Archive for the ‘alternative energy’ Category
Now this from Harvard University researchers: “bionic leaf 2.0,” which turns sunlight into liquid fuel, introduced in the academic journal Science earlier this month.
In what is called an artificial version of photosynthesis in plants, the study says the “bionic leaf 2.0” “aims to make use of solar panels for splitting molecules of water into oxygen and hydrogen. On separation of the water compounds, hydrogen is moved into a chamber for consumption by bacteria. A specialized metal catalyst and carbon dioxide in the chamber then helps generate a liquid fuel.”
Daniel Nocera, the Patterson Rockwood Professor of Energy at Harvard University, and Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, have developed a system that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels. What’s cool about this is that using sunlight to convert it into liquid fuels would reduce the vast areas of land usually used for producing plants that generate biofuels. According to a study by the University of Virginia, about 4 per cent of the world’s farmland is currently under crops for fuel rather than crops for food.
The paper, whose lead authors also include postdoctoral fellow Chong Liu and graduate student Brendan Colón, is described in a June 3 paper published in Science.
“This is a true artificial photosynthesis system,” Nocera said in a Harvard Gazette article. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.” While the study shows the system can be used to generate usable fuels, its potential doesn’t end there, said Silver, who is also a founding core member of the Wyss Institute at Harvard University.
“The beauty of biology is it’s the world’s greatest chemist — biology can do chemistry we can’t do easily,” she said. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.”
The new system builds on previous work by Nocera, Silver, and others, which — though it was capable of using solar energy to make isopropanol — faced a number of challenges. Chief among those, Nocera said, was the fact that the catalyst used to produce hydrogen — a nickel-molybdenum-zinc alloy — also created reactive oxygen species, molecules that attacked and destroyed the bacteria’s DNA. To avoid that, researchers were forced to run the system at abnormally high voltages, resulting in reduced efficiency.
“For this paper, we designed a new cobalt-phosphorous alloy catalyst, which we showed does not make reactive oxygen species,” Nocera said. “That allowed us to lower the voltage, and that led to a dramatic increase in efficiency.” Read the rest of this entry »
If it gets too hot, get out of the battery! Researchers at Stanford University have developed a lithium-ion battery that shuts down automatically as it begins to overheat.
Lithium-ion batteries are used in nearly all portable electronics. They’re light, can store a lot of energy and are easily recharged, but they are also susceptible to overheating if damaged. A short circuit in the battery often leads to fire. A recent article in Nature Energy by a team of Stanford researchers reveals a safe battery design that features “a fast and reversible thermoresponsive polymer switching material that can be incorporated inside batteries to prevent thermal runaway.”
The new Stanford battery uses a polyethylene film that has embedded particles of nickel with nanoscale spikes. Researchers coated the spikes with graphene, a conducting material, so that electricity can flow over the surface. When the temperature rises the film expands, and at about 70 degrees Celsius (160 degrees Fahrenheit) the conducting spikes no longer touch each other, breaking the circuit – causing the battery to shut down.
Once the battery shuts down, the runaway thermal reaction is avoided and the battery cools; eventually the nickel spikes are brought back into contact and the electricity flow resumes.
“We can even tune the temperature higher or lower depending on how many particles we put in or what type of polymer materials we choose,” said Zhenan Bao, a professor of chemical engineering at Stanford and a member of the research team.
The Nature Energy article [Nature Energy 1, Article number: 15009 (2016) doi:10.1038/nenergy.2015.9] says: “Batteries with this self-regulating material built in the electrode can rapidly shut down under abnormal conditions such as overheating and shorting, and are able to resume their normal function without performance compromise or detrimental thermal runaway. Our approach offers 103–104 times higher sensitivity to temperature changes than previous switching devices.”
This has the potential of averting the catastrophic fires seen in hoverboards, laptops and aircraft.
The article was written by the researchers Zheng Chen, Po-Chun Hsu, Jeffrey Lopez, Yuzhang Li, John W. F. To, Nan Liu, Chao Wang, Sean C. Andrews, Jia Liu, Yi Cui and Zhenan Bao.
Image: Stanford researchers use a polyethylene film in lithium-ion batteries to shut down the battery if it gets too hot. Credit: Stanford University/IDGNS
Here’s the next installment of our close read of Pope Francis’ Encyclical Letter on climate change, Laudato Si’.
