‘Artificial leaf’ concept inspires research into solar-powered fuel production: Rice University


A schematic and electron microscope cross-section show the structure of an integrated, solar-powered catalyst to split water into hydrogen fuel and oxygen. The module developed at Rice University can be immersed into water directly to produce fuel when exposed to sunlight. Credit: Jia Liang/Rice University

Rice University researchers have created an efficient, low-cost device that splits water to produce hydrogen fuel.

The platform developed by the Brown School of Engineering lab of Rice materials scientist Jun Lou integrates catalytic electrodes and  that, when triggered by sunlight, produce electricity. The current flows to the catalysts that turn water into hydrogen and oxygen, with a sunlight-to-hydrogen efficiency as high as 6.7%.

This sort of catalysis isn’t new, but the lab packaged a  layer and the electrodes into a single module that, when dropped into water and placed in sunlight, produces hydrogen with no further input.

The  introduced by Lou, lead author and Rice postdoctoral fellow Jia Liang and their colleagues in the American Chemical Society journal ACS Nano is a self-sustaining producer of  that, they say, should be simple to produce in bulk.

“The concept is broadly similar to an artificial leaf,” Lou said. “What we have is an integrated module that turns sunlight into electricity that drives an electrochemical reaction. It utilizes water and sunlight to get chemical fuels.”

Perovskites are crystals with cubelike lattices that are known to harvest light. The most efficient perovskite  produced so far achieve an efficiency above 25%, but the materials are expensive and tend to be stressed by light, humidity and heat.

“Jia has replaced the more expensive components, like platinum, in perovskite solar cells with alternatives like carbon,” Lou said. “That lowers the entry barrier for commercial adoption. Integrated devices like this are promising because they create a system that is sustainable. This does not require any external power to keep the module running.”

Liang said the key component may not be the perovskite but the polymer that encapsulates it, protecting the module and allowing to be immersed for long periods.

“Others have developed catalytic systems that connect the solar cell outside the water to immersed electrodes with a wire,” he said. “We simplify the system by encapsulating the perovskite layer with a Surlyn (polymer) film.”

The patterned film allows sunlight to reach the solar cell while protecting it and serves as an insulator between the cells and the electrodes, Liang said.

“With a clever system design, you can potentially make a self-sustaining loop,” Lou said. “Even when there’s no sunlight, you can use stored energy in the form of chemical fuel. You can put the hydrogen and oxygen products in separate tanks and incorporate another module like a fuel cell to turn those fuels back into electricity.”

The researchers said they will continue to improve the encapsulation technique as well as the solar themselves to raise the efficiency of the modules.

More information: Jia Liang et al, A Low-Cost and High-Efficiency Integrated Device toward Solar-Driven Water Splitting, ACS Nano (2020). DOI: 10.1021/acsnano.9b09053

Journal information: ACS Nano

Provided by Rice University

Promising Lithium Production from US Sedimentary Deposits – America’s ‘Lithium Valley’ may be Key to New Energy Economy


Lithium is an essential component of electric vehicle batteries which occurs abundantly in the Earth’s crust in many different forms, roughly classified as pegmatites (“hard rock”), brines, and sedimentary deposits (which you may sometimes hear erroneously generalized as “clays”)

America’s Lithium Valley

Do you think driving a Tesla or plugging-in to solar power are environmentally-conscious choices? Then you should know it’s almost certain the batteries in those systems traveled around the world two or three times before they were even installed. That’s not very “green,” is it? Lithium-ion batteries, found in so many things we use every day, often have a rather costly carbon footprint. That could soon change with a discovery that’s just a couple hours north of Tesla’s Gigafactory. A Canadian mining company, LithiumAmericas, identified what’s one of the world’s largest lithium deposits inside the footprint of an ancient volcano. NBCLX Storyteller Chase Cain takes us to the ancient volcano in Nevada that could hold the future of a green energy boom in the West.

Currently, only pegmatite and brine resources are used to produce lithium chemical products commercially.

But a host of new players aiming to produce lithium using sedimentary deposits in Western North America and around the world are coming on the scene.

The sedimentary deposit projects claim to take advantage of favorable chemistry of processing the sediments, sometimes described as the “best of both worlds” when compared to pegmatites and brines. In this article, I will share what are some of the most promising features of sedimentary deposit projects, who’s working on developing these deposits, and why investors and mainstream capital markets should take them seriously as future sources of lithium chemical products. It will be helpful to understand some of the pros and cons of processing pegmatites and brines into lithium chemical products to understand the “best of both worlds” argument for the sedimentary deposits.

Pegmatites

In pegmatites, lithium is strongly bound in crystal structures like aluminosilicates (Al, Si oxides) and because the lithium is so tightly bound in the structure, the mineral requires aggressive processing to remove it to make lithium chemicals.

Spodumene [(LiAl(SiO3)2] is the most widely mined lithium-bearing pegmatite, and has been successfully developed into a significant source of lithium commercially (representing around half of global supply in 2019). It is first dug up and crushed to smaller pieces. The crushed material is then “upgraded” to remove waste materials from the mine that are not spodumene and don’t contain lithium. Once upgraded, calcination (heating to ~1,000°C) is used to convert the crystal to a different structure that is more amenable to removing the lithium.

These high temperatures are typically generated using coal or natural gas, meaning the carbon footprint of roasting pegmatites is typically higher than processing of other lithium resources.

