[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Swiss team develops effective and low-cost solar water-splitting device; 14.2% solar-to-hydrogen efficiency
August 25, 2016
Using commercially available solar cells and none of the usual rare metals, researchers at the Swiss Center for Electronics and Microtechnology (CSEM) and École Polytechnique Fédérale de Lausanne (EPFL) have designed an intrinsically stable and scalable solar water splitting device that is fully based on earth-abundant materials, with a solar-to-hydrogen conversion efficiency of 14.2%.
The prototype system is made up of three interconnected, new-generation, crystalline silicon solar cells attached to an electrolysis system that does not rely on rare metals. The device has already been run for more than 100 hours straight under test conditions. The method, which surpasses previous efforts in terms of stability, performance, lifespan and cost efficiency, is published in the Journal of The Electrochemical Society.
Lux: Total is leading example of oil supermajor expanding into solar plus storage and distributed generation
August 09, 2016
France-based Total is the first oil supermajor aggressively to enter new areas of business including solar plus storage and distributed generation, notes Lux Research in a new report: “Superpower Darwinism: What Big Oil Can and Cannot Do About Total’s Billion-Dollar Battery Move.”
Even though viable battery companies have become harder and more expensive to buy since Total’s $1-billion acquisition of Saft (earlier post), the oil supermajors—BP, Chevron, ConocoPhillips, Exxon Mobil, Royal Dutch Shell and Total—have cash piles ranging from $5 billion to $30 billion each, despite shrinking profits since 2012 and uncertainty about timing of the eventual recovery of oil prices.
Tesla acquiring SolarCity in $2.6B all-stock deal; expected close of transaction in Q4
August 01, 2016
Tesla and SolarCity reached agreement for the automaker’s purchase of the solar company in an all-stock deal valued at $2.6 billion—slightly less than the original $2.8-billion proposal made by Tesla just over a month ago. (Earlier post.) SolarCity will operate as a wholly-owned subsidiary of Tesla.
The all-stock transaction is valued based on the 5-day volume-weighted average price of Tesla shares as of 29 July 2016. Under the agreement, SolarCity stockholders will receive 0.110 Tesla common shares per SolarCity share, valuing SolarCity common stock at $25.37 per share based on the 5-day volume weighted average price of Tesla shares as of 29 July2016. The original proposal was an exchange ratio of 0.122x to 0.131x shares of Tesla common stock for each share of SolarCity common stock.
Rice team develops “antenna-reactor” plasmonic catalysts for increased energy savings and efficiency in catalytic processes
July 24, 2016
Researchers at Rice University’s Laboratory for Nanophotonics (LANP), with colleagues at Princeton University, have developed a new method for uniting light-capturing photonic nanomaterials and high-efficiency metal catalysts, creating an “antenna-reactor” plasmonic catalyst.
By placing a catalytic reactor particle adjacent to a plasmonic antenna, the highly efficient and tunable light-harvesting capacities of plasmonic nanoparticles can be exploited to increase absorption and hot-carrier generation significantly in the reactor nanoparticles. The modularity of this approach provides for independent control of chemical and light-harvesting properties and paves the way for the rational, predictive design of efficient plasmonic photocatalysts, the researchers suggest in their open-access paper, published in Proceedings of the National Academy of Sciences (PNAS).
Musk’s “Master Plan, Part Deux”; expands Tesla to heavy-duty electric trucks and urban transport; integrated energy generation and storage
July 21, 2016
Master Plan Part 1—public now for ten years—outlined (1) the creation of an expensive low-volume electric car (Roadster) to fund (2) a medium-volume electric car (Model S, X) at a lower price to create (3) an affordable high volume car (Model 3) and (4) provide solar power. Master Plan v2.0 takes Tesla into integrated energy generation and storage (i.e., Tesla’s acquisition of Solar City, earlier post) as well as into heavy-duty electric vehicles and urban transport.
Stanford solar tandem cell shows promise for efficient solar-driven water-splitting to produce hydrogen
June 23, 2016
Researchers at Stanford University, with colleagues in China, have developed a tandem solar cell consisting of an approximately 700-nm-thick nanoporous Mo-doped bismuth vanadate (BiVO4) (Mo:BiVO4) layer on an engineered Si nanocone substrate. The nanocone/Mo:BiVO4 assembly is in turn combined with a solar cell made of perovskite.
When placed in water, the device immediately began splitting water at a solar-to-hydrogen conversion efficiency of 6.2%—matching the theoretical maximum rate for a bismuth vanadate cell. Although the efficiency demonstrated was only 6.2%, the tandem device has room for significant improvement in the future, said Stanford Professor Yi Cui, a principal investigator at the Stanford Institute for Materials and Energy Sciences and senior author of an open access paper describing the work published in Scientific Advances.
