Prospects of renewable energy - a feasibility study in the Australian context

Given the recent increasing public focus on climate change issues, there is a need for robust, sustainable and climate friendly power transmission and distribution systems that are intelligent, reliable, and green. Current power systems create environmental impacts as well as contributing to global warming due to their utilization of fossil fuels, especially coal, as carbon dioxide is emitted into the atmosphere. In contrast to fossil fuels, renewable energy is starting to be used as the panacea for solving climate change or global warming problems. This paper describes a feasibility study undertaken to investigate the potentialities of renewable energy including the prospective locations in Australia for renewable energy generation, in particular solar and wind energy. Initially, a hybrid model has been developed to investigate the prospects of wind energy for typical Australian region considering production cost, cost of energy, emission production and contribution from renewable energy using the Hybrid Optimization Model for Electric Renewable (HOMER), a computer model developed by the USA’s National Renewable Energy Laboratory (NREL). This model also explores suitable places around Australia for wind energy generation using statistical analysis. Subsequently, the usefulness of solar energy in the Australian context and suitable locations for solar energy generation are also investigated using a similar hybrid model. Finally, the model has been developed to investigate the prospects of renewable energy in particular wind and solar energy including specific locations in Australia that would be suitable for both wind and solar energy generation. From simulation analysis it is clearly observed that Australia has enormous potentialities for substantially increased use of renewable energy; a large penetration of renewable energy sources into the national power system would reduce CO₂ emissions significantly, contributing to the reduction of global warming.     

我国清洁能源碳减排效益分析及发展顺序

发展低碳能源是应对全球气候变化、实现电力低碳化发展的有效途径,最终要以发电技术在具体工程项目中应用来实现,衡量各技术的经济可行性、评价可再生能源发电技术CO2的减排效益是关键。分析了当前我国主要5种低碳发电技术置换火电的碳减排成本及产生的碳减排效益,并对2020年低碳能源发电技术的碳减排潜力进行了测算。结果表明,水电发电成本及相应的碳减排成本最低,核电其次,光伏发电最高,应优先发展水电、大力开发核电,同时积极发展风电等其他低碳能源。     

Joint electricity and carbon market for Northeast Asia energy interconnection

Decarbonization of the electricity sector is crucial to mitigate the impacts of climate change and global warming over the coming decades. The key challenges for achieving this goal are carbon emission trading and electricity sector regulation, which are also the major components of the carbon and electricity markets, respectively. In this paper, a joint electricity and carbon market model is proposed to investigate the relationships between electricity price, carbon price, and electricity generation capacity, thereby identifying pathways toward a renewable energy transition under the transactional energy interconnection framework. The proposed model is a dynamically iterative optimization model consisting of upper- level and lower-level models. The upper-level model optimizes power generation and obtains the electricity price, which drives the lower-level model to update the carbon price and electricity generation capacity. The proposed model is verified using the Northeast Asia power grid. The results show that increasing carbon price will result in increased electricity price, along with further increases in renewable energy generation capacity in the following period. This increase in renewable energy generation will reduce reliance on carbon-emitting energy sources, and hence the carbon price will decline. Moreover, the interconnection among zones in the Northeast Asia power grid will enable reasonable allocation of zonal power generation. Carbon capture and storage (CCS) will be an effective technology to reduce the carbon emissions and further realize the emission reduction targets in 2030-2050. It eases the stress of realizing the energy transition because of the less urgency to install additional renewable energy capacity.     

中国燃煤发电节能技术的发展及前景

我国一次能源结构决定了发电以煤电为主的基本格局,当前国内火力发电行业需要解决的两大突出问题是高能耗和严重的环境污染。2009年全国发电机组平均供电煤耗341g/(kW.h),高于330g/(kW.h)的国际平均水平。大力发展新型高效节能性火力发电技术,对进一步提高我国火力发电机组的发电效率,减少燃煤大气污染物排放具有十分重要的意义。发达国家正积极发展更高参数的超超临界火力发电技术(600℃/700℃),我国也把"超(超)临界燃煤发电技术"列入"863计划"。可以预见,在我国近中期电力事业的发展中,会把发展更高参数的超临界技术作为火电建设的主要方向。IGCC发电技术是未来煤炭能源系统的基础,被公认为是世界上最清洁的燃煤发电技术。随着煤气化技术和燃气轮机技术的不断发展和进步,IGCC将朝着大容量、高效率、低排放的方向发展。大型直接空冷发电技术是解决我国西北部富煤贫水地区火力发电的有效手段,以2×600MW机组为例,空冷机组比湿冷机组节水约80%左右。通过对火力发电机组各系统的集成与优化,可在现有超超临界机组技术不变的情况下,最大限度地利用余热回收,提高整个机组的发电效率,从而降低煤耗,实现机组在运行过程中的节能。     

