燃煤电站购电协议（PPA）两部制电价设计规则解析

购电协议(PPA)是电站类项目以项目融资形式筹建的关键协议文本。以印尼电力市场通行的购电协议为例,着重分析其核心条款电价定价的设计机制,阐述两部制电价的计算方法和影响因素,帮助深入理解"照付不议"的定价原则。     

Dynamics of risk management tools and auctions in the second phase of the Brazilian Electricity Market reform

In 2004, the reform of the Brazilian Electricity Market underwent a thorough revision. One of its causes was the electricity rationing that began in June 2001 and lasted until February 2002. Among other measures, the 2004 revision devised new mechanisms intended to reduce risks associated to contracts settled in electricity auctions and those related to investments in new generation plants. As 4 years have passed since the onset of the reform's revision, sufficiently enough data are now available for an analysis of the post-revision dynamics of the Brazilian Electricity Market. This is the purpose of the present paper. We focus on the dynamics of the different types of electricity auctions and on the so-called Mechanism for Compensation of Surpluses and Deficits, both created in the wake of the 2004 revision. The ultimate goal is to understand the behavior of the agents involved in auctions – notably buyers and sellers of electricity – and propose remedial actions to eliminate existing loopholes in the present regulatory framework. To achieve this goal, four steps were necessary. Firstly, a data base to support the analysis was built. Then, the main drivers of the dynamics of the risk management tools were identified. Finally, consequences of the implemented changes were discussed and corrections for observed pitfalls proposed.     

Evolution of China’s power dispatch principle and the new energy saving power dispatch policy

With social economic reform in the past decades, the power industry of China is gradually evolving from a highly integrated one toward an electricity market, which can be characterized based on the transition of the power dispatch principle. To attract investment in the power generating industry, China introduced non-state-owned power plants to the original system of a highly vertically integrated power industry with annual power generation quota guarantees, which makes the traditional economic dispatch principle not applicable. The newly debuted energy saving power dispatch (ESPD) is an attempt to fully exploit the maximum energy savings and was implemented by an administrative code. Starting in August 2007, the pilot operation of the ESPD was implemented in five provinces, but after two years, it is still not widely applied all over the country. This paper details the transition of China’s power dispatch principle with particular attention to its origin and content. Moreover, the factors that influence the ESPD’s actual energy saving effect are discussed, as well as the sustainability of the policy.     

Insurance strategy for mitigating power system operational risk introduced by wind power forecasting uncertainty

The increasing penetration of wind power significantly affects the reliability of power systems due to its intrinsic intermittency. Wind generators participating in electricity markets will encounter operational risk (i.e. imbalance cost) under current trading mechanism. The imbalance cost arises from the service for mitigating supply-demand imbalance caused by inaccurate wind forecasts. In this paper, an insurance strategy is proposed to cover the possible imbalance cost that wind power producers may incur. First of all, a novel method based on Monte Carlo simulations is proposed to estimate insurance premiums. The impacts of insurance excesses on premiums are analyzed as well. Energy storage system (ESS) is then discussed as an alternative approach to balancing small wind power forecasting errors, whose loss claims would be blocked by insurance excesses. Finally, the ESS and insurance policy are combined together to mitigate the imbalance risks of trading wind power in real-time markets. With the proposed approach, the most economic power capacity of ESS can be determined under different excess scenarios. Case studies prove that the proposed ESS plus insurance strategy is a promising risk aversion approach for trading wind power in real-time electricity markets.     

