Supply function equilibria with capacity constraints and pivotal suppliers

The concept of a supply function equilibrium (SFE) has been widely used to model generators' bidding behavior and market power issues in wholesale electricity markets. Observers of electricity markets have noted how generation capacity constraints may contribute to market power of generation firms. If a generation firm's rivals are capacity constrained then the firm may be pivotal; that is, the firm could substantially raise the market price by unilaterally withholding output. However the SFE literature has not fully considered the impact of capacity constraints and pivotal firms on equilibrium predictions. We characterize the set of symmetric supply function equilibria for uniform-price auctions when firms are capacity constrained and show that this set is increasing as capacity per firm rises. We provide conditions under which asymmetric equilibria exist and characterize these equilibria. In addition, we compare results for uniform-price auctions to those for discriminatory auctions, and we compare our SFE predictions to equilibrium predictions of models in which bidders are constrained to bid on discrete units of output.     

Ein Vergleich ausgewählter europäischer Strombörsen

We study the rules of selected european energy exchanges and compare their institutional design. In most countries (except for the UK) a uniform price mechanism is used. The rules differ, however, in the possibilities to express complementary cost components in the bids. Also the degree of international coupling of markets is very different across countries. Our comparison of the markets allows to identify attractive trading rules and yields insights on an effective electricity market design.     

Bidding asymmetries in multi-unit auctions: Implications of bid function equilibria in the British spot market for electricity

This paper introduces and tests Bid Function Equilibria (BFE) in the British spot market for electricity. BFE extend von der Fehr and Harbord's (1993) multi-unit auction model of wholesale electricity markets by allowing firms to have heterogeneous costs for different generating units. Pure-strategy equilibria in BFE predict asymmetric bidding by producers: a single firm (the “price-setter") bids strategically while other firms (“non-price-setters") bid their costs. We test for asymmetries in firms' bid functions in the British spot market between 1993 and 1995 and find strong empirical support for the theory. We conclude that BFE have important implications for the design and governance of electricity markets.     

Price Sensitivity of Hourly Day-ahead and Quarter-hourly Intraday Auctions in Germany

The introduction of the quarter-hourly intraday auction in 2014 for the German market confirms a tendency towards short-term energy markets. The reason for the new market was the need to trade shorter periods than just hours a day-ahead to minimize open positions in the more volatile continuous intraday trading. The increased production capacity of solar power boosted this requirement for new short-term power products. The quarter-hourly market shows a distinctive zigzag price formation. We identify two influencing factors: first, the solar residual that combines the trading of solar power ramps around midday as well as the gradients of consumption and thermal power plant ramps throughout the course of the day, and second, a characteristic two stage market design with higher liquidity for the hourly than for the quarter-hourly auction. Therefore, demand, solar generation and inflexible ramps of thermal power plants are hedged at the hourly day-ahead auction and use the quarter-hourly auction only to balance the remaining differences. To prove this argument the price sensitivities of the hourly day-ahead and quarter-hourly intraday auctions in Germany are compared based on actual bid and ask curves from 2015 and 2016. Finally, the development of an adequate design of future spot markets is discussed.     

Einfluss der CO2-Zertifikatspreise auf die Stromgestehungskosten im deutschen Energiemix

In the past, electricity generation costs in Germany’s energy mix depended for the most part on the development of fossil fuel prices. Despite the strongly increasing share of renewable energies in the energy mix, the generation of electricity from fossil fuel power plants, especially brown and bituminous coal power plants, still dominates in Germany today. Alongside fossil fuels as an increasing cost factor, the price of CO₂ is also gaining importance as a price factor in the production of electricity from fossil fuel power plants. The establishment of the European Emission Trading Scheme (EU ETS) in 2005 formed the basis of CO₂ emissions pricing, and was oriented on the emission reduction targets of the European Union. Although the price of CO₂-certificates in free trade is shown on several stock exchanges, the CO₂ price is still policy driven. The amount of free allocated and traded CO₂-certificates is set on a European policy level. Current decisions on temporary limitations of the trade volume have corresponding effects on exchange prices. This article aims to investigate the impact of CO₂-certificate prices on electricity generation costs in the German energy mix. Comparing real CO₂ prices to forecasts for 2013 provides findings on the effects that the political decisions of the European Parliament with regard to the limitation of the trade volume of available CO₂-certificates have on electricity generation costs in the German energy mix.     

The impact of introducing seven-day-trading on the Austrian electricity market

This paper analyses the impacts of the new daily green electricity production forecasting policy by the Austrian Green Electricity Settlement Agency (OEMAG) and the newly introduced seven-day electricity trading mechanism by the European Energy Exchange (EEX) on the Austrian electricity market. By treating these two market policy alterations as natural experiments and applying statistical and econometric methods to a unique data set, it is investigated whether thereby (i) a reduction of the green electricity production forecasting uncertainties and (ii) a generally more efficient electricity market with accompanying lower net costs is attained. Furthermore, we analyse whether (iii) seven-day-trading helps to mitigate the Friday-Monday effect that is often observed on stock and other exchanges markets. Finally, we investigate whether or not (iv) the underlying market design might tempt OEMAG to systematically overstate its forecasts on green power generation.     