The roasting is a fundamental aspect of extraction of lithium from spodumene because of their crystal structure, and it is difficult to get around this. Some other pegmatites may not require this roasting step however.

img_1752 Lithium Mining in Nevada

This calcination process is followed by a chemical treatment to extract the lithium. This gives a mostly pure lithium concentrate (called the leachate) which can be refined into lithium chemical products with a relatively simple technological approach involving addition of chemicals.

Pegmatites are a good source of lithium because they are easy to manipulate from a mining engineering perspective, and the leachate obtained from the chemical treatment isn’t heavily contaminated with elements with similar chemical characteristics to lithium (ex. alkali/alkaline earths like Na, K, Mg, Ca, Sr), meaning the impurities are easy to remove from the leachate. The waste produced from spodumene operations can be simply put aside or used for other applications like concrete manufacturing and other applications.

Lithium can be produced from other minerals like lepidolite and zinnwaldite using similar flowsheets to spodumene, but some modifications are required depending on the unique mineralogy.

Brines

Brine resources are very different from pegmatites from a lithium extraction and processing perspective.

Brines are high concentration salty reservoirs in which salts are dissolved (ex. Li, Na, K, Mg, Ca, Sr are common cations, or positively charged species, while Cl, SO4, BO3, and CO3 are common anions, or negatively charged species, in these resources). The minerals in brines start off as volcanic materials but over millions of years, rain and geochemical phenomena cause them to dissolve in water and concentrate in basins. Brines can be as high as 20-40% salt by mass, meaning that if you were to evaporate away the water from the brine, around 20-40% of the mass would be left behind as white or clear crystals.

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Read More: US Lithium Mining May Get a Boost …

Brines are liquid, meaning that they need to be pumped to the surface for processing, not dug up and crushed like pegmatites are mined. This means that they do not require roasting or leaching operations to put the lithium into solution for further processing – the lithium is already dissolved. There are two ways to remove lithium from brines.

First, evaporation pond systems can be used to evaporate the water from the brine, leaving behind contaminant salts and an “end brine” of mostly lithium chloride which is processed into lithium carbonate by adding sodium carbonate. This process only works for high lithium concentration brines with low impurities in places with no rainfall, and there is concern that if brine is pumped out from too deep in the salar, freshwater may be sucked in, diluting the salar and destroying potable water resources used by humans.

Second, direct lithium extraction (DLE) processes can be used to remove lithium from the natural brine to produce a highly pure concentrate, leaving behind a “spent brine” containing all the original components of the natural brine but without the lithium. This spent brine needs to be reinjected and/or separated from the natural brine so that the two don’t mix, or else the natural lithium-bearing brine will be diluted by the spent brine containing no lithium, making it impossible to extract more lithium from the reservoir.

image-asset.png?format=750w

Sedimentary Deposits

As mentioned above, sedimentary deposits are considered to share some of the positive attributes of both pegmatites and brines. Sedimentary deposits are created when lithium is washed out of volcanic materials into basins where the salts and minerals dry, creating chemical structures in which the lithium is bound up in a mineral, but much less strongly compared to pegmatite resources. They typically have the consistency of dirt, not hard rock, and often break up when placed in water. If the lithium was not bound in a mineral at all, it would wash out in water forming a brine (this is typically not observed).

A number of leading projects are proposing not using any roasting, meaning the lithium is bound in the mineral with an “intermediate” strength compared to pegmatites and brines. A chemical leach is used to extract the lithium from the sediment, after which the waste sediment can be stored in mounds or back-filled into an open pit.

The lack of requirement to roast the sediment is a positive asset for these resources because it means that natural gas pipelines may not necessarily need to be built to process the sediment. Some projects report requiring upgrading of the sediment ore to remove contaminants which would “unnecessarily” consume acid, and in October 2019, only one project is proposing to use a roasting step in their flowsheet. The benefit of processing a sediment containing “loosely bound” lithium is that the solid waste can be easily disposed of without diluting the original resource, similar to the waste materials from after removing lithium from pegmatites.

The sedimentary deposit projects have some promising attributes for a future of supplying lithium to the battery industry, but reagent inputs will need to be optimized thoroughly for each individual project. Every sediment is different and the flowsheets of the different projects may look quite different. The chemistry of the sediments varies significantly (which is also the case for brines), and each project will need to take this into account. Currently, most public pre-feasibility studies show that tens to hundreds of times excess of reagents are used to create the lithium leachates. This implies low lithium concentrations in the leachate compared to pegmatite-derived leachates, and high concentrations of impurities like Na, K, and Mg.

This explains why most projects currently propose by-product sales to reduce apparent OPEX (electricity, sulfuric acid, boric acid, potash, etc.) because these are likely high OPEX flowsheets if they were “pure play” lithium.

Further, the high porosity and low particle size of the sediments mean that they “hold on” to leachate during leaching, and solid/liquid separations will be key to extracting most of the lithium as leachate from the spent ore. When this is done poorly, the ore “gums up” and a significant amount of lithium is lost with the waste.

The “in between” strength of how lithium is chemically bound in sediments results in some of their “best of both world” characteristics when compared to brines and pegmatites, and these strengths should be taken advantage of in future flowsheet development. New leaching techniques and reagent management flowsheets may be helpful in unlocking these sedimentary materials to produce high lithium concentration, low impurity concentration leachates that can be more easily processed into battery quality lithium chemical products. The sedimentary deposit lithium projects are young, but I believe that some of them will be built in the near future.

