美国可再生能源证书交易市场

可再生能源发电产业正由早期靠政府扶持逐步进入商业化阶段,其中以可再生能源配额制(RPS)和可再生能源证书(RECs)交易市场为典型。RECs分为捆绑式和非捆绑式两种形式,其主要商业应用模式包括:用来满足可再生能源RPS要求;批发捆绑式RECs;作为独立产品销售非捆绑式RECs;远期销售RECs;聚集小系统的RECs参与强制和自愿市场。RECs的价格是通过市场竞争来决定的,体现了可再生能源所具有的环境价值,在理想情况下,RECs的价格等于可再生能源和常规电力的边际成本之差。此外,RECs价格还受到很多其他因素的影响。RECs市场由自愿市场和强制市场组成,交易方式主要有3种:单一短期合同购买非捆绑式RECs;短期和长期合同混合购买非捆绑式和捆绑式RECs;在零售市场没有开发的情况下,美国公用事业主要依靠长期合同购买捆绑式电力。为了保证RECs交易的方便和非重复性销售,购买RECs需通过审计机构独立认证和核实。美国的许多思路和做法值得我国借鉴。     

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.     

Energy‐cost‐aware flow shop scheduling considering intermittent renewables,energy storage,and real‐time electricity pricing

The industrial sector is one of the major energy consumers that contribute to global climate change. Demand response programs and on‐site renewable energy provide great opportunities for the industrial sector to both go green and lower production costs. In this paper, a 2‐stage stochastic flow shop scheduling problem is proposed to minimize the total electricity purchase cost. The energy demand of the designed manufacturing system is met by on‐site renewables, energy storage, as well as the supply from the power grid. The volatile price, such as day‐ahead and real‐time pricing, applies to the portion supplied by the power grid. The first stage of the formulated model determines optimal job schedules and minimizes day‐ahead purchase commitment cost that considers forecasted renewable generation. The volatility of the real‐time electricity price and the variability of renewable generation are considered in the second stage of the model to compensate for errors of the forecasted renewable supply; the model will also minimize the total cost of real‐time electricity supplied by the real‐time pricing market and maximize the total profit of renewable fed into the grid. Case study results show that cost savings because of on‐site renewables are significant. Seasonal cost saving differences are also observed. The cost saving in summer is higher than that in winter with solar and wind supply in the system. Although the battery system also contributes to the cost saving, its effect is not as significant as the renewables.     

Distributed solar renewable generation: Option contracts with renewable energy credit uncertainty

Solar energy is rapidly emerging thanks to the decreasing installation cost of solar panels and the renewable portfolio standard imposed by state governments, which gave birth to the Renewable Energy Credit (REC) and the Alternative Compliance Payment (ACP). To make profits from the REC market in addition to reduced energy costs, more and more home and business owners choose to install solar panels. Recently, third-party financing has become a common practice in solar panel investments. We discuss optimal timing for the host to potentially buy back the solar panels after being installed for a period of time and how to incorporate the optimal timing into a power purchase agreement between the host and the third-party developer. Because the REC price is a major source of uncertainty and also due to the ACP capping the REC price, we first propose a REC price forecasting model that specifically considers the ACP values. Then by a modified real option structure, we model the buyback contract as a real option and solve it with an approximate dynamic program based Monte Carlo simulation method. We find that as the ACP value increases, the value of the buyback option also increases under optimal timing. The method used does not only apply to solar projects but also to other distributed renewable projects that are third-party financed, such as wind generations.     

碳价格水平提升条件下的可再生能源发电投资决策研究

鉴于提高碳价格对可再生能源发电投资具有双重影响,因此有必要研究碳价格提升条件下的发电投资决策。以风电和燃气发电为例,基于自由竞争发电市场下的竞价原理,构建碳价格提升条件下发电投资决策的非合作博弈模型,给出不同碳价格水平下各发电商容量投资的纳什均衡状态。结果表明,该模型能有效地量化碳价格的提升对可再生能源发电投资决策的影响,有助于政府制定合理的碳价格。     

Efficient pricing and investment in electricity markets with intermittent resources

Facing growing technological and environmental challenges, the electricity industry needs effective pricing mechanism to promote efficient risk management and investment decisions. In a restructured electricity market with competitive wholesale prices and traditionally regulated retail rates, however, there are technical and institutional barriers that prevent dynamic pricing with price responsive demand. In regions with limited energy storage capacity, intermittent renewable resources present special challenges. This could adversely affect the effectiveness of public policies causing inefficient investments in energy technologies. In this paper, we present an updated economic model of pricing and investment in restructured electricity market and use the model in a simulation study for an initial assessment of renewable energy strategy and alternative pricing mechanisms. A key objective of the study is to shed light on the policy issues so that effective decisions can be made to improve efficiency.     

