Stand-alone power system

About: Stand-alone power system is a research topic. Over the lifetime, 8650 publications have been published within this topic receiving 192397 citations. The topic is also known as: Stand-alone photovoltaic power system.

Optimal Power Scheduling for Smart Grids Considering Controllable Loads and High Penetration of Photovoltaic Generation

Abstract: The distributed generator (DG) has a huge economical and environmental potential, especially if it is based on renewable energy sources (RESs). It is very important for the future development of smart grids. However, high penetration of DGs into distribution systems can cause voltage deviations beyond the statutory range, and reverse power flow toward the substation transformer. Consequently, it can increase the distribution system losses if it is not well supervised. Thus, in order to meet smart grid objectives, DGs have to be controlled in coordination with other power resources existing in the distribution system. Controllable loads (CLs) can also help in promoting smart grids through demand response (DR) application. Therefore, this paper proposes a decision technique of an optimal reference schedule for DGs, battery energy storage system (BESS), CLs, and tap changing transformers. The main objective of the proposed optimization problem is to achieve loss reduction in the distribution system. However, other aims such as voltage control and power flow smoothing have been achieved. The optimization is performed based on predicted values of load demand and DG generation. Simulations are conducted for one operation day to illustrate the optimality of the proposed scheduling method and to assess the impact of CLs in smart grids.

New CHP partnerships offering balancing of fluctuating renewable electricity productions

Abstract: Combined heat and power (CHP) as well as intermittent renewable energy sources (RES) are key elements in future cleaner electricity production systems. This article presents solutions which will integrate fluctuating renewable electricity supplies, such as wind power, into electricity systems using small and medium-sized combined heat and power plants (CHP). Such solutions call for a new organisational setup of partnerships and software tools. The software tools will allow the new partnerships to offer services which are currently only offered by big power plants to electricity markets. The article presents recent results of the development and implementation of such partnerships and focuses on the methodologies and computer tools necessary in order to allow the partnerships to optimise their behaviour on the market. The use of such tools and methodologies makes groups of small CHP plants able to replace large power stations and, at the same time, allows for the integration of a higher share of RES in the electricity supply, resulting in a decrease in both fossil fuels and CO2 emissions.

A Simple Operating Strategy of Small-Scale Battery Energy Storages for Energy Arbitrage under Dynamic Pricing Tariffs

Abstract: Price arbitrage involves taking advantage of an electricity price difference, storing electricity during low-prices times, and selling it back to the grid during high-prices periods. This strategy can be exploited by customers in presence of dynamic pricing schemes, such as hourly electricity prices, where the customer electricity cost may vary at any hour of day, and power consumption can be managed in a more flexible and economical manner, taking advantage of the price differential. Instead of modifying their energy consumption, customers can install storage systems to reduce their electricity bill, shifting the energy consumption from on-peak to off-peak hours. This paper develops a detailed storage model linking together technical, economic and electricity market parameters. The proposed operating strategy aims to maximize the profit of the storage owner (electricity customer) under simplifying assumptions, by determining the optimal charge/discharge schedule. The model can be applied to several kinds of storages, although the simulations refer to three kinds of batteries: lead-acid, lithium-ion (Li-ion) and sodium-sulfur (NaS) batteries. Unlike literature reviews, often requiring an estimate of the end-user load profile, the proposed operation strategy is able to properly identify the battery-charging schedule, relying only on the hourly price profile, regardless of the specific facility’s consumption, thanks to some simplifying assumptions in the sizing and the operation of the battery. This could be particularly useful when the customer load profile cannot be scheduled with sufficient reliability, because of the uncertainty inherent in load forecasting. The motivation behind this research is that storage devices can help to lower the average electricity prices, increasing flexibility and fostering the integration of renewable sources into the power system.