The healthy mining jurisdiction of Western North America, proximity of the deposits to American battery manufacturers, and potential for low carbon intensity means that they have excellent potential for helping supply lithium for batteries in the near future, and that they should be followed closely.

A map of these projects is seen below.

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Acknowledgments

Thanks to all those who influenced this article through including Anna WallTom BensonGene Morgan, and Davd-Deak

New Catalyst Recycles Greenhouse Gases into Fuel and Hydrogen Gas: KAIST and Rice University


greenhouse gas 1 ImageForNews_27007_15820400184564587

       The Korea Advanced Institute of Science and Technology (KAIST

Scientists have taken a major step toward a circular carbon economy by developing a long-lasting, economical catalyst that recycles greenhouse gases into ingredients that can be used in fuel, hydrogen gas, and other chemicals. The results could be revolutionary in the effort to reverse global warming, according to the researchers. The study was published on February 14 in Science.

“We set out to develop an effective catalyst that can convert large amounts of the greenhouse gases carbon dioxide and methane without failure,” said Cafer T. Yavuz, paper author and associate professor of chemical and biomolecular engineering and of chemistry at KAIST.

The catalyst, made from inexpensive and abundant nickel, magnesium, and molybdenum, initiates and speeds up the rate of reaction that converts carbon dioxide and methane into hydrogen gas. It can work efficiently for more than a month.

This conversion is called ‘dry reforming’, where harmful gases, such as carbon dioxide, are processed to produce more useful chemicals that could be refined for use in fuel, plastics, or even pharmaceuticals. It is an effective process, but it previously required rare and expensive metals such as platinum and rhodium to induce a brief and inefficient chemical reaction.

Other researchers had previously proposed nickel as a more economical solution, but carbon byproducts would build up and the surface nanoparticles would bind together on the cheaper metal, fundamentally changing the composition and geometry of the catalyst and rendering it useless.

“The difficulty arises from the lack of control on scores of active sites over the bulky catalysts surfaces because any refinement procedures attempted also change the nature of the catalyst itself,” Yavuz said.

The researchers produced nickel-molybdenum nanoparticles under a reductive environment in the presence of a single crystalline magnesium oxide. As the ingredients were heated under reactive gas, the nanoparticles moved on the pristine crystal surface seeking anchoring points. The resulting activated catalyst sealed its own high-energy active sites and permanently fixed the location of the nanoparticles — meaning that the nickel-based catalyst will not have a carbon build up, nor will the surface particles bind to one another. (Article continues below **)

Read More from Rice University: Rice reactor turns greenhouse gas into pure liquid fuel

Greenhouse Gas 2 0722_FUEL-1-rn

This schematic shows the electrolyzer developed at Rice to reduce carbon dioxide, a greenhouse gas, to valuable fuels. At left is a catalyst that selects for carbon dioxide and reduces it to a negatively charged formate, which is pulled through a gas diffusion layer (GDL) and the anion exchange membrane (AEM) into the central electrolyte. At the right, an oxygen evolution reaction (OER) catalyst generates positive protons from water and sends them through the cation exchange membrane (CEM). The ions recombine into formic acid or other products that are carried out of the system by deionized (DI) water and gas. Illustration by Chuan Xia and Demin Liu

 

Greenhouse Gas 20170327_pr4602_co2tocnt

 

 

(** New catalyst recycles greenhouse gases into fuel and hydrogen gas continues)

“It took us almost a year to understand the underlying mechanism,” said first author Youngdong Song, a graduate student in the Department of Chemical and Biomolecular Engineering at KAIST. “Once we studied all the chemical events in detail, we were shocked.”

The researchers dubbed the catalyst Nanocatalysts on Single Crystal Edges (NOSCE). The magnesium-oxide nanopowder comes from a finely structured form of magnesium oxide, where the molecules bind continuously to the edge. There are no breaks or defects in the surface, allowing for uniform and predictable reactions.

“Our study solves a number of challenges the catalyst community faces,” Yavuz said. “We believe the NOSCE mechanism will improve other inefficient catalytic reactions and provide even further savings of greenhouse gas emissions.”

This work was supported, in part, by the Saudi-Aramco-KAIST CO2 Management Center and the National Research Foundation of Korea.

Other contributors include Ercan Ozdemir, Sreerangappa Ramesh, Aldiar Adishev, and Saravanan Subramanian, all of whom are affiliated with the Graduate School of Energy, Environment, Water and Sustainability at KAIST; Aadesh Harale, Mohammed Albuali, Bandar Abdullah Fadhel, and Aqil Jamal, all of whom are with the Research and Development Center in Saudi Arabia; and Dohyun Moon and Sun Hee Choi, both of whom are with the Pohang Accelerator Laboratory in Korea. Ozdemir is also affiliated with the Institute of Nanotechnology at the Gebze Technical University in Turkey; Fadhel and Jamal are also affiliated with the Saudi-Armco-KAIST CO2 Management Center in Korea.


Story Source:

Materials provided by The Korea Advanced Institute of Science and Technology (KAIST)Note: Content may be edited for style and length.