Tesla makes ~$2.8B all-stock offer to acquire SolarCity
June 21, 2016
Tesla Motora has made an all-stock offer worth approximately $2.8B to acquire all of the outstanding shares of solar energy provider SolarCity. Subject to completing due diligence, Tesla is proposing an exchange ratio of 0.122x to 0.131x shares of Tesla common stock for each share of SolarCity common stock. This proposal represents a value of $26.50 to $28.50 per share, or a premium of approximately 21% to 30% over the recent closing price of SolarCity’s shares.
Tesla Chairman and CEO Elon Musk is also Chairman of SolarCity; Antonio Gracias, CEO of investor Valor Management Corp., is on both Tesla and SolarCity boards. Musk and Gracias recused themselves from voting on the proposed acquisition at the Tesla Board meeting, and will recuse themselves from the SolarCity Board meeting which will consider the offer.
Harvard “bionic leaf 2.0” exceeds efficiency of photosynthesis in nature; hydrogen and liquid fuels
June 03, 2016
Researchers at Harvard have created a hybrid water splitting–biosynthetic system based on a biocompatible Earth-abundant inorganic catalyst system to split water into molecular hydrogen and oxygen (H2 and O2) at low driving voltages.
Grown in contact with these catalysts, the bacterium Ralstonia eutropha then consumes the produced H2 to synthesize biomass and fuels or chemical products from low CO2 concentration in the presence of O2. The scalable system has a CO2 reduction energy efficiency of ~50% when producing bacterial biomass and liquid fuel alcohols, scrubbing 180 grams of CO2 per kWh of electricity. Coupling this hybrid device to existing photovoltaic systems would yield a CO2 reduction energy efficiency of ~10%, exceeding that of natural photosynthetic systems, the researchers said in their paper published in the journal Science.
New $30M ARPA-E program to produce renewable liquid fuels from renewable energy, air and water
April 26, 2016
The US Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) announced up to $30 million in funding for a new program for technologies that use renewable energy to convert air and water into cost-competitive liquid fuels. (DE-FOA-0001562)
ARPA-E’s Renewable Energy to Fuels through Utilization of Energy-dense Liquids (REFUEL) program seeks to develop technologies that use renewable energy to convert air and water into Carbon Neutral Liquid Fuels (CNLF). The program is focused in two areas: (1) the synthesis of CNLFs using intermittent renewable energy sources and water and air (N2 and CO2) as the only chemical input streams; and (2) the conversion of CNLFs delivered to the end point to another form of energy (e.g. hydrogen or electricity).
U Copenhagen team discovers “reverse photosynthesis” process for the breakdown of biomass for fuels or chemicals production
April 04, 2016
Researchers at the University of Copenhagen have discovered a natural process for the breakdown of biomass they describe as “reverse photosynthesis”—as opposed to the building of biomass as is the case with photosynthesis. Combined with a specific enzyme, the energy of sunlight can break down plant biomass.
Oxidative processes are essential for the breakdown of plant biomass. Lytic polysaccharide monooxygenases (LPMOs)—a class of powerful and widely distributed oxidative enzymes—oxidize the most recalcitrant polysaccharides. These enzymes require extracellular electron donors. In their work, described in an open access paper in the journal Nature Communications, the University of Copenhagen team researchers investigated the effect of using excited photosynthetic pigments as electron donors.
Researchers develop all-weather solar cell that generates power from rain as well as from sun
April 03, 2016
While many technical advances have made solar cells more efficient and affordable, a disadvantage remains in the fact that solar cells produce no power when it’s raining. Now, however, researchers from the Ocean University of China (Qingdao) and Yunnan Normal University (Kunming, China) have developed an all-weather solar cell that is triggered by both sunlight and raindrops by combining an electron-enriched graphene electrode with a dye-sensitized solar cell.
The new solar cell can be excited by incident light on sunny days and raindrops on rainy days, yielding an optimal solar-to-electric conversion efficiency of 6.53% under AM 1.5 irradiation and current over microamps as well as a voltage of hundreds of microvolts by simulated raindrops. Their work is published as a “Very Important Paper” in the journal Angewandte Chemie.
UTA researchers demonstrate one-step solar process to convert CO2 and H2O directly into renewable liquid hydrocarbon fuels
February 23, 2016
Researchers at the University of Texas at Arlington have demonstrated a new solar process for the one-step, gas-phase conversion of CO2 and H2O to C5+ liquid hydrocarbons and O2 by operating the photocatalytic reaction at elevated temperatures and pressures.
