By Aditya Chhatre
Let’s sit back and think about how many things we have used today need a battery – a phone, laptop, computer, watch, television, car, bike and other household electronic appliances. Basically, this is a non-exhaustive list and we are all surrounded by batteries. Batteries represent a 113.4-billion-dollar market and is expected to grow to 310.8-billion-dollar market till 2027. As a product batteries have been revolutionary for mobilizing most of the electronic devices we use today. Moreover, electric vehicle, which once considered commercially non-viable, have now reached a comparable scenario with the conventional internal combustion engine vehicles. Now, batteries are set to bring a change in the energy landscape of the power sector. Electricity has one of the largest supply chains in the world in the form of power grids, however with no inventory for storage. Storing electricity has never been a common phenomenon considered for grids. Power plants and grid operators always have been critical about matching the electricity generation with its demand. There are also fines levied upon power plants if they do not abide by the regulations for generation. A new application, energy storage for power grid services, has created a surge in battery demand in recent years. Future power grids are on their way to be flexible and more stable. The journey of batteries from a non-viable and costly solution to this newly found use case in the power grids has not been an easy one. Although it has lot of interesting caveats to explain the evolution of battery applications of almost 200 years.
Batteries – a revolution
A battery is a device governed by a chemical reaction which generates electricity. It is a simple electro-chemical device. It requires two different metals and an electrolyte to work. This all started in 1799 when Alessandro Volta invented the first modern battery. It was nothing but a stack of silver and zinc coins separated but a brine-soaked cardboard. The higher number of such coins, resulted in higher amount of electricity generation. Things changed with the invention of dynamo in 1831 which gave an opportunity to generate electricity on demand. Even though the battery technology has been the same as Alessandro Volta’s invention, modern-day battery innovations are carried out by scientist swapping the metals with other metal chemistries and electrolyte. This resulted in designing of rechargeable batteries in 1859. These rechargeable batteries were nothing but the robust lead-acid batteries. Then after world war-II nickel based batteries (cadmium, hydride) showed up powering the early camera flashes and some of the electric vehicles. Finally, in 1991 Sony introduced the first commercial lithium-ion battery. This invention of lithium-ion batteries have had a revolutionary effect on the markets of consumer electronics and electric cars. Electronics such as laptops and mobile phones were enabled to be compact and light weight. This transformation created huge demands of lithium-ion and the battery market sprung up. Although this was just the beginning of the journey. The features these battery technologies were still amicable only for low-capacity applications and yet were not ready to be considered for large capacity applications such as electric vehicles or grid energy storage.
It is usually not straightforward to explain the growth of any sector or industry as there are number of elements associated with it. Each factor plays a specific role and the result is the combination of these efforts. Although, it is interesting to narrow down these factors and analyze the evolution of the technology. The grid application for batteries is one such sector which has been influenced by diverse factors. Each of these elements are intriguing and worth to be narrowed down further.
The climate demands
During the mid-20th century, the greenhouse gases became a major topic of concern in many fields. Eventually scientist believed that this effect was mainly due to carbon intensive human activities. The effects were distinctly visible in cities due to its concentrated population and because of significant increase in the use of fossil fuel driven cars. Along with the climate effect, the realization of finite source of crude oil alarmed governments and sectors such as oil and vehicle manufacturers. Rethinking was needed on fossil-fuel based vehicles. As businesses had to survive, they focused their investments in sectors of auto industry for electric vehicles and also in clean energy technologies such as solar and wind. Both these technologies depend upon powerful batteries which store energy for a long amount of time. In those days the prevalent technologies like lead-acid and nickel-based batteries which were designed for robust application and were not suitable for electric vehicle market. A new battery chemistry was desperately needed which could serve powerful and lightweight applications. Also, this technology needed to meet the standards of being environmentally friendly.
Why is lithium a winner?
A complex product like battery has large number of technical parameters. Although, these parameters are useful as batteries are sensitive to the user behavior and the working conditions. Acknowledging these guidelines and parameters ensure maximum efficiency. Amongst these there are 4 of such factors which can be considered as primary parameters for evaluation of a battery technology. Energy density and power density define the electricity a battery can store and provide based on the chemistry of the metals used. Energy efficiency is the second parameter which is crucial for any electrical appliance. Lastly, life of a battery is usually counted by the charging and discharging cycles it serves.