Journal Reference:

  1. Youngdong Song, Ercan Ozdemir, Sreerangappa Ramesh, Aldiar Adishev, Saravanan Subramanian, Aadesh Harale, Mohammed Albuali, Bandar Abdullah Fadhel, Aqil Jamal, Dohyun Moon, Sun Hee Choi, Cafer T. Yavuz. Dry reforming of methane by stable Ni–Mo nanocatalysts on single-crystalline MgOScience, 2020; 367 (6479): 777 DOI: 10.1126/science.aav2412

New catalyst material produces abundant Cheap Hydrogen – Using Renewable Energy (Wind, Solar) to Create and Store Cheap Clean Energy on Demand – Queensland University of Technology


new water splittinh 1 news-image New catalyst material produces abundant cheap hydrogen – QUT

QUT chemistry researchers have discovered cheaper and more efficient materials for producing hydrogen for the storage of renewable energy that could replace current water-splitting catalysts.

Professor Anthony O’Mullane said the potential for the chemical storage of renewable energy in the form of hydrogen was being investigated around the world.

“The Australian Government is interested in developing a hydrogen export industry to export our abundant renewable energy,” said Professor O’Mullane from QUT’s Science and Engineering Faculty.

Watch the Video

“In principle, hydrogen offers a way to store clean energy at a scale that is required to make the rollout of large-scale solar and wind farms as well as the export of green energy viable.

“However, current methods that use carbon sources to produce hydrogen emit carbon dioxide, a greenhouse gas that mitigates the benefits of using renewable energy from the sun and wind.

“Electrochemical water splitting driven by electricity sourced from renewable energy technology has been identified as one of the most sustainable methods of producing high-purity hydrogen.”

Professor O’Mullane said the new composite material he and PhD student Ummul Sultana had developed enabled electrochemical water splitting into hydrogen and oxygen using cheap and readily available elements as catalysts.

“Traditionally, catalysts for splitting water involve expensive precious metals such as iridium oxide, ruthenium oxide and platinum,” he said.

“An additional problem has been stability, especially for the oxygen evolution part of the process.

“What we have found is that we can use two earth-abundant cheaper alternatives – cobalt and nickel oxide with only a fraction of gold nanoparticles – to create a stable bi-functional catalyst to split water and produce hydrogen without emissions.

“From an industry point of view, it makes a lot of sense to use one catalyst material instead of two different catalysts to produce hydrogen from water.”

Professor O’Mullane said the stored hydrogen could then be used in fuel cells.

“Fuel cells are a mature technology, already being rolled out in many makes of vehicle. They use hydrogen and oxygen as fuels to generate electricity – essentially the opposite of water splitting.

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“With a lot of cheaply ‘made’ hydrogen we can feed fuel cell-generated electricity back into the grid when required during peak demand or power our transportation system and the only thing emitted is water.”

“Gold Doping in a Layered Co-Ni Hydroxide System via Galvanic Replacement for Overall Electrochemical” was published in Advanced Functional Materials.

Super Secret Perovskite Solar Cell Company Bursts Out Of Stealth Mode


HPT has collaborated with NREL on perovskite ink for solar cells, like this one developed by NREL researcher David Moore (Photo by Dennis Schroeder, NREL).

For the past six years, a major US oil and gas holding company has been collaborating with the National Renewable Energy Lab on new breakthrough perovskite solar cell research. What a twist!

The effort has been conducted through a relatively new division of the firm and it hasn’t attracted much attention, except that earlier this month they finally let something slip on the newswires and now the cat’s out of the bag.

Oil Company Hearts Perovskite Solar Cells

The holding company in question is Hunt Consolidated, Inc., parent of the 80-year-old privately held global oil and gas leader Hunt Oil and of a somewhat lesser known entity called Hunt Perovskite Technologies.

So, why has a major fossil fuel company been collaborating with NREL on cutting edge research leading to the next generation of low cost solar cells?

After all, other global oil and gas stakeholders are venturing into renewable energy. However, they are mainly focused on market-proven technologies that don’t disrupt their fossil fuel business, at least not for the time being.

Hunt’s new perovskite research is a whole ‘nother kettle of fish. It could have a profound, widespread impact on the energy marketplace and accelerate the transition from fossil fuels to renewables.

That’s because perovskite technology can push down solar costs far below today’s costs. Perovskite solar cells are also lighter and more flexible, which means they have a greater range of application.

For a bonus, perovskite solar cells can be “printed” with a relatively conventional high-volume manufacturing process.

Perovskite solar cells are only just beginning to edge out of the laboratory, now that researchers have finally worked out the kinks. Once they hit the shelves, they will kick the global solar market into a whole new level of activity.

As for why Hunt, last week Forbestook a crack at the mystery and noted that the current head of the family business, Hunter L. Hunt, spent the past 10 years creating and then spinning off a new high voltage power line company.

That venture, along with the company’s investment arm Hunt Energy Enterprises, indicates that Hunt Oil is looking more holistically at new high tech opportunities in the energy market aside from just digging up stuff out of the ground.

More & Better Perovskite Solar Cells

The main challenge with perovskite as a solar cell material is durability, and researchers have been trying various formulas to improve durability without sacrificing too much solar conversion efficiency.

Hunt Perovskite Technologies launched in 2013 with a focus on the perovskite durability problem, as a corporate partner of NREL.

The work came to fruit late last year, when Hunt was able to demonstrate an ink-based manufacturing process for its new solar cell, to the satisfaction of the International Electrotechnical Commission. According to Hunt, the new solar cell exceeds IEC standards for temperature, humidity, white light and ultraviolet stress while achieving a fairly impressive solar conversion efficiency of 18%.

