show how the sustainability and carbon efficiency, or otherwise, of BECCS depends entirely on the choices made throughout the BECCS supply chain.
In this perspective, we detail how solvent-based carbon capture integrated with conversion can be an important element in a net-zero emission economy. Carbon capture and utilization (CCU) is a ...promising approach for at-scale production of green CO2-derived fuels, chemicals and materials. The challenge is that CO2-derived materials and products have yet to reach market competitiveness because costs are significantly higher than those from conventional means. We present here the key to making CO2-derived products more efficiently and cheaper, integration of solvent-based CO2 capture and conversion. We present the fundamentals and benefits of integration within a changing energy landscape (i.e., CO2 from point source emissions transitioning to CO2 from the atmosphere), and how integration could lead to lower costs and higher efficiency, but more importantly how CO2 altered in solution can offer new reactive pathways to produce products that cannot be made today. We discuss how solvents are the key to integration, and how solvents can adapt to differing needs for capture, conversion and mineralisation in the near, intermediate and long term. We close with a brief outlook of this emerging field of study, and identify critical needs to achieve success, including establishing a green-premium for fuels, chemicals, and materials produced in this manner.
Beyond 90% capture: Possible, but at what cost? Brandl, Patrick; Bui, Mai; Hallett, Jason P. ...
International journal of greenhouse gas control,
February 2021, 2021-02-00, 2021-02-01, Letnik:
105, Številka:
C
Journal Article
Recenzirano
Odprti dostop
•Origins of 90% capture assumption explained.•Cost of near 100% capture calculated.•CO2 concentration drives costs of capture.
Carbon capture and storage (CCS) will have an essential role in meeting ...our climate change mitigation targets. CCS technologies are technically mature and will likely be deployed to decarbonise power, industry, heat, and removal of CO2 from the atmosphere. The assumption of a 90% CO2 capture rate has become ubiquitous in the literature, which has led to doubt around whether CO2 capture rates above 90% are even feasible. However, in the context of a 1.5 °C target, going beyond 90% capture will be vital, with residual emissions needing to be indirectly captured via carbon dioxide removal (CDR) technologies. Whilst there will be trade-offs between the cost of increased rates of CO2 capture, and the cost of offsets, understanding where this lies is key to minimising the dependence on CDR. This study quantifies the maximum limit of feasible CO2 capture rate for a range of power and industrial sources of CO2, beyond which abatement becomes uneconomical. In no case, was a capture rate of 90% found to be optimal, with capture rates of up to 98% possible at a relatively low marginal cost. Flue gas composition was found to be a key determinant of the cost of capture, with more dilute streams exhibiting a more pronounced minimum. Indirect capture by deploying complementary CDR is also assessed. The results show that current policy initiatives are unlikely to be sufficient to enable the economically viable deployment of CCS in all but a very few niche sectors of the economy.
•With heat recovery, carbon negative power plants can be 38%HHV efficient.•BECCS plant efficiency and carbon negativity are strongly related.•Sustainably sourced biomass is key to net atmospheric CO2 ...removal.•Co-firing can reduce SOx formation.
This study evaluates the performance of a 500 MW pulverised fuel BECCS system. A performance matrix is developed to assess the opportunities for BECCS performance improvement in terms of: energy efficiency, carbon intensity, and pollutant emissions. The effect of fuel properties was analysed for variable (i) coal type (high/medium sulphur content), (ii) biomass type (wheat straw and wood chips), (iii) moisture content, and (iv) biomass co-firing proportion %. It was observed that the co-firing of biomass increased the quantity and quality of waste heat available for recovery from the exhaust gas. The opportunities to improve energy efficiency in the BECCS system include enhancing heat recovery and using high performance solvents for CO2 capture, such as biphasic materials. Implementing these approaches increased the power generation efficiency from 31%HHV (conventional MEA system) to 38%HHV (using an advanced biphasic solvent with heat recovery). Furthermore, power generation efficiency was found to influence the carbon intensity on an annual basis and annual capacity (load factor) of the BECCS system. Significant reductions to SOX emissions were achieved by increasing biomass co-firing % or using low sulphur coal.