The photothermocatalytic process for the synthesis of hydrocarbons—including liquid alkanes, aromatics, and oxygenates, with carbon numbers (Cn) up to C13—ran in a flow photoreactor operating at elevated temperatures (180–200 °C) and pressures (1–6 bar) using a 5% cobalt on TiO2 catalyst and under UV irradiation. A paper describing the process is published in Proceedings of the National Academy of Sciences (PNAS).
New photoelectrode with enhanced visible light absorption for improved solar water-splitting for hydrogen production
February 16, 2016
A team of researchers at Ulsan National Institute of Science and Technology (UNIST), Korea University, and the Korea Advanced Institute of Science and Technology (KAIST) has developed a new type of multilayered (Au NPs/TiO2/Au) photoelectrode that could boost the ability of solar water-splitting to produce hydrogen.
This multilayered photoelectrode is a two-dimensional hybrid metal-dielectric structure, comprising three layers of gold (Au) film; an ultrathin TiO2 layer (20 nm), and gold nanoparticles (Au NPs). In a study, reported in the journal Nano Energy, the team reported that the photoelectrode shows high light absorption of about 90% in the visible range 380-700 nm, as well as significant enhancement in photo-catalytic applications.
Berkeley team develops host-guest nanowires for efficient water splitting and solar energy storage
February 04, 2016
Although metal oxides that absorb visible light are attractive for use as photoanodes in photoelectrosynthetic cells, their performance is often limited by poor charge carrier transport. Researchers from UC Berkeley and colleagues have now addressed this issue by using separate materials for light absorption and carrier transport.
The team reports on their host-guest system of Ta:TiO2|BiVO4 as a photoanode for use in solar water splitting cells in an open-access paper in the journal ACS Central Science. BiVO4 acts as a visible light-absorber and Ta:TiO2 acts as a high surface area electron conductor. The host–guest nanowire architecture allows for simultaneously high light absorption and carrier collection efficiency for efficient solar water oxidation.
New German ecoPtG project seeks to make power-to-gas commercially viable with help of automotive technology
In collaboration with engineering partner IAV, the Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (Centre for Solar Energy and Hydrogen Research Baden-Württemberg, ZSW); the Reiner Lemoine Institut (RLI); and Wasserelektrolyse Hydrotechnik (HT) are researching cost-effective methods of producing hydrogen with the help of automotive technology. In the ecoPtG project, the researchers and engineers are developing an alkaline water electrolyzer with an output of 100 kW. They aim to demonstrate that CO2-neutral hydrogen can be produced in a cost-effective manner and intend to facilitate the storage of electricity.
Electricity is increasingly being generated from fluctuating renewable sources. Solar and wind energy generation depends on the weather and is subject to significant fluctuations. At times, renewable energy production thus temporarily exceeds regional demand. Hydrogen produced according to the power-to-gas method can play a role in resolving this challenge and decarbonizing the transport sector. By converting electricity to gas, solar and wind power become storable. If required, hydrogen can be reconverted or used as environmentally compatible fuel for fuel cell vehicles.
NREL research advances photoelectrochemical production of hydrogen using molecular catalyst
December 21, 2015
Researchers at the Energy Department’s National Renewable Energy Laboratory (NREL) have made advances toward affordable photoelectrochemical (PEC) production of hydrogen. A paper on their work is published in Nature Materials.
The PEC process uses solar energy to split water into hydrogen and oxygen. The process requires special semiconductors, the PEC materials and catalysts to split the water. Previous work used precious metals such as platinum, ruthenium and iridium as catalysts attached to the semiconductors. A large-scale commercial effort using those precious metals wouldn’t be cost-effective, however.
Purdue, EPFL team propose Hydricity concept for integrated co-production of H2 and electricity from solar thermal energy
December 16, 2015
Researchers from Purdue University and École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland are proposing a new integrated process involving the co-production of hydrogen and electricity from solar thermal energy—a concept they label “hydricity”. They describe their proposal in a paper in the Proceedings of the National Academy of Sciences (PNAS).
The hydricity process entails integrating solar water power (SWP) cycle and solar thermal hydrogen production technologies and a turbine-based hydrogen power cycle with suitable improvements of each for compatibility and beneficial interaction.
Stanford team increases power of corrosion-resistant solar cells; advance for solar fuels
November 30, 2015
Researchers at Stanford, with colleagues at University College Cork in Ireland, have shown how to increase the power of corrosion-resistant solar cells, setting a record for solar energy output under water. Instead of pumping electricity into the grid, the power these cells produce would be used in the production of solar fuels.
