Electric vehicles can be less green than classic fuel cars, Norwegian study finds

A Norwegian University of Science and Technology study released Thursday found electric vehicles have a potential for higher eco-toxicity and greenhouse impact than conventional cars. The study includes an examination of the electric car’s life cycle as a whole rather than a study of the electric car’s environmental impact during the use phase.

A Nissan Leaf electric car recharging at an on-street public charging station in Amsterdam

The researchers conducted a comparison of the environmental impact of electric cars in view of different ratios of green-to-fuel electricity energy sources. In the case of mostly coal- or oil-based electricity supply, electric cars are disadvantageous compared to classic diesel cars with the greenhouse effect impact being up to two times larger.

The researchers found that in Europe, electric cars pose a “10% to 24% decrease in global warming potential (GWP) relative to conventional diesel or gasoline vehicles”.

The researchers suggest to improve eco-friendliness of electric vehicles by “reducing vehicle production supply chain impacts and promoting clean electricity sources in decision making regarding electricity infrastructure” and using the electric cars for a longer time, so that the use phase plays a more important role in the electric vehicle life cycle.

 

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Australian scientists develop culture to destroy reef-killing starfish

Following a study linking poisonous crown-of-thorns starfish to 42 percent of Australia’s Great Barrier Reef destruction in recent decades, James Cook University Centre of Excellence for Coral Reef Studies in Queensland has developed a culture to destroy the reef-killing starfish, announced yesterday. The researchers have carried out successful trials of the culture against the starfish.

Crown-of-Thorns starfish near Qamea Island in Fiji.
Image: Matt Wright.

The culture is a beef extract similar to Bovril, the ABC (Australian Broadcasting Corporation) reported.

The culture is expected to replace a manual treatment of the problem, involving a poison injection delivered by a diver to each starfish. One of the researchers, Jairo Rivera Posada, stressed urgency and scale of the threat: “In the current outbreak in the Philippines they removed as many as 87,000 starfish from a single beach”.

The researchers said the culture infects a starfish with bacteria that kill it within just 24 hours and spread by contact with other individuals of the species. This means divers would need to inject just one starfish to infect and destroy many individuals living close to each other.

The researchers recommended addressing the problems behind starfish outbreaks: “Any attempts to control these outbreaks will be futile without also addressing the root cause of outbreaks, including loss of starfish predators as well as increased nutrients that provide food for larval starfishes” referring to the agricultural run-off along the reef coast.

The researchers concluded the culture works and needs testing of its impact on other sea species.

Solar-powered airplane makes first international flight

The solar-powered airplane, Solar Impulse, touched down at the Brussels National Airport late Friday night, after completing a 13-hour flight from its home base in Payerne, Switzerland. It was the first international flight by a fully solar-powered aircraft.

The experimental aircraft was piloted by André Borschberg, co-founder and chief engineer for the Solar Impulse project, which hopes to circumnavigate the globe using only the sun’s energy in 2013. “Our goal is to create a revolution in the minds of people…to promote solar energies — not necessarily a revolution in aviation,” Bertrand Piccard, the group’s other co-founder, said in an interview after the flight.

Solar Impulse during its first flight on December 3, 2009 Image: Matth1.

 The aircraft collects energy from the sun using 12,000 extremely thin solar cells affixed to the wings and tail section. An on-board battery can store enough electricity to fly all night, allowing the Solar Impulse to stay aloft indefinitely. This allowed the aircraft to maintain a holding pattern over the Brussels airport as other flights landed and conditions were right for the Solar Impulse to land. Because the aircraft weighs only about 3,500 pounds and has a wingspan of 200 feet, it is extremely sensitive to wind and needs calm conditions to land safely.

China finds USD 100 bn mineral deposits in Tibet

China continues to strike it rich in Tibet as geologists discovered 102 types of mineral deposits in over 3000 mine beds with an estimated value of about USD 100 billion.

Chromium, One ounce worth of ultra-high purity chromium crystals.

So far, over 3,000 mine beds, deposits or mineralised sites with as many as 102 types of mineral were discovered in Tibet Autonomous Region (TAR), Chinese official media reported, quoting officials from the regional bureau of land and resources.

The mineral resources in the Himalayan region have an estimated potential value up to 600 billion yuan (USD 100 billion), it said. Among the variety of mineral reserves, Tibet is reported to have large chromium and cuprum (copper) far higher than other regions of mainland China. Twelve other mineral reserves rank among the top five across the whole country.

Fine-tuning photosynthesis

A new analysis by MIT researchers could make it possible to design more efficient artificial systems that mimic the way plants harvest the energy of sunlight through photosynthesis.

