Supply modes for renewable-based distributed energy systems and their applications:case studies in China

Distributed energy systems(DES),as an integrated energy system with coupled distributed energy resources,have great potential in reducing carbon dioxide emissions and improving energy efficiencies.Considering the background of urbanization and the energy revolution in China,the study investigates the renewable-based DESs supply modes and their application in China.A new method is proposed to classify DESs supply modes into three categories considering the renewable resource in domination,and their application domains are discussed.A comprehensive model is given for economic and environmental evaluation.Typical case studies show that the renewable-based DES systems can supply the energy in a cost-effective and environment-friendly way.Among them,the biomass waste dominated supply mode can not only achieve"zero"carbon emissions but also"zero"energy consumption,even though not yet economically attractive under the present policy and market conditions.Thus,recommendations are given to promote the further deployment of renewable-based DESs,regarding their supply modes,policy requirements,and issues to be addressed.

Study on business models of distributed generation in China

Along with the implementation of electricity sales-side reform and incremental power distribution investment liberalization under China’s new round of electricity market reform, the main subjects of distributed generation investment, construction, and operations have become more various, and the approaches as well as the ways that distributed generation takes part in the market have been more flexible. How to operate distributed generation economically and efficiently in this market environment has become an urgent issue to be addressed. Based on the domestic development situation of China’s distributed generation, this paper introduces typical existing business models of distributed generation, and elaborates the correlation between electricity market reform and business models of distributed generation in depth in combination with the contents of electricity market reform. At last, several business models of distributed generation which are feasible to be implemented in China have been proposed under the new electricity market reform based on successful international distributed generation operation experiences in the terms of stimulating stakeholders’ participation in the investment and operations of distributed generation. Characteristics of these recommended models are compared and analyzed as well.

Integrated Energy System Planning at Modular Regional-user Level Based on a Two-layer Bus Structure

An integrated energy system(IES)planning method with modular simulation and optimization models is proposed in this paper.A two-layer bus structure is adopted in the simulation model,where the external bus structure is used for power balance while the internal bus structure simulates the fast dynamics of electricity and slow dynamics of heat network in detail.In addition,an improved self-adaptive genetic algorithm(GA)is adopted in the optimization model to solve the multi-dimension and multi-time-scales optimization problem for the regional-user level IEPS.The proposed method can improve the extension flexibility of the system optimal planning model with expected accuracy.A case study is used to verify the effectiveness of the proposed planning method.

Reactive power operability of distributed energy resources for voltage stability of distribution networks

The penetration level of distributed energy resources(DERs)is increasing and has significant impact on the voltage stability of distribution networks.Based on the various types of DERs with distinct reactive power characteristics(RPC),their different contributions to the system voltage stability require classification.Firstly,the features of DERs are reviewed and classified based on their RPC,to investigate different distributed generation technologies for reactive power support in distribution networks.Then,the concept of a relative available transmission capacity index(RATCI),which is based on power transfer margin of the power-voltage curve considering the non-negligible distribution network resistance,is proposed to quantify and evaluate the voltage stability by integrating DERs with the defined reactive power types.Case studies have been conducted for an IEEE 33-bus distribution network to calculate the system RATCI for the mixed integration of DERs.Results show that the multitype and multi-locational integration of DERs can improve the voltage stability of a distribution network.