The impact of uncertainties on the UK's medium-term climate change targets

The UK is committed to ambitious medium- and long-term climate change targets, including a commitment to an 80% reduction in emissions from 1990 levels by 2050. Whilst emissions have fallen significantly since 1990, further reductions will be increasingly difficult to achieve. The government has agreed carbon budgets to the late 2020s that are consistent with the long-term 80% target. However, increasing energy prices since the mid-2000s and the 2008 financial crisis have led to cracks in the political consensus in support of these budgets and targets.This paper carries out an assessment of the feasibility of the UK's agreed low carbon pathway over the medium term, with a particular focus on the fourth carbon budget (2023–27). It analyses the uncertainties associated with the specific changes that may be necessary to comply with this carbon budget – including measures to decarbonise electricity, heat and transport. This analysis focuses on ‘instrumental’ uncertainties associated with specific areas of the energy system (e.g. the decarbonisation of heat in households) and ‘systemic’ uncertainties that tend to have more pervasive implications for the energy system as a whole (e.g. uncertainties associated with public attitudes). A framework is developed that sets out and analyses the key uncertainties under those two broad categories, in terms of their complexity and their potential impact on the fourth carbon budget. Through the application of this framework the paper also considers strategies to mitigate or manage these uncertainties, and which actors could help develop and implement these strategies.     

Heat Roadmap Europe: Combining district heating with heat savings to decarbonise the EU energy system

Six different strategies have recently been proposed for the European Union (EU) energy system in the European Commission's report, Energy Roadmap 2050. The objective for these strategies is to identify how the EU can reach its target of an 80% reduction in annual greenhouse gas emissions in 2050 compared to 1990 levels. None of these scenarios involve the large-scale implementation of district heating, but instead they focus on the electrification of the heating sector (primarily using heat pumps) and/or the large-scale implementation of electricity and heat savings. In this paper, the potential for district heating in the EU between now and 2050 is identified, based on extensive and detailed mapping of the EU heat demand and various supply options. Subsequently, a new ‘district heating plus heat savings’ scenario is technically and economically assessed from an energy systems perspective. The results indicate that with district heating, the EU energy system will be able to achieve the same reductions in primary energy supply and carbon dioxide emissions as the existing alternatives proposed. However, with district heating these goals can be achieved at a lower cost, with heating and cooling costs reduced by approximately 15%.     

Emissions reduction scenarios in the Argentinean Energy Sector

In this paper the LEAP, TIAM-ECN, and GCAM models were applied to evaluate the impact of a variety of climate change control policies (including carbon pricing and emission constraints relative to a base year) on primary energy consumption, final energy consumption, electricity sector development, and CO₂ emission savings of the energy sector in Argentina over the 2010–2050 period. The LEAP model results indicate that if Argentina fully implements the most feasible mitigation measures currently under consideration by official bodies and key academic institutions on energy supply and demand, such as the ProBiomass program, a cumulative incremental economic cost of 22.8 billion US$(2005) to 2050 is expected, resulting in a 16% reduction in GHG emissions compared to a business-as-usual scenario. These measures also bring economic co-benefits, such as a reduction of energy imports improving the balance of trade. A Low CO₂ price scenario in LEAP results in the replacement of coal by nuclear and wind energy in electricity expansion. A High CO₂ price leverages additional investments in hydropower. By way of cross-model comparison with the TIAM-ECN and GCAM global integrated assessment models, significant variation in projected emissions reductions in the carbon price scenarios was observed, which illustrates the inherent uncertainties associated with such long-term projections. These models predict approximately 37% and 94% reductions under the High CO₂ price scenario, respectively. By comparison, the LEAP model, using an approach based on the assessment of a limited set of mitigation options, predicts an 11.3% reduction. The main reasons for this difference include varying assumptions about technology cost and availability, CO₂ storage capacity, and the ability to import bioenergy. An emission cap scenario (2050 emissions 20% lower than 2010 emissions) is feasible by including such measures as CCS and Bio CCS, but at a significant cost. In terms of technology pathways, the models agree that fossil fuels, in particular natural gas, will remain an important part of the electricity mix in the core baseline scenario. According to the models there is agreement that the introduction of a carbon price will lead to a decline in absolute and relative shares of aggregate fossil fuel generation. However, predictions vary as to the extent to which coal, nuclear and renewable energy play a role.     

