Feature

Options for energy storage


Joyce Laird

Part 2: Energy storage doesn't just have to involve batteries, continues Joyce Laird.

In part 1 of this article, we looked at how batteries are considered the primary format for energy storage. But that's not to say that other technologies are not being developed.

Moving beyond batteries

Moving power storage/distribution away from battery technology, Dr Timothy Maxwell and John Fleming are in the middle of a very unique project at Texas Tech University (TTU). It addresses not only affordable electricity storage, but affordable fuel and even fertilisers. Maxwell is a faculty member and Professor of Mechanical Engineering at TTU. James Anderson and John Fleming are his partners in Electrogen HydroFuels LLC.

“We have developed a way to convert electricity into a liquid fuel by taking the hydrogen from water using electrolysis and the nitrogen from the air to make ammonia. Once we have the anhydrous ammonia, it can be used in a gen-set to regenerate electricity and also be used as vehicle fuel and as a fertiliser,” Maxwell says.

“The basic technology of using ammonia as a fuel has been around for a long time but it could not be done economically. That's what we've done. It rounds out to about US$1/gallon as a fuel. As a storage venue, it is efficient and makes the national grid much more effective because it gets around the big problem with all the renewables which is the infrastructure,” Fleming adds. “It's very cost effective because the ammonia is made right where the need is. It does not need to be transported. Only the generated electricity is transported. This opens up a wealth of potentials.

“Typically a gas station sells about a 4000 to 5000 gallons of gasoline a day. We will manufacture the ammonia machines in optional standard 40 ft. shipping containers. That's about a 4 MW of electric power input per machine. Put those lines into the hands of a controllable distribution company, and they can effectively sell that power. They can also fuel vehicles and sell by-product as fertiliser,” Fleming says.

The processor puts the hydrogen through an electrolysis process where nitrogen is pulled out of the air using off-the-shelf technology. The hydrogen and nitrogen go through a modified Haber process to make ammonia. The systems at TTU will use new engine technologies that are exactly on a par with all other forms of generating electricity efficiently. However, the technology goes beyond energy storage because it is multi-purpose.

The TTU research has drawn interest from Shell Oil and Chevron for obvious reasons – big oil wants to stay on the leading edge of alternative liquid fuels because they see the writing on the wall. “It also gives them the other avenues for revenue aside from vehicle fuel. In the long run, it may prove more profitable than oil. It certainly costs less than oil exploration, drilling, refining and transporting. The US military, large chemical companies and agricultural companies have also shown interest in backing the development of this process,” Fleming says

“Once the initial technology is done, the estimated final capital cost is US$200,000 for each system. That is extremely cheap compared to all other systems. Think of it as a 4 MW energy generation plant in a 40 ft. shipping container,” Fleming says.

“This can be installed anywhere: at a renewables source, at a utility plant or at a corner gas station. It is very flexible,” Maxwell adds. “The best part is that this does not need subsidies to exist. The technology stands on its own merit economically very well.”

Supporting innovation

Support comes from various places. Below are three very diverse entities that all have a focused interest in supporting innovation in energy storage, each with a unique view on the market.

The Copper Development Association (CDA) based in NY, USA, is a not-for-profit organisation for the copper industry: “CDA promotes the use of copper materials as a sustainable, efficient application for the business industry and the home. My role is to promote the use of copper in energy efficient applications in all areas,” Zolaikha Strong, Director, Sustainable Energy, says.

“One area we are looking at is battery storage: The batteries I am talking about are large scale and can be connected to a wind or solar utility facility to give power in times of intermittency. The batteries ramp up and provide power when there is no sun or wind. They also help maintaining power if there are disturbances on the grid. These batteries use either lithium or copper – both can support the heavy current demands, but copper is more cost effective between the two in these applications,” she explains.

Strong says that the CDA investigates these markets by conducting market analysis – usually as a third party. In respect to the energy storage market, CDA asked energy consultant KEMA to conduct a five-year market assessment. “We created an advisory council and shared the results with the energy storage association, whose members are the basic developers that are bringing these batteries to the various markets.

The test was important in determining the use of copper in the applications and for understanding the energy storage market as a whole. Our energy storage study is the first comprehensive study to be conducted on this topic and we are happy to share it. Of course we do not promote one technology or initiative over another. The opportunity to learn about copper's many benefits is available to everyone.”

Strong adds that proven reliability is the main benefit copper brings to storage batteries: “Reliability is the main focus. Right now, copper is key to reliability. It is the most conductive, it has high heat constraints, it is recyclable and environmentally friendly. Copper fits into the total message of sustainability for a clean, energy efficient market. Utilities depend on that reliability; otherwise they face financial penalties and public relation nightmares if they have outages to deal with. Copper, because of its composite, is the most reliable metal out there.”