A comprehensive method to find RPO trajectory and incentive scheme for promotion of renewable energy in India with study of impact of RPO on tariff

Renewable Purchase Obligation (RPO) regime in India started in 2011 with the announcement of benchmark RPO (BRPO) of states for the Financial Year (FY) 2011 by respective State Electricity Regulatory Commissions (SERC), to promote Renewable Energy (RE). The report submitted to Forum of Regulators (FoR) in this regard has recommended uniform rate of increase of BRPO of states and studied the impact of RPO on tariff for FY 2011–2015. However, more rigorous analysis is needed for fixing BRPO in a scientific manner and for fair allocation of incentives to promote RE. This paper attempts to evaluate all states on a common platform to find BRPO, giving due weightage to the state-wise energy demand and RE generation, ensuring minimum change in BRPO of consecutive years and hence less impact of RPO on tariff. To encourage the states to align their actual RPO with BRPO, a financial incentive scheme is proposed giving due weightage to RE consumption, RE capacity addition and RPO compliance of the states. The methods are illustrated for the Indian states using real system data. A study of RPO's impact on electricity tariff of Indian states is also conducted and reported for FY 2011–2015, considering Renewable Energy Certificate (REC).     

关于在电力市场环境下建立和促进可再生能源发电价格体系的研究

本文介绍了在开放的竞争性电力市场环境下,制定和实施特殊的上网电价政策来促进可再生能源发电发展的国际经验,总结归纳了政策制定的基本原则、方法和典型的价格体系,对各类价格政策的实施效果以及对我国的适用性进行了分析。提出在竞争性电力市场环境下,采用特殊的价格政策和机制,可以起到鼓励可再生能源发电市场发展和带动技术进步、产业升级的效果。我国应吸取国外的成功经验,根据我国可再生能源电价政策的实施情况,对政策予以适时调整,完善价格政策体系。     

Multi-objective optimal design of hybrid renewable energy systems using PSO-simulation based approach

Recently, the increasing energy demand has caused dramatic consumption of fossil fuels and unavoidable raising energy prices. Moreover, environmental effect of fossil fuel led to the need of using renewable energy (RE) to meet the rising energy demand. Unpredictability and the high cost of the renewable energy technologies are the main challenges of renewable energy usage. In this context, the integration of renewable energy sources to meet the energy demand of a given area is a promising scenario to overcome the RE challenges. In this study, a novel approach is proposed for optimal design of hybrid renewable energy systems (HRES) including various generators and storage devices. The ε-constraint method has been applied to minimize simultaneously the total cost of the system, unmet load, and fuel emission. A particle swarm optimization (PSO)-simulation based approach has been used to tackle the multi-objective optimization problem. The proposed approach has been tested on a case study of an HRES system that includes wind turbine, photovoltaic (PV) panels, diesel generator, batteries, fuel cell (FC), electrolyzer and hydrogen tank. Finally, a sensitivity analysis study is performed to study the sensibility of different parameters to the developed model.     

可再生能源绿证价格季节性测算方法研究

  目的  在市场化交易模式消纳可再生能源发电的发展趋势下,“市场电价+绿证收入”将成为未来可再生能源发电企业的主要经营模式。以可再生能源发电参与现货电能量市场为研究大背景,对可再生能源绿色电力证书的价格进行研究。  方法  基于现货电能量市场的优化出清模型,应用可再生能源全生命周期成本测算理论,以满足可再生能源发电企业的内部收益为目的,建立了绿证-电能量市场耦合的优化模型,并结合可再生能源季节性出力特性,提出了可再生能源绿证价格季节性曲线及其波动区间的仿真和测算方法。  结果  不同类型的可再生能源绿证价格不同,不同类型的可再生能源绿证价格的气候相关性亦不相同。  结论  绿证价格的科学合理测算不仅可以帮助可再生能源发电企业进行收益评估和制定更为准确的投资决策,还为电力市场主体与交易中心提供相关决策支持。     