Long-term CO2 emissions reduction target and scenarios of power sector in Taiwan

This study analyses a series of carbon dioxide (CO₂) emissions abatement scenarios of the power sector in Taiwan according to the Sustainable Energy Policy Guidelines, which was released by Executive Yuan in June 2008. The MARKAL-MACRO energy model was adopted to evaluate economic impacts and optimal energy deployment for CO₂ emissions reduction scenarios. This study includes analyses of life extension of nuclear power plant, the construction of new nuclear power units, commercialized timing of fossil fuel power plants with CO₂ capture and storage (CCS) technology and two alternative flexible trajectories of CO₂ emissions constraints. The CO₂ emissions reduction target in reference reduction scenario is back to 70% of 2000 levels in 2050. The two alternative flexible scenarios, Rt4 and Rt5, are back to 70% of 2005 and 80% of 2005 levels in 2050. The results show that nuclear power plants and CCS technology will further lower the marginal cost of CO₂ emissions reduction. Gross domestic product (GDP) loss rate in reference reduction scenario is 16.9% in 2050, but 8.9% and 6.4% in Rt4 and Rt5, respectively. This study shows the economic impacts in achieving Taiwan's CO₂ emissions mitigation targets and reveals feasible CO₂ emissions reduction strategies for the power sector.     

Exploring the competitiveness of hydrogen-fueled gas turbines in future energy systems

Hydrogen is currently receiving attention as a possible cross-sectoral energy carrier with the potential to enable emission reductions in several sectors, including hard-to-abate sectors. In this work, a techno-economic optimization model is used to evaluate the competitiveness of time-shifting of electricity generation using electrolyzers, hydrogen storage and gas turbines fueled with hydrogen as part of the transition from the current electricity system to future electricity systems in Years 2030, 2040 and 2050. The model incorporates an emissions cap to ensure a gradual decline in carbon dioxide (CO₂) levels, targeting near-zero CO₂ emissions by Year 2050, and this includes 15 European countries.The results show that hydrogen gas turbines have an important role to play in shifting electricity generation and providing capacity when carbon emissions are constrained to very low levels in Year 2050. The level of competitiveness is, however, considerably lower in energy systems that still allow significant levels of CO₂ emissions, e.g., in Year 2030. For Years 2040 and 2050, the results indicate investments mainly in gas turbines that are partly fueled with hydrogen, with 30–77 vol.-% hydrogen in biogas, although some investments in exclusively hydrogen-fueled gas turbines are also envisioned. Both open cycle and combined cycle gas turbines (CCGT) receive investments, and the operational patterns show that also CCGTs have a frequent cyclical operation, whereby most of the start-stop cycles are less than 20 h in duration.     

低碳发展时代的世界与中国能源格局

哥本哈根会议认定了"2℃"和"在2050年前全球排放量减到1990年的一半",到2050年,碳减排要求世界人均能耗不高于2.5t标煤/a。能源碳强度ω是一个反映碳排放与能源结构关系的新指标,利用它与一次能源消费中生成并排放二氧化碳的各种形式能源所占比率γ的关联式ω=2.4γ进行推算:按照450情景方案,二氧化碳排放峰值307×108t出现在2020年,而能耗峰值在2030年左右;按照丹麦方案,二氧化碳排放峰值320×108t出现在2025年,能耗峰值也大约在2030年,将达到273×108t标煤/a,人均3.3t标煤/a。碳排放峰值年越推迟,达到2050年远期目标的难度越大。按照丹麦方案,2030~2050年的20年间,需平均每年减排10×108t二氧化碳,同时与450情景方案相比,大气中二氧化碳总量将增加400×108t以上。根据中国政府宣布的2010~2020年的减排目标推算,2020年能耗为41×108t标煤,二氧化碳排放约74×108t,中国只要能做到能耗强度每5年降低20%,就能够实现此目标。中国应在2020年之前快速发展非化石能源、加速产业转型、大力发展天然气、大幅提高能效,这样就完全能够与世界减排同行。     

