Empirical observations of bidding patterns in Australia's National Electricity Market

For more than a decade, electricity industries have been undergoing reform worldwide. However, there are various, sometimes contradictory, conclusions about the performance of these restructured electricity markets. Market performance depends largely on how each market participant responds to the market design — including market rules, market operational procedures, and information revelation. In this paper, we identify and examine the strategies adopted by generators in Australia's National Electricity Market, based on publicly available data for the period from May 1, 2002 to May 31, 2003. We try to understand and answer some basic questions like how generators respond collectively or individually to changes in market conditions (e.g. load changes) and why they behave in this way. The statistics calculated from the data show that wide variations in the frequency of strategic bidding and rebidding exist; that generators more frequently use capacity offers as a strategic tool than price offers; that large generating units are more likely to use capacity strategies to control market prices; and that generators are capable of responding to changes in market conditions.     

Dynamic competition in electricity markets under uncertainty

We study discrete-time infinite-horizon imperfect competition between asymmetric firms producing from different technologies. Specifically, one firm produces from hydroelectric units and the others operate thermal generators. This type of structure is common in some electricity markets. What makes this research interesting is that firms have different types of constraints, face different kinds of uncertainties, need to allocate their resources over time, and yet produce strategically. For the renewable energy holder, the key issue is how to allocate water between current and future electricity generation given the thermal firms' strategic actions along with demand and/or water inflow uncertainties. We analyze equilibrium outcomes (e.g., the price distribution) and market inefficiencies stemming from both production constraints and imperfect competition. We show that equilibrium price volatility and skewness are generally lower than optimal, although average price is higher than optimal. The hydro producer under-utilizes the available water, which leads to more water being available to smooth price fluctuations. However, in the extreme case of water inflows so plentiful that the hydro firm is never constrained, prices can be more volatile than optimal. We also demonstrate that the lack of social optimality of the market outcome is tempered by the capacity constraints: the welfare loss under the oligopoly market structure is much less than would occur in the absence of water and capacity constraints. These results are demonstrated using numerical simulations of the infinite horizon game, one of which is calibrated to match the characteristics of the Ontario wholesale electricity market.     

A dynamic network analysis of spot electricity prices in the Australian national electricity market

This study applies dynamic network analysis to the power sector, examining the relationship between regional spot electricity prices in the Australian National Electricity Market (NEM). In particular, we employ principal component analysis and generate Granger causality networks to examine the degree of interconnectedness of the NEM in a time-varying setting. We find that the derived measures of interdependence can be related to actual market events such as price spikes, unexpected high demand for electricity, sudden increases in price volatility, rebidding of dominant generators, the temporary or permanent outage of major power stations, and upgrades and limitations in transmission capacity. In the analysed network, we find that stronger dependence is exhibited by regional markets that are linked through interconnectors, while the direction of Granger causality can be related to interregional trade. We further examine the usefulness of the derived measures for forecasting distributional characteristics of spot prices such as the maximum price, volatility, price spreads, or upcoming periods of price spikes. Our results suggest that the derived network measures have predictive power, albeit limited, for the behaviour of spot electricity prices in the NEM.     

偏差电量考核下风光储混合发电商的市场均衡博弈研究

为了更直观地分析风光储混合发电商对市场均衡博弈结果和市场力的影响,在偏差电量考核衡量风光储混合发电出力随机波动性的基础上,综合考虑各发电商的出力限制和储能系统的运行约束,建立以风光储混合发电商和传统发电商收益最大化为目标的市场均衡博弈模型,调用CPLEX软件求解利用非线性互补函数处理得到的混合整数规划模型,并对比分析了风光储混合发电商作为价格接受者和影响者参与电力市场竞争对均衡博弈电价和投标出力的影响。结果表明,风光储混合发电商参与电力市场竞争可抑制传统发电商的市场力,对电价有显著的"削峰填谷"作用;当风光储混合发电商作为价格影响者时,对电价的影响会减弱,但其收益有所增加。     

An agent-based analysis of the German electricity market with transmission capacity constraints

While some agent-based models have been developed for analyzing the German electricity market, there has been little research done on the emerging issue of intra-German congestion and its effects on the bidding behavior of generator agents. Yet, studies of other markets have shown that transmission grid constraints considerably affect strategic behavior in electricity markets. In this paper, the implications of transmission constraints on power markets are analyzed for the case of Germany. Market splitting is applied in the case of congestion in the grid. For this purpose, the agent-based modeling of electricity systems (AMES) market package developed by Sun and Tesfatsion is modified to fit the German context, including a detailed representation of the German high-voltage grid and its interconnections. Implications of transmission constraints on prices and social welfare are analyzed for scenarios that include strategic behavior of market participants and high wind power generation. It can be shown that strategic behavior and transmission constraints are inter-related and may pose severe problems in the future German electricity market.     