Impact of public policy uncertainty on renewable energy investment: Wind power and the production tax credit

It is generally understood that the pattern of repeated expiration and short-term renewal of the federal production tax credit (PTC) causes a boom–bust cycle in wind power plant investment in the US. This on–off pattern is detrimental to the wind industry, since ramp-up and ramp-down costs are high, and players are deterred from making long-term investments. It is often assumed that the severe downturn in investment during “off” years implies that wind power is unviable without the PTC. This assumption turns out to be unsubstantiated: this paper demonstrates that it is not the absence of the PTC that causes the investment downturn during “off” years, but rather the uncertainty over its return. Specifically, it is the dynamic of power purchase agreement (PPA) negotiations in the face of PTC renewal uncertainty that drives investment volatility. With contract negotiations prevalent in the renewable energy industry, this finding suggests that reducing uncertainty is a crucial component of effective renewable energy policy. The PTC as currently structured is not the only means, existing or potential, for encouraging wind power investment. Using data from a survey of energy professionals, various policy instruments are compared in terms of their perceived stability for supporting long-term investment.     

Pan-European management of electricity portfolios: Risks and opportunities of contract bundling

Due to the liberalization of energy markets in the European Union, today's European utilities not only focus on electricity supply, but also offer exchange-traded “structured products” or portfolio management for unbundling financial and physical risk positions. Many utilities are only able to provide these services in their domestic markets. In a globalized economy, the need for a centrally organized pan-European portfolio management has arisen, as it allows a simplified commodity sourcing in combination with an optimized risk management. In this paper, we examine the challenges to be overcome for establishing a European-wide bundling of electricity contracts. For this purpose, a case study based on the business perspective of RWE Supply & Trading in Central and Eastern Europe is carried out. In a first step, we analyze general requirements for a pan-European bundling of electricity contracts. Then, RWE's situation in Europe is examined, based on which we finally propose a concept to meet customer demands in Central and Eastern Europe.     

China's large-scale power shortages of 2004 and 2011 after the electricity market reforms of 2002: Explanations and differences

Since the electricity market reforms of 2002, two large-scale power shortages, one occurring in 2004 and one in 2011, exerted a tremendous impact on the economic development of China and also gave rise to a fierce discussion regarding electricity system reforms. In this paper, the background and the influence scale of the two power shortages are described. Second, reasons for these two large-scale power shortages are analyzed from the perspectives of power generation, power consumption and coordination of power sources and grid network construction investments. Characteristics of these two large-scale power shortages are then summarized by comparatively analyzing the performance and the formation of the reasons behind these two large-scale power shortages. Finally, some effective measures that take into account the current status of electricity market reforms in China are suggested. This paper concludes that to eliminate power shortages in China, both the supply and the demand should be considered, and these considerations should be accompanied by supervisory policies and incentive mechanisms.     

Germany's nuclear power plant closures and the integration of electricity markets in Europe

This paper examines the potential implications of national policies that lead to a sudden increase of wind power in the electricity mix for interconnected European electricity markets. More specifically, it examines market integration before and after the closures of eight nuclear power plants that occurred within a period of a few months in Germany during 2011. The short- and- long run interrelationships of daily electricity spot prices, from November 2009 to October 2012, in: APX-ENDEX, BELPEX, EPEX-DE, EPEX-FR, NORDPOOL, OMEL and SWISSIX; and wind power in the German system are analysed. Two MGARCH (Multivariate Generalized Autoregressive Conditional Heteroscedasticity) models with dynamic correlations are used to assess spot market behaviour in the short run, and a fractional cointegration analysis is conducted to investigate changes in the long-run behaviour of electricity spot prices. Results show: positive time-varying correlations between spot prices in markets with substantial shared interconnector capacity; a negative association between wind power penetration in Germany and electricity spot prices in the German and neighbouring markets; and, for most markets, a decreasing speed in mean reversion.     

