Energy Storage News
(and Other Related News)

Category 1 Category 2 Date Comment Source





Silicon PV Heterojunctions 8/12/2017 Solar panel design incorporates two technical innovations: heterojunction cells and bifacial cells. read story PV-Tech





Energy Storage General Topics
8/8/2017 A number of news stories have been posted on the internet recently about energy storage research being carried about by the X skunk works of Alphabet Inc. whose parent company is Google. This energy storage system converts electrical current to sensible heat and cold in molten salt and antifreeze tanks respectively. According to the stories the stored energy will be reconverted to electricity in some sort of air powered turbine. There is a lot of talk about the potential low cost and long cycle life of such a system compared to lithium ion batteries. I have seen no information on the round trip efficiency (=electrical energy out/electrical energy in). This efficiency is likely to be less than 0.5 with significant economic consequences. A brief discussion of the economics of round trip storage efficiency can be found at the link to the right. Economics of Energy Storage Efficiency





micro-cpv
8/1/2017 Concentrated photo voltaic (CPV) systems which use concentrating optics and high efficiency multi-junction solar cells have been attempting to compete with 1 sun solar cells in the large scale utility PV market place without much success. CPV systems harvest substantially more energy per unit area of solar panel but have still been unable to compete with the falling costs of 1 sun solar cells. Now a new development called micro-cpv holds out the promise of putting high CPV efficiency a into flat panel fixed tilt configuration appropriate for roof top installations. The paper referenced by this post describes a system of fixed lenses which produces a concentrated spot of light which moves linearly by a small amount (1cm) as the sun moves in the sky. The high efficiency solar cells which are laminated onto a stiff flat surface can then be move linearly to stay within the concentrated area throughout the day. Whether micro CPV can compete in this market either is not clear. As solar cell costs have dropped installation costs on existing roofs have risen significantly as a fraction total cost and are relatively much higher than in utility scale installations. Higher efficiency (and thus a smaller number of panel installations per roof) will reduce these costs, although whether or not this reduction can offset other excess costs of the system remains to be seen. arpae-summit.com k




Lithium Ion Batteries Lithium Iron Phosphate Batteries 7/30/2017 The lithium iron phosphate cathode chemistry has been in existence for some time. It has lower energy density than the cobalt based cathodes which are typically used in consumer electronics and in electric vehicles. However, it has longer cycle life and is inherently safer with respect to explosions and fires. A number of battery manufacturers are promoting this technology for grid storage applications in competition with the nickel-manganese-cobalt (NMC) based cathode chemistry of the Tesla Powerwall storage systems. Valence, a manufacturer of lithium iron batteries based in the lithium/iron/phosphate cathode chemistry have successfully entere the market for hybrid and full electric buses. Apparently regular routes with centralized fast charging stations allow these lower energy density batteries to work effectively. Thus the lower lifetime cost and superior safety of this battery type have earned them a market share in this transportation niche. valence.com





Lithium Sulfur Battery
7/24/2017 Swedish and Italian researchers have developed a gel polymer electrolyte for lithium sulfur batteries which which greatly reduces the dissolution of polysulfides formed in the cathode. Since polysulfide dissolution is a major factor leading to short cycle life for lithium sulfur batteries this innovation could lead to much longer cycle life for this high energy density battery chemistry. Green Car Congress





Wind Energy Kite Energy 7/5/2017 Makani is a US base kite energy research group which has been acquired by Google. They started their research using ground based generators which were turned by kit tethers. Now they are pursuing and energy harvesting system in which the generator are flown on the kites and the electrical power is transmitted to the ground through electrical cable that form part of the kite tethers. They are the only kite energy group I know of that is pursing this option. Makani





Wind Energy Kite Energy 7/5/2017 Kite Power Systems is a British research group developing kite based energy harvesting systems. Kite Power Systems





Wind Energy Kite Energy 7/5/2017 Twingtec is another Swiss kite energy company. Their kite looks like and airplane and has both horizontal and vertical propellers. However it still uses a generator sitting on the grown which is turn by the tension in the kite tether. Twingtec





Wind Energy Kite Energy 7/5/2017 Enerkite is a German research consortium active the the field kite energy Enerkite





Wind Energy Kite Energy 7/5/2017 Kitepower is another Dutch research consortium developing energy harvesting high altitude kites. Kitepower