Interactions and implications of renewable and climate change policy on UK energy scenarios

As a response to the twin challenges of climate change mitigation and energy security, the UK government has set a groundbreaking target of reducing the UK’s economy-wide carbon emissions by 80% from 1990 levels by 2050. A second key UK energy policy is to increase the share of final energy consumption from renewables sources to 15% by 2020, as part of the wider EU Renewable Directive. The UK’s principle mechanisms to meet this renewable target are the Renewable Obligation (RO) in the electricity sector, the Renewable Transport Fuel Obligation (RTFO), and most recently the Renewable Heat Programme (RHP) for buildings. This study quantifies a range of policies, energy pathways, and sectoral trade-offs when combining mid- and long-term UK renewables and CO₂ reduction policies. Stringent renewable policies are the binding constraints through 2020. Furthermore, the interactions between RO, RTFO, and RHP policies drive trade-offs between low carbon electricity, bio-fuels, high efficiency natural gas, and demand reductions as well as resulting 2020 welfare costs. In the longer term, CO₂ reduction constraints drive the costs and characteristics of the UK energy system through 2050.     

The greenhouse gas regional inventory project (GRIP): Designing and employing a regional greenhouse gas measurement tool for stakeholder use

Regional and local policy-making on carbon reduction requires user-friendly greenhouse gas inventory and quantitative scenario tools. We present one such tool – the Greenhouse Gas Regional Inventory Project (GRIP) – and discuss stakeholder reaction to this interactive computer-based approach. We then provide results on a set of 38 stakeholder-led interviews that were undertaken using GRIP to explore prospects for achieving deep cuts (−60%) in CO₂ emissions by 2050 in the North West region of England. Seventeen energy stakeholders, despite being engaged in a professional capacity with the climate change and carbon reduction issues, struggled to find ways to reduce emissions by as much as 60% by 2050. This should worry policy makers in central government who consider that local and regional implementation of energy policy will be straightforward. Our findings, we argue, support a greater role for energy policy making at the sub-national regional scale in England.     

中国中长期碳减排战略目标初探(Ⅰ)——中国分阶段温室气体减排目标的提出及其依据

减少温室气体排放已刻不容缓,一系列研究显示,温升2℃是人类生活不受气候变化干扰的上限,大致550μL/L二氧化碳当量的温室气体浓度或约450～500μL/L的二氧化碳浓度对应2℃的温升。达到稳定浓度时的2005年以后的累积排放量和2005年的排碳数据一起才可以计算出最终的减排量化指标,而拐点年代和逐年排放量是可调控的动态指标。核实本世纪上半叶的累积排放量,并将排放额度分解到各个国家和地区是一项十分艰巨且很迫切的任务。我国的碳减排可分为2005～2020年的前期、2021～2035年的中期和2036～2050年的后期。权威部门曾推算了一系列数据,但与当前掌握的实际数据对比,对2010年的碳排放预测数据均偏低。有学者提出我国2005～2050年间的排碳额度为370Gt,约为全世界的28%,比例基本合理。如果2050年二氧化碳排放总量确定为140×108t,则中国为40×108t,人均2.6t,形势非常严峻。把我国2020年二氧化碳排放量控制在100×108t以内十分必要;我国碳减排中期处于拐点过渡期,我国的拐点将直接影响世界的拐点,应争取拐点出现在2025年,过渡期为2020～2030年;我国2050年与2035年的二氧化碳排放量差值应为45×108t,只要依靠非化石能源替代化石能源、采用CCS技术、最大限度地采用零碳排放甚至负碳排放的替代燃料就能得到控制,但仍然存在许多不确定因素,有待深入研究。     