大用户直购电环境下电网公司的风险管理

电力市场环境下的直购电导致了电网公司风险,从政策风险、运营风险、运行风险3个角度分析了直购电所引起电网公司的风险类型,表明了各种风险是相互关联而存在的,在此基础上论述了相应的风险管理办法,指出通过有效的风险评估办法可以判断其交易策略是否在可接受范围内,从而在规避风险的同时帮助电网公司达到期望利润,最后确立了考虑直购电的电网公司风险管理阶段框图     

发电企业应用全面风险管理体系的分析与建议

电力市场化机制的引入,可以有效地促进发电企业竞争,提高运行效率,优化资源配置,同时也带来了许多不确定因素,使得发电企业面临风险的概率日益增加。面对我国发电行业发展的现状,增强风险意识,树立风险观念,加强风险管理将是发电企业的重要任务。结合应用实例,介绍了发电企业全面风险管理体系建设的经验,并提出了进一步完善的措施和建议。     

Image sequence-based risk behavior detection of power operation inspection personnel

A novel image sequence-based risk behavior detection method to achieve high-precision risk behavior detection for power maintenance personnel is proposed in this paper. In this method, the original image sequence data is first separated from the foreground and background. Then, the free anchor frame detection method is used in the foreground image to detect the personnel and correct their direction. Finally, human posture nodes are extracted from each frame of the image sequence, which are then used to identify the abnormal behavior of the human. Simulation experiment results demonstrate that the proposed algorithm has significant advantages in terms of the accuracy of human posture node detection and risk behavior identification.     

A review on the economic dispatch and risk management of the large-scale plug-in electric vehicles (PHEVs)-penetrated power systems

Nowadays, the deterioration of ecological environment and the ever rising gas price make green transportation our relentless pursuit. Energy-saving, low-emission even zero-emission electric vehicles (EVs) have been considered as one solution to the problem. With the rapid development of plug-in electric vehicle (PHEV) and forceful support and incentives from the government, PHEV and its supporting facilities are being gradually popularized. When randomly being connected to the power grid in large scale, PHEVs will bring new challenges to power grid in operation and management. This paper presents an overall review on historical research on power system integrated with electric vehicles and especially focuses on economic dispatch of PHEV in the electricity market. The paper also discusses the joint scheduling problem considering other renewable energy resources and risk management of PHEV-penetrated power systems.     

Congestion management enhancing transient stability of power systems

In a competitive electricity market, where market parties try to maximize their profits, it is necessary to keep an acceptable level of power system security to retain the continuity of electricity services to customers at a reasonable cost. Congestion in a power system is turned up due to network limits. After relieving congestion, the network may be operated with a reduced transient stability margin because of increasing the contribution of risky participants. In this paper, a novel congestion management method based on a new transient stability criterion is introduced. Using the sensitivity of corrected transient stability margin with respect to generations and demands, the proposed method so alleviates the congestion that the network can more retain its transient security compared with earlier methods. The proposed transient stability index is constructed considering the likelihood of credible faults. Indeed, market parties participate by their security-effective bids rather than raw bids. Results of testing the proposed method along with the earlier ones on the New-England test system elaborate the efficiency of the proposed method from the viewpoint of providing a better transient stability margin with a lower security cost.     

A quantitative risk assessment of hydrogen fuel cell forklifts

With the increasing deployment of hydrogen fuel cell forklifts, it is essential to understand the risks of incidents involving these systems. A quantitative risk assessment (QRA) study was conducted to determine the potential hydrogen release scenarios, probabilities, and consequences in fuel cell forklift operations. QRA modeling tools, such as fault tree analysis (FTA) and event sequence diagrams (ESD), were used together with hydrogen systems data. This work provides insights into the fatality risk from a hydrogen fuel cell forklift and the reliability of its design and components. The analysis shows that the expected fatal accident rate of a hydrogen forklift is considerably higher than current fatal injury rates observed by the Bureau of Labor Statistics for industrial truck operators and material handling occupations. Nevertheless, the average individual risk posed to forklift drivers was found to be likely tolerable based on current risks accepted by industrial truck operators. Jet fires are found to dominate the system's risk, however, the risk of explosions is also considerable. An importance measures analysis shows that these risks could be mitigated by improving the design and reliability of pressure relief devices, as well as other components prone to leak such as filters and check valves. We also identify sources of uncertainty and conservatisms in the QRA process that can guide future research in hydrogen systems. These results provide powerful insight into improvements in the design of fuel cell forklifts to reduce risk and enable the safe deployment of this key technology for a decarbonized future.     