考虑低谷调峰限制和环境成本的发电容量规划

提出一种考虑低谷调峰限制的含可再生能源电力系统发电容量规划模型,该模型能确保通过运行调度最优发电容量组合满足规划年中每一天的低谷调峰限制,然后结合筛选曲线法和拉格朗日松弛法进行求解。而且,为了研究环境成本对发电容量规划和系统调峰性能的影响,在发电成本中增加CO₂排放成本。最后,算例分析验证所提方法的合理性和有效性,结果表明了在高渗透率可再生能源电力系统发电容量规划中综合考虑低谷调峰限制和环境成本的必要性。     

Climate change mitigation with integration of renewable energy resources in the electricity grid of New South Wales,Australia

The implementation of climate change mitigation strategies may significantly affect the current practices for electricity network operation. Increasing penetration of renewable energy generation technologies into electricity networks is one of the key mitigation strategies to achieve greenhouse gas emission reduction targets. Additional climate change mitigation strategies can also contribute to emission reduction thereby supplementing the renewable energy generation participation, which may be limited due to technical constraints of the network. In this paper, the penetration requirements for different renewable energy generation resources are assessed while concurrently examining other mitigation strategies to reduce overall emissions from electricity networks and meet requisite targets. The impacts of climate change mitigation strategies on the demand and generation mix are considered for facilitating the penetration of renewable generation. New climate change mitigation indices namely change in average demand, change in peak demand, generation flexibility and generation mix have been proposed to measure the level of emission reduction by incorporating different mitigation strategies. The marginal emissions associated with the individual generation technologies in the state of New South Wales (NSW) are modelled and the total emissions associated with the electricity grid of NSW are evaluated.     

Performance of wholesale electricity markets with high wind penetration

This paper examines the impact of progressively deeper levels of wind generation and/or abatement on the performance of a wholesale market and its incumbent thermal generators with non-convex unit commitment constraints. Comparison is made to the result that marginal cost pricing should induce investors to build the least-cost capacity mix, since it is not clear that this will hold in renewable-rich systems.It is first found that unit commitment and forecast uncertainty do not cause significant departure from this result when the generator fleet is optimal. ‘Optimality' in this sense is determined in a capacity expansion problem that does not feature unit commitment, and which allows thermal generators to be built or retired as greater renewable generation or abatement is mandated. In contrast, the wholesale market with no retirement of thermal generation experiences progressively greater disparity between total system prices and costs, and lower returns to generators, simply due to over-capacity rather than any form of variability-related market failure. A carbon price is observed to be far superior to a renewable portfolio standard when the existing set of thermal generators do not retire, but this difference is less stark when the generation mix is optimal. The implications of these results for market design and system planning are then discussed.     

Making carbon dioxide sequestration feasible: Toward federal regulation of CO2 sequestration pipelines

As the United States moves closer to a national climate change policy, it will have to focus on a variety of factors affecting the manner in which the country moves toward a future with a substantially lower carbon footprint. In addition to encouraging renewable energy, smart grid, clean fuels and other technologies, the United States will need to make substantial infrastructure investments in a variety of industries. Among the significant contributors to the current carbon footprint in the United States is the use of coal as a major fuel for the generation of electricity. One of the most important technologies that the United States can employ to reduce its carbon footprint is to sequester the carbon dioxide (“CO₂”) from coal-fired power plants. This article focuses on the legal and policy issues surrounding a critical piece of the necessary sequestration infrastructure: CO₂ pipelines that will carry CO₂ from where it is removed from fuel or waste gas streams to where it will be sequestered. Ultimately, this article recommends developing a federally regulated CO₂ pipeline program to foster the implementation of carbon sequestration technology.     