Legacy companies like Hunt are not going to shed their fossil fuel interests willy-nilly, but in a press statement Hunter Hunt indicated that his family business is prepping for change.

“We strategically chose to develop perovskite solar several years ago; we envisioned its strategic importance as an innovative new energy technology in addressing the world’s energy needs for the future, as well playing a part in combating climate change,” he said.  “As part of the global energy transition that is occurring, our solar team is hoping to make a meaningful contribution.”

10 Predictions for the Solar and Storage Market in the 2020s


Rooftop_Solar_Community_Austin_Texas_Shutterstock_XL_721_420_80_s_c1Branding and reputation will be increasingly important in the energy storage market.

All-in-one systems will be the new normal

1. Lots of storage

Batteries will be incentivized or mandated for practically every new solar PV system across the U.S. by 2025. As more homeowners and businesses deploy PV systems to reduce their electricity bills and ensure backup power, simple net metering will increasingly be replaced by time-of-use rates and other billing mechanisms that aim to align power prices with utility costs. We already see these trends in California and several states in the Northeast.

 

Solar systems with batteries are going to be about twice as expensive as traditional grid-direct installations, so in that sense, we will see actual costs increase as the mix shifts toward batteries. But while system costs will go up, we need to be careful to parse the actual equipment and soft costs from the consumer’s cost net of tax credits and incentives. Equipment costs for batteries and other hardware are generally flat to slightly down.

3. More battery and inverter packages from the same brand

Since the battery represents the dominant cost in an energy storage system (ESS), inverter companies will increasingly offer branded batteries. In turn, inverter companies packaging third-party batteries will eventually make way for savvy battery companies that can package the whole system.

4. Energy storage systems treated like heat pumps and air conditioners

California’s new Title 21 requirements make solar PV systems standard issue, and we can expect a future update to do the same for energy storage. By then, builders will be able to choose the ESS line they want to work with, and the whole process will look almost exactly like it does for home mechanical appliances like water heaters and HVAC systems. The only question will be whether the ESS is packaged with solar panels or kept separate.

Standards will evolve

5. Reputation will matter — a lot

The lack of meaningful industry metrics in energy storage creates an environment where branding and reputation become important, since users have little information beyond messaging and word of mouth. Long-term, this will create a barrier to entry for new battery startups, so expect fewer total players once a handful of brands emerge as high-confidence choices.

6. New safety standards and code requirements catch up to technology

Last October, the National Fire Protection Association published the first edition of the NFPA 855 code, which establishes an industrywide safety standard for energy storage systems. Test standards, including UL 9540, and UL 9540A, as well as building and electrical codes, such as the National Electrical Code (NEC/NFPA 70), International Residential Code and International Fire Code, are already being updated to harmonize with NFPA 855. The upshot is that kilowatt-hour capacity limits, siting and protective equipment requirements are becoming standardized and more accessible for both installers and inspectors to understand and apply.

All things will remain technical

7. Real automation and optimization software will outpace flashy interfaces

Third-party owners have specific PV fleet-management needs and often have proprietary software that their ESS needs to interface with daily. IEEE 2030.5 and related standards will help facilitate this need. Local installers have little in the way of hard requirements, but they and their customers will expect systems to be easy to install and operate.

In the long term, we’ll see real automation and optimization rather than the data-palooza common today. Many interfaces report too much data, and simplifying systems to hide irrelevant data will be necessary to avoid alienating the more mainstream consumers.

8. Still waiting for vehicle-to-grid

While V2G is not primarily a technical challenge, some manufacturers like Nissan and Honda have made significant headway. The challenge is more procedural than technical. V2G applications will take off when vehicle manufacturers and interface providers come to terms with how and when an electric vehicle’s battery is used for grid services or backup and how that impacts the EV’s warranty.

There’s also a consumer confidence problem to overcome, especially for those relying solely on their EV for transportation. We’re more likely to see “second-life” EV batteries repackaged for stationary storage — which is much easier to manage than trying to use the battery in the car.

9. AC and DC coupling will both be around for the foreseeable future

Given the latest National Electrical Code requirements for rapid shutdown, as well as the fact that module-level systems (e.g., Enphase and SolarEdge) represent the majority of installed systems, AC coupling is the clear choice for existing system owners to add batteries.

AC coupling will enjoy at least a temporary boom in popularity as people with existing PV systems seek to add storage. However, most advantages of AC coupling are for retrofits, and the majority of new systems will enjoy lower costs and better performance via DC coupling. DC coupling is arguably going to become more dominant once the PV-only retrofit market is saturated.

10. Battery pack voltage will increase dramatically

A century of lead-acid battery dominance has entrenched 48 volts (DC) as the standard battery system voltage. Systems with voltages up to 1,000 VDC are deployed using standard lead-acid cells, but it is only practical for engineered commercial and industrial or utility systems.

The Ohm’s law tradeoff between current and voltage pushed the EV industry, which needs to reduce weight and cost everywhere it can, to quickly migrate to high-voltage battery packs using 3- to 4-VDC lithium-ion cells. Similarly, the stationary energy storage industry is adopting higher-voltage battery packs to reduce the cost of battery inverters. Since conductor losses increase and decrease exponentially with current, higher battery voltages also enable better system efficiency.

The decade of the 2020s will ring in the age of mass solar-plus-storage solution deployment, allowing businesses and residents to tap into renewables more efficiently, protect against outages, save money and live more sustainably.

