Battery storage power station

A battery storage power plant is a form of energy storage power plant which uses a group of batteries to store electrical energy. As of 2019 the maximum power of battery storage power plants is an order of magnitude less than pumped storage power plants, the most common form of grid energy storage. In terms of storage capacity, the largest battery power plants are about two orders of magnitude less than pumped hydro plants. Battery storage power plants are used for short-term peak power and ancillary services, such as frequency control. A battery storage power plant is a form of energy storage power plant which uses a group of batteries to store electrical energy. As of 2019 the maximum power of battery storage power plants is an order of magnitude less than pumped storage power plants, the most common form of grid energy storage. In terms of storage capacity, the largest battery power plants are about two orders of magnitude less than pumped hydro plants. Battery storage power plants are used for short-term peak power and ancillary services, such as frequency control. Structurally battery storage power plants and uninterruptible power supplies (UPS) are comparable, although the former are larger. The batteries are housed for security in their own warehouses or in containers. As with a UPS, a problem is that electrochemical energy is stored or emitted in the form of direct current (DC), while electric power networks are usually operated with alternating current (AC). For this reason, additional inverters are needed to connect the battery storage power plants to the high voltage network. This kind of power electronics include GTO thyristors, commonly used in high-voltage direct current (HVDC) transmission.Various accumulator systems may be used depending on the power-to-energy ratio, the expected life time and, of course, the costs. In the 1980s, lead-acid batteries were used for the first battery-storage power plants. During the next few decades, nickel-cadmium and sodium-sulfur batteries were increasingly used. Since 2010, more and more utility-scale battery storage plants rely on lithium-ion batteries thanks to the fast decrease in the cost of this technology, driven by the electric automotive industry. Lithium-ion batteries are mainly used, some redox flow system have emerged and lead-acid batteries are still used in small budget applications. There are numerous suppliers of large battery storage. Since they do not require any mechanical movement, battery storage power plants allow extremely short control times and start times, in the range of few 10s of ms at full load. As well as shaving power peaks of up to a few hours, thanks to that reactivity they can they can also dampen the fast oscillations (second) that appear when electric power networks are operated close to their maximum capacity. These instabilities are voltage fluctuations with periods of up to several 10s of seconds and can soar in worst cases to high amplitudes, which can lead to regional blackouts. A properly sized battery storage power plant can efficiently counteract these oscillations. Therefore, applications are found primarily in those regions where electrical power systems are operated at full capacity, causing a risk in the grid stability. Large storage plants (Na-S) can also be used in combination with intermittent renewable energy source in standalone hybrid micro-grids. Some systems, operating at high temperature (Na-S) or using corrosive components are subject to failure even if they are not used (calendar ageing). Other technologies suffer from deterioration caused by charge-discharge cycles (cycle ageing), especially at high charging rates. These two types of ageing cause a loss of performance (capacity or voltage decrease), overheating and may eventually lead to critical failure (electrolyte leaks, fire, explosion). Some batteries can be maintained to prevent loss of performance due to ageing. For example, non-sealed lead-acid batteries produce hydrogen and oxygen from the aqueous electrolyte when overcharged. The water has to be refilled regularly to avoid damage to the battery and the inflammable gases have to be vented out to avoid explosion risks. However, this maintenance has a cost and recent batteries, such as Li-Ion, are designed to have a long lifespan without maintenance. Therefore, most of the current systems are composed of securely sealed battery packs which are electronically monitored and replaced once their performance falls below a given threshold. Sometimes battery storage power stations are built with flywheel storage power systems in order to conserve battery power. Flywheels may handle rapid fluctuations better than older battery plants.