日本是否会放弃核能——日本能源政策走向分析

能源作为日本震后经济社会发展的中长期政策大纲《日本再生基本战略》的主要支柱之一,日本能源政策的走向尤为值得关注.从短期看,日本将加大核能监管,继续扩大核电制造出口,完全弃核是不可能的;从长期看,日本会逐步降低核能在能源结构中的比例.由于核电的关停,造成日本电力供应不足,进而导致对火力发电政策的支持力度增强,未来对化石能源的依赖局面仍将持续.同时,由于核能政策的调整,一方面使得节能及提高能源使用效率成为新的支柱,另一方面可再生能源将成为重要的发展方向.近10年来,日本可再生能源占能源结构的比例一直没什么变化,约为10％,这与日本政府支持核能战略的政策导向不无关系.日本当前发展可再生能源的主要障碍是缺乏政府的长期政策扶持,其次是开发难度大、发电成本高、系统稳定性低.日本目前需要解决的课题包括全量购买制度等相关政策的导入,大幅度降低成本和解决稳定性关键技术,有效解决可再生能源利用的地域化差异等.总的来看,日本新的能源政策基本是围绕减少对核电的依赖和应对全球气候变暖来制定的.     

Impact of a large penetration of wind generation on the GB gas network

Wind power is expected to be the major element of renewable electricity generation in Great Britain (GB) by 2020 with a capacity of around 30 GW. The potential impact of a large amount of wind generation on the GB gas network was investigated using a combined gas and electricity network model. The varying nature of gas and electric power flows, network support facilities such as gas storage and compressors, and the power ramping characteristics of various power plants were considered. Three case studies were modelled, one case uses the existing network and the other two make use of a hypothesised network in 2020 with two distinct levels of wind generation representing low and high wind periods. The simulation results show that a large penetration of wind generation will influence the electricity generation mix as the wind power varies. Gas-fired generation is used to compensate for wind variability. This will cause increased flows and compressor power consumption on the gas network. Linepack depletion during low wind periods was shown to limit the ability of the gas network to fully supply gas-fired generators.     

Multi-stage stochastic optimization framework for power generation system planning integrating hybrid uncertainty modelling

In this paper, a multi-stage stochastic optimization (MSO) method is proposed for determining the medium to long term power generation mix under uncertain energy demand, fuel prices (coal, natural gas and oil) and, capital cost of renewable energy technologies. The uncertainty of future demand and capital cost reduction is modelled by means of a scenario tree configuration, whereas the uncertainty of fuel prices is approached through Monte Carlo simulation. Global environmental concerns have rendered essential not only the satisfaction of the energy demand at the least cost but also the mitigation of the environmental impact of the power generation system. As such, renewable energy penetration, CO_2,eq mitigation targets, and fuel diversity are imposed through a set of constraints to align the power generation mix in accordance to the sustainability targets. The model is, then, applied to the Indonesian power generation system context and results are derived for three cases: Least Cost option, Policy Compliance option and Green Energy Policy option. The resulting optimum power generation mixes, discounted total cost, carbon emissions and renewable share are discussed for the planning horizon between 2016 and 2030.     

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.     

Short-term impact of green certificates and CO2 emissions trading in the Swedish district heating sector

Swedish district-heating (DH) systems use a wide range of energy sources and technologies for heat-and-power generation. This provides the DH utilities with major flexibility in changing their fuel and technology mix when the economic conditions for generation change. Two recently introduced policy instruments have changed the DH utilities’ costs for generation considerably; the tradable green-certificate (TGC) scheme introduced in 2003 in Sweden, and the tradable greenhouse-gas emission permit (TEP) scheme introduced in the EU on January 1, 2005. The objective of this study is to analyse how these two trading schemes impact on the operation of the Swedish DH sector in terms of changes in CHP generation, CO₂ emissions, and operating costs. The analysis was carried out by comparing the most cost-effective operation for the DH utilities, with and without, the two trading schemes applied, using a model that handles the Swedish DH-sector system-by-system. It was found that the volume of renewable power generated in CHP plants only increased slightly owing to the TGC scheme. The TGC and the TEP schemes in force together, however, nearly doubled the renewable power-generation. CO₂ emissions from the DH sector may either increase or decrease depending on the combination of TGC and TEP prices. The overall CO₂ emissions from the European power-generation sector would, however, be reduced for all price combinations assuming that increased Swedish CHP generation replaces coal-condensing power (coal-fired plants with power generation only) in other European countries. The trading schemes also lower the operational costs of the DH sector since the cost increase owing to the use of more expensive fuels and the purchase of TEPs is outweighed by the increased revenues from sales of electricity and TGCs.     

