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Distributed, consensus-based algorithms have emerged as a promising approach for the coordination of distributed energy resources (DER) due to their communication, computation, privacy and reliability advantages over centralized approaches. However, state-of-the-art consensus-based algorithms address the DER coordination problem in independent time periods and therefore are inherently unable to capture the time-coupling operating characteristics of flexible demand (FD) and energy storage (ES) resources. This paper demonstrates that state-of-the-art algorithms fail to converge when these time-coupling characteristics are considered. In order to address this fundamental limitation, a novel consensus-based algorithm is proposed which includes additional consensus variables. These variables express relative maximum power limits imposed on the FD and ES resources which effectively mitigate the concentration of the FD and ES responses at the same time periods and steer the consensual outcome to a feasible and optimal solution. The convergence and optimality of the proposed algorithm are theoretically proven while case studies numerically demonstrate its convergence, optimality, robustness to initialization and information loss, and plug-and-play adaptability. [ABSTRACT FROM AUTHOR]

The use of hydropower has expanded in recent years in southwest China, playing a key role in the success of China's West-to-East energy strategy. Although installed hydropower capacity has reached a record high, the problem of abandoned water has intensified and has been gradually highlighted by researchers. Abandoned water has resulted in a significant waste of carbon-free and inexpensive renewable energy, which is not conducive to China's goals to reduce emissions to save energy. This waste has seriously affected the development of China's hydropower industry. Therefore, now is the time to analyze the main reasons for the abandoned water problem and to identify the crux of the problem. In this paper, we collected the actual operation data of all the power stations in the case area and established the mathematical model according to the quantity of abandoned water as well as the actual and the theoretical output curve of the power station to quantify the abandoned water into energy loss. We then classified the abandoned water according to three groups of causes, namely, generation-side, line-side, and market-side causes. In 2016, the total energy loss of abandoned water of Sichuan Province was 28.73 × 109 kW h, of which the generation-, line-, and market-side causes account for 7.76%, 11.68%, and 80.56% of the energy loss, respectively. Therefore, the market-side causes are the main cause for the abandoned water problem. Such market-side causes primarily include the imbalance between electricity supply and demand, the provincial barriers of the local government system and its mechanisms, and the hysteresis congestion of the transmission lines. Seizing the favorable opportunity presented by new power system reforms in China, this study proposes several market-oriented measures to improve hydropower consumption capacity. [ABSTRACT FROM AUTHOR]

• The long-term impacts of demand flexibility on deregulated systems are investigated. • Bi-level optimization model of a generation company's investment problem is proposed. • The proposed model captures energy shifting and reserve provision of flexible demand. • Different market design options around the allocation of reserve payments are tested. Demand flexibility has attracted significant interest given its potential to address techno-economic challenges associated with the decarbonisation of electricity systems. However, previous work has investigated its long-term impacts through centralized generation planning models which do not reflect the current deregulated environment. At the same time, existing market-based generation planning models are inherently unable to capture the demand flexibility potential since they neglect time-coupling effects and system reserve requirements in their representation of the electricity market. This paper investigates the long-term impacts of demand flexibility in the deregulated environment, by proposing a time-coupling, bi-level optimization model of a self-interested generation company's investment planning problem, which captures for the first time the energy shifting flexibility of the demand side and the operation of reserve markets with demand side participation. Case studies investigate different cases regarding the flexibility of the demand side and different market design options regarding the allocation of reserve payments. The obtained results demonstrate that, in contrast with previous centralised planning models, the proposed model can capture the dependency of generation investment decisions and the related impacts of demand flexibility on the electricity market design and the subsequent strategic response of the self-interested generation company. [ABSTRACT FROM AUTHOR]