The challenge of meeting Canada’s greenhouse gas reduction targets

In 2007, the Government of Canada announced its medium- and long-term greenhouse gas (GHG) emissions reduction plan entitled Turning the Corner, proposed emission cuts of 20% below 2006 levels by 2020 and 60–70% below 2006 levels by 2050. A report from a Canadian government advisory organization, the National Round Table on Environment and Economy (NRTEE), Achieving 2050: A carbon pricing policy for Canada, recommended “fast and deep” energy pathways to emissions reduction through large-scale electrification of Canada’s economy by relying on a major expansion of hydroelectricity, adoption of carbon capture and storage for coal and natural gas, and increasing the use of nuclear.     

Hybrid modelling of long-term carbon reduction scenarios for the UK

This paper summarizes the development of a new hybrid MARKAL–Macro (M–M) energy system model for the UK. This hybrid model maintains the technological and sectoral detail of a bottom-up optimisation approach with aggregated energy demand endogeneity and GDP impacts from a single sector neoclassical growth model. The UK M–M model was developed for underpinning analysis of the UK's groundbreaking mandatory long-term − 60% carbon dioxide (CO₂) emissions reduction target. Hybrid modelling illustrates that long-term UK CO₂ emission reductions are feasible. However, there are endemic uncertainties, notably a trade-off between behavioural and technological decarbonisation options with resultant energy system impacts in the requirements for zero-carbon electricity. UK M–M model sensitivity runs further illustrate the range of energy system interactions including the deployment of the UK's limited CO₂ storage capacity, alternate timing of power vs. transport sectoral reductions, the relative ease of switching between electricity generation portfolios, and substitution opportunities between natural gas and coal. The macro-economic cost impacts range from 0.3% to 1.5% reduction in UK GDP by 2050, with higher cost estimates strongly influenced by pessimistic assessments of future low-carbon technologies. However cost impacts from the UK M–M model are likely to be in the lower range for stringent CO₂ reduction pathways as the simplicity of the reduced form macro-linkage omits competitiveness and transitional impacts on the UK economy.     

Societal penetration of hydrogen into the future energy system: Impacts of policy,technology and carbon targets

Decarbonization of the energy system is a key goal of the Paris Agreements, in order to limit temperature rises to under 2° Celsius. Hydrogen has the potential to play a key role through its versatile production methods, end uses and as a storage medium for renewable energy, engendering the future low-carbon energy system. This research uses a global model cognizant of energy policy, technology learning curves and international carbon reduction targets to optimize the future energy system in terms of cost and carbon emissions to the year 2050. Exploring combinations of four exploratory scenarios incorporating hydrogen city gas blend levels, nuclear restrictions, regional emission reduction obligations and carbon capture and storage deployment timelines, it was identified that hydrogen has the potential to supply approximately two percent of global energy needs by 2050. Irrespective of the quantity of hydrogen produced, the transport sector and passenger fuel cell vehicles are consistently a preferential end use for future hydrogen across regions and modeled scenarios. In addition to the potential contribution of hydrogen, a shift toward renewable energy and a significant role for carbon capture and storage is identified to underpin carbon target achievement by 2050.     

Electricity consumption and CO2 capture potential in Spain

In this paper, different electricity demand scenarios for Spain are presented. Population, income per capita, energy intensity and the contribution of electricity to the total energy demand have been taken into account in the calculations. Technological role of different generation technologies, i.e. coal, nuclear, renewable, combined cycle (CC), combined heat and power (CHP) and carbon capture and storage (CCS), are examined in the form of scenarios up to 2050. Nine future scenarios corresponding to three electrical demands and three options for new capacity: minimum cost of electricity, minimum CO₂ emissions and a criterion with a compromise between CO₂ and cost (CO₂-cost criterion) have been proposed. Calculations show reduction in CO₂ emissions from 2020 to 2030, reaching a maximum CO₂ emission reduction of 90% in 2050 in an efficiency scenario with CCS and renewables. The contribution of CCS from 2030 is important with percentage values of electricity production around 22–28% in 2050. The cost of electricity (COE) increases up to 25% in 2030, and then this value remains approximately constant or decreases slightly.     