Model‐based approach for planning renewable energy transition in a resource‐constrained electricity system—A case study from India

Globally, electricity systems are going through transitions. The contributions from renewable energy‐based power generation, both in installed capacity and electricity generation, are moving from marginal to the mainstream. India is not an exception; it is aggressively pursuing this transition by fixing steep targets for renewable capacity additions. While the cost of renewable energy sources is expected to fast reach grid parity, the policy interventions play a critical role in ramping up the efforts to support the proposed investments in renewable capacity and renewable electricity generation. In this respect, this research attempts to analyze the effectiveness of renewable energy policies such as Renewable Purchase Obligation (RPO) and Renewable Energy Certificate mechanisms in tapping the renewable energy potential in India. We propose a mixed‐integer linear programming model‐based approach to evaluate the effectiveness of the above interventions in the Indian context. The model is developed and validated as a low carbon electricity planning tool to optimally meet the dynamic electricity demand and RPO targets as well as to manage the unmet total electricity demand and RPO targets. The Karnataka state electricity system (a state in south India) is chosen as a case study. The results suggest that Karnataka Electricity System is moving toward a sustainable renewable energy future even without any support from nonsolar Renewable Energy Certificate policy. However, policy interventions are critical for optimally utilizing the solar generation capacity.     

Does bulk electricity storage assist wind and solar in replacing dispatchable power production?

This paper discusses the impact of bulk electric storage on the production from dispatchable power plants for rising variable renewable electricity shares. Two complementary optimization frameworks are used to represent power systems with a varying degree of complexity. The corresponding models approximate the wholesale electricity market, combined with the rational retirement of dispatchable capacity. Two different generic storage technologies are introduced exogenously to assess their impact on the system.The analysis covers two countries: France, where the power supply's large nuclear share allows for the discussion of storage impact on a single generator type; and Germany, whose diverse power supply structure enables storage interactions with multiple electricity generators. In the most general case, additional storage capacity increases dispatchable power production (e.g. nuclear, coal) for small wind and solar shares, i.e. it compensates the replacement induced by renewable energies. For larger variable renewable electricity volumes, it actively contributes to dispatchable power replacement. In a diverse power system, this results in storage-induced sequential mutual replacements of power generation from different plant types, as wind and solar capacities are increased.This mechanism is strongly dependent on the technical parameters of the storage assets. As a result, the impact of different storage types can have opposite signs under certain circumstances. The influence of CO₂ emission prices, wind and solar profile shapes, and power plant ramping costs is discussed.     

中国中长期碳减排战略目标初探(Ⅱ)——中国煤炭消费过程的碳排放及减排措施

中国能源领域排放的二氧化碳主要来自煤炭,因此煤炭消费过程中的碳减排措施尤为重要。煤炭的主要用户是发电部门,基于应对气候变化的需要,煤电行业的低碳途径不得不考虑采用CCS技术。不论是新建燃煤电厂,还是今后在传统电厂改建过程中增设CCS设施已是大势所趋,预计多数仍将采用MEA法脱除烟气中二氧化碳这一成熟技术。由于MEA法技术经济指标不够先进,估计10~20年内必将出现更先进的脱二氧化碳工艺技术。传统的燃煤锅炉增加CCS的经济效益已经逊于IGCC-CCS,预计2020年后IGCC电厂将成为新建煤电厂的首选方案。20年后采用临氢气化炉与燃料电池FC发电相结合、把高温的热能和甲烷的化学能直接转化为电力的IGFC高效燃煤电厂或将成功应用,IGFC综合能量转化效率比IGCC相对高出1/2~3/4,发展前景不可低估。钢铁、水泥和化工等高耗煤工业部门可通过节能和采用CCS技术降低碳排放,其余用煤的工业部门和分散用户则应考虑节能或用天然气等低碳燃料替代,间接起到减排效果。预计2050年燃煤发电和高耗煤工业总计将排放二氧化碳4.6Gt,如果二氧化碳捕集量是2.9Gt,则净排放量为1.7Gt。加上其他难以捕集二氧化碳的工业、部门及民用煤排放二氧化碳1.0Gt,合计二氧化碳净排放量为2.7Gt(情景A)。如果采用更先进的技术和严格的节能减排措施,可减少煤炭消耗0.31Gt标煤,减少二氧化碳排放0.5Gt,使煤源二氧化碳净排放量减少到2.2Gt(情景B)。无论哪种情景,实施CCS的任务都十分艰巨。     