This new work, published in Nature Materials, was led by Stanford materials scientist Paul McIntyre, whose lab has been a pioneer in the field of artificial photosynthesis. Artificial photosynthesis proposes using the energy from specialized solar cells to combine water with captured carbon dioxide to produce industrial fuels.
JCAP researchers propose artificial photosynthetic system for high-yield production of ethanol
November 09, 2015
A team at the Joint Center for Artificial Photosynthesis (JCAP) at Lawrence Berkeley National Laboratory and UC Berkeley is proposing an artificial photosynthesis scheme for direct synthesis and separation to almost pure ethanol with minimum product crossover using saturated salt electrolytes.
In a paper in the RSC journal Energy & Environmental Science, Professor Alexis Bell and postdoc Meenesh Singh describe the novel design of an integrated artificial photosynthetic system that continuously produces >90 wt% pure ethanol using a polycrystalline copper cathode and an IrO2 anode at a current density of 0.85 mA cm-2. The annual production rate of > 90 wt% ethanol using such a photosynthesis system operating at 10 mA cm-2 (12% solar-to-fuel (STF) efficiency) can be 15.27 million gallons per year per square kilometer, corresponding to 7% of the industrial ethanol production capacity of California, they suggest.
Sandia team boosts hydrogen production activity by molybdenum disulfide four-fold; low-cost catalyst for solar-driven water splitting
October 07, 2015
A team led by researchers from Sandia National Laboratories has shown that molybdenum disulfide (MoS2), exfoliated with lithiation intercalation to change its physical structure, performs as well as the best state-of-the-art catalysts for the hydrogen evolution reaction (HER) but at a significantly lower cost. An open access paper on their study is published in the journal Nature Communications.
The improved catalyst has already released four times the amount of hydrogen ever produced by MoS2 from water. To Sandia postdoctoral fellow and lead author Stan Chou, this is just the beginning: “We should get far more output as we learn to better integrate molly with, for example, fuel-cell systems,” he said.
Rice team demonstrates plasmonic hot-electron solar water-splitting technology; simpler, cheaper and efficient
September 05, 2015
Researchers at Rice have demonstrated an efficient new way to use solar energy for water splitting. The technology, described in a paper in the ACS journal Nano Letters, relies on a novel plasmonic photoelectrode architecture of light-activated gold nanoparticles that harvest sunlight to drive photocatalytic reactions by efficient, non-radiative plasmon decay into “hot carriers”—highly excited electrons.
In contrast to past work, the new architecture does not utilize a Schottky junction—the commonly used building block to collect hot carriers. Instead, the team observed large photocurrents from a Schottky-free junction due to direct hot electron injection from plasmonic gold nanoparticles into the reactant species upon plasmon decay.
Joint IEA-NEA report details plunge in costs of renewable electricity; nuclear competitive with other baseload power sources
August 31, 2015
|2010 and 2015 LCOE ranges for solar and wind technologies. Source: IEA/NEA. Click to enlarge.|
The cost of producing electricity from renewable sources such as wind and solar has been falling for several years. A new report, a joint project by the International Energy Agency and the Nuclear Energy Agency, provides in detail the contrasting costs for different power generation technologies around the world and shows that renewable sources can produce electricity at close to or even below the cost of new fossil fuel-based power stations, depending upon conditions such as resources and appropriate market and regulatory frameworks.
The report, Projected Costs of Generating Electricity: 2015 Edition, also shows that new nuclear power plants generate electricity more cheaply than other established “baseload” sources—mainly coal- and gas-fired power plants—over the full lifetime of facilities when financing costs are relatively low.
JCAP team reports first complete “artificial leaf”; >10% solar-to-hydrogen conversion efficiency
August 28, 2015
Researchers at the Joint Center for Artificial Photosynthesis (JCAP) report the development of the first complete, efficient, safe, integrated solar-driven system—an “artificial leaf”—for splitting water to produce hydrogen. JCAP is a US Department of Energy (DOE) Energy Innovation Hub established at Caltech and its partnering institutions in 2010.
The new system has three main components: two electrodes—one photoanode and one photocathode—and a membrane. The photoanode uses sunlight to oxidize water molecules, generating protons and electrons as well as oxygen gas. The photocathode recombines the protons and electrons to form hydrogen gas. A key part of the JCAP design is the plastic membrane, which keeps the oxygen and hydrogen gases separate. If the two gases are allowed to mix and are accidentally ignited, an explosion can occur; the membrane lets the hydrogen fuel be separately collected under pressure and safely pushed into a pipeline.