طرح حراج برای بازارهای انرژی ذخیره ای محلی

In this paper we develop an auction mechanism that is designed for a local energy market. It aims to enable regionally or virtually restricted trading of ancillary services, which enhances the position of the balance group responsible party beyond that of simple accounting. Furthermore, it makes local market participants somewhat more independent from the transmission grid operator, but at the same time provides incentives for investments in distributed generation technologies. A wider spread of these technologies can help to save CO2 emissions, while at the same time a part of them can also be used to counter the fluctuations of energy from volatile renewable sources, such as wind and solar power. Because of their relatively high margins and small share in total production, ancillary services are well-suited for a remuneration scheme. Participants in the auction are, thus, private households, which impose specific design characteristics on the auction. Most importantly, it needs to be transparent and easy to understand, as homeowners will typically not have the insights of a professional trader as well as lack a similar position and motivation. Also, the confinement to a single balance group, i.e. a local market, means that especially in the beginning of the trading only a small number of bidders can be expected. Therefore, competition will initially be limited, so that the auction design needs to be adapted accordingly. In order to test the performance of the proposed auction market design under varying information policies, a simple agent-based simulation program has been developed. We find that the theoretical predictions hold and that competition quickly leads to price convergence.

In recent years ancillary services in electricity markets and especially such providing reserve energy have received increasing attention. This is due to several facts. First of all, the increase of the share of unpredictably fluctuating renewable energy in total energy production has led to a higher demand for reserve capacities to buffer those fluctuations. Secondly, new technological and societal developments have started to offer new ways of meeting this demand. Smaller and larger consumers can offer some of their loads and capacities to external control or even offer load adjustments at certain times of the day themselves. They can further participate in virtual power plants (VPPs) to sell power produced in large numbers of small-scale, distributed home devices, such as micro combined-heat-and-power (CHP) plants or photovoltaics. So far, this has been limited to the trade of real power. Balancing energy market mechanisms have only been examined in pilot projects with microgrids, i.e. only under these special circumstances has household energy been used as reserve energy. The purpose of this paper is to show how in current circumstances decentralized generation can be used beneficially for a regional energy system with an appropriate auction design. In particular, this paper aims at determining a valid auction mechanism that suits a local reserve energy market with all its special needs and characteristics, as discussed below. Once this mechanism is defined, it needs to be evaluated as to how bidders in such a market behave over time. The details with respect to how this mechanism can eventually be implemented optimally are side issues and will, therefore, only be treated briefly. Keeping in mind the characteristics of bidders in a local energy auction, the problem that needs to be solved is, thus, to find an adequate and reliable remuneration for each provider of reserve capacity and energy. At the same time, the auction mechanism needs to be as simple and easily understandable as possible in order not to turn down potential participants, while reducing opportunities for strategic behavior to a minimum. Moreover, transaction costs in a market with such small quantities need to be low in order to leave room for at least a minimal profit. The analysis of an auction for such a matter entails many parts. Electricity auctions are a specific type of auction because the good is perfectly divisible and non-storable, which means transactions need to happen in real time or at least at a predefined point of time in the future. This type of auction can be compared to the treasury auction, which has received considerable scientific attention in the past. So far, game-theoretic analyses of reserve auctions with the properties needed in a local market are very limited. The remainder of the paper is structured as follows: In Section 2, the literature on theoretical analysis, electricity auctions, and reserve energy auctions is reviewed. In Section 3, the market is briefly described as a preparation of the auction model, which is explained in the same section. It is presented for both the asymmetric and the symmetric case and solved accordingly. Section 4 introduces the simulation and theoretical considerations of the strategies implemented, and the results of the simulation. Section 5 explains the technical backgrounds of the simulation as well as the results obtained. Section 6 provides a conclusion and some suggestions for future research.

In this paper a new auction model for a local reserve energy market has been introduced and tested in a simulation. It has been designed to accommodate the special needs of non-expert bidders such as private households. This model can be used to revolutionize the reserve energy market, as a balance group responsible party is given the chance to self-supply reserve energy. Thereby it serves several purposes as it helps to further integrate decentralized and renewable energy penetration, but can also help to lower the costs for reserve energy by cutting back the market power of the currently dominating, large-scale utility companies. Final energy consumers can profit from this twice because they are the ones providing the energy and getting paid for it as well as having to pay a lower energy bill, once the market provides cheaper reserve energy. At the same time the mechanism supports the remuneration and subsidy schemes for decentralized and renewable energy that are already in place. In the long run, when promotion schemes eventually expire, it can serve as a long-lasting incentive scheme for investments in the designated technologies. This is supported by both the results from the theoretical investigation of the symmetric case and the simulation of the asymmetric case. We found that the information policy in the market has a significant influence on the speed of convergence and also a small effect on the equilibrium market price that is finally reached. In the extreme treatment with no information provided, the effect on the equilibrium price becomes substantial and, even more importantly, is sustained indefinitely, which emphasizes the importance of the design choice. The advantage of such a market-based incentive scheme is that it eliminates itself when it is no longer needed. This can happen under two circumstances: Firstly, as soon as further investments in the supported technologies do not enhance total welfare anymore and secondly, as soon as the slope of the learning curves for the respective technologies has reached its minimum alongside with the unit costs of the technologies, such that the acquisition happens without the need of subsidies. Furthermore, the concept can be used in a microgrid to solve the issue of remuneration of ancillary services. If a barter economy is desired in such circumstances, bids can easily be translated into amounts of energy that may be consumed at a later point in time. Beyond energy markets the design can also be applied in other small, possibly local markets, for example those known in the financial sector, i.e. cloud financing or crowd funding. These are characterized by a rather non-professional environment (usually no banks or other financial institutions participate) and aim to gather a certain, predetermined amount of financial resources. Whether an explicit reservation price makes sense in those circumstances remains to be determined. An implicit reservation price is, however, certainly given by the prevailing conditions of the official financial sector. Moreover, competition is likely to be much more quantity-based, as market participants might like to invest a certain amount and only fine-tune according to the prices on the market. Subsequent research will need to examine how actual human bidders react to the proposed design and whether theoretical predictions as well as simulation results hold. To this end, we plan to conduct a laboratory experiment as an empirical test of the validity of the design. This is also supposed to investigate the importance of the auction format on truth-revealing behavior in this context. Field tests can further validate these findings and enable the investigation of practical issues. Finally, it would also be interesting to examine some other parameters than those chosen alongside the possibility of market entry and mechanisms to prevent collusion.