Renewable portfolio standard (RPS) with tradable green certificate (TGC) scheme has important influences on the market equilibrium outcomes and generation firms’ strategic behaviors. The main objective of this paper is to investigate that under the RPS with TGC scheme, who and how to exercise the market power, and to what extent market powers are exercised in the electricity wholesale and TGC markets. This is achieved by firstly proposing a two-stage joint equilibrium model based on the oligopolistic competition equilibrium theory. The model is then formulated as an equilibrium problem with equilibrium constraints (EPEC) by using the backward induction method, which is further solved by the nonlinear complementarity approach. Finally, simulation results show that renewable firms tend to withhold some of TGCs to raise the TGC prices when the RPS is relatively low, otherwise they choose to cut down their electricity output to reduce the volume of TGC and raise the TGC price. Moreover, facing the increasing TGC price, fossil fuel firms tend to withhold their electricity output to decrease the demand of TGCs and lower the TGC price. This study has meaningful implications for design of the electricity markets with TGC market.

High wind power penetration presents many challenges to the flexibility and reliability of power system operation. In this environment, various demand response (DR) programs have received much attention. As an effective measure of DR programs, interruptible load (IL) programs have been widely used around the world. This paper addresses the concern of how the IL program impacts the equilibrium outcomes of electricity markets with wind power. First, a market demand model is developed to take consideration of the IL program. Next, a Cournot equilibrium model for electricity markets with an IL program and wind power is presented. The introduction of the IL program leads to a non-smooth equilibrium problem. To solve this equilibrium problem, a novel solution method is proposed. Finally, considering that wind power penetration will increase the risks faced by the conventional generators, the conditional value at risk is employed to measure the risk, so that the impact of the IL program on the generators’ risk can also be examined. Numerical examples are presented to verify the effectiveness of the method. It is shown that the IL program can lower market price and its volatility significantly. In addition, the IL program can help generators reduce their risks in the market, especially when the uncertainty in wind power output is relatively large.

No abstract

Integration of risk factors into decision-making model for interruptible load management plays a valuable role for power suppliers to mitigate price risks and improve their profitability in electricity market environment. A decision-making model is developed for power suppliers to determine the interruptible load volume purchased from interruptible consumers. The power suppliers' tradeoff between the wholesale market and interruptible load is considered as a portfolio selection problem. The conditional value-at-risk is employed to describe and measure the risk faced by power suppliers. In addition, a risk constraint is added to the decision-making model to take into account the risk preference of power suppliers. The Monte Carlo simulation-based numerical examples are presented to validate the reasonableness and effectiveness of the proposed model. It is also shown that the more averse to the risk, the larger volume of interruptible load the power supplier will choose. Furthermore, in order to hedge the wholesale market risk, the volume of interruptible load increases with increasing uncertainty in the wholesale market price.

No abstract