Because electric power generation by wind generators or solar batteries makes some inconstancy, energy storage subsystems became the important part in energy supply systems. The electric power accumulated for a day is delivered in a network at evening hours or at moments of peak consumption, when energy amounts, generated by a solar power-station, appear to be not enough for consumer needs. Thus it is necessary to understand that system of energy accumulation and storage is not simply an accumulator, leading global companies understant this concept in some other words. Manufacturers offer complex solutions that include both actual accumulators (storage units) and software solution that provide control over accumulator condition and optimal load balancing.
The review of global market of the electric power accumulation systems is provided below, we selected the most innovative companies and technologies to present potential solutions variety and diversity of actual technical basis. Thus the estimation possibly intercepted some wonderful and even revolutionary ideas that either are simply impossible to implement due to technical reasons or such implementation will not bring some positive economic effect. Our review list based on companies that already have large resources and able to present the completed innovative decisions, and their reliability and perspectives are confirmed by finished project lists.
When Redflow company from Australia declared about market launch of home powerful storage batteries with liquid electrolyte, many specialists did not take it with a grain of interest. However, during sales launch in March 2016 first samples got positive reviews. Nowadays Redflow is mainly oriented to the internal Australian market of solar energy consumers.
Permanent "green" tariff reduction combined with growing prices on energy sources make Zcell liquid electrolyte batteries into more and more attractive option for households. The energy storage system developed by the Australian engineers is based on 10 kW zinc-bromine storage battery. Accumulating energy from solar batteries, it gives power back at peak-load moments, at evening and night hours. it is It is quite reasonable to mention some advantages of the battery:
Main problems, as some experts suppose, are related to zinc-bromine accumulator, that is very effective at longtitude cycles of energy accumulation and storage, but not so good at short charge-discharge cycles. In addition, most customers got used to be oriented on lithium-ion accumulators, that makes further commercialization of ZCell a bit problematic, especially outside Australia.
Tesla is gradually becoming one of global leaders in the area of energy storage systems creation. Novadays Tesla presents two versions of such systems: Powerwall and Powerpack. First can be used in private households and small office apartments, second is intended for enterprises, able to work with high currents and for large number of consumers.
Household version of Powerwall has several models: 7 kW battery costs approximately 3 thousand US dollars, 10 kW option with 3,5 thousand US dollars price and most powerful 14 kW model (5,5 thousand dollars, accumulator capacity is enough for twenty-four hours energy supply of a house with two bedrooms. Customers must pay additional fee of 1500 - 1600 dollars for installation works, invertors and other consumable and expendable materials. Battery dimensions are about one meter breadthways and longwise, thickness is about 18 cm, weight is 100 kg. Accumulator recharge is possible both from wind generator/solar battery and from power grid. Powerwall can be installed indoors or outdoors, operational temperature may vary from − 20 to +43 Celsium degrees. Producer claims 10-years warranty for the battery.
Industrial version of Powerpack has 100 kW of power, but its construction enables easy combination of separate elements into large systems with total power up to 100 MW, that is quite enough for power supply of large industrial object. Approximate price tag is 250 dollars for 1 kW.
Sonnen company is the undoubted leader at German market of the domestic energy storage systems, total sale rates are over 10 thousand home power systems. Sonnen presents storage batteries with different capacity from 2 to 16 kW/h, and claims that operation time is no less than the 10 thousand discharge/charge cycles with 80% maximum possible discharge rate. Recently the company acts not only as equipment producer but also positions itself as service provider at electricity market.
In November 2015 Sonnen started an ambitious project in Germany. SonnenCommunity platform is a possibility to create virtual pool for proprietors of solar systems and electric batteries. Surpluses of electric power, generated by solar batteries, can be distributed among participants of virtual network. For example, some power amount can be transferred to charge storage batteries of other network member or sold on wholesale market in future. Taking into account rapid decline of "green" electric power tariffs, this will allow green power producers to sell it in real time mode when prices are most favourable. Any user, who purchased Sonnen equipment, can be connected to the virtual network. Sonnen also uses new software that can visualize aggregated storage in real-time.
Market experts recognize Sonnen as the most real competitor of Tesla company, which already sold about thousand systems for domestic solar power-stations. Indeed, the cost of energy storage is lower in Tesla systems, but Sonnen insists on better operational time and charge/discharge cycles quantity.
In Japan, where about 1 million new houses are erected annually, Zero Energy Homes (ZEH) standard will become mandatory in 2020. Panasonic and other Japanese firms, being direct competitors of Tesla’s Gigafactory, already sell turn-key solutions for domestic solar power stations to their local customers, making electric power storage system as an additional feature. Panasonic will implement its own "smart city” project near Yokohama. It is planned that all domestic solar power-stations and systems of energy accumulation within city perimeter will be incorporated in the single network. This will allow not only to provide energetic safety of the city but also to enter the Japanese wholesale market of electric power.
Panasonic is one of the largest producers of powerful storage batteries in the world, large production volumes allow company to sell their products at very attractive prices. Smart Towns is a young, ambitious project, where Panasonic will try to realize new approaches in accumulation and further distribution of electric energy. Thus the company will use the recent Canadian experience, where Panasonic realized large "Sunny batteries + accumulator" project. The company plans to implement a few projects on construction of electricity storage systems for dwelling houses in Australia, even though strong competition at this market.
NGK Insulators from Japan was one of the first companies to enter the world market of electricity accumulation and storage systems, offering technology of sulphuric-natrium batteries with liquid electrolyte. Nowadays total power of NGK Insulators accumulators all over the world makes about 3 GW, accumulators of this very type form the greatest network of electric storage batteries in whole world, located in Japan. From 2007 to 2010 the company’s share at long-duration electricity storage accumulators market was about 66%. Due to technological features, sulphuric-natrium batteries have a large operational time, but are subject to fire risk at high temperatures.
In spite of the fact that lithium-ion batteries fit better for creation of large systems of electricity storage than liquid electrolyte accumulators, the latter will hold their positions as alternative technology for the long-term accumulation of electric power for some time. For example, quite recently NGK Insulators won a tender to build large system of energy accumulation (35 МW- 280 MW) in Italy.
The French Saft company became one of main newsmakers since it was purchased by Total petroleum giant for 1 billion of US dollars, which makes it the largest acquisition for accumulator producers. Before ownership changes company was an active participant in different projects all over the world, creating systems of electric power storage and management, based on lithium-ion batteries of Saft own production. Main Saft efforts were concentrated on projects in remote areas with high prices of electric power. Installation of 1,2 MW electric system power for a remote settlement on Alaska, large solar power-station in Anahole (Hawaii), and also newest contract on construction of the 10 MW system of energy accumulation in Puerto Rico can be considered as bright examples of company’s work.
Market experts make prudent comments on proprietor changes, noting that at the beginning the company will not be able to compete with such well-known industry leaders as LG Chem, Samsung SDI, Tesla and Panasonic, at least on the production volumes.