Carbon capture and storage potential in coal-fired plant in Malaysia—A review

Secure, reliable and affordable energy supplies are necessary for sustainable economic growth, but increases in associated carbon dioxide (CO₂) emissions, and the associated risk of climate change are a cause of major concern. Experts have projected that the CO₂ emissions related to the energy sector will increase 130% by 2050 in the absence of new policies or supply constraints as a result of increased fossil fuel usage. To address this issue will require an energy technology revolution involving greater energy efficiency, increased renewable energies and nuclear power, and the near-decarbonisation of fossil fuel-based power generation. Nonetheless, fossil fuel usage is expected to continue to dominate global energy supply. The only technology available to mitigate greenhouse gas (GHG) emissions from large-scale fossil fuel usage is carbon capture and storage (CCS), an essential part of the portfolio of technologies that is needed to achieve deep global emission reductions. However, CCS technology faces numerous issues and challenges before it can be successfully deployed. With Malaysia has recently pledged a 40% carbon reduction by 2020 in the Copenhagen 2009 Climate Summit, CCS technology is seen as a viable option in order to achieve its target. Thus, this paper studies the potential and feasibility of coal-fired power plant with CCS technology in Malaysia which includes the choices of coal plants and types of capture technologies possible for implementation.     

The Tyndall decarbonisation scenarios—Part II: Scenarios for a 60% CO2 reduction in the UK

This paper describes the Tyndall decarbonisation scenarios, the first to take account of CO₂ emissions from the whole of the UK's energy system, including emissions from international shipping and aviation. It builds on Part I, which outlined the backcasting methodology developed to generate the scenarios. The five scenarios produced through this process articulate alternative vision of a substantially decarbonised society in 2050, ranging from a halving of energy consumption from current levels to a near doubling. This work demonstrates that a 60% reduction in the UK's CO₂ emissions is achievable, even when all CO₂ sources are taken into account. The impacts and consequences of the scenarios were assessed by means of a multi-criteria framework which cautions us that the high energy demand scenarios will have a large impact on broader sustainability criteria.     

How to support growth with less energy

Economic growth with less use of primary energy and lower carbon emissions can be achieved through existing and new technical solutions and by behavioural change. These solutions secure growth with lower carbon emissions and reduce our dependence on oil and gas, thereby improving security of energy supply. The implication of the Energy White Paper goal of reducing CO₂ emissions by 60% by 2050 is a six-fold reduction in the carbon intensity of the UK economy, and further reductions will be needed. Efficient and renewable supply, distribution and end-use technologies have multiplicative effects, but constraining demand growth is crucial to the rate and extent of reducing emissions. Goals include reductions in the energy intensity of transport and buildings and in the energy intensity of major building materials with the development of technologies and demand management. There will also need to be infrastructural developments that encourage low-carbon technologies and increase energy diversity and security of supply, better low-carbon planning and improved co-ordination of planning, building control and other policy tools, better monitoring and feedback on the real performance of energy-efficient technologies, and improved capabilities to model whole energy systems, including demand and supply as well as social and economic issues.     

Recognizing the role of uncertainties in the transition to renewable hydrogen

Achieving the goal of net zero emissions targeted by many governments and businesses around the world will require an economical zero-emissions fuel, such as hydrogen. Currently, the high production cost of zero emission ‘renewable’ hydrogen, produced from electrolysis powered by renewable electricity, is hindering its adoption. In this paper, we examine the role of uncertainties in projections of techno-economic factors on the transition from hydrogen produced from fossil fuels to renewable hydrogen. We propose an integrated framework, linking techno-economic and Monte-Carlo based uncertainty analysis with quantitative hydrogen supply-demand modelling, to examine hydrogen production by different technologies, and the associated greenhouse gas (GHG) emissions from both the feedstock supply and the production process. The results show that the uncertainty around the cost of electrolyser systems, the capacity factor, and the gas price are the most critical factors affecting the timing of the transition to renewable H₂. We find that hydrogen production will likely be dominated by fossil fuels for the next few decades if the cost of carbon emissions are not accounted for, resulting in cumulative emissions from hydrogen production of 650 Mt CO₂-e by 2050. However, implementing a price on carbon emissions can significantly expedite the transition to renewable hydrogen and cut the cumulative emissions significantly.     

