High Distributed Energy Resources Research Articles

A quasi-static time-series approach to assess the impact of high distributed energy resources penetration on transmission system expansion planning

Due to advancements in solar cell fabrication and inverter-based technology, as well as decreasing acquisition costs, solar distributed generation systems have emerged as a promising renewable source. Furthermore, electrification of the transportation system is an alternative promoted by many governments to mitigate the dependency on fossil fuels and achieve the goals of decarbonizing the economy. However, interconnecting a large quantity of distributed energy resources (DERs) to the power system reveals technical problems affecting the entire system. Planning coordinators and grid operators need to understand the full-spectrum impact of DERs on the power system to ensure secure and reliable grid planning and operations. The operation of a Hydro-Québec transmission system planned for 2030 is simulated in quasi-static time series mode with a massive integration of 1 million of electric vehicles and 1000 – 3000 MW of distributed photovoltaics. This paper provided findings on assessment of high DER penetrations impacts on the transmission system in terms of voltage control, mitigation means used, MVAR availability and consumption margin, generating unit optimal operation, and switching actions of several equipment.

A Benders decomposition approach for solving a two-stage local energy market problem under uncertainty

New consumer-centric electricity market schemes have emerged as an alternative to manage the energy balancing locally in distribution networks with high distributed energy resources (DERs) penetration. Peer-to-peer (P2P) energy trading has become an attractive scheme for reducing user and distribution system operators (DSO) costs through the energy surplus exchange between the energy community users, where the uncertainty of DERs and the consumption are challenging issues that require suitable managing for a proper market operation. This article presents a novel two-stage stochastic mixed-integer linear programming model to address the scheduling day-ahead problem of an energy community operating under a P2P energy trading scheme. The formulation proposed minimizes the expected community cost considering the network limitations, ensuring fair trading in the local energy market (LEM), and allowing the prosumers to act as buyers or sellers depending on their load consumption and self-generation. In order to reduce the shared information by consumers/prosumers that trade energy, the proposed model is decomposed into a master problem (MP) and subproblems (SPs) to manage the network constraints and the market requirements, respectively. With this purpose, the Benders decomposition approach is implemented using the recently introduced Strengthened Benders cuts to address the binary variables related to the market and battery operation in the SPs. The model and the algorithm are tested in the 69-bus radial distribution system, considering from 3 to 39 agents trading energy to measure the model scalability. In this analysis, the algorithm convergence shows that the proposed methodology reduces the LEM’s shared information without increasing the energy community cost.

Three-phase power cooperative management of distribution network with high distributed energy resources penetration

With increasing penetrations of energy resources accessing, the problems caused by reverse power flow in the low-voltage network are aggravated. A power cooperative management method based on distributed optimization is proposed to optimize system operation by managing single-phase and three-phase distributed resources respectively. An optimization under-layer is proposed to minimize the voltage deviation and power loss, in which line parameters are removed to reduce topological dependence. An optimization upper-layer is proposed to constrain the power exchange of point of common coupling. Power correction factors are proposed to ensure power reduction consistency on each resource. Constraint coefficients are proposed to define the prioritize of optimization objectives under different conditions. Taking the photovoltaic system as an example, simulation is performed based on cases under three typical scenarios. Simulation results demonstrate that the proposed method could reduce voltage deviation and unbalance by upper-layer optimization, which as well as could constrain the power exchange in the point of the common coupling under scenarios with adequate illumination and without solar.

Stakeholders’ Perspectives of Design Options for a Rooftop Solar PV Self-consumption Scheme in Thailand

Adoption of solar photovoltaic (PV) power generation systems has been accelerating around the world, contributing to the debate about the future of policy and regulation in a high distributed energy resources future. As one of the leaders in solar investment in Southeast Asia, Thailand has recently shifted its policy framework for the support of small scale, distributed solar PV systems from subsidizing power export through feed-in tariff toward a policy that is focused on self-consumption. This paper investigates stakeholder perspectives of the detailed design options for self-consumption schemes for supporting rooftop solar PV installations. The research methodology employed questionnaires and focus group discussion in order to capture stake-holder perspectives for each element of rooftop solar PV self-consumption schemes. In all, the data derived from questionnaires and focus group discussion involved a total of 72 stakeholders. The results indicate that most stakeholder groups expressed a strong desire for compensation for excess generation of PV electricity from rooftop PV systems. While the majority of electric utilities prefer a system of net billing with real-time buyback, designed to minimize revenue losses, consumers and policymakers preferred a net-metering-based compensation scheme for supporting use of rooftop PV electricity in Thailand.