Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Making "Renewable" Viable: Drexel Engineers Develop New Technology for Grid-Level Electrical Energy Storage

13.07.2012
In the aftermath of the recent United Nations Rio+20 Conference on Sustainable Development, the focus of many industrialized nations is beginning to shift toward planning for a sustainable future.

One of the foremost challenges for sustainability is efficient use of renewable energy resources, a goal that hinges on the ability to store this energy when it is produced and disburse it when it is needed.

A team of researchers from Drexel University’s College of Engineering have taken up this challenge and has developed a new method for quickly and efficiently storing large amounts of electrical energy.

The Challenge of Renewable Energy

Electrical energy storage is the obstacle preventing more widespread use of renewable energy sources such as wind and solar power. Due to the unpredictable nature of wind and solar energy, the ability to store this energy when it is produced is essential for turning these resources into reliable sources of energy. The current U.S. energy grid system is used predominantly for distributing energy and allows little flexibility for storage of excess or a rapid dispersal on short notice.

The Drexel’s team of researchers is putting forward a plan to integrate into the grid an electrochemical storage system that combines principles behind the flow batteries and supercapacitors that power our daily technology.

Existing Technology

Batteries store a large amount of energy, but are relatively slow in discharging it and they have a limited lifespan, or cycle-life, than their counterparts – electrochemical capacitors, which are commonly called “supercapacitors” or “ultracapacitors.”

Conventional supercapacitors provide a high power output with minimal degradation in performance for as many as 1,000,000 charge-discharge cycles. The capacitor can rapidly store and discharge energy, but only in small amounts compared to the battery.

The obstacle in the way of using either a battery or a supercapacitor to store energy in the grid is that energy storage ability is inextricably tied to the size of the battery or the supercapacitor being used. Supercapacitors, similar to lithium-ion batteries, are manufactured in fairly small cells ranging in size from a coin to a soda can. Large amounts of expensive material, such as metal current collectors, polymer separators and packaging, would be required to construct a battery or supercapacitor of the size necessary to function effectively in the energy grid.

“Packing together thousands of conventional small devices to build a system for large-scale stationary energy storage is too expensive,” said Dr. Yury Gogotsi, director of the A.J. Drexel Nanotechnology Institute and the lead researcher on the project. “A liquid storage system, the capacity of which is limited only by the tank size, can be cost-effective and scalable.”

A Grid Energy Storage Solution

The team’s research yielded a novel solution that combines the strengths of batteries and supercapacitors while also negating the scalability problem. The “electrochemical flow capacitor” (EFC) consists of an electrochemical cell connected to two external electrolyte reservoirs - a design similar to existing redox flow batteries which are used in electrical vehicles.

This technology is unique because it uses small carbon particles suspended in the electrolyte liquid to create a slurry of particles that can carry an electric charge.

Uncharged slurry is pumped from its tanks through a flow cell, where energy stored in the cell is then transferred to the carbon particles. The charged slurry can then be stored in reservoirs until the energy is needed, at which time the entire process is reversed in order to discharge the EFC.

The main advantage of the EFC is that its design allows it to be constructed on a scale large enough to store large amounts of energy, while also allowing for rapid disbursal of the energy when the demand dictates it.

“By using a slurry of carbon particles as the active material of supercapacitors, we are able to adopt the system architecture from redox flow batteries and address issues of cost and scalability,” Gogotsi said

In flow battery systems, as well as the EFC, the energy storage capacity is determined by the size of the reservoirs, which store the charged material. If a larger capacity is desired, the tanks can simply be scaled up in size. Similarly, the power output of the system is controlled by the size of the electrochemical cell, with larger cells producing more power.

“Flow battery architecture is very attractive for grid-scale applications because it allows for scalable energy storage by decoupling the power and energy density,” said Dr. E.C. Kumbur, director of Drexel’s Electrochemical Energy Systems Laboratory. “Slow response rate is a common problem for most energy storage systems. Incorporating the rapid charging and discharging ability of supercapacitors into this architecture is a major step toward effectively storing energy from fluctuating renewable sources and being able to quickly deliver the energy, as it is needed.”

This design also gives the EFC a relatively long usage life compared to currently used flow batteries. According to the researchers, the EFC can potentially be operated in stationary applications for hundreds of thousands of charge-discharge cycles.

“This technology can potentially address cost and lifespan issues that we face with the current electrochemical energy storage technologies,” Kumbur said.

“We believe that this new technology has important applications in [the renewable energy] field,” said Dr. Volker Presser, who was an assistant research professor in the Department of Materials Science and Engineering at the time the initial work was done. “Moreover, these technologies can also be used to enhance the efficiency of existing power sources, and improve the stability of the grid.”

This concept for energy storage was recently published in a special issue of Advanced Energy Materials focused on next-generation batteries. The team’s ongoing work is focused on developing new slurry compositions based on different carbon nanomaterials and electrolytes, as well as optimizing their flow capacitor design. The group is also designing a small demonstration prototype to illustrate the fundamental operation of the system.

“We have observed very promising performance so far, being close to that of conventional packaged supercapacitor cells,” Gogotsi said. “However, we will need to increase the energy density per unit of slurry volume by an order of magnitude, and achieve it using very inexpensive carbon and salt solutions to make the technology practical.”

Britt Faulstick | Newswise Science News
Further information:
http://www.drexel.edu

More articles from Power and Electrical Engineering:

nachricht Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH

nachricht Engineers find better way to detect nanoparticles
14.08.2017 | Washington University in St. Louis

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>