Mixed Oligopoly and Market Power Mitigation: Evidence from the Colombian Wholesale Electricity Market*

Using information on price bids in wholesale electricity pools and empirical techniques described in the literature on electricity markets, this study identifies the market power mitigation effect of public firms in the Colombian market. The results suggest that while private firms exercise less market power than is predicted by a profit-maximization model, there are marked differences between private and public firms in their exercise of unilateral market power. These findings support the hypothesis of the market power mitigation effect of public firms.     

Cournot competition in wholesale electricity markets: The Nordic power exchange,Nord Pool

Horizontal shifts in bid curves observed in wholesale electricity markets are consistent with Cournot competition. Quantity competition reduces the informational requirements associated with evaluating market performance because the price-cost margins of all producers then depend on the same inverse residual demand curve instead of one for each firm. We apply the model to the day-ahead market of the Nordic power exchange, Nord Pool, for the years 2011-13. We reject the null hypothesis of perfect competition in all specifications. Results suggest that the average price-cost margin across the sample period was around four percent.     

Access Pricing and Network Expansion in Natural Gas Markets

In this paper, we discuss different indirect approaches to cope with local market power in natural gas markets, in particular the extension of pipeline capacity as an instrument to combat nodal market power. One perspective, as expressed in Cremer and Laffont (Eur. Econ. Rev. 46:928–935, 2002) is that a discriminatory access price can correct for market failure and induce an increase in output. We argue, on the contrary, that the opposite holds: non-discriminatory access to the pipeline system will lead to overcapacity, and is thus the preferable strategy.     

Economics and Design of Capacity Markets for the Power Sector

Capacity markets are a means to assure resource adequacy. The need for a capacity market stems from several market failures the most prominent of which is the absence of a robust demand-side. Limited demand response makes market clearing problematic in times of scarcity. We present the economic motivation for a capacity market, present one specific market design that utilizes the best design features from various resource adequacy approaches analyzed in the literature, and we discuss other instruments to deal with the problems. We then discuss the suitability of the market for Europe and Germany in particular.     

An experimental test of automatic mitigation of wholesale electricity prices

In several major deregulated electricity generation markets, the market operator uses an “automatic mitigation procedure” (AMP) to attempt to suppress the exercise of market power. A leading type of AMP compares the offer price from each generation unit with a recent historical average of accepted offer prices from that same unit during periods when there was no transmission-system congestion to impede competition. If one or more units' offer prices exceed the recent historical average by more than a specified margin, and if these offer prices raise the market-clearing price by more than a specified margin, the market operator replaces the offending offer prices with lower ones. In an experiment, we test an AMP of this type. We find that it keeps market prices close to marginal cost if generation owners have low market power in uncongested periods. However, with high market power in uncongested periods, a condition that may apply in many parts of the world, the generation owners are able to gradually raise the market price well above short-run marginal cost in spite of the AMP. We also test the effect of the AMP on the frequency with which high-variable-cost units are used, inefficiently, in place of low-variable-cost units.     

INEFFICIENCIES AND MARKET POWER IN FINANCIAL ARBITRAGE: A STUDY OF CALIFORNIA'S ELECTRICITY MARKETS*

For two years prior to the collapse of California's restructured electricity market, power traded in both a forward and a spot market for delivery at the same times and locations. Nonetheless, prices in the two markets often differed in significant and predictable ways. This apparent inefficiency persisted, we argue, because most firms believed that trading on inter‐market price differences would yield regulatory penalties. For the few firms that did make such trades, it was not profit‐maximizing to eliminate the price differences entirely. Skyrocketing prices in 2000 changed the major buyers' (utilities') incentives and exacerbated the price differentials between the markets.     

Who should own a renewable technology? Ownership theory and an application

We investigate the market implications of ownership of a new low-cost production technology. We relate our theoretical findings to measure the impact of renewable energy penetration into electricity markets and examine how the ownership of renewable capacity changes market outcomes (prices, outputs, emissions). As current public policies influence renewable energy ownership, this research provides useful insights for policy makers. We show how and why ownership of renewable capacity matters when there is market power in energy market. We apply our findings to the wholesale electricity market in Ontario, Canada, to analyze the impact of different ownership structures for wind capacity expansions. Using both simulation analysis and empirical analysis of market data, we show that the price-reducing effects of wind expansion are smaller when a larger strategic firm owns new wind capacity. Lastly, we show that the effect of wind ownership on emissions depends on both the amount of generation displaced by wind output and the emissions rate of displaced generation.     

A Multivariate Commodity Analysis with Time-Dependent Volatility—Evidence from the German Energy Market

In recent years commodity markets (in particular electricity, coal, and emissions) encountered extreme price movements and phases of high price volatility. Utility companies are naturally exposed to these kinds of market movements and thus have to set-up an appropriate risk management system. We show that the nonstationary behavior of recent energy prices can be captured by time-dependent (and possibly stochastic) volatility models. We compare their statistical performance and their impact on risk management applications by calculating risk metrics such as value-at-risk. Based on a comprehensive backtesting study we conclude that our suggested models outperform stationary models in most cases and therefore should be considered superior for risk management applications.     