Co-benefits of CO2 emission reduction in a developing country

In this paper, we examine the co-benefits of reducing CO₂ emissions in Thailand during 2005–2050 in terms of local pollutant emissions as well as the role of renewable-, biomass- and nuclear-energy. It also examines the implications of CO₂ emission reduction policy on energy security of the country. The analyses are based on a long term energy system model of Thailand using the MARKAL framework. The study shows that the power sector would account for the largest share (over 60%) in total CO₂ emission reduction followed by the industrial and transport sectors. Under the CO₂ emission reduction target of 30%, there would be a reduction in SO₂ emission by 43% from the base case level. With the CO₂ emission reduction target of 10–30%, the cumulative net energy imports in the country during 2005–2050 would be reduced in the range of over 16 thousand PJ to 26 thousand PJ from the base case emission level. Under the CO₂ emission reduction targets, the primary energy supply system would be diversified towards lower use of coal and higher use of natural gas, biomass and nuclear fuels.     

Role of natural gas in meeting an electric sector emissions reduction strategy and effects on greenhouse gas emissions

With advances in natural gas extraction technologies, there is an increase in the availability of domestic natural gas, and natural gas is gaining a larger share of use as a fuel in electricity production. At the power plant, natural gas is a cleaner burning fuel than coal, but uncertainties exist in the amount of methane leakage occurring upstream in the extraction and production of natural gas. At higher leakage levels, the additional methane emissions could offset the carbon dioxide emissions reduction benefit of switching from coal to natural gas. This analysis uses the MARKAL linear optimization model to compare the carbon emissions profiles and system-wide global warming potential of the U.S. energy system over a series of model runs in which the power sector is required to meet a specific carbon dioxide reduction target across a number of scenarios in which the availability of natural gas changes. Scenarios are run with carbon dioxide emissions and a range of upstream methane emission leakage rates from natural gas production along with upstream methane and carbon dioxide emissions associated with production of coal and oil. While the system carbon dioxide emissions are reduced in most scenarios, total carbon dioxide equivalent emissions show an increase in scenarios in which natural gas prices remain low and, simultaneously, methane emissions from natural gas production are higher.     

Decarbonizing Europe's power sector by 2050 — Analyzing the economic implications of alternative decarbonization pathways

The European Union aims to reduce greenhouse gas emissions by 80–95% in 2050 compared to 1990 levels. The transition towards a low-carbon economy implies the almost complete decarbonization of Europe's power sector, which could be achieved along various pathways. In this paper, we evaluate the economic implications of alternative energy policies for Europe's power sector by applying a linear dynamic electricity system optimization model in over 36 scenarios. We find that the costs of decarbonizing Europe's power sector by 2050 vary between 139 and 633 bn €₂₀₁₀, which corresponds to an increase of between 11% and 44% compared to the total system costs when no CO₂ reduction targets are implemented. In line with economic theory, the decarbonization of Europe's power sector is achieved at minimal costs under a stand-alone CO₂ reduction target, which ensures competition between all low-carbon technologies. If, however, renewable energies are exempted from competition via supplementary renewable energy (RES-E) targets or if investments in new nuclear and CCS power plants are politically restricted, the costs of decarbonization significantly rise. Moreover, we find that the excess costs of supplementary RES-E targets depend on the acceptance of alternative low carbon technologies. For example, given a complete nuclear phase-out in Europe by 2050 and politically implemented restrictions on the application of CCS to conventional power plants, supplementary RES-E targets are redundant. While in such a scenario the overall costs of decarbonization are comparatively high, the excess costs of supplementary RES-E targets are close to zero.