Fig. 1 explains the dominance of Li-ion batteries for all 4 considered primary parameters compared with other battery types. Certainly, there are application wherein other battery types are preferred such as lead-acid which are suitable for car starter batteries or inverters. However, the untapped potential of lithium brought Li-ion batteries to the forefront for further research. With consistent and combined efforts from scientist and manufacturers, a stable lithium-ion battery was designed and commercialized in 1991 by Sony. Since then, there were attempts to construct a stable and better chemistry than the Li-ion batteries. But these attempts are not yet successful. As this invention has given humans an opportunity to transition to a fossil free society, in 2019, John Goodenough, Stanley Whittingham and Akira Yoshino were awarded the Nobel Prize in chemistry for ‘development of lithium-ion’.
Growth of the clean tech
After lithium-ion battery technology revolutionized the industry of mobile phones and laptops, they still were behind for the user levels with respect to the technology and also with the prices. In 2003, Tesla emerged as a pioneer in the auto industry and had the vision to comprehend the idea of electric vehicles. After 5 years, in 2008, Tesla commercialized its first ever electric vehicle ‘Roadster’. It was the first time that such high number of batteries were stacked up and used for an intensive application such as electric vehicles. This gave other manufacturers a sense of belief in the technology. Gradually businesses increased their investments in research and development of lithium-ion batteries for electric vehicles. In the next years the patents filed for lithium-ion batteries increased(Fig 2). The technology has been improving since then. Besides that, the demand of Li-ion batteries made the supply chains of raw materials stronger and more efficient. This led in reduction of prices of Li-ion batteries from 1128 $/kwh in 2008 to around 140 $/kwh in 2020. As the demand of electric vehicles and Li-ion batteries is nowhere near its peak, the price reduction trend is expected to continue and the prices are anticipated to get even below 100 $/kwh in the next years.
A similar shift to the low carbon intensive techniques was a need in the 1990s in the sector of electricity generation. Most of the electricity generated was with fossil fuels such as carbon and oil. This urgency to get the emissions in control resulted in deploying resources for the generation of electricity through solar and wind plants. By nature, these renewable energy power plants are highly dependent on weather conditions. This leads to inconsistency in generation resulting in situations of shortages or abundance of electricity. Power grids are the means of transmission for carrying electricity from the generation locations to the consumer location. Voltages and frequencies for the grid are to be maintained at a certain value for functioning of the grid. Any changes could lead to failure of grid with load shedding. Such variability caused by these renewable energy resource makes the grid unstable. To compensate to this variability, energy storage plants are required to compensate and maintain the stability in electricity grid. Conventionally hydro power is the most common energy storage power plant used to maintain these imbalances of the grid. These hydro power plants require large amount of land. Also, it is not convenient to build hydro power plants at specific locations where the grids are congested. With these constraints hydro power plants are probably not the solution for the need of decentralized energy storage facilities.
The more the share of renewables in the grid, higher the possibility of instabilities in the grid. This has led to increase in deployment of energy storage facilities. Lead-acid batteries were previously used for grid applications to support operations to maintain voltage and frequencies. Even though this application was comparatively on a small scale, the need of such ancillary services is predicted to increase in the future. But as lithium-ion batteries have proved to be more efficient, they have come up as a dominant solution with the market share more than 90% for power grid applications. Along with system operation applications, storing the extra power generated by solar and wind power plants is another important application which is economical for the plant owners. Plant owners can now unleash the full capacity of the plant by storing the extra electricity generated. This stored electricity can then be used to sell at situations when electricity prices are high giving plant owners additional monetary benefits. Fig. 3 shows the four different services, a utility scale battery system can provide.
Large scale lithium-ion battery systems, even though they are dominant today, have questions such as recyclability and fire breakouts to be answered. But the change is that manufacturers are already thinking about recycling during its design stage. This has helped recycling to go global right from the beginning. Tesla co-founder, JB Straubel, had quit Tesla in 2019 and joined a startup to build battery recycling facilities. Also, research is been carried out and the systems are built taking into account the safety precaution for fires problems. Surely, there are alternate technologies such as lead-acid and redox flow batteries for similar grid applications. In some cases, these battery chemistries might be even better. However, these alternate technologies would take time to establish and meet such high demands in such a small span of time. Especially when the climate targets are so urgent. On the other hand, lithium-based batteries are already matured and hence are predicted to be dominant choice for batteries for the next 10-15 years.
Certainly, various policies are designed to support existing sectors with energy storage technologies. Many countries are investing in large scale battery storage applications and relying on it to strengthen solar and wind power plant portfolios as they increase their dispatchability, and allow revenue stacking from arbitrage and ancillary services offered to the power grid. According to the new policy scenario of IEA, the installed of battery storage systems globally is predicted to be 218 GW in 2040 which is just 23 GW in 2020. These battery systems will surely play a key role in energy transition from the fossil fuels.