The study is the latest in an ongoing series examining the process of photosynthesis and the different variables that determine its efficiency, conducted by Associate Professor of Chemistry Jianshu Cao and his postdocs and colleagues. The new work, which looks at artificial photosynthetic systems based on self-assembling molecules designed by researchers at of the University of California, Berkeley, follows a paper they published in October in the New Journal of Physics that examined the factors that determine the efficiency of natural photosynthesis.

Graphic: Christine Daniloff

The hope, being pursued by various research teams around the world, is to be able to eventually produce synthetic chemical systems that mimic nature’s process of photosynthesis and thereby produce a more efficient way of harnessing the sun’s energy than today’s photovoltaic panels, and that can be used to produce some kind of fuel that can be stored and used when needed, eliminating the intermittency problems of solar power. Understanding how to maximize the efficiency of the process is one step toward being able to create such a system.

The new research, by Cao and postdoctoral fellow Ji-Hyun Kim, found that there are many possible shapes that can be formed by bundles of chromophores — the reaction centers within molecules that actually absorb particles of light from the sun, or that transfer that energy or convert it into chemical forms that can be stored for later use. Among other configurations, the chromophores readily either adopt a helical shape (like a bedspring) or form a stack of disks. In their analysis, the stacked-disk configuration proved especially easy to fine-tune for optimal efficiency.

There are three basic types of chromophores: acceptors, which absorb the light’s energy; donors, which emit light; and bridges, which transfer the energy from one reaction center to another. In systems composed mainly of donors and acceptors, the addition of extra bridges can greatly increase the efficiency of the process, the researchers found. In addition, specific ratios of acceptor to donor sites lead to the most efficient transfer of energy. Their findings were published in The Journal of Physical Chemistry, and the work was supported by the MIT Energy Initiative, the Singapore-MIT Alliance for Research and Technology, the National Science Foundation and the MIT Center for Excitonics.

In the related work published last month, Cao, Class of 1942 Professor of Chemistry Robert Silbey, and their postdoctoral fellow, Jianlan Wu, had found that the efficiency of natural photosynthesis can be improved by adding just the right amount of noise — that is, random fluctuations. Since noise usually reduces efficiency, this finding was somewhat counter-intuitive. Adding more noise could also decrease the efficiency, they found. “There’s an optimum amount” of noise, Silbey explains, that produces the most efficient transfer of energy.

To explain why a certain amount of noise could be helpful, he offers the analogy of friction from the road while driving a car. Of course, friction slows the car somewhat, thus decreasing efficiency, and with too much friction the car could grind to a halt. But if there were no friction at all — such as on a perfectly smooth icy surface — the wheels would just spin and the car would not move at all. There is an optimum amount of friction somewhere in the middle, and that’s also the case with noise in a photosynthetic system. In the case of photosynthesis, energy is being transferred from one part of the molecule to the next, and random environmental fluctuations — or noise — can add a push to the moving electrons carrying the energy and help propel them along, up to a point; but too much of this extra push can have the opposite effect, scattering the excitons so they are less likely to make it to the reaction center where that energy is harnessed.

The specific photosynthetic systems the team studied included those from green sulfur bacteria, which have a very common type of multi-chromophoric aggregates that perform the energy conversion, Silbey says.

While many teams of researchers have studied the way photosynthesis takes place in different plants, algae and bacteria, this work looked at the underlying quantum-mechanical processes and calculated how a variety of different variables affected the efficiency of the system, Cao says. “We think we have a very general picture of it now, that can be used for optimal design” of new, synthetic light-harvesting systems. This could allow fine-tuning of the timescales, temperatures and molecular configurations to get the maximum energy output from a given amount of sunlight. The search for general optimization in light-harvesting systems is currently being pursued by several other groups, including those of MIT professor of mechanical engineering Seth Lloyd, Alan Aspuru-Guzik of Harvard University, and Martin Plenio of Ulm, Germany.

This theoretical analysis was triggered by experiments in the last few years, including those by Greg Engel, an assistant professor of chemistry at the University of Chicago, which demonstrated the quantum-mechanical basis for biological photosynthesis. “That’s what got the theorists all worked up,” Cao says, and led them to search for basic understandings that could lead to the most efficient possible systems. The next step will be for others to apply this understanding to the design of new synthetic systems.

Engel, who was not involved in this MIT research, says it is “a beautiful piece of work.”  He adds that “for a long time we have known that photosynthesis has been optimized by evolution, but understanding the way it was optimized provides a way to move forward” in trying to design similarly optimized synthetic systems. “Now that we can take advantage of this and copy some of the underlying design principles” nature has used, he says, “it opens up many new opportunities for us to take advantage of the three-and-a-half billion years of R&D that nature has done.”

But this is just the beginning of a long process in terms of applying this understanding, Engel says: “There is still a great deal of work to be done. This is not the answer, this is the beginning of the roadmap, the first signpost along the way.”

MIT analysis shows how synthetic systems for capturing the sun’s energy could be made more efficient.

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