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How Much Can CCUS Technology Reduce Carbon Dioxide Emissions?
According to an OECD International Energy Agency (IEA) report, once CCUS technology is commercialized, it is expected to account for 18% of the total reduction.
The International Energy Agency predicted in a 2021 report that 90% of captured carbon dioxide will be processed through CCS and 10% through CCU.
The contribution of CCUS to reducing global energy sector CO2 emissions in the Sustainable Development Scenario evolves over the projection period, with three distinct periods. In the first phase to around 2030, the focus is on capturing emissions from existing power plants and factories. In the power and industry sectors, over 85% of all CO2 emissions captured in this decade are from plants retrofitted with CO2 capture equipment: coal-fired power units (and, to a lesser extent, gas-fired power units); chemical plants (mainly fertilisers), cement factories, and iron- and steelworks. Some low-cost CO2 capture opportunities in hydrogen and bioethanol production are also developed, building on the current portfolio of projects. Total capture reaches 840 Mt in 2030. Cumulatively to 2030, CCUS contributes around 4% of the overall emissions reductions in the Sustainable Development Scenario relative to the Stated Policies Scenario.
During the second phase, from 2030 to 2050, the contribution of CCUS to cumulative emissions reductions grows to 12% relative to the Stated Policies Scenario. CCUS deployment expands most rapidly in the cement, steel and chemicals sectors, which together account for around one third of the total growth in global CO2 capture during that period. In power generation, the focus shifts to natural gas-fired stations, which help to integrate variable renewable energy sources (mainly solar and wind) in some regions by providing short-term flexibility and to balance seasonal variations in electricity demand or renewable generation, for which batteries are less well suited. Hydrogen production from fossil fuels (primarily natural gas) is responsible for a fifth of the overall growth in CO2 capture in the 2030-50 time frame, driven by increasing hydrogen demand in long-distance transport modes (such as trucks and shipping). BECCS also expands significantly, accounting for around 15% of the growth in CO2 capture over that period. By 2050, around half of BECCS capacity is in the power sector and the remainder primarily in producing alternative low-carbon fuels, in particular biofuels. BECCS benefits from economies of scale and cost reductions through technological advances and learning-by-doing, which are generally highest at the early stages of the adoption of a technology.
How Can CCUS Contribute to Stable, Zero-Emissions Power Systems?
The power sector is the largest emitter of CO2 today, at around 40% of global energy-related CO2 emissions. Electricity demand almost triples over the period to 2070 in the Sustainable Development Scenario (equivalent to adding the Chinese grid every eight years), driven by economic growth, electrification of end uses and increased access to electricity in developing economies. The power sector is nonetheless among the fastest to decarbonise in the Sustainable Development Scenario, reaching net-zero emissions during the 2050s and removing emissions from the atmosphere on a net basis thereafter. Although there are a wide range of low-carbon alternatives available for power generation, CCUS is projected to play an important role for three key reasons:
1. CCUS can help to avoid the “lock-in” of emissions from the vast fleet of existing fossil-fuelled power plants through retrofits.
2. CCUS enables the sector to become net-negative though biomass-fuelled power plants with CCS (BECCS).
3. CCUS can help to meet the growing need for system flexibility as the share of variable renewable energy technologies in generation and the need for “dispatchable” capacity increases (IEA, 2020b).
Flexibility to deal with short-term and seasonal variability of electricity demand and supply is critical to ensure the stable and reliable operation of power systems. Coal and gas-fired power plants, which can adjust their power output on demand, have traditionally been the main sources of flexibility. Demand response (whereby consumers are encouraged to shift their consumption in response to price signals or other incentives), enhanced grid interconnections with neighbouring power systems, and energy storage are expected to play an increasingly important role in providing flexibility. Technological innovations in batteries and other forms of energy storage, some of them already commercially used today, may ultimately be able to meet the need for short-term flexibility without the need for fossil-fuel based generating plants (IEA, 2018). However, batteries may not be able to sufficiently replace dispatchable forms of generation in meeting seasonal variations in demand and output from variable renewables, which can be very pronounced in many regions. Alternatives to manage these seasonal variations, such as large-scale storage of hydrogen or ammonia, are at least today more expensive.
Coal- and gas-fired power plants with CCUS could provide system balancing services and flexibility over different time-scales, from ultra-short notice to seasonal variations. Retrofitting existing coal- and gas-fired power plants with carbon capture appears to have a small to negligible impact on their operational flexibility. In fact, it could increase short-term flexibility where the capture system and power block are able to operate independently, allowing the plant to boost power output by switching off the capture system to reduce the energy required to run it, although this would increase the CO2 emissions of the plant during those periods.
In the Sustainable Development Scenario, CCUS contributes some 15% of the cumulative emissions reduction of the power sector globally over the period to 2070. The amount of CO2 captured from fossil fuel power plants worldwide increases continuously over the projection horizon, reaching 220 Mt in 2030 and 4.0 Gt in 2070. Coal plants dominate in the period to 2040, mainly due to retrofits. After 2040, plants fuelled by gas and biomass play an increasing role. By 2070, a total of 1 100 GW of generating capacity is equipped with CCUS, producing around 6 000 TWh of electricity (or 8% of global power generation). At that time, all remaining coal- and gas-fired electricity generation and half of biomass-fired generation (all of which are dedicated BECCS plants) is associated with CCUS.
In the last phase from 2050 to 2070, the amount of CO2 captured jumps by 85%, as carbon removal and the use of CO2 accelerate. Around 45% of the growth during this period comes from BECCS and 15% from DAC, while capture from natural gas dominates the increase in CO2 capture from fossil fuels, driven by the production of hydrogen and electricity in regions with low-cost gas resources. In 2070, about 35% of all CO2 emissions captured are from bioenergy or DAC, most of which are stored, generating negative emissions to balance all remaining emissions from transport, industry and buildings so as to achieve a net-zero emissions energy system. Around one fifth of all the CO2 captured from bioenergy or directly from the air is used in combination with clean hydrogen to produce synthetic hydrocarbon fuels, notably for use in aviation, where synthetic fuels meet 40% of aviation fuel demand. The scale-up of carbon removal in the Sustainable Development Scenario implies an average of around 50 BECCS and 5 DACS plants of 1 Mt/year being added each year from 2020 to 2070. By 2070, 800 Mtoe (33 EJ), or more than a quarter of global primary bioenergy use, is linked to BECCS, with almost half of the bioenergy in the power and fuel transformation sectors being used in plants equipped with capture facilities. The deployment of these carbon removal technologies is constrained by their cost-competitiveness with other mitigation measures and (potentially) access to suitable storage, with BECCS also constrained by the availability of sustainable bioenergy and DAC by the availability of low-cost electricity and heat.
The Sustainable Development Scenario reaches net-zero emissions from the energy sector within five decades on the back of ambitious technological change and optimised innovation systems comparable to the fastest and most successful clean energy technology innovation success stories in history. The Faster Innovation Case explores the opportunity to accelerate this transition to bring the global energy system to net-zero emissions 20 years earlier, by 2050. This variant of the Sustainable Development Scenario considers a more rapid deployment of new technologies, and innovative techniques to enable additional carbon removal, for example by expanding sustainable biomass supply.
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