Energy Storage Medley: Hydrogen, CAES, Li-ion, NaS, NiCad
May 25, 2010 - Eric Wesoff - greentechmedia.com
Energy storage remains one of the missing pieces of a widespread renewable energy future.
Despite Amory Lovins' arguable claim that renewables in tandem with energy efficiency can serve as effective baseload power, we absolutely need a larger role for energy storage to make renewables effective. And, Mr. Lovins, please note, for the foreseeable future -- we still need fossil fuels and nuclear power.
Many Storage Technologies, Many Applications
Utility-scale energy storage in the field today is limited to pumped hydro, a few large deployments using compressed air energy storage (CAES), hundreds of megawatts of sodium sulphur (NaS) batteries, mostly in Japan, and some experiments with banks of lithium-ion batteries, nickel-cadmium batteries and regenerative fuel cells (flow batteries).
Improvements in batteries, fuel cells, hydrogen storage, ultracapacitors, flywheels, phase-change materials, SMES, etc., will come from incremental advances in materials science. Although a black swan would be most welcome in this field, we are dealing with the limits of known elements, compounds and physics. Maybe some revolutionary advance will rock our paradigms, but for now, improvements in energy storage will come from hard, slow work in the labs of materials scientists.
A few firms are looking into energy storage via ammonia synthesis. The concept is to use energy generated by remote or offshore wind turbines to perform "solid-state ammonia synthesis" and transport that ammonia by land or sea to be used as a fuel. This obviates the need for distant wind farms to be expensively connected to the grid.
Doty Energy wants to use off-peak wind energy to efficiently synthesize fuels, like gasoline and diesel, from CO2 and water. According to the company founder, David Doty, strong arguments for the concept include: (1) the energy storage density in stable liquid fuels is two orders of magnitude greater than the energy storage density in batteries, (2) the energy stored in liquid fuels can then be used seamlessly within our current transportation infrastructure, and (3) the chemical processes being developed promise the scalability needed to competitively replace petroleum-based fuels. Doty's process electrolyzes water and combines the generated hydrogen with CO in a Fischer-Tropsch process to produce the liquid fuels.
Amongst the many energy storage technologies we've covered:
Gravel-based thermal storage from Isentropic Energy -- Thermal Energy Storage Breakthrough?
Ultracapacitors -- Maxwell and the Promise of Ultracapacitors
And since there are a variety of flavors of utility-scale storage applications -- frequency control, load levelling, peak shaving, spinning reserve, etc. -- different applications will call for different technologies. Grid storage could be an $8 billion market by 2016.
Energy Storage Policy
Technology isn't the only element spurring on energy storage -- policy is an accelerant, as well. As reported last week, AB 2514, supported by California Assembly representative Nancy Skinner and state Attorney General and gubernatorial candidate Jerry Brown, will require utilities to obtain 2.25% of their peak power from storage systems by 2014 and 5% of their peak power from storage by 2020.
Here's an article by Rep Jay Inslee, the Democratic Congressional Representative from Washington, on The New Storage Economy.
The Hydrogen Highway is Not Dead.
Vitalie Stavila of Sandia National Labs presented at a conference last week on the technical progress of using complex metal hydrides for reversible hydrogen storage.
Sandia is leading the Metal Hydride Center of Excellence looking to reach the goals that the DOE has set for hydrogen storage through the development of reversible metal hydrides materials.
Although Steve Chu and the DOE have slowed down hydrogen research in favor of our current energy policy (that's a joke, we don't have an energy policy), hydrogen fuel and storage is alive and well in research labs. There is still a community of scientists laboring to improve performance and discover materials to enable the hydrogen highway.
Hydrogen has almost three times the energy content of gasoline (120MJ/kg vs. 44MJ/kg), but the low density of H2 gas means low volumetric energy content. Hydrogen is abundant, but it exists only in the form of compounds. And volumetric compression and storage remain problematic.
Metal hydrides represent a class of materials with volumetric densities higher than gaseous or liquid hydrogen that could enable effective solid state hydrogen storage. There is a DOE hydrogen storage program with stated goals, but according to a presentation by Sunita Satyapal of the DOE, "No [hydrogen] technology meets targets." Here's a link to a long list of DOE publications on hydrogen research.
This remains complex stuff and heady materials science. Some of the more promising materials being investigated are complex metal hydrides, including metal alanates, amides, borohydrides and their derivatives. The DOE wants a reversible 5.5% hydrogen storage system and according to Stavila, "As of now, none of the materials investigated so far satisfy all of the DOE targets."
There is also a time factor involved in getting these materials to absorb and release hydrogen. Despite significant improvements in the storage capacity, most of the hydride materials still require high temperatures to decompose and release their hydrogen.
Michael Kanellos reported on a virus that makes hydrogen and I covered Sun Catalytix, a VC-funded company looking to inexpensively electrolyze water.
Venture Capitalists Vie For the Winning Energy Storage Technology
It's Not Just Startups Going After Utility-Scale Energy Storage
GE is also an investor in battery maker A123.
The Cost of Lithium-ion Batteries for Utility-Scale Storage
And Finally, a Few Words on Ultracapacitors
Market researchers predict that the ultracapacitor (a.k.a. supercapacitor or double-layer capacitor) market will grow rapidly in the coming years, reaching $500 million by 2011 or 2012. This growth will likely be driven by the automotive and transportation sector, as well as by applications in renewable energy, consumer electronics and industrial power management.
Steve Pluvia, a frequent commenter on the GTM comment boards, said, "EEStor is nothing more than a vehicle for a Canadian pump-n-dump, specifically Zenn Motors. Zenn has a powerful Canadian hype team supported by a crooked bucket shop (Paradigm Capital), paid promoters and degenerate gamblers."
EEStor has received funding from Kleiner Perkins, although Kleiner may have elected not to participate in their most recent funding round. Other than that, nothing to report on EEStor except the usual unsubstantiated blog chatter.
Stanford University received $1 million from the ARPA-E program to develop an "all-electron battery," a new class of electrical energy storage devices for electric vehicles. The new battery stores energy by moving electrons rather than ions and uses a novel architecture that has potential for very high energy density.
Penn State University also received $1 million for "a novel energy storage device based on a 3D nanocomposite structure with functional oxides that provide a very high effective capacitance."
For EEStor, this might represent competition or corroboration or even an IP challenge.
Here's a link to a report on ultracapacitor technology and applications from GTM Research.