Transmission capacities and competition in Western European electricity market

The integration of national electricity markets into a single European one is expected to reduce the ability of dominant players to exercise market power. This paper investigates whether or not existing transmission capacities of cross-border interconnectors are sufficient to achieve this result and create vigorous competition in the market. A model with two decision levels is used. On the first level profit maximizing generators play Cournot game against each other. On the last level the system operator clears the market and determines flows in the network to maximize social welfare subject to a set of physical constraints. As each strategic generator anticipates her impact on equilibrium prices and congestion in the system, her optimization problem is subject to equilibrium constraints from the system operator's problem.The analysis demonstrates that interconnector capacities in Western Europe are insufficient for integration alone to reduce the exercise of market power. I compare several possible competition-enhancing policies: expansion of interconnectors and different scenarios of national markets’ restructuring. I show that although increase of line capacity is a useful tool to stimulate competition in an integrated market, it is not a substitute for the restructuring of large players.     

Area price and demand response in a market with 25% wind power

Denmark, east and west of the Great Belt are bidding areas with separate hourly area prices for the Nord Pool power exchange, covering four Nordic countries and parts of Germany. The share of wind power has now increased to 25% on an annual basis in western Denmark. This has a significant impact not only on the electricity wholesale prices, but also on the development of the market. Hourly market data are available from the website of Danish TSO from 1999. In this paper these data are analysed for the period 2004–2010. Electricity generators and customers may respond to hourly price variations, which can improve market efficiency, and a welfare gain is obtained. An important limitation for demand response is events of several consecutive hours with extreme values. The analysis in this paper is a summary and update of some of the issues covered by the EU RESPOND project. It shows that extreme events were few, and the current infrastructure and market organisation have been able to handle the amount of wind power installed so far. This recommends that geographical bidding area for the wholesale electricity market reflects external transmission constraints caused by wind power.     

Price formation in electricity forward markets and the relevance of systematic forecast errors

Since the liberalisation of the European electricity sector, forward and futures contracts have gained significant interest of market participants due to risk management reasons. For pricing of these contracts an important fact concerns the non-storability of electricity. In this case, according to economic theory, forward prices are related to the expected spot prices which are built on fundamental market expectations. In the following article the crucial impact parameters of forward electricity prices and the relationship between forward and future spot prices will be assessed by an empirical analysis of electricity prices at the European Energy Exchange and the Nord Pool Power Exchange. In fact, price formation in the considered markets is influenced by historic spot market prices yielding a biased forecasting power of long-term contracts. Although market and risk assessment measures of market participants and supply and demand shocks can partly explain the futures-spot bias inefficiencies in the analysed forward markets cannot be ruled out.     

Electricity prices and generator behaviour in gross pool electricity markets

Electricity market liberalisation has become common practice internationally. The justification for this process has been to enhance competition in a market traditionally characterised by statutory monopolies in an attempt to reduce costs to end-users. This paper endeavours to see whether a pool market achieves this goal of increasing competition and reducing electricity prices. Here the electricity market is set up as a sealed bid second price auction. Theory predicts that such markets should result with firms bidding their marginal cost, thereby resulting in an efficient outcome and lower costs to consumers. The Irish electricity system with a gross pool market experiences among the highest electricity prices in Europe. Thus, we analyse the Irish pool system econometrically in order to test if the high electricity prices seen there are due to participants bidding outside of market rules or out of line with theory. Overall we do not find any evidence that the interaction between generator and the pool in the Irish electricity market is not efficient. Thus, the pool element of the market structure does not explain the high electricity prices experienced in Ireland.     

Good volatility,bad volatility: What drives the asymmetric connectedness of Australian electricity markets?

Efficient delivery of network services and the electricity infrastructure to meet the long-term consumer's interests are the main objectives and the strategies of a national electricity market, while the main interests of generators are to maximize their profit through pricing strategies. Therefore, the objective of this study is to explore whether electricity prices across the four Australian States display symmetric price volatility connectedness. The study is the first attempt in the literature to make use of intraday 5-min Australian dispatch electricity prices, spanning the period December 8th, 1998 to May 5th, 2016 to quantify asymmetries in volatility connectedness emerging from good, and bad volatility. The results provide supportive evidence that the Australian electricity markets are connected asymmetrically implying the presence of some degree of market power that is exercised by generators across regional electricity markets.     

