We’ve all heard, “The wind isn’t always blowing and the sun isn’t always shining,” but actually it is. Granted location is everything but wind is almost entirely caused by the effects of the sun which, each hour, delivers 175 million million watts of energy to the earth. As the energy heats the planet’s surface it causes air to rise. This rising air creates an area of low pressure at the surface into which cooler air is sucked, and it is this flow of air that we know as “wind. Simply put, wind is caused by differences in the atmospheric pressure which the sun plays a large part in. As these forces are hard at work, how can we take full advantage of the power they emit? Energy storage has already made its debut and with great success. ‘Elon Musk’s Battery Farm Is an Undeniable Success,’ says Popular Mechanics, writer Caroline Delbert. The article goes on to say, “The Neoen-owned Hornsdale Power Reserve is literally a facility full of Tesla PowerPacks that receives and stores energy from nearby wind and solar farms.” The resiliency and savings of this energy storage system is remarkable. However, energy storage technology shouldn’t stop there. In a new paper, researchers at Tianjin University in China examine battery technologies. Three broad conclusions are drawn from their analysis – that research should move in the direction of novel battery systems aimed at meeting all the requirements of grid level energy storage, that cost efficiency requirements mean efforts should focus on batteries based on cheap, abundant materials. And finally, that modelling and comparison between different battery technologies is vital in establishing the best option for a given use case.
It may come as a surprise that while lithium-ion batteries are, by far, the most commonly used battery for grid-scale energy storage, recent studies show they are not the most appropriate. Determining the best battery for the job, researchers in China examined lead-acid, lithium-ion, zinc-air, nickel/metal-hydrogen and sodium-sulfur batteries to assess their properties in terms of round-trip efficiency, specific energy and capacity, operating voltage, cycling life, self-discharge performance, cost, environmental impact and safety. Zinc-air batteries were ranked first because zinc-air devices have relatively high specific energy and capacity. These devices also scored highly on cost, safety and eco-friendliness. Lithium-ion batteries came second in the grid-scale storage ranking. Concerns over raw material sourcing, costs and safety are downsides for the industry’s current chemistry of choice. William Chueh, Associate Professor of Materials Science and Engineering at Stanford University, feels to get to utility-scale they “need to consider a cost reduction of 10-20x.” Currently, lithium-ion can affordably store up to 4 hours of energy but they are a fire risk and the ability to hold a charge fades over time. Additional alternatives being considered include flow batteries and thermal energy storage. Flow batteries do not pose a fire risk and are not prone to capacity fading over time. Within the world of flow batteries, Primus Power is using zinc bromine flow batteries and ESS Inc. is using iron flow battery systems. Storage is not unlimited with flow battery systems and they still face the materials/cost challenge.
There are other forms of storage being put to the test that are neither chemical or battery based. Energy Vault, modeled after pumped hydro power, uses gravity and kinetic energy for long-duration energy storage. They employ an automated system with machine vision software. The Energy Vault uses cranes and wires to move 35-ton bricks up and down depending on energy needs. The sheer size of the operation has some doubting it as a replacement for chemical batteries.
Thermal storage has the potential to store energy longer than flow batteries. Antora Energy uses excess energy to heat up carbon blocks and when needed that heat is converted back into electricity using a heat engine. As explained by Antora’s Co-founder and CTO, Justin Briggs, they are using a thermo-photovoltaic (TPV) heat engine, a more cost effective method than the commonly used steam or gas turbine. TPV is a solar cell but instead of capturing sunlight, this captures light radiated from the hot storage medium and converts that into electricity. This should allow them to store days if not weeks of storage with cheaper raw materials. Please watch the entire youtube video, The Future of Energy Storage beyond lithium in batteries, to see all the companies working on new batteries and new technologies for energy storage.
William Chueh, at Stanford University stated, “There are hundreds of companies working on scaling up and manufacturing new battery technology.” So regardless of your location, the sun is always shining and the wind is always blowing and soon the technology will exist to store that power effectively and affordably. The question is, which battery will it be? Or better yeat, what alternative technologies will surface that can provide utility-scale storage at a reasonable price?
Source: energycentral