Wind Energy Kite Energy 7/5/2017 SwissKitePower is yet another research consortium developing kite base wind energy harvesting systems. SwissKitePower





Wind Energy Kite Energy 7/5/2017 Ampyx Power is Dutch/Australian engineering research group also also working on harvest high altitude winds using tethered kites. Their kites, however, look more like traditional aircraft than like single wing kites. Ampyx Power





Wind Energy Kite Energy 7/5/2017 KITEEnrgy is another Italian research consortium working to develop high altitude wind harvesting based on tethered kites. KITEnrg





Wind Energy Kite Energy 7/4/2017 A number of years ago Hugo Bardi posted a story on a website called The Oil Drum about an Italian research consortium called Kitegen Research which was developing a wind energy system based on high altitude kites whose tethers would be used to mechanically drive a ground based electrical generator. The idea of this energy harvesting system is to harvest the high energy content of high altitude winds with an system which is very dematerialized compared to traditional wind turbines. Most of the energy harvested by traditional wind turbines comes from a relatively small portion of the blades near the tips. A high strong tower and very long blades are required to harvest this energy. The hope is that tethered kites can harvest energy with a much lower ratio of high cost engineered material per unit of energy produced and thus lower production costs. A recent Google search revealed that Kitegen Research is still in existence. A more general search for kite energy revealed that a number of other research groups have joined them in their quest to use kites to harvest high altitude wind energy. Kitegen





Chemical Potential Energy hydrogen 4/13/2017 Researchers at the National Renewable Energy Laboratory in Golden Colorado have achieved a record efficiency of 16.3% for the direct conversion of sunlight to hydrogen using gallium based multijunction semiconductor devices. Of course gallium based multijunction solars cells have achieved 46% efficiency in the conversion of sunlight to electricity. If you use this current to electrolyze water at 60% efficiency your net sunlight to hydrogen efficiency is 27.6% and you don't have to immerse your delicate light harvesting semiconductors in an acid bath. So it is not clear that this achievement is cause for any great excitement. Nature Energy





Chemical Potential Energy hydrogen 04/23/17 Hydrogen storage based on catalytic amine reforming of methanol is demonstrated. Gravimetric energy density (HHV) is 5.5 times lower than gasoline. JACS





Chemical Potential Energy P 5/5/2017 A proof of concept experiment has shown that perovskite quantum dots can be in a light harvesting device which photocatalytically reduces CO2 to CO Journal of the American Chemical Society





Compressed Air Energy Storage Adiabatic compressed air energy storage 3/28/2017 European Research Project on Compressed Air/Thermal Storage energy storage system which would not require fossil fuel burning. RICAS





Compressed Air Energy Storage Adiabatic compressed air energy storage 4/12/2017 A Canadian company called Hydrostor is developing a compressed air energy storage system which which utilized the hydrostatic pressure deep body of water to store air at constant pressure. Their storage system also extracts and store the heat of compression which is recombined with the compressed air to run an expander turbine/generator. They claim 60% roundtrip efficiency for this energy storage system. Hydrostor





Compressed Air Energy Storage
05/13/12 If air is mixed with water vapor then the air can be compressed with only a small rise in the temperature of the air/water mixture. Several groups are trying to use this so-called isothermal compression process to store energy. more rheomega.com http:\\energystoragenews.theworldisfinite.com/Energy Storage Round Trip Efficiency.html




Decentralized Energy
4/9/2017 Cheap portable hydrogen peroxide generator could provide off-grid solar powered water purification. Chemistry World





Flow Batteries Hybrid Flow Batteries 7/3/2017 A startup company called ESS Inc. has developed a hybrid flow battery whose metallic chemistry uses only the element iron. Traditional flow batteries have only liquid phase chemical interactions in the liquid electrolytes in the two half cells. A hybrid flow battery has a solid state chemical interaction in one the half cells. In the ESS battery iron is plated onto the solid cathode in the negative half cell during cell charging. Such solid state chemical processes are regarded as being more problematic than dissolved liquid phase processes with respect to long cycle life. ESS claims, however, that their battery design can withstand 20,000 cycles at 80% DOD. This number compares favorably with the 4500 cycles at 80% DOD achieved by NGK Insulator's sodium sulphur batteries. essinc.com