Need to be cost-effective

The Electric Power Research Institute (EPRI) is an independent resource research organisation based in the US, but with a focus on the global electric power generation industry. They encompass everyone involved in the generation, distribution, and use of electric power to ensure they are working toward the right requirements.

“Because of our independent and unbiased nature, we can bring all parties together in an environment where there is trust and candid conversations without the feeling that there is any commercial side or benefit in moving in any particular direction,” Haresh Kamath, Manager Distributed Energy Resources Program Manager for Energy Storage, says. “We don't represent any side. We look at it only in terms of how can the electric industry benefit from this in terms of enhanced reliability and affordability of electric power, with as small an environmental footprint as possible, and how does it support the public good.

“We are looking for storage technology options that are safe, reliable, proven and that are cost-effective to install, use and manufacture. Sometimes, one technology can be the starting point for the next step up in a different technology. One excellent example of this is lithium-ion. 25 years ago lithium-ion batteries did not exist. Today, everyone on earth is carrying around at least one lithium-ion battery at any given time,” he says. “So, even though it is not inherently a low cost technology, we still think it has a lot of opportunity in utility applications because it has been proven and it has been manufactured in such volume that the cost has already come down substantially.”

EPRI is also looking at other technologies for the next 10-15 years: “Sodium-ion batteries are similar to lithium-ion batteries but can be based on water electrolytes. They can be manufactured relatively inexpensively if manufactured to the same scale as lithium-ion. There are also sodium-sulphur and sodium-nickel-chloride. There are advanced wood lead-acid technologies, and some leading edge technologies are using nano-technologies to make existing batteries work better.

“Another class is flow batteries where the energy is stored in liquid rather than solid electrolyte. The advantage of these systems is that you can store huge amounts of energy in a relatively compact and simple way. It is always better to store energy in a liquid rather than be limited by solid electrodes. But a lot of work needs to be done before flow batteries reach the same level of maturity as some other batteries. We think there may be some breakthroughs in a few years,” Kamath says.

“Metal air batteries or air-breathing batteries are also getting a lot of interest. These are batteries where one of the electrodes is oxygen in the air. This means they can take advantage of ambient oxygen instead of carrying around all the reactants, resulting in a very compact solution.” By doing that, they actually absorb air when they are discharging and release air when they are charging.

Kamath notes that there are many energy plants using different forms of storage today – the most common being pumped-hydro. “There is about 125 GW of that type of power storage worldwide and about 90 MW of lithium-ion battery storage. Also, there is several hundred megawatts of compressed energy storage, where air is compressed and stored in underground caverns and then run backwards through turbines to re-generate the electricity. Almost every utility is currently playing with some type of overall storage, from West Virginia, USA, to China.”

The power of levitation

Sullivan & Worchester LLP is a law firm with locations in Boston, New York, and Washington, D.C. S&W also has a joint venture, ZAG/S&W, with a law firm in Tel Aviv, Israel, and international alliances in Europe and Asia. “We focus on energy technology development on a global basis,” Jim Wrathall, Counsel says. “It is very important to look at this on the global scale because there are many opportunities for cross-border technology transfers, and also to learn what types of policies are effective for incentivising adoption of advanced energy technology.

“One project I'm involved in is in the area of hydrogen, which is a very promising energy storage technology. This project uses hydrogen storage in a systems based approach. Interstate Traveller Company has developed an advanced transportation system based on MagLev (magnetic levitation). The concept uses opposing magnets to ‘float’ the train, which makes it easier to power.

“The basic technology has been around for some time and it is well proven. The innovation created by ITC involves a combination of advanced MagLev technology and a centre rail of the track covered with solar panels. They have the mathematics worked out so that only about a third of the power generated by the solar panels is needed for the train, leaving the remaining two thirds available for excess energy generation,” Wrathall explains.

“Because the system footprint will be sited along the interstate highways, there are plenty of places to put storage facilities. The energy storage technology is hydrogen based. Every few miles down the track they will have a hydrolysis installation that will turn the excess solar power into hydrogen. And taking this one step beyond, the centre rail of the track will have internal piping for transporting liquid or vapour products, as well as wires for transmitting electricity after conversion. This effectively creates an alternative grid for storage and distribution to put power back onto a system through the hydrogen solution. It makes the hydrogen concept cost effective because it is being done over a distributed scale.”

Conclusion

A wide range of technologies, all moving toward the same goal. Like power generation itself this may develop into using several storage technologies to meet end requirements. Whatever the technology mix that comes out on top, it has to be linked to effective long-range distribution and work very cost-effectively with all electrical power generation methods.

About: Joyce Laird has an extensive background writing about the electronics industry; semiconductor development, R&D, wafer/foundry/IP and device integration into high density circuit designs.

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Comments

ANUMAKONDA JAGADEESH said

04 November 2012
Excellent post.
Dr.A.Jagadeesh Nellore(AP),India
E-mail: anmakonda.jagadeesh@gmail.com

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