Congestion management rules and trading strategies in the Spanish electricity market

This paper analyses the economic incentives embodied in the rules governing the resolution of transmission constraints in the Spanish wholesale electricity market and the way these incentives may have influenced on the trading behaviour of both the generators and the demand side. The evidence obtained is consistent with them responding to these incentives. In particular, buyers would respond to the way congestion costs are billed to them by abandoning the daily market in favour of the intraday market as far as possible. Additionally, some strategic generators may have been prompted the system operator to require them to inject electricity into the system to solve network congestions. Finally, these results may contribute to shed light on what should be expected of the reform in the aforementioned rules.     

Measuring the competitiveness benefits of a transmission investment policy: The case of the Alberta electricity market

Transmission expansions can increase the extent of competition faced by wholesale electricity suppliers with the ability to exercise unilateral market power. This can cause them to submit offer curves closer to their marginal cost curves, which sets market-clearing prices closer to competitive benchmark price levels. These lower wholesale market-clearing prices are the competitiveness benefit consumers realize from the transmission expansion. This paper quantifies empirically the competitiveness benefits of a transmission expansion policy that causes strategic suppliers to expect no transmission congestion. Using hourly generation-unit level offer, output, market-clearing price and congestion data from the Alberta wholesale electricity market from January 1, 2009 to July 31, 2013, an upper and lower bound on the hourly consumer competitiveness benefits of this transmission policy is computed. Both of these competitiveness benefits measures are economically significant, which argues for including them in transmission planning processes for wholesale electricity markets to ensure that all transmission expansions with positive net benefits to electricity consumers are undertaken.     

Welfare implications of capacity payments in a price-capped electricity sector: A case study of the Texas market (ERCOT)

The aim of this paper is to analyze the welfare consequences of introducing capacity compensation payments in restructured and liberalized electricity markets. For that purpose, we set up a two-stage framework in which two kinds of electricity generators, peak load and base load generators, choose their capacity investment levels first and then compete on the basis of bids in a centralized market to sell electricity to consumers. We use data from the Texas ERCOT to evaluate consumers' welfare. We find that the introduction of capacity payments has two countervailing effects. On the one hand, it increases the wholesale electricity price. On the other hand, it reduces price volatility and increases the reliability of the system. We find that capacity payments are more beneficial for consumers in a perfectly competitive market than in the presence of certain degree of market power.     

Multiscale entropy analysis of crude oil price dynamics

Price formation in crude oil markets is the result of the action of many participants (e.g., producers, governments, speculators, etc.) whose effects are perceived at different time scales, from days to years. The diversity of participants as well as the occurrence of extreme socio-political events yields a market with complex price evolution. This paper uses entropy methods to monitor the evolution of crude oil price movements. As the complexity of the price can depend of the time horizon, entropy computations are performed for different time scales via low-pass filtering of the price difference dynamics. The results are interpreted in term of relative market efficiency concepts in the sense that high entropy values should be related to a more complex and, hence, less predictable market evolution. It is shown that the highest market efficiency is found for small time scales up to one or two weeks. The multiscale entropy pattern for high time scales, longer than one quarter, is interesting as it shows alternating periods of high and low entropy levels. Interestingly, this alternating pattern has a dominant spectral component of about 4.3 years, which could be related to macroeconomic (Kitchin) business cycles. It is shown that U.S. recessions in the recent 25 years are coincident with periods of reduced entropy levels, meaning that during economic downturn the long-run market complexity is drastically reduced. The possible effects of extreme events (e.g., Iraq War) are analyzed in terms of the relative market efficiency, suggesting that some events have affected the short-term but not the long-term market complexity. Overall, these results show that methods based on entropy concepts can shed light on the structure of crude oil markets as well as on its link to macroeconomic conditions and socio-political extreme events.     

Predictability of price movements in deregulated electricity markets

In this paper we investigate predictability of electricity prices in the Canadian provinces of Alberta and Ontario, as well as in the US Mid-C market. Using scale-dependent detrended fluctuation analysis, spectral analysis, and the probability distribution analysis we show that the studied markets exhibit strongly anti-persistent properties suggesting that their dynamics can be predicted based on historic price records across the range of time scales from 1 h to one month. For both Canadian markets, the price movements reveal three types of correlated behavior which can be used for forecasting. The discovered scenarios remain the same on different time scales up to one month as well as for on- and off-peak electricity data. These scenarios represent sharp increases of prices and are not present in the Mid-C market due to its lower volatility. We argue that extreme price movements in this market should follow the same tendency as the more volatile Canadian markets. The estimated values of the Pareto indices suggest that the prediction of these events can be statistically stable. The results obtained provide new relevant information for managing financial risks associated with the dynamics of electricity derivatives over time frame exceeding one day.     