Redefining RECs—Part 2: Untangling certificates and emission markets

Renewable energy and greenhouse gas emissions markets are currently in a state of confusion regarding the treatment of Renewable Energy Certificate (RECs). How should emission-trading schemes treat RECs? How can emission mitigation policies provide real incentives for renewable generation? The objective of REC markets should be to promote additional renewable energy investments. The author asserts that defining RECs in terms of attributes, especially off-site attributes, does not further this goal. Ambiguous language such as “environmental attribute” or “environmental benefit” creates confusion in the marketplace while failing to address the relevant coordination issues with Renewable Portfolio Standard compliance markets, voluntary emission offset markets, or emission cap-and-trade markets. Specifically, defining RECs in terms of off-site attributes creates a number of problems, including that once an emissions cap-and-trade scheme is in place, such definitions of a REC can become indefensible. The author proposes to redefine RECs in terms of on-site attributes, which resolves the aforementioned problems and allows compliance and voluntary renewable energy and emission markets to function without conflicts. Ideally, environmental commodities should be homogeneous, first best measures of the relevant environmental good, as well as easily measured and verified. The author proposes tradable environmental commodities that achieve these characteristics.     

Profit-based conventional resource scheduling with renewable energy penetration

Technological breakthroughs in renewable energy technologies (RETs) enabled them to attain grid parity thereby making them potential contenders for existing conventional resources. To examine the market participation of RETs, this paper formulates a scheduling problem accommodating energy market participation of wind- and solar-independent power producers (IPPs) treating both conventional and RETs as identical entities. Furthermore, constraints pertaining to penetration and curtailments of RETs are restructured. Additionally, an appropriate objective function for profit incurred by conventional resource IPPs through reserve market participation as a function of renewable energy curtailment is also proposed. The proposed concept is simulated with a test system comprising 10 conventional generation units in conjunction with solar photovoltaic (SPV) and wind energy generators (WEG). The simulation results indicate that renewable energy integration and its curtailment limits influence the market participation or scheduling strategies of conventional resources in both energy and reserve markets. Furthermore, load and reliability parameters are also affected.     

Medium term market perspectives,goal prices and competitiveness of renewable resources in the Italian energy system

Using a multiperiodal LP model (MARKAL) the authors assessed the likely potential of solar thermal and biogas systems under various circumstances. The study covered the period 1980–2005, in five segments of five years. It focused only on the subsystem of the energy end-uses which can be substituted for by solar and biogas technologies. In this paper we show the main results of the study regarding the competitiveness of the single solar and biogas technologies in different scenarios and their sensitivity to incentives and prices, together with the essential technical data regarding demand and supply technologies which produced those results. The analysis performed of the potential penetration of renewable technologies into the Italian energy system shows that their contribution will remain very marginal if the price of conventional energy carriers remains constant in constant money. However, the objective of removing with renewable technologies 1.5 per cent of the total Italian energy consumption appears to be realistic in the short-medium term.     

Market power in renewable portfolio standards

Renewable portfolio standard (RPS), which requires a certain percentage of electricity production from renewables, has received considerable attention. One emerging issue is the possibility of strategic behavior in the renewable energy certificate/credit (REC) market, and its spillover effects on the electricity market. This paper develops dominant firm-competitive fringe models that account for market power. We show that market power could have significant impacts on the REC and power prices. In particular, when a nonrenewable generator is a dominant firm and a renewable generator is a competitive fringe, the nonrenewable firm has a strong incentive to lower the REC price, even to zero for avoiding REC costs. The zero REC price would negate price impacts in the power market, thereby mitigating market power of the dominant firm. However, this could lead to an underinvestment in renewables in the long run as subsidies received by renewables in form of RECs vanish. Therefore, regulatory agencies need to carefully oversee the market performance to ensure a healthy development of renewable industries under the RPS policies.     

Additionality of wind energy investments in the U.S. voluntary green power market

In the United States, electricity consumers are told that they can “buy” electricity from renewable energy projects, versus fossil fuel-fired facilities, through participation in voluntary green power markets. The marketing messages communicate to consumers that they are causing additional renewable energy generation and reducing emissions through their participation and premium payments for a green label. Using a spatial financial model and a database of registered Green-e wind power facilities, the analysis in this paper shows that the voluntary Renewable Energy Certificate (REC) market has a negligible influence on the economic feasibility of these facilities. Nevertheless, voluntary green power marketers at least implicitly claim that buying their products creates additional renewable energy. This study indicates the contrary. Participants in U.S. voluntary green power markets associated with wind power, therefore, appear to be receiving misleading marketing messages regarding the effect of their participation. In the process of completing this analysis, a potentially relevant factor in explaining investor behavior was identified: the potential for the overlap of voluntary REC markets with compliance REC markets that supply utilities need to meet their obligations of Renewable Energy Portfolio Standard (RPS). The majority of state RPS rules allow for regional or even national sourcing of RECs, meaning that projects are generally eligible to provide compliance RECs to utilities not only in their home states, but in several other states.     

