Sustainable energy storage is in great demand. Researchers at Uppsala University have therefore developed an all-organic proton battery that can be charged in a matter of seconds. The battery can be charged and discharged over 500 times without any significant loss of capacity. Their work has been published in the scientific journal Angewandte Chemie.

The researchers have been able to demonstrate that their battery can be easily charged using a solar cell. Charging can also be accomplished without the aid of the advanced electronics that, for example, lithium batteries require. Another advantage of the battery is that it is unaffected by ambient temperature.

“I’m sure that many people are aware that the performance of standard batteries declines at low temperatures. We have demonstrated that this organic proton battery retains properties such as capacity down to as low as -24°C,” says Christian Strietzel of Uppsala University’s Department of Materials Science and Engineering.

A great many of the batteries manufactured today have a major environmental impact, not least due to the mining of the metals used in them.

“The point of departure for our research has therefore been to develop a battery built from elements commonly found in nature and that can be used to create organic battery materials,” explains Christian Strietzel.

For this reason, the research team has chosen quinones as the active material in their battery. These organic carbon compounds are plentiful in nature, among other things occurring in photosynthesis. The characteristic of quinones that researchers have utilised is their ability to absorb or emit hydrogen ions, which of course only contain protons, during charging and discharging.

An acidic aqueous solution has been used as an electrolyte, the vital component that transports ions inside the battery. As well as being environmentally friendly, this also provides a safe battery free from the hazard of explosion or fire.

“There remains a great deal of further development to be done on the battery before it becomes a household item; however, the proton battery we have developed is a large stride towards being able to manufacture sustainable organic batteries in future,” says Christian Strietzel.

When three scientists won the Nobel Peace Prize last year for their work on lithium-ion batteries, The New York Times was one of many outlets that drew the connection between improved energy storage and the fate of our planet: “By storing electricity generated when sunlight and wind are at their peak, lithium-ion batteries can reduce dependence on fossil fuel energy sources and help lessen the impact of climate change.”

This perfectly articulates the gauntlet we face today. How can we transition to using solar and wind to power the world when the sun isn’t shining and the air is still? The answer is to improve energy storage technology, which requires time, careful research, and expert engineering that goes beyond the scope of most other challenges we face today. Because of this, the path to meeting this objective cannot rely on uncertain venture capital raises or traditional fundraising models. As public awareness around the challenge of energy storage grows, we need public funding and support to help this sector of the energy industry rise with it.

The State of Green Energy
Today, many individuals, homes, and businesses benefit from wind and solar energy, and innovations and improvements in these fields are promising. Furthermore, interest in climate change has grown in the past several years, and I’m not just talking about Greta Thunberg’s voyage across the Atlantic. Research by Pew found that concerns about climate change have broadly increased since 2013.

In this rapidly evolving environment, it’s hard not to feel like we’re on the brink of making a huge breakthrough, if only we can innovate and execute fast enough. According to the U.S. Energy Information Administration’s July 2019 report, “Operating utility-scale battery storage power capacity has more than quadrupled from the end of 2014 (214 MW) through March 2019 (899 MW). Assuming currently planned additions are completed and no current operating capacity is retired, utility-scale battery storage power capacity could exceed 2,500 MW by 2023.”

These numbers herald major developments in the energy storage industry, and much of this is driven by the need to get better batteries into consumers’ hands faster. But that doesn’t mean the pace of research has changed. Consumer products from AirPods to pacemakers have set a new high bar for wireless charging and electric battery life. And that is where we find our current limit.

Electric Vehicles Have Gone Mainstream
One of the most exciting changes in the past decade is the arrival of affordable electric vehicles (EVs) in the consumer market. Prius drivers and early Tesla adopters have ushered in a new age in which cities and towns have to think about their charging infrastructure for EVs.

In 2018 alone, EV sales exceeded two million units globally—an increase of 63% year-over-year—but there are still significant barriers to EV adoption. On the road, EVs remain limited by the energy they can store and where the next available charging station is located. And this significantly hurts their appeal to drivers who are used to traveling with the assurance that there will be a gas station waiting for them at the next exit. As major corporations such as Amazon work with EV manufacturers including Rivian to develop new fleets of electric delivery vehicles, it’s reasonable to hope that these fleets will bring increased incentives for public investment in charging infrastructure for EVs across the country.

A new conveyor-based system offers an alternative energy storage technology. The heart of the system is a reversible conveyor belt that converts between electrical energy and gravitational potential energy by transporting bulk granular materials between two stockpiles at different elevations.

The U.S. Department of Energy reported that the total solar energy production in the U.S. increased from 28,924 GWh in 2014 to 96,147 GWh in 2018. During the same time period, it said the total energy produced by wind in the U.S. increased from 181,655 GWh to 274,952 GWh. Grid operators must keep the supply and demand for energy in balance. Traditionally, operators balanced supply and demand for electricity by modifying the supply to match demand. However, wind and solar generators cannot change the energy they supply as easily as conventional coal and gas power plants. To balance the supply and demand for power, many grid operators with large solar and wind assets are utilizing energy storage facilities to increase the demand for power when the supply would otherwise outstrip demand.

Currently, there are four commercialized energy storage technologies deployed in the U.S. They are pumped hydro storage (PHS), compressed air energy storage (CAES), advanced battery energy storage (ABES), and flywheel energy storage (FES). As of June 2018, 94% of U.S. energy storage assets were PHS. PHS commands a huge market share because unlike ABES its lifetime is measured in decades instead of years. PHS technology was proven more than a century ago, and the cost per MWh stored and dispatched are lower than all its competitors.

PHS systems require large volumes of water that are not readily available in all regions of the world. Conveyor Dynamics Inc. (CDI) has developed a new energy storage system analogous to PHS, but instead of transporting water between reservoirs, the conveyor energy storage (CES) system stores and releases energy by moving bulk granular material between stockpiles. Like PHS, CDI’s system utilizes low-cost and proven equipment that has been deployed for decades. The company expects the CES system to provide a competitive alternative to PHS in arid regions of the world.

1. The conveyor energy storage system utilizes a motor-generator scheme similar to technology employed at a pumped hydro storage facility. When energy is to be stored, the motor-generator drives a conveyor to move bulk granular material from a lower stockpile to an upper stockpile. When energy is to be supplied by the system, the motor-generator is driven by the conveyor as the bulk granular material is transported from the upper stockpile back to the lower stockpile through gravitational force. Courtesy: Conveyor Dynamics Inc. (CDI)

Figure 1 shows the operating principle of the CES system. The heart of the system is a reversible conveyor belt that converts between electrical energy and gravitational potential energy by transporting bulk granular materials between two stockpiles at different elevations. The reversible conveyor is driven by an electric motor-generator controlled with a four-quadrant inverter drive.

To store energy the reversible conveyor receives ore from feeder conveyors below the low-elevation stockpile and discharges the material onto the high-elevation stockpile. To release energy, the conveyor reverses direction, receives material from feeder conveyors under the high-elevation stockpile, and discharges this material onto the lower-elevation stockpile.