Flow Batteries
7/3/2017 Scientists have developed an aqueous flow battery based on organic and organometallic reactants with a capacity retention of 99.99% per cycle. The metallic elements used appear to be iron and chromium. Vanadium based flow batteries have very high capacity retention, but concern exists about the scalability of vanadium supply. Iron of course is very abundant in the earth's crust. Chromium has about the same abundance as vanadium but is currently substantially cheaper ($17/gram-mole compared to $112/gram-mole). Of course supply scalability is a complex issue which cannot be simply project from crustal abundance or from current prices. ACS Energy Letters





Fuel Cells
6/30/2017 2% gold nano-clusters on α-molybdenum carbide particles allows fuel cells to use CO as a fuel. Unfortunately the significance of this development could be the increasing use of reformed hydrocarbon fuels as an energy source for fuel cells, not very good news if you are hoping to leave substantial portion of existing fossil hydrocarbon reservoirs in place in the earth's crust. Chemistry World





Gravitational Potential Energy
08/02/10 Some years ago a company (now defunct) called Mechanical Electric Inc. was proposing to store electrical energy in elevated weights inside high rise buildings. I wrote about why I thought this ideas was economically impractical here.






Gravitational Potential Energy
05/16/14 A company called ARES is planning to build energy storage systems which use electricity to drive a loaded train up an mountain side and then to recover the energy at the train rolls down the mountainside. more Ares





Gravitational Potential Energy
05/16/14 A company called ARES is planning to build energy storage systems which use electricity to drive a loaded train up an mountain side and then to recover the energy at the train rolls down the mountainside. more Ares





Lithium Ion Battery Anodes
4/8/2017 Bio-inspired materials with hierarchical nanopores can be used for lithium ion battery anodes and other applications requiring efficient mass transport. Nature





Lithium Ion Battery Cathodes
5/14/2017 Low temperature electrodepostion of Litihium ion battery cathodes Science Advances





Magnesium Batteries
7/3/2017 Magnesium/Iodine rechargeable battery demonstrated Nature Communications





Sodium Sulfur Batteries
09/08/09 The Japanese Company NGK Insulators is the sole manufacturer of high temperature sodium sulfur batteries for utility scale electrical energy storage. more NGK Insulators





Solar Cells Bifacial Solar Cells 7/3/2017 China PV manufacturer Longi Solar has achieved mass production for its bi-facial PERC (passivated emitter rear contact) solar cells. Bi-facial solar cells in which both surfaces of the cell can convert sunlight to electricity can be manufactured with very little additional cost and can increase the effective cell efficiency by 10 to 30% by harvesting defused light on the rear surface of the cell. The extra efficiency achieved depends on the details of the solar panel deployment and of the particular solar environment of each installation. pv-tech.org





Solar Cells
4/1/2017 Resonant energy transfer of triplet excitons from pentatene to inorganic semiconductor nanocrystals may lead to more efficient harvesting of solar energy. Nature Materials





Solar Cells
4/11/2017 Researchers at Kaneka Corporation have produce single junction silicon PV cells with a record efficiency of 26.5%. These cells use hetrojunctions in which band gap and of the P-type and N-type regions are different as opposed to homojunction cells in which the bandgaps are the same in both regions. Nature Energy





Supercapacitors
3/31/2017 Thin film graphene supercapacitors with fractal electrodes achieve 30 times the energy density of non- fractal designs. Nature





Supercapacitors
5/5/2017 This paper shows that structural water included transition metal oxides pseudo capacitors with higher energy/power density ACS Chemistry of Materials





Thermal Energy Storage
10/11/09 Molten nitrate salts can be use for sensible heat storage in concentrating solar power installations. The stored heat is later converted to electricity via a steam turbine. stanford.edu





Thermal Energy Storage
11/01/09 Graphite Energy has developed a high temperature (>2000C) thermal energy storage system using graphite the storage medium. It is not really clear what the market is for this technology, but Graphite Energy seems most hopeful about using it to enhance the efficiency of combined cycle gas turbines. more Graphite Energy




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Thermal Energy Storage
2/17/2017 Siemens develops high temperature thermal energy system using rocks as the storage medium and a steam turbine and the electrical power delivery device. Siemens





Tidal energy
3/27/2017 Dual vertical axis turbines place on either side of flow accelerating body ('bluff body') can be used to extract energy from tidal or river flows. Maritime Journal





Water Desalinaton
5/21/2017 Graphene aerogel floating on salt water produces steam under solar radiance and can thus be used to desalinate sea water. Chemistry World





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