Preliminary exploration on low-carbon technology roadmap of China’s power sector

Climate change poses huge challenges to the sustainable development of human society. As a major CO₂ emission source, decarbonization of power sector is fundamental for CO₂ emission abatement. Therefore, considering the “carbon lock-in” effects, it’s critical to formulate an appropriate roadmap for low-carbon generation technologies. In this paper, key low-carbon technology solutions are firstly identified according to their developing prospects and the fundamental realities of China’s power sector. Then, costs, reduction effects and potentials for the key technology options are evaluated. On this basis, typical scenarios are selected and a scenario set is established which identifies and incorporates the key low carbon factors, and a multi-scenario analysis is implemented to China’s power sector based on a comprehensive power mix planning model. Then, contributions of CO₂ reduction among the key technology solutions are revealed. Prospect for CO₂ emission reduction is discussed, which informs the possible emission trajectories towards 2030. Finally, low-carbon technology roadmaps under specific scenarios are elaborated, which implies corresponding optimal evolution of power generation mix.     

A review on distributed generation impacts on electric power system

In 2021, the world's total installed capacity of generation units based on renewable energy sources (not including hydropower) amounted to about 1674 GW: over 825 GW and 849 GW of wind and solar power plants were installed respectively. The growing of the installed capacity of these distributed generators is a response to the increasing the power consumption, global environmental issues and has also become possible due to the development of technology in field of power semiconductor devices. However, on the way of large-scale implementation of distributed generators based on renewable energy sources, traditional electric power system meets new challenges to ensure the reliability and sustainability of new electric power systems with renewable energy sources. In particular, distributed generators change processes in the electric power system, impact to the parameters and power balance, change the magnitude and direction of power flow and short-circuit current, which determines the need to update the settings of the relay protection and automation systems of traditional electric power system and to coordinate their operation with automatic control systems of installed distributed generators. The above-mentioned tasks form a number of scientific research directions, one of which is a task of determining optimal size and location of distributed generators. The main purpose of this optimization task is to reduce power losses, operating and total electricity cost, improve the voltage profile, etc. In addition, the correct and reasonable placement of distributed generators defines an effective planning of the operating modes of electric power system and power plants (especially based on renewable energy sources, the operating modes of which depend on weather conditions and can be sharply variable).The paper highlighted the impacts of distributed generators on power losses, the voltage level, maintaining the power balance and the possibility of participating in the frequency regulation, and short-circuit current in power system. The optimization criteria, the main limiting conditions, as well as methods for solving this optimization problem are considered. This review will help the System operators and investing companies, especially in Russia, to form the main aim, objective function and constraints that will aid to meet their load demand at minimum cost and to choose from the options available for optimization of location and capacity of distributed generators.     

Using natural gas generation to improve power system efficiency in China

China's electricity sector faces the challenge of managing cost increases, improving reliability, and reducing its environmental footprint even as operating conditions become more complex due to increasing renewable penetration, growing peak demand, and falling system load factors. Addressing these challenges will require changes in how power generation is planned, priced, and dispatched in China. This is especially true for natural gas generation, which is likely to play an important role in power systems worldwide as a flexible generation resource. Although natural gas is commonly perceived to be economically uncompetitive with coal in China, these perceptions are based on analysis that fails to account for the different roles that natural gas generation plays in power systems—baseload, load following, and peaking generation. Our analysis shows that natural gas generation is already cost-effective for meeting peak demand in China, resulting in improved capacity factors and heat rates for coal-fired generators and lower system costs. We find that the largest barrier to using natural gas for peaking generation in China is generation pricing, which could be addressed through modest reforms to support low capacity factor generation.     

Power to the people

Even before September 11, the world's governments were beginning to look at energy policy in the light of new pressures. Fluctuating oil and gas prices had already brought energy security to the fore in some countries, and the declining nuclear industry is creating fear of a looming gap in electricity generation capacity on both sides of the Atlantic. Finally, the need to reduce greenhouse gas emissions has been highlighted again by the Third Assessment Report of the Inter-Governmental Panel on Climate Change. The United States response to these pressures has been to ignore the climate change issue and retreat into an old style predict and provide mentality to tackle energy security. It forecasts the need for up to 1900 new large scale power stations to meet its escalating demand for energy. But if climate change is taken seriously, as the rest of world's governments do, more innovative methods of delivering secure energy supplies, whilst cutting greenhouse gases, have to be found. Clearly renewable energy will be at the forefront of such a strategy, but the implications for energy policy go far deeper than just replacing one set of electricity generators with another. The whole policy framework will need an overhaul. Chris Hewett, Institute for Public Policy Research, UK looks at options for the road ahead and how decentralised energy systems can help deliver the sort of low carbon economy needed to prevent climate change.