Distribution System Modeling and Analysis

Economic assessment of photovoltaic battery systems based on household load profiles

Residential photovoltaic systems can reduce reliance on grid electricity, which may be desirable for numerous reasons. However, the economic viability of such systems is dependent on effective use of excess electricity generation, most often through net or bi-directional metering. With recent cost reductions in residential-scale lithium ion battery storage systems, these may be a practical alternative. In this work, we model the lifetime performance and economics of residential photovoltaics with lithium ion batteries across all 50 states in the U.S. We investigate in detail how photovoltaic size and battery capacity affect performance and cost metrics in California, Georgia, and Massachusetts. We find that with appropriate sizing, photovoltaic-battery systems can be more affordable than photovoltaics alone. We demonstrate that these systems may be competitive with grid prices when the federal investment tax credit and favorable financing terms are used, and we calculate the sell-back price required for bi-directional metering to reach cost parity with photovoltaic-battery systems in every state.

An economic analysis of residential photovoltaic systems with lithium ion battery storage in the United States

A modular high-resolution demand-side management model to quantify benefits of demand-flexibility in the residential sector

Electricity storage compared to net metering in residential PV applications

Economic assessment of residential PV systems with self-consumption and storage in Portugal

Photovoltaic microgeneration (μG) located near the domestic consumers is expected to increase more in the future. Known issues regarding high μG penetration are voltage rise and reverse power flow. The concept of self-consumption and storage is emerging as a way to improve network power supply quality and to facilitate the integration of small renewable energy sources in low voltage networks. This paper intends to give a further contribution by assessing the improvements provided by allowing domestic clients to consume and store the energy they produce. The tool at hand to study the situation is the unbalanced three-phase load flow algorithm, based on the power summation technique, improved with the capability of explicitly compute the neutral voltages. The behaviour of a test radial distribution grid is assessed in different operating conditions, namely winter/summer, μG penetration level and μG operating mode. Voltage profile, active power flow in the service transformer and losses are monitored. The results suggest that self-consumption with storage operating mode is a promising solution. Voltage excursions above normal grid voltage operating limits were not observed, the situation of reverse active power flow does not occur and the power losses are reduced.

Self-consumption and storage as a way to facilitate the integration of renewable energy in low voltage distribution networks

Nowadays, a strong concern to decrease greenhouse gas emissions is encouraging the implementation of renewable energy sources closer to end-users, in low-voltage (LV) distribution networks. Due to the expected high microgeneration (μG) penetration level, several problems are likely to arise, such as overvoltages and reverse power flow. This study presents a review of the several techniques used to deal with these problems. These are compared in terms of their capacity to smooth the voltage profile and avoid reverse power flow. An unbalanced three-phase power flow algorithm, based on current summation method for radial distribution networks, is proposed. A study based on a highly unbalanced test radial LV distribution network for a typical summer day, with a high μG penetration, is performed. The voltage profile, active power flow in the service transformer, and power losses on the network are the monitored electrical quantities. The obtained results indicate that self-consumption with storage is the recommended solution to eliminate overvoltages, to avoid reverse power flow and allow for a decreasing in the power losses. Nevertheless, the economic viability of this solution must be carefully assessed, because the profitability of the project is not straightforward at the current time.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-rpg.2017.0482

Assessment of overvoltage mitigation techniques in low-voltage distribution networks with high penetration of photovoltaic microgeneration

The impact of harmonics compensation ancillary services of photovoltaic microgeneration in low voltage distribution networks

The ongoing increase of PhotoVoltaic (PV) microgeneration, pointing to high levels of penetration, can lead to the occurrence of overvoltages. Moreover, the inherent unbalanced nature of the LV distribution grid is a difficulty that must be considered when designing countermeasures. On the other hand, storage systems are suitable devices that can help the process of voltage control. This paper proposes a control system for a real-time energy management system, using Multi-Objective Particle Swarm Optimization (MOPSO) on a highly unbalanced LV distribution network, with batteries and a high share of PV. The purpose of the control system is the optimization of four objectives: Voltage Unbalance Factor (VUF), voltage deviation, active power losses and PV curtailment, wherein four scenarios were considered for assessment. This study is conducted using an unbalanced three-phase power flow algorithm. A comparison of residential and community storage is performed. The results show that the inclusion of storage devices near the prosumers’ PV systems is the recommended solution to enhance voltage stability and balance. Moreover, a significant reduction of active power losses in the LV network is observed.

Fernando M. Camilo

Papers

Economic assessment of residential PV systems with self-consumption and storage in Portugal

Self-consumption and storage as a way to facilitate the integration of renewable energy in low voltage distribution networks

Assessment of overvoltage mitigation techniques in low-voltage distribution networks with high penetration of photovoltaic microgeneration

The impact of harmonics compensation ancillary services of photovoltaic microgeneration in low voltage distribution networks

Energy management in unbalanced low voltage distribution networks with microgeneration and storage by using a multi-objective optimization algorithm