*** Re-Posted from Green-Tech Media

Scientists create solar panel by combining protein and quantum dots


2-sunCredit: CC0 Public Domain

Scientists at the National Research Nuclear University MEPhI (Russia) have created a new type of solar panel based on hybrid material consisting of quantum dots (QDs) and photosensitive protein. The creators believe that it has great potential for solar energy and optical computing.

The results of the MEPhI study were published in Biosensors and Bioelectronics.

Archaeal proteins of unicellular organisms, , can convert the energy of light into the energy of chemical bonds (like chlorophyll in plants). This occurs due to the transfer of a positive charge through the . Bacteriorhodopsin acts as a , which makes it a ready-to-use natural element of the solar panel.

A key difference between bacteriorhodopsin and chlorophyll is its ability to operate without oxygen, allowing the archaea to live in very aggressive environments like the depths of the Dead Sea. This ability has evolutionarily led to their high chemical, thermal, and optical stability. At the same time, by pumping protons, bacteriorhodopsin changes color many times in a billionth of a second. This is why it is a promising material for creating holographic processing units.

Scientists of MEPhI have been able to significantly improve the properties of bacteriorhodopsin by binding it to quantum dots (QDs)—semiconductor nanoparticles capable of concentrating  on a scale of just a few nanometers and transmitting it to bacteriorhodopsin without emitting light.

“We have created a highly efficient, operating photosensitive cell that generates electrical current by converting light under very low photon excitation. Under normal conditions, such a cell doesn’t work because photosensitive molecules such as bacteriorhodopsin effectively absorb light only in a very narrow energy range. But quantum dots do this in a very wide range and can even convert two lower-energy photons into one high-energy photon as if stacking them,” a researcher at MEPhI and one of the authors of the study, Viktor Krivenkov said.

According to the researcher, creating conditions for the radiation of high-energy photon, a quantum dot may not radiate it but rather transmit it to bacteriorhodopsin. Thus, MEPhI scientists have engineered a cell capable of operating under the irradiation from the near-infrared to the ultraviolet regions of the optical spectrum.

“We use an interdisciplinary approach at the intersection of chemistry, biology, particle physics and photonics. Quantum dots are produced using chemical synthesis methods, then they are coated with molecules that make their surface simultaneously biocompatible and charged, after which they are bound to the surface of the archean bacteriorhodopsin -containing purple membranes of Halobacterium salinarum. As a result, we have obtained hybrid complexes with very high (about 80%) efficiency of excitation  transfer from  to bacteriorhodopsin,” the leading scientist of the MEPhI Nano-Bioengineering Laboratory, Igor Nabiev said.

According to the researchers, the obtained results show the potential for creating highly effective photosensitive elements based on biostructures. They may be used, not only to provide , but also in optical computing.

The authors emphasized the very high quality of the bio-hybrid nanostructured material and the prospect of surpassing the best commercial samples with a possible increase in efficiency by a substantial margin. The next goal of the research team in this direction is to optimize the structure of the photosensitive cell.


Explore further

Protein changes precede photoisomerization of retinal chromophore


More information: Victor Krivenkov et al. Remarkably enhanced photoelectrical efficiency of bacteriorhodopsin in quantum dot – Purple membrane complexes under two-photon excitation, Biosensors and Bioelectronics (2019). DOI: 10.1016/j.bios.2019.05.009

Journal information: Biosensors and Bioelectronics

A Peek into the Future of … The Battery Technology ‘Pipeline’


Berkeley Lab battery researcher Gerbrand Ceder (Credit: Roy Kaltschmidt/Berkeley Lab)

Scientist Gerbrand Ceder evaluates some of the most promising battery technologies in development

Lithium ion is probably the most advanced technology available for the packs of rechargeable batteries you’ll buy this holiday season. The batteries also power the vast majority of consumer devices, electric vehicles, and grid storage systems.

Despite their ubiquity, lithium-ion batteries have disadvantages. Metals used in the batteries are becoming expensive and one crucial metal, cobalt, is relatively rare and has had recent media focus on questionable mining practices in some regions. Plus, the batteries can overheat and, when damaged, occasionally catch fire.

With its deep expertise in materials research, materials design, and energy storage technologies, Berkeley Lab is working on better battery alternatives. Gerbrand Ceder, a battery researcher in the Materials Science Division, details four battery technologies being studied by Berkeley Lab scientists that could make a big difference in the future.

Cobalt- and Nickel-Free Batteries

The reservoirs of a lithium-ion battery, the anode and the cathode, store lithium. When the battery is in use, lithium ions move to the cathode from the anode with the aid of a liquid electrolyte, typically an organic solvent, generating an electric current. When the battery charges, the reverse occurs.

Materials used to store lithium in lithium-ion batteries typically contain cobalt and nickel. Cobalt is scarce and expensive and has been linked with questionable practices in regions where it is mined.

The technology would solve these problems by eliminating cobalt and reducing or eliminating nickel. Iron or manganese, both of which are inexpensive, would ideally be used instead, Ceder said.

Possible uses: In consumer electronics and vehicles.

When available: Five to six years. 

Multi-Valent Batteries

Instead of using lithium ions, which are “single valent,” this technology would use materials with ions that carry more charge, like magnesium, calcium, or possibly aluminum. These so-called “multi-valent batteries” could therefore be much smaller and more powerful than lithium-ion batteries.

Possible uses: In portable electronics and electric vehicles “if we can make it work,” said Ceder, who is also a UC Berkeley professor in materials science and engineering.