Intra-day and regime-switching dynamics in electricity price formation

This paper analyses the complex, non-linear effects of spot price drivers in wholesale electricity markets: their intra-day dynamics and transient irregularities. The context is the UK market, after the reforms introduced in March 2001, analysed with an original set of price drivers reflecting economic, technical, strategic, risk, behavioural and market design effects. Models are estimated separately as daily time-series of the 48 half-hourly trading periods. All coefficients exhibit substantial intra-day variation, relating to the heterogeneity of operating plants and market design aspects. This reveals a market responding to economic fundamentals and plant operating properties, with learning and emergent financial characteristics, as well as some strategic manipulation of capacity, most effectively exercised by the more flexible plants. Using regime-switching parameters, the effects of capacity margin and inter-day capacity adjustment are elucidated, suggesting rent-seeking behaviour, despite the relatively low prices at the time. Overall, high-frequency, aggregate fundamental price models can usefully uncover critical aspects of market performance, evolution and agent behaviour.     

Large-scale solutions

For more than a century, we have accepted the premise that once electricity is produced, it cannot be stored. This lack of storage causes extreme electricity price volatility (compared with other commodities) and hourly fluctuations in wholesale market prices, and has prompted specialized real-time markets that provide price fluctuations in 5- or 10-min intervals. The hourly volatility reflects the widely disparate costs of production from different resources that lead to a steep supply curve in most markets; that steep supply curve, coupled with highly variable demand and an inelastic demand curve in today's markets, makes for high volatility.     

Electricity market price volatility: The case of Ontario

Price volatility analysis has been reported in the literature for most competitive electricity markets around the world. However, no studies have been published yet that quantify price volatility in the Ontario electricity market, which is the focus of the present paper. In this paper, a comparative volatility analysis is conducted for the Ontario market and its neighboring electricity markets. Volatility indices are developed based on historical volatility and price velocity concepts, previously applied to other electricity market prices, and employed in the present work. The analysis is carried out in two scenarios: in the first scenario, the volatility indices are determined for the entire price time series. In the second scenario, the price time series are broken up into 24 time series for each of the 24 h and volatility indices are calculated for each specific hour separately. The volatility indices are also applied to the locational marginal prices of several pricing points in the New England, New York, and PJM electricity markets. The outcomes reveal that price volatility is significantly higher in Ontario than the three studied neighboring electricity markets. Furthermore, comparison of the results of this study with similar findings previously published for 15 other electricity markets demonstrates that the Ontario electricity market is one of the most volatile electricity markets world-wide. This high volatility is argued to be associated with the fact that Ontario is a single-settlement, real-time market.     

Trading behaviour on the continuous intraday market Elbas

Intraday markets for electricity allow for trading of energy until shortly before the period of delivery. This offers market participants a possibility to reduce their expected imbalances and to offer own unused flexibility. Because this form of distributed balancing before the period of delivery can be profitable for market participants as well as beneficial for system operations, intraday trading is expected to gain more importance in future, especially with increasing shares of variable renewable energy sources in the generation mix.So far, intraday markets are still a research field with many open questions. This paper contributes by a first analysis of intraday trades on Elbas, one of the European intraday markets. The analysis gives a detailed picture on trading activity and price development and is intended to improve understanding of continuous intraday trading.Findings include that trading activity differs significantly between price zones, that most trades occur in the last hours before gate closure and that market participants have to handle substantial price variations during the trading period. The paper also investigates the imbalance settlement rules in the Nordic countries and studies which effects one- and two-price imbalance settlement systems have on the market participants' profitability of intraday trading.     

Support schemes for renewable electricity in the European Union: Producer strategies and competition

Current discussion about how to reform European support schemes for renewable electricity neglects certain risks of market power in wholesale electricity markets. In a stylized Cournot model of interacting spot and forward electricity markets, I analyze how different price-based support schemes affect producer strategies and, ultimately, competition in the wholesale market. I compare the strategic behavior of renewable and conventional producers in terms of electricity production and forward market sales in the presence of two different price-based support schemes: feed-in tariffs and feed-in premiums. I show that the feed-in premium, which is the European Commission's current scheme of choice, may enhance market power and favor conventional electricity production. It may also reduce the likelihood of achieving the political objective to increase production from renewable energy sources.