A new thinking for renewable energy model: Remote sensing‐based renewable energy model

This paper mainly focuses on the two issues through remote sensing: assessment of the renewable energy potential and integration of the renewable energy model. Three methods for assessing the renewable energy potential with remote sensing (RS) are proposed. The methods can provide more precise evaluation of renewable energy potential, which is the first vital step to develop renewable energy model. The paper then first presents three integrations of the renewable energy model with RS and points out that with respect to the problems one of them is employed. The assessment methods based on RS and the integrations with RS are illustrated by a simple example with Europe solar energy data set. The results show that Germany is the optimal country to install photovoltaic with a capacity of 137 125 GW. Copyright © 2009 John Wiley & Sons, Ltd.     

Fruitful symbiosis: Why an export bundled with wind energy is the most feasible option for North African concentrated solar power

The idea of generating electricity in North Africa using concentrating solar thermal power (CSP) has been around for some time now but has recently gained momentum through the Mediterranean Solar Plan (MSP) and the formation of the Desertec Industrial Initiative. This paper argues that while the large-scale deployment of CSP in North Africa does not seem economically attractive for either European or African institutions or countries on their own at present, combining domestic use and electricity exports could be profitable for both parties. A detailed economic portfolio covering both solar and wind power plants can achieve competitive price levels, which would accelerate the diffusion of solar technology in North Africa. This portfolio could be financed partially by exporting electricity from solar thermal plants in North Africa via HVDC interconnections to European consumers. Sharing the costs in this way makes it possible to generate solar electricity for the domestic market at a reasonable cost. Some of the electricity produced from the solar power plants and wind parks in North Africa is sold on European energy markets in the form of a long-term contracted solar–wind portfolio, which would qualify for support from the financial incentive schemes of the European Member States (e.g. feed-in tariffs). This transfer of green electricity could help to meet the targets for energy from renewable energy sources (RES) in the EU Member States as the new EU Directive of 2009 opened the European electricity market to imports from third states.     

Energy security in Group of Seven (G7): a quantitative approach for renewable energy policy

This study examined the renewable energies and their impact on the economies of the Group of Seven (G7) countries. Results showed that the electricity produced from wind energy in the United States and then Germany is more than any other member countries. Due to its voluminous volcanoes, Italy has had favorable conditions for the development of geothermal energy, which has led it to be used as an efficient energy source in Italy. Results also showed that the installed capacity of geothermal systems is the lowest and hydropower systems are the highest in all G7 countries. It also concluded that, despite the high share of hydropower energy from total renewable energy capacity, the use of wind and solar energies is rapidly rising. As a result, it found that the development of solar energy occurs faster than the other renewable energies.     

Levelized cost of electricity (LCOE) of renewable energies and required subsidies in China

The development and utilization of renewable energy (RE), a strategic choice for energy structural adjustment, is an important measure of carbon emissions reduction in China. High cost is a main restriction element for large-scale development of RE, and accurate cost estimation of renewable power generation is urgently necessary. This is the first systemic study on the levelized cost of electricity (LCOE) of RE in China. Results indicate that feed-in-tariff (FIT) of RE should be improved and dynamically adjusted based on the LCOE to provide a better support of the development of RE. The current FIT in China can only cover the LCOE of wind (onshore) and solar photovoltaic energy (PV) at a discount rate of 5%. Subsidies to renewables-based electricity generation, except biomass energy, still need to be increased at higher discount rates. Main conclusions are drawn as follows: (1) Government policy should focus on solving the financing problem of RE projects because fixed capital investment exerts considerable influence over the LCOE; and (2) the problem of high cost could be solved by providing subsidies in the short term and more importantly, by reforming electricity price in the mid-and long-term to make the RE competitive.     

欧盟可再生能源发展的新政策及对我国的启示

欧洲的可再生能源发展取得了很大的成就,并建立了有效的支持可再生能源发展的政策体系和框架,是世界可再生能源发展的领先者.文章介绍了欧盟在2007年1月提出的可再生能源发展的新的政策目标以及近期采取的新行动,并提出借鉴欧洲经验,支持我国可再生能源发展的行动建议.