Using carbon dioxide for enhanced oil recovery (CO2-EOR) has been widely cited as a potential catalyst for gigatonne-scale carbon capture and storage (CCS) deployment. Carbon dioxide enhanced oil ...recovery could provide revenues for CO2 capture projects in the absence of strong carbon taxes, providing a means for technological learning and economies of scale to reduce the cost of CCS. We develop an open-source techno-economic Model of Iterative Investment in CCS with CO2-EOR (MIICE), using dynamic technology deployment modeling to assess the impact of CO2-EOR on the deployment of CCS. Synthetic sets of potential CCS with EOR projects are created with typical field characteristics and dynamic oil and CO2 production profiles. Investment decisions are made iteratively over a 35 year simulation period, and long-term changes to technology cost and revenues are tracked. Installed capacity at 2050 is used as an indicator, with 1 gigatonne per year of CO2 capture used as a benchmark for successful large-scale CCS deployment. Results show that current CO2 tax and oil price conditions do not incentivize gigatonne-scale investment in CCS. For current oil prices ($45 per bbl–$55 per bbl), the final CO2 tax must reach $70 per tCO2 for gigatonne-scale deployment. If oil price alone is expected to induce CCS deployment and learning, oil prices above $85 per bbl are required to promote the development of a gigatonne-scale CCS industry. Nonlinear feedbacks between early deployment and learning result in large changes in final state due to small changes in initial conditions. We investigate the future of CCS in five potential ‘states of the world’: an optimistic ‘Base Case’ with a low CO2 tax and low oil price, a ‘Climate Action’ world with high CO2 tax, a ‘High Oil’ world with high oil prices, a ‘Depleting Resources’ world with an increasing deficit in oil supply, and a ‘Forward Learning’ world where mechanisms are in place to drive down the cost of CCS at rates similar to other clean energy technologies. Through multidimensional sensitivity analysis we outline combinations of conditions that result in gigatonne-scale CCS. This study provides insight levels of taxes, learning rates, and oil prices required for successful scale-up of the CCS industry.
Bioenergy with carbon capture and storage (BECCS), and other negative emissions technologies (NETs), are integral to all scenarios consistent with meeting global climate ambitions. BECCS's ability to ...promptly remove CO
2
from the atmosphere in a resource efficient manner, whilst being a net energy generator to the global economy, remains controversial. Given the large range of potential outcomes, it is crucial to understand how, if at all, this technology can be deployed in a way which minimises its impact on natural resources and ecosystems, while maximising both carbon removal and power generation. In this study, we present a series of thought experiments, using the Modelling and Optimisation of Negative Emissions Technologies (MONET) framework, to provide insight into the combinations of biomass feedstock, origin, land type, and transport route, to meet a given CO
2
removal target. The optimal structure of an international BECCS supply chain was found to vary both quantitatively and qualitatively as the focus shifted from conserving water, land or biomass, to maximising energy generated, with the water use in particular increasing threefold in the land and biomass use minimisation scenario, as compared to the water minimisation scenario. In meeting regional targets, imported biomass was consistently chosen over indigenous biomass in the land and water minimisation scenarios, confirming the dominance of factors such as yield, electricity grid carbon intensity, and precipitation, over transport distance. A pareto-front analysis was performed and, in addition to highlighting the strong trade-offs between BECCS resource efficiency objectives, indicated the potential for tipping points. An analysis of the sensitivity to the availability of marginal land and agricultural residues showed that (1) the availability of agricultural residues had a great impact on BECCS land, and that (2) water use and land use change, two critical sustainability indicators for BECCS, were negatively correlated. Finally, we showed that maximising energy production increased water use and land use fivefold, and land use change by two orders of magnitude. It is therefore likely that an exclusive focus on energy generation and CO
2
removal can result in negative consequences for the broader environment. In spite of these strong trade-offs however, it was found that BECCS could meet its electricity production objective without compromising estimated safe land use boundaries. Provided that the right choices are made along BECCS value chain, BECCS can be deployed in a way that both satisfies its resource efficiency and technical performance objectives.