Comparative risk assessment of liquefied and gaseous hydrogen refueling stations

Several countries are incentivizing the use of hydrogen (H₂) fuel cell vehicles, thereby increasing the number of H₂ refueling stations (HRSs), particularly in urban areas with high population density and heavy traffic. Therefore, it is necessary to assess the risks of gaseous H₂ refueling stations (GHRSs) and liquefied H₂ refueling stations (LHRSs). This study aimed to perform a quantitative risk assessment (QRA) of GHRSs and LHRSs. A comparative study is performed to enhance the decision-making of engineers in setting safety goals and defining design options. A systematic QRA approach is proposed to estimate the likelihood and consequences of hazardous events occurring at HRSs. Consequence analysis results indicate that catastrophic ruptures of tube trailer and liquid hydrogen storage tanks are the worst accidents, as they cause fires and explosions. An assessment of individual and societal risks indicates that LHRSs present a lower hazard risk than GHRSs. However, both station types require additional safety barrier devices for risk reduction, such as detachable couplings, hydrogen detection sensors, and automatic and manual emergency shutdown systems, which are required for risk acceptance.     

Modeling business risk: The effect of regulatory revision on renewable energy investment - The Iberian case

Regulatory risk is commonly accepted as one of the most important risks in the energy business, particularly renewable energy. With the recent changes (in June 2014) in the Spanish regulatory framework, investors' returns might be significantly affected. Further, as the Spanish and the Portuguese electricity systems are integrated, a change in the regulatory framework of Spain might also affect renewable energy policies and investment strategies in Portugal. This study is a projection of business risk under the assumption that the Portuguese government may adopt similar regulatory changes. Monte Carlo method is used to simulate the data under different scenarios. Applying Net Present Value and Real Options approaches, a 50 MW wind power project is evaluated. This study has considered the delay option to study five regulatory scenarios. A higher value for the delay option suggests that a high financial loss is expected if new wind power projects of similar capacity are implemented under the new regulatory framework.     

Analysis of wind power generation operation management risk in China

The Chinese government has made an important effort to diversify the country's energy mix and exploit different sources of renewable energy. Although China's installed wind power capacity has undergone a dramatic expansion over the past six years, the electricity generated from wind power has not increased as expected. Meanwhile, operational risks, such as high generation cost, mismatch between capacity and generation, intermittent wind power generation, power grid construction lag, deficient policy, and operation mechanism, have become increasingly prominent. If not controlled, these risks will negatively affect wind power development in China. Therefore, this paper established a quantitative analysis model of wind power operation management risk from two aspects, feed-in tariff and grid electricity (electricity being connected to the grid), based on an analysis of wind power operation management risk in China. Moreover, this study quantitatively assessed the risk of the operational management of a wind farm in Inner Mongolia. Finally, corresponding risk control strategies for the healthy development of wind power generation in China were proposed.     

Risk-involved stochastic performance of hydrogen storage based intelligent parking lots of electric vehicles using downside risk constraints method

Today, the utilizations of hydrogen storage systems (HSS), renewable generation units (PV and wind generation) and distributed energy units are increased in the intelligent parking lots (IPL) in order to charge the electric vehicles (EVs) with clean energy sources. In this work, the uncertainties of upstream grid price, the demand of IPL, wind speed, solar irradiation and temperature are modeled via scenario approach based on stochastic programing. Furthermore, the downside risk constraints method (DRCM) is applied to consider risk related to uncertainties to get risk-involved stochastic performance of hydrogen storage based intelligent parking lots of electric vehicles. The proposed risk-based formulation is modeled using mixed-integer linear programming (MIP) which is implemented under GAMS software and solved via CPLEX solver. Two cases namely risk-averse and risk-neutral strategies are studied and compared to show the effects of DRCM implementation. The obtained results demonstrate the expected performance cost (EPC) of IPL is slowly raised while risk-in-cost (RIC) is significantly reduced due to model of risk related to uncertainties.