The Top 5: Improbable Energy Storage Possibilities Turned into Reality

The storage for renewable energy in particular has become one of the main talking points in the energy industry across the globe for the sake of transition to a green future. Intermittent energy sources like wind and solar power often lack the ability, or fall short in their capacity, to accommodate postponed usage. Thus, there has been a strong dialogue for an efficient and economically viable energy storage system for a while now.

The demand for global energy storage market size & share was valued at approximately USD 211 billion in 2021 and is expected to grow above a CAGR of 8.45 per cent, reaching over USD 436 billion by 2030, as per a Facts and Factors report. Growing tension over constant energy supply in some parts of the world will be the driving force for the significant growth rate of the market.

Recent scientific breakthroughs in storage solutions, including advancements in lithium-ion batteries and water electrolysis-based hydrogen production, signify significant strides in addressing this challenge. Concurrently, research within the realm of renewable energy has contributed to mitigating the environmental footprint of emerging technologies such as batteries, cells, and energy management systems, all while enhancing their economic viability.

Every industry-leading technology was just a strange idea in its infancy. Similarly, even in the energy storage sector, many such novel and strange ideas pop up once in a while with the potential to change the course of the industry. This article focuses on some of the strangest energy storage possibilities that have come forth, thanks to these research endeavours. Here’s our top Strangest Energy Storage Possibilities.

#1 Flow Batteries

Flow battery technology has become quite renowned in a world looking to search for ways for energy storage and utilisation. The Global Flow Battery market size will grow from $289 million in 2023 to $805 million by 2028, clocking a CAGR of 22.8 per cent in the period, as per one report. Flow batteries are proven to be ideal for efficient and scalable energy storage and are finding their footing in utilities, industrial, commercial, and residential applications.

This is a rechargeable battery that operates using an electrolyte flowing through one or multiple electrochemical cells from corresponding tanks. Using a basic flow battery design, boosting the energy storage capacity is as simple as adding more electrolytes to the tanks. The electrochemical cells can be linked either in series or in parallel, which determines the overall power capability of the flow battery setup. This separation of energy capacity and power capability is a significant characteristic of flow battery systems.

Flow battery technology offers modular and scalable systems that can be made to suit a wide range of applications, from power ratings of watts to megawatts, and with energy durations of many hours or even days.

There are various types of flow batteries penetrating the market. Many startups have come up in recent times offering various types of flow battery technologies. These include Multi-Day Redox Flow Battery of Sinergy Flow, Redox Flow Membranes of Cellfion, Organic Flow Batteries of Fluxx XII, Water-based Flow Batteries of Quino Energy, Liquid-Flow Batteries of Zhonghe Energy Storage, etc.

Last year, A 100MW/400MWh vanadium flow battery system, the largest of its kind in the world, was put into operation in Dalian in northeast China. Lausitz Energie Bergbau AG (LEAG) and ESS Tech Inc. are also planning to install a 50MW/500MWh iron redox flow battery in Germany as part of a broader partnership for the deployment of the US company’s energy storage technology in the country.

#2 Molten Salt Battery

The molten salt battery is specifically engineered to capture thermal energy from thermal solar arrays. It then releases this stored energy during nighttime hours when the Sun isn’t shining. This process generates steam to power a traditional steam generator, ensuring a consistent energy supply for consumers. Solar concentrators concentrate the Sun’s thermal radiation and apply it to directly or indirectly heat a high-capacity salt with a suitable melting point, like potassium nitrate, which melts at 370°C (698°F). This high-temperature salt is stored in an insulated container until its energy is needed.

Molten salt batteries are particularly useful for large-scale grid storage applications, despite having a round-trip energy efficiency of only approximately 70 per cent.

Molten salt thermal storage facilities are gaining traction worldwide. A Danish consortium consisting of Hyme Energy and Bornholms Energi & Forsyning is building a pilot project to store clean electricity with molten salt. The system will likely start providing heat, power and ancillary services by 2024. China’s energy storage pilots also include grid-powered molten salt. Last year, a $28 million small molten-salt thermal energy storage unit was commissioned in Zhejiang Province. It is powered by excess wind and photovoltaic electricity. A $140 million molten salt storage project had its investment agreement signed in Jiangsu, the province just north of Shanghai.

