Optimal Combinatorial Electricity Markets

The deregulation of the electricity industry in many countries has created a number of marketplaces in which producers and consumers can operate in order to more effectively manage and meet their energy needs. To this end, this paper develops a new model for electricity retail where end-use customers choose their supplier from competing electricity retailers. The model is based on simultaneous reverse combinatorial auctions, designed as a second-price sealed-bid multi-item auction with supply function bidding. This model prevents strategic bidding and allows the auctioneer to maximise its payoff. Furthermore, we develop optimal single-item and multi-item algorithms for winner determination in such auctions that are significantly less complex than those currently available in the literature

Designing Coalition-Proof Reverse Auctions over Continuous Goods

This paper investigates reverse auctions that involve continuous values of different types of goods, general nonconvex constraints, and second stage costs. We seek to design the payment rules and conditions under which coalitions of participants cannot influence the auction outcome in order to obtain higher collective utility. Under the incentive-compatible Vickrey-Clarke-Groves mechanism, we show that coalition-proof outcomes are achieved if the submitted bids are convex and the constraint sets are of a polymatroid-type. These conditions, however, do not capture the complexity of the general class of reverse auctions under consideration. By relaxing the property of incentive-compatibility, we investigate further payment rules that are coalition-proof without any extra conditions on the submitted bids and the constraint sets. Since calculating the payments directly for these mechanisms is computationally difficult for auctions involving many participants, we present two computationally efficient methods. Our results are verified with several case studies based on electricity market data

Combinatorial auctions in practice

We survey the uses of combinatorial auctions that have been deployed in practice, giving emphasis to their key representational and economic aspects. In addition, we discuss behavioral economics considerations on both the bidder and auctioneer sides of the market, and the interrelated topics of simplicity and trust, highlighting key opportunities for future work

Market-Based Task Allocation Mechanisms for Limited Capacity Suppliers

This paper reports on the design and comparison of two economically-inspired mechanisms for task allocation in environments where sellers have finite production capacities and a cost structure composed of a fixed overhead cost and a constant marginal cost. Such mechanisms are required when a system consists of multiple self-interested stakeholders that each possess private information that is relevant to solving a system-wide problem. Against this background, we first develop a computationally tractable centralised mechanism that finds the set of producers that have the lowest total cost in providing a certain demand (i.e. it is efficient). We achieve this by extending the standard Vickrey-Clarke-Groves mechanism to allow for multi-attribute bids and by introducing a novel penalty scheme such that producers are incentivised to truthfully report their capacities and their costs. Furthermore our extended mechanism is able to handle sellers' uncertainty about their production capacity and ensures that individual agents find it profitable to participate in the mechanism. However, since this first mechanism is centralised, we also develop a complementary decentralised mechanism based around the continuous double auction. Again because of the characteristics of our domain, we need to extend the standard form of this protocol by introducing a novel clearing rule based around an order book. With this modified protocol, we empirically demonstrate (with simple trading strategies) that the mechanism achieves high efficiency. In particular, despite this simplicity, the traders can still derive a profit from the market which makes our mechanism attractive since these results are a likely lower bound on their expected returns

Exploiting Weak Supermodularity for Coalition-Proof Mechanisms

Under the incentive-compatible Vickrey-Clarke-Groves mechanism, coalitions of participants can influence the auction outcome to obtain higher collective profit. These manipulations were proven to be eliminated if and only if the market objective is supermodular. Nevertheless, several auctions do not satisfy the stringent conditions for supermodularity. These auctions include electricity markets, which are the main motivation of our study. To characterize nonsupermodular functions, we introduce the supermodularity ratio and the weak supermodularity. We show that these concepts provide us with tight bounds on the profitability of collusion and shill bidding. We then derive an analytical lower bound on the supermodularity ratio. Our results are verified with case studies based on the IEEE test systems

Auctioning Greenhouse Gas Emissions Permits in Australia

The allocation of permits is an important design aspect of an emissions trading scheme. Traditionally, governments have favoured the free allocation of greenhouse gas permits based on individual historical emissions (‘grandfathering’) or industry benchmark data. Particularly in the EU, the free allocation of permits has proven complex and inefficient and the distributional implications are politically difficult to justify; auctioning emissions permits has therefore become more popular. The EU is now moving to auction more than 50 per cent of all permits in 2013, and in the US the Regional Greenhouse Gas Initiative (RGGI) has begun auctioning more than 90 per cent of total allowances. Another case in point is the Australian proposal for a Carbon Pollution Reduction Scheme (CPRS), which provides for auctioning a significant share of total permits. This paper discusses the proposed Australian CPRS’s auction design. A major difference to other emissions trading schemes is that the CPRS plans to auction multiple vintages of emissions permits simultaneously.Auctions, carbon auctions, greenhouse gas auctions

A Troubled Asset Reverse Auction

The US Treasury has proposed purchasing $700 billion of troubled assets to restore liquidity and solve the current financial crisis, using market mechanisms such as reverse auctions where appropriate. This paper presents a high-level design for a troubled asset reverse auction and discusses the auction design issues. We assume that the key objectives of the auction are to: 1) provide a quick and effective means to purchase troubled assets and increase liquidity; 2) protect the taxpayer by yielding a price for assets related to their value; and 3) offer a transparent rules-based process that minimizes discretion and favoritism. We propose a two-part approach. Part 1. Groups of related securities are purchased in simultaneous descending clock auctions. The auctions operate on a security-by-security basis to avoid adverse selection. To assure that the auction for each security is competitive, the demand for each security is capped at the total quantity offered by all but the largest three sellers. Demand bids from private buyers are also allowed. The simultaneous clock auctions protect the taxpayer by yielding a competitive price for each security and allow bidders to manage liquidity constraints and portfolio risk. The resulting price discovery also improves the liquidity of the securities that are not purchased in the auctions. Part 2. Following Part 1, the remaining quantity is purchased in descending clock auctions in which many securities are pooled together. To minimize adverse selection, reference prices are calculated for each security from a model that includes all of the characteristics of each security including the market information revealed in the security-by-security auctions of Part 1. Bids in the pooled auctions are specified in terms of a percentage of the reference price for each security.Auctions, financial auctions, financial crisis