BECCS performance can be measured by a wide range of technical and sustainability indicators, which can be negatively correlated. An exclusive focus on BECCS technical performance - CO
2
removal and electricity production, can result in negative consequences for the broader environment.
•We present a new electricity systems model – a hybrid between a generation expansion and a unit commitment model.•We quantify and qualify the role and value of CCS, energy storage and renewable ...energy.•We show how the availability of different low-carbon technologies impact the optimal capacity mix and generation patterns.•Ultimately, the incremental system value of a power technology is a function of the prevalent system design and constraints.
A new approach is required to determine a technology's value to the power systems of the 21st century. Conventional cost-based metrics are incapable of accounting for the indirect system costs associated with intermittent electricity generation, in addition to environmental and security constraints. In this work, we formalise a new concept for power generation and storage technology valuation which explicitly accounts for system conditions, integration challenges, and the level of technology penetration. The centrepiece of the system value (SV) concept is a whole electricity systems model on a national scale, which simultaneously determines the ideal power system design and unit-wise operational strategy. It brings typical Process Systems Engineering thinking into the analysis of power systems. The model formulation is a mixed-integer linear optimisation and can be understood as hybrid between a generation expansion and a unit commitment model. We present an analysis of the future UK electricity system and investigate the SV of carbon capture and storage equipped power plants (CCS), onshore wind power plants, and grid-level energy storage capacity. We show how the availability of different low-carbon technologies impact the optimal capacity mix and generation patterns. We find that the SV in the year 2035 of grid-level energy storage is an order of magnitude greater than that of CCS and wind power plants. However, CCS and wind capacity provide a more consistent value to the system as their level of deployment increases. Ultimately, the incremental system value of a power technology is a function of the prevalent system design and constraints.
Biomass can be converted into a range of different end-products; and when combined with carbon capture and storage (CCS), these processes can provide negative CO2 emissions. Biomass conversion ...technologies differ in terms of costs, system efficiency and system value, e.g. services provided, market demand and product price. The aim of this study is to comparatively assess a combination of BECCS pathways to identify the applications which offer the most valuable outcome, i.e. maximum CO2 removal at minimum cost, ensuring that resources of sustainable biomass are utilised efficiently. Three bioenergy conversion pathways are evaluated in this study: (i) pulverised biomass-fired power plants which generate electricity (BECCS), (ii) biomass-fuelled combined heat and power plants (BE-CHP-CCS) which provide both heat and electricity, and (iii) biomass-derived hydrogen production with CCS (BHCCS). The design and optimisation of the BECCS supply chain network is evaluated using the Modelling and Optimisation of Negative Emissions Technology framework for the UK (MONET-UK), which integrates biogeophysical constraints and a wide range of biomass feedstocks. The results show that indigenous sources of biomass in the UK can remove up to 56 MtCO2/yr from the atmosphere without the need to import biomass. Regardless of the pathway, Bio-CCS deployment could materially contribute towards meeting a national CO2 removal target and provide a substantial contribution to a national-scale energy system. Finally, it was more cost-effective to deploy all three technologies (BECCS, BE-CHP-CCS and BHCCS) in combination rather than individually.
Display omitted
•Indigenous sources of biomass in the UK could generate up to 56 MtCO2 of negative emissions per year.•All three pathways (electricity, heat, hydrogen) provides a substantial energy supply for the UK.•It is more cost-effective to deploy technologies in combination, BE-CHP-CCS with BECCS and BHCCS.•The cost-optimal combination of technologies is a function of the H2, electricity and heat price.•Capital cost savings (e.g. retrofit existing plants) and high capture rates enhance deployment.
PDF