Market Coupling and the CWE Project

The article copes with the ongoing effort to establish implicit auctions to allocate transmission capacity on cross-border interconnectors in the power grid. By the means of implicit auctions (in contrast to explicit auctions), cross-border capacities are included in the clearing of local power exchanges. Concerning the day ahead auction, ‘market coupling’ plays an important role. Market coupling connects (formerly often national) electricity markets, simplifying cross-border trade. One of the main drivers of market coupling projects is the pursuit of European market integration i.e. allowing for convenient cross-border trade. The other reason is the perception that explicit auctions of transmission capacity (in addition to energy auctions which are often performed later) do sometimes lead to sub-optimal results. The objective function of market coupling is the maximisation of total welfare of all connected markets. Further to the explanation of different market coupling models (also regarding capacity calculation), the current development in Europe is wrapped up—including the CWE market coupling (Central Western Europe) project. The CWE market coupling is announced to start in fall 2010, coupling the day-ahead electricity markets of Belgium, France, Germany, Luxembourg and the Netherlands.     

MERCHANT TRANSMISSION INVESTMENT*

We examine the performance attributes of a merchant transmission investment framework that relies on ‘market driven’ investment to increase transmission network capacity needed to support competitive wholesale markets for electricity. Under a stringent set of assumptions, the merchant investment model has a remarkable set of attributes that appears to solve the natural monopoly problem and the associated need for regulating electric transmission companies. We expand the merchant model to incorporate several attributes of wholesale power markets and transmission networks that the merchant model ignores. These include market power in wholesale electricity markets, lumpiness in transmission investment opportunities, stochastic attributes of transmission networks and associated property rights definition issues, strategic behavior by potential merchant transmission investors and issues related to the coordination of transmission system operators and merchant transmission owners. Incorporating these more realistic attributes of transmission networks and the behavior of transmission owners and system operators leads to the conclusion that several potentially significant inefficiencies may result from reliance on the merchant transmission investment framework. Accordingly, it is inappropriate for policymakers to assume that they can avoid dealing with the many challenges associated with stimulating efficient levels of investment in electric transmission networks by adopting the merchant model.     

Negative Strompreise und der Vorrang Erneuerbarer Energien

With the appearance of negative prices a discussion about flaws in the design of the German electricity market arose. We show that negative prices are not only due to the integration of electricity from renewable energy sources. Negative prices can actually increase welfare. Yet, a loss of welfare does arise because of the priority feed-in of these sources. They are inclined to deliver energy even when the cost of production exceeds the market price, i.e. the electricity’s value. We suggest to remove the priority feed-in combined with a modification of the feed-in tariffs. Thereby, renewable electricity producers will suffer no drawbacks but social welfare increases.     

Real-Time Pricing and Imperfect Competition in Electricity Markets*

We analyze the effects of the adoption of real-time pricing (RTP) of electricity when generating firms have market power. We find that an increase in consumers on RTP contracts decreases peak prices and increases off-peak prices, increases consumer surplus (both for switching and non-switching consumers) and welfare, while decreasing industry profits, with these effects being magnified by the extent of market power. We illustrate these results by calibrating our model to the New Zealand electricity market, and find that taking into account the market power of generating firms increases the efficiency gains from RTP adoption by 41%.     

Evaluating the impact of divestitures on competition: Evidence from Alberta’s wholesale electricity market

Asset divestitures play a central role in antitrust and competition policy. Despite their importance, empirical evidence on their impacts on market competition is limited. We analyze market power in Alberta’s wholesale electricity market, where transitional arrangements that virtually divested generation assets from large incumbents were put in place during market restructuring in the early 2000’s and expired at the end of 2020. Subsequently, average peak hour prices rose by 120% the year after their expiry. We demonstrate that nearly two-thirds of this increase can be explained by elevated market power from the large suppliers. Further, exploiting variation in the allocation of the divested assets across heterogeneous firms, we demonstrate that market power execution is elevated when the divested assets are controlled by large strategic firms. Our findings highlight the important role that asset divestitures and their allocations can have on market competition. Our analysis also raises concerns over the ability of restructured electricity markets to facilitate sufficient competition through entry and the potential need for regulatory intervention.     

The European Single Market in Electricity: An Economic Assessment

The European single market in electricity has been promoted vigorously by the European Commission since 1996. We discuss how national electricity markets and cross-border electricity markets have been reshaped by the process. We examine the Commission’s own work on evaluating the benefits of the single market. We look at the wider evidence of impact on prices, security of supply, the environment, and innovation. We conclude that the institutional changes are extensive and there has been significant market harmonisation and integration. However, the measured benefits are difficult to identify, but likely to be small. This is partly because over the same period there has been a large rise in subsidised renewable generation that is driven by the decarbonisation agenda.