#3 Carbon Dioxide Storage

Under sufficient pressure, carbon dioxide can be easily stored in liquid form at room temperature. This condensed state occupies significantly less space and also presents an opportunity for energy gain during the phase transition.

Charging the carbon dioxide battery involves using energy to compress gaseous CO2 into liquid form. The heat generated during compression is stored in a thermal energy storage system. For power extraction, the liquid CO2 is heated using stored heat and then expanded through a turbine, generating power. The system utilizes a sealed CO2 setup, storing energy in pressure and phase change rather than chemical reactions. While not precisely a battery, similar to hydroelectric pumped storage, it functions as an energy storage system.

The system benefits from common and simple equipment. No radical processes—just gas compression and turbine expansion. Unlike lithium-ion solutions, it avoids expensive rare materials and extensive copper wiring.

An Italian startup, and the maker of the world’s first CO2 battery, Energy Dome announced its official entry into the US market. The firm was awarded funding and networking support from Hawaii and Bay Area-based Elemental Excelerator, which invests in climate tech deployment. In April this year, Energy Dome raised 40 million euros ($44 million) from investors to fund expansion in the US, bringing total investments raised by the firm to around 54 million euros.

In June 2023, Italy based Energy Dome announced the launch of a commercial long-duration energy storage technology plant in Sardinia. Energy Dome is currently constructing its first full-scale power plant with a capacity of 20MW-200MWh, which will be operational by the end of 2023.

Energy Dome revealed it was already working with several utilities, independent power producers, and corporate customers, for a pipeline of more than 9 Gigawatt hours (GWh) in markets such as the US, Europe, South America, India, and Australia.

#4 Gravity Energy Storage

Gravity energy storage captures gravitational energy in a storage device, such as stacked concrete blocks. It draws surplus energy from the grid, converting it into potential energy as the blocks rise, ready for release when needed. In essence, what goes up inevitably comes back down.

Energy Vault, situated in Switzerland, has engineered an advanced automated setup for arranging and disarranging 35-ton gravity blocks using a six-arm crane reaching 70 meters in height. For reference, 1 ton is approximately 2,200 pounds. This sustainable technique doesn’t depend on land availability or reservoir utilization. Following a 2020 prototype, the company is now striving to construct 200-meter-high Resiliency Centers, each comprising 20 stories, named Energy Vault Resiliency Centers.

Gravitricity is another company in this field, developing a gravity-based energy storage system involving lifting heavy weights, up to 12,000 tons, in deep shafts and releasing them as needed. In India, it has joined forces with Panitek Power for a 12-month project to pinpoint sites for a demonstration project. New Energy Let’s Go and Gravity Power employ their stacking methods using water hydraulics. Pumped Energy Transfer Stations (PETS) also leverage water gravity for energy production. With two basins, these stations initially pump water from the lower to the upper basin.

#5 Thermal Ice Storage

Thermal ice storage, or thermal energy storage, operates akin to a battery for a building’s air-conditioning setup. It combines regular cooling equipment with an energy storage tank to move a building’s cooling requirements to off-peak nighttime hours. During these off-peak periods, ice is produced and stored in energy storage tanks. This stored ice is subsequently utilized for cooling occupants in the building the following day.

In a proposed project, Nostromo aims to deploy its innovative IceBrick system across approximately 120 buildings, offering a combined energy storage capacity equivalent to 100/275 MW/MWh. This initiative will lead to lowered energy expenses for the buildings and an annual reduction of 40,000 tons of carbon emissions. Additionally, it will facilitate the incorporation of more renewable energy sources, provide demand flexibility, and enhance the power grid’s resilience.

Nostromo recently completed the IceBrick system installation at the Beverly Hilton and Waldorf Astoria hotels in Beverly Hills. This implementation is expected to supply cooling energy to these hotels at less than half the current cost and decrease their annual scope 2 carbon emissions by 150-200 metric tons.