(Note: emphasis added by me)
Climate as a common good
The climate is a common good, belonging to all and meant for all. At the global level, it is a complex system linked to many of the essential conditions for human life. A very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system. In recent decades this warming has been accompanied by a constant rise in the sea level and, it would appear, by an increase of extreme weather events, even if a scientifically determinable cause cannot be assigned to each particular phenomenon. Humanity is called to recognize the need for changes of lifestyle, production and consumption, in order to combat this warming or at least the human causes which produce or aggravate it. It is true that there are other factors (such as volcanic activity, variations in the earth’s orbit and axis, the solar cycle), yet a number of scientific studies indicate that most global warming in recent decades is due to the great concentration of greenhouse gases (carbon dioxide, methane, nitrogen oxides and others) released mainly as a result of human activity. Concentrated in the atmosphere, these gases do not allow the warmth of the sun’s rays reflected by the earth to be dispersed in space. The problem is aggravated by a model of development based on the intensive use of fossil fuels, which is at the heart of the worldwide energy system. Another determining factor has been an increase in changed uses of the soil, principally deforestation for agricultural purposes. (Para. 23) Read the rest of this entry »
Leave it to the French to make something as mundane as a wind turbine into a work of art by installing two of them on the Eiffel Tower.
Yes, that Eiffel Tower, which itself is a monument to both creativity and sustainability: when it was built in 1889 it was only intended to last for 20 years. In the ensuing 126 years the tower has gone through many renovations, but the latest sends a decidedly green message whirling into the future.
Earlier this year, the renewable energy firm Urban Green Energy installed two wind turbines inside the metal scaffolding of the tower. The turbines will produce 10,000 kilowatt hours, enough to power the tower’s first floor commercial establishments, which include restaurants, a souvenir shop, and exhibits about the history of the tower.
The turbines are part of a plan to reduce the environmental impact of the tower. Société d’Exploitation de la Tour Eiffel (SETE), the organization that runs the tower, is also installing rainwater collection systems, LED lights, and solar panels on it. Read the rest of this entry »
Here are the details from President Obama’s Executive Order that intends to the Federal Government’s greenhouse gas (GHG) emissions 40 percent over the next decade from 2008 levels — saving taxpayers up to $18 billion in avoided energy costs — and increase the share of electricity the Federal Government consumes from renewable sources to 30 percent.
Complementing the effort, several major Federal suppliers announced commitments to cut their own GHG emissions.
For the record, here are excerpts from the White House Fact Sheet:
“Together, the combined results of the Federal Government actions and new supplier commitments will reduce GHG emissions by 26 million metric tons by 2025 from 2008 levels, the equivalent of taking nearly 5.5 million cars off the road for a year. And to encourage continued progress across the Federal supply chain, the Administration is releasing a new scorecard to publicly track self-reported emissions disclosure and progress for all major Federal suppliers, who together represent more than $187 billion in Federal spending and account for more than 40 percent of all Federal contract dollars.
“Since the Federal Government is the single largest consumer of energy in the Nation, Federal emissions reductions and progress across the supply chain will have broad impacts. The new commitments announced today support the United States’ international commitment to cut net GHG emissions 26-28 percent below 2005 levels by 2025, which President Obama first announced in November 2014 as part of an historic agreement with China…” Read the rest of this entry »
Genera recently published an infographic overview of different biomass feedstocks and guidelines for choosing the best solution for every biomass project. The infographic highlights key supply chain elements and explores which biomass crops are best suited for an application.
While not comprehensive to all feedstocks, the document gives customers, stakeholders, and policy makers a better understanding of the unique dynamics associated with biomass feedstocks.
Genera says choosing the right feedstock or feedstock portfolio is critical to the success of any project. “In many cases, raw feedstock is 50 percent or more of the total cost of producing renewable biofuels and biochemical. Optimizing a project’s feedstock portfolio has a significant impact on profitability.”
Here’s the deal: air travel emissions pump more than 650 million metric tons of carbon pollution into the air each year – that’s equivalent to the pollution from 136 million cars. It’s not likely that airplanes will go away anytime soon, which makes the increased use of sustainable biofuels critical to reducing the industry’s carbon footprint.
According to a first-of-its-kind scorecard released earlier this month by the Natural Resources Defense Council, “the industry is making strides in adopting sustainable biofuels, with some airlines doing better than others as they incorporate these new fuels into their fleets. Air France/KLM is by far the leader of the pack.”
Debbie Hammel, senior resource specialist with NRDC’s Land & Wildlife Program and author of the scorecard, “As the world rises to the challenge of curbing climate change and cutting carbon pollution, addressing air travel pollution has to be part of the mix. The aviation sector has been pretty proactive about this issue, and an industry-wide increase in the use of sustainably produced biofuels is definitely on the horizon.”
NRDC’s Aviation Biofuel Sustainability Scorecards evaluated airlines’ adoption of biofuels, focusing on the use of leading sustainability certification standards, participation in industry initiatives to promote sustainability certification, public commitments to sustainability certification in sourcing, and the monitoring and disclosure of important sustainability metrics.
Read the rest of this entry »