When available: This technology is “the most ambitious but therefore probably also the most difficult,” Ceder said. It’s at least 10 years away.

Sodium-Ion Batteries

These batteries would replace the lithium in lithium-ion batteries with sodium. A sodium-ion battery would operate exactly the same as a lithium one, except instead of moving lithium ions, it would move sodium ions. Sodium is much cheaper than lithium, and the materials that would be used to store sodium could also be cheaper than those to store lithium, which are primarily cobalt and nickel-based oxides. Eventually, these batteries could cost less than half of lithium-ion batteries, Ceder said.

Possible uses: For electrical power grids to store excess power, often from solar and wind, for later use.

When available: The technology is “almost to the point where it can work,” Ceder said, “but the question is whether it will get market traction.” With market traction, the technology might be three to four years away, he said. 

Solid-State Batteries

This technology would replace the highly flammable liquid electrolytes of some lithium-ion batteries with an nonflammable solid material. The primary benefit would be improved safety, but it might be possible to use other storage materials and increase the energy content, Ceder said. In addition to being safer, such batteries could reduce costs and weight by eliminating the need for cooling and other safety devices.

Possible uses: In both electric vehicles to reduce costs and increase range and in consumer devices.

When available: At least four or five years away.

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Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratoryand its scientists have been recognized with 13 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe.

Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy’s Office of Science.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science. 

SOCAL Considering the Promise of a Project that Provides Desalinated Water AND … Renewable Energy


The contraption, reminiscent of Rube Goldberg, would produce two of Southern California’s most precious and essential resources: water and electricity.

The electricity would be renewable. And the drought-proof, desalinated ocean water could prove more environmentally friendly — and cheaper — than the water produced from three other desalters proposed for Southern California.

The idea, developed by Silicon Valley-based Neal Aronson and his Oceanus Power & Water venture, caught the attention of the Santa Margarita Water District. The agency quickly saw the project’s viability to fill a void.

“Somebody looked at a problem differently than anybody has in the past,” said district General Manager Dan Ferons. “It’s really creative and got us excited about it. … It could become a primary source of water for south Orange County.”

While Oceanus’s proposals at locations in Mexico and Chile have advanced to the preliminary engineering phases, it remains in the conceptual stage for a plant in northern Camp Pendleton.

But because south Orange County is almost entirely dependent on imported water — and vulnerable to shortages during droughts and earthquakes that can disrupt imported flows — the Santa Margarita Water District last summer signed a non-binding memorandum of understanding with Oceanus for possible participation.

“You don’t want to have just one source of water,” Ferons said, noting that the district is also interested in desalted water from two other plants proposed for the region.

“We thought, ‘Here’s another opportunity to increase our resilience.’ It made sense to encourage and support the project while they pull it together.”

How it works

The Oceanus process begins by pumping water from the ocean to a reservoir some 1,000 feet above sea level, using solar and wind energy to power the two-way pump turbines during daylight hours when those renewable sources are plentiful. During the evening and early morning, water would be released to run downhill, most of it churning through turbines to create electricity when solar and wind energy are unavailable.

Additionally, a portion of the downhill water would be diverted into a desalination operation, where gravity would force it through reverse osmosis membranes that remove the salt.

Relying on gravity rather than electricity to push water through the filters is key to making it cheaper than the water that someday could be produced at desalination plants proposed for Huntington Beach, Dana Point and El Segundo.

Meanwhile, the salty brine byproduct would be mixed with the other outward-bound seawater, greatly diluting it before entering the ocean. Concerns linger among some environmentalists about the harm that the brine would inflict on marine life at other proposed plants, something that would be minimized by the Oceanus approach.

“No one has done this type of project anywhere in the world,” said Oceanus CEO Aronson, whose background is in real estate development and renewable energy projects. “It’s climate resilient. And we’re not planning to use any energy beyond pumping water from the ocean. … I’m a huge believer in the value this integration can bring.”

Inspiration and invention

The idea of creating energy by releasing water to drive turbines is hardly a new one — that’s how hydroelectric dams work. Even the idea of pumping water into reservoirs when electric rates are low and releasing it when they spike — a process known as pumped-storage hydroelectricity — has been used for over a century, Aronson said.

He recalled seeing such plants while vacationing with his parents in Switzerland and France as a child.

Neal Aronson, CEO of Oceanus Power & Water. (Courtesy of Oceanus Power & Water)

And then, in 2014, while developing a solar farm project near the San Luis Reservoir in Merced County, he sized up his project sitting in the shadow of the reservoir and began imagining future sites for pumped-storage hydroelectricity.

Solar and wind are great but what do you do at night?” Aronson said. “Chemical batteries aren’t the right solution for large-scale energy storage.”

While batteries increasingly are being used in California to store solar and wind energy for use during off hours, Aronson points out that those batteries have a limited life span, are still expensive, and can have negative environmental consequences as they have a carbon footprint and are not yet recyclable.

After Aronson began thinking about pumped-storage hyrdoelectricity plants, his focus sharpened to the possibility of building such plants along the coast, using ocean water — something that was only being done in Japan.

Next, the desalter portion of the plant clicked into place.

“In conversations with engineers, one kind of flippantly said, ‘If you’re going to stick a straw in the ocean and suck water out, why don’t you desalinate it while you’re at it,’ ” Aronson recalled. “And we figured out, yeah, you can do that.”

Next steps

Oceanus, founded in 2015, is farthest along with its plans in Chile, where Aronson said he may have all permits necessary to break ground within two years.

The proposal in Sonora, Mexico, on the Sea of Cortez sounds more tentative. While Oceanus has a site, a feasibility study is still underway by the Binational Desalination Work Group. If the U.S.-Mexico entity decides to go forward, Oceanus would likely compete with other bidders. The water would go to both Mexico and to southernmost U.S. states that depend on increasingly uncertain water supplies from the Colorado River.

Camp Pendleton is farther off still. Aronson said he has had talks with the base, the Navy and the Department of Defense, but the decision to go forward has not yet been made. A selling point for the military is that the plant could help the base become more resilient and self-sufficient in terms of water and electricity, which is of particular interest to the Department of Defense, Aronson said.

“The first step is to get them to draft and issue a solicitation for something like this, and we would bid into it,” Aronson said. He declined to speculate on how long it might take for the project to get off the ground, but Santa Margarita Water District’s Ferons estimated a minimum of five years.

While Aronson envisions building a solar farm to power a plant in Sonora, he said a Camp Pendleton plant would likely use power from the state electrical grid during hours when it’s being fed by renewable sources.

Three Innovations To Upend The Energy Storage Market


The battery craze isn’t really about batteries at all. It’s about something far grander than a battery, which is simply a conduit to a much bigger story.

Batteries are like the internet without Wifi. 

The holy grail is energy storage.

And while perpetually bigger batteries themselves have emerged as the dominant solution to our energy storage needs, their reliance on rare earths elements and some metals that are controversially sourced, as well as the fact that their product life is quite limited, indicates they are simply a stop along the way to more creative innovations. 

Already, there are several challenger solutions that have the potential to rise above the battery as the answer to our energy storage needs.

Gravity 

One of these solutions is gravity. Several companies across the world are using gravity for energy storage or rather, moving objects up and down to store and, respectively, release stored electricity.

One of these, Swiss-based Energy Vault, uses a six headed crane to lift bricks when renewable installations are producing electricity than can be consumed and drop them back down when demand for electricity outweighs supply. The idea may sound eccentric but kinetic energy, according to a Wall Street Journal report on these companies, is getting increasingly popular.

The idea draws on hydropower storage: that involves pushing water uphill and storing it until it is needed to power the turbines, when it is released downhill. On instead of water, these companies use gravity, essentially lifting and dropping heavy objects. Energy Vault uses bricks and says 20 brick towers could power up to 40,000 households for a period of 24 hours. Related: Oil Suppliers Slash Prices To Save Asian Market Share

Another company, in the UK, lifts and drops weights in abandoned mine shafts. 

Gravitricity, which last year ran a crowdfunding campaign that raised $978,000 (750,000 pounds), is using abandoned shafts to raise and lower weights of between 500 and 5,000 tons with a system of winches. According to the company, the system could be configured for between 1 and 20 MW peak capacity. The duration of power supply, however, is even more limited than Energy Vault’s, at 15 minutes to 8 hours.

The duration of power supply is an important issue. When the wind dies down and the sky is overcast, this could last more than a day as evidenced by the wind drought in the UK two years ago, when wind turbines were forced to idle for a week.

Heat

Gravity-base storage is one alternative to batteries, some of it cheaper than batteries, but for the time being, less reliable than batteries if we are thinking about a 100-percent renewable-powered grid. Another solution is thermal storage.

EnergyNest is one developer of thermal energy storage. It works by pumping a heated fluid along a system of pipes and storing it in a solid material. The heat flows into the material from top to bottom and is released into this material where it stays until it is needed again. Then, the flow gets reversed, with cold fluid (thermal oil or water) flowing from the bottom up, heating up in the process and exiting the storage system. Related: Restarted Saudi, Kuwaiti Oilfields To Pump 550,000 Bpd By End-2020

Then there is liquid air storage as an alternative to batteries. It works by separating the carbon dioxide and the oxygen from the nitrogen in the air and then storing this nitrogen in liquefied form. When needed to generate electricity, it is regasified. The process of liquefaction is powered by the excess electricity that needs to be stored and when a peak in demand requires more electricity generation, it is reheated and regasified, and used to power a turbine. According to experts, the process is not 100-percent efficient, with rates ranging from 25 percent to 70 percent.

Geothermal

Yet another potential alternative to batteries for energy storage is using geothermal energy to store heat and then releasing it to generate more electricity. The so-called sensitized thermal cells developed by researchers from the Tokyo Institute of Technology are technically batteries, as they use electrodes to move electrons. But on the flip side, it does not work with intermittent energy such as solar or wind. It taps the potential of geothermal energy, an underused renewable source.

Not all of these energy storage idea swill take off. Not all of them will prove viable enough to become widely adopted. Yet some alternatives to batteries will likely work well enough to provide an alternative to the dominant technology. Alternatives are important when you are aiming for 100-percent renewable electricity. 

EVs

Failing that, we could simply use our EV batteries as energy storage for excess power from solar and wind installations, as the International Renewable Energy Agency said earlier this month. While a strain on the grid when they charge, IRENA said, electric cars could juice up at the right time to take in surplus power and then release it back into the grid if that grid is a smart one. In 2050, around 14 terawatt-hours (TWh) of EV batteries would be available to provide grid services, compared to 9 TWh of stationary batteries, according to the agency. One way or another, slowly and with difficulty, we are heading into a much more renewable energy future.

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