Monday, December 9, 2013

Reverse engineering for fuel

Making carbon dioxide by burning hydrocarbons is easy. A pair of novel catalysts recently made by researchers at the University of Illinois at Chicago could make it far more practical to do the reverse, converting carbon dioxide and water into fuel.

Because running this reaction normally requires large amounts of energy, it has been economical only in rare cases. But if the process could be done commercially, liquid fuels could be made from the exhaust gases of fossil-fuel power plants.

The new work, described this week in the journal Nature Communications, improves on a pair of catalysts discovered last year that more efficiently turn carbon dioxide into carbon monoxide, which can then be made into gasoline and other products. Those catalysts produce carbon monoxide slowly, however, and one is made of silver, so it’s expensive.

But the Illinois researchers have demonstrated that it’s possible to replace the silver with relatively inexpensive carbon fibers while maintaining about the same efficiency. And the technique produces carbon monoxide about 10 times faster. It may be possible to incorporate the catalysts into an “artificial leaf.” Right now, if the process were to run on sunlight, it would require at least two pieces of equipment: a solar panel to generate electricity, and then a reactor to form the carbon monoxide. A leaf-inspired system would absorb energy from the sun and use it to drive the chemical reactions directly, rather than making electricity first!

Monday, December 2, 2013

The piggy box is never full!

The world is losing its forests at a rate of 13 million hectares (32 million acres) a year, contributing one-third of the world's atmospheric carbon dioxide emissions. The share is higher in developing countries where forests are being razed to make way for agriculture. However, this is inevitable as demand for crops keeps increasing. The challenge has been to make the developed world compensate in ways which could limit the deforestation.
REDD+ finance, the money needed to set up and implement a system that pays countries to leave forests standing, has followed a long road since the 2007 U.N. Framework Convention on Climate Change meeting in Bali, Indonesia, where nations pledged to take meaningful action to reduce emissions from deforestation. A 2008 study found it would cost between $17.2 billion and $28 billion per year to cut the global rate of deforestation in half.
According to a recent policy brief from the Overseas Development Institute, $2.72 billion has been pledged for REDD+ since 2007 through five multilateral funds and two bilateral funds, more than half of it to Indonesia and Brazil. About one-tenth of the pledges have been disbursed to projects on the ground. But it has just not been substantial enough.

At the Warsaw meet, the U.S. State Department pledged $25 million last week as part of a major new $280 million funding initiative aimed at slowing deforestation and stemming its effect on world carbon emissions. The United States joined Norway, the United Kingdom and the World Bank in launching the "BioCarbon Fund Initiative for Sustainable Forest Landscapes." The fund will provide incentives to developing countries that are taking steps to limit the chopping and razing of trees under the United Nations' Reducing Emissions from Deforestation and Forest Degradation program, or REDD+.The United States will be the new fund's smallest national donor, compared with Norway's $135 million and the United Kingdom's $120 million. The fund will be administered by the World Bank's BioCarbon Fund, a public-private initiative aimed at finding ways to sequester carbon.
But some observers expressed disappointment that the U.S. and its partners didn't put forward a more substantial sum.
Since the 2009 climate conference in Copenhagen, Denmark, there haven't been any substantial pledges to fund REDD+ past 2012. Although Norway has said it will fund REDD+ through 2020, a concrete commitment has been absent.
REDD+ negotiators expect diplomats in Warsaw this week to approve text on five scientific and technical decisions that will lay the groundwork for finance. These include: human rights and environmental safeguards; the definitions of drivers of deforestation; ways for measuring countries' reference levels, or the base line upon which to measure forest loss; monitoring, reporting and verification of emissions reduction; and the creation of a national forest monitoring system.

Besides the BioCarbon Fund, the World Bank houses two other major coffers for REDD+, the Forest Carbon Partnership Facility and the Forest Investment Fund. The FCPF is divided into two funds, one to help countries get ready to implement a REDD+ program and another to pay for verified emissions reductions.

Forests constitute what is known as the planet's lungs, and when they disappear in chunks, it is the health of the whole biosystem that suffers. Not limited to the area or nation that applies the axe, deforestation affects everyone. That is why it is imperative that initiatives must go beyond rhetoric and mere symbolism.

Making energy truly accessible

A creative way of selling solar energy is gaining traction in sub-Saharan Africa: customers can pay as they go.
Only one in six rural inhabitants in sub-Saharan Africa has access to electricity. For households living off the grid, kerosene lamps are the primary lighting source. The World Bank estimates that breathing kerosene fumes is the equivalent of smoking two packs of cigarettes a day, and two thirds of adult females with lung cancer in developing nations are nonsmokers.
Some observers rightly point out how the poorest people in the world are not just paying a bit more for their energy, they’re paying a disproportionate amount! Across the U.S. and U.K. electricity from a utility costs between 10 to 15 cents per kilowatt-hour (kWh). A villager in rural Kenya or Rwanda, however, pays an equivalent cost of $8 per kWh for kerosene lighting. Often 30 percent or more a family's income is spent on kerosene. Charging a mobile phone is even more expensive. That same villager would pay nearly 400 times more to charge a mobile phone in rural Kenya than in the U.S.

Solar-powered charger kits are a promising alternative, but
many rural families cannot afford the up-front cost of these systems, which start at $50.
With a Pay-As-You-Go model (PAYG) for solar kits, on the other hand, customers can instead pay an up-front fee of around $10 for a solar charger kit that includes a two- to five-watt solar panel and a control unit that powers LED lights and charges devices like mobile phones. Then they pay for energy when they need it—frequently in advance each week—or when they can (say, after a successful harvest). In practice, kits are paid off after about 18 months and subsequent electricity is free to the new owner. PAYG customers are finding that instead of paying $2 to $3 a week for kerosene, they pay less than half that for solar energy.
A US company has integrated an analog modem into their solar charger that “talks” with the customer’s mobile phone to authenticate a transaction.  Companies report that the PAYG business model replicates well from country to country. They reach rural communities by working with local distribution partners within each country, who also make money from each solar kit sale.

Yet challenges remain. Many PAYG start-ups are running into limits of working capital; companies front the initial cost of these solar kits and are not fully reimbursed for 18 months. This leads to cash flow constraints that intensify when customers default. 

But for now, the advantages are more, in terms of energy accessibility and reducing pollution from burning kerosene and firewood!

Monday, November 25, 2013

Upping sea level rise

Sea-level rise in this century is likely to be 70-120 centimeters if greenhouse-gas emissions are not mitigated, a broad assessment of the most active scientific publishers on that topic has revealed. The 90 experts participating in the survey anticipate a median sea-level rise of 200-300 centimeters by the year 2300 for a scenario with unmitigated emissions.

In contrast, for a scenario with strong emissions reductions, experts expect a sea-level rise of 40-60 centimeters by 2100 and 60-100 centimeters by 2300. The survey was conducted by a team of scientists from the USA and Germany.

"While the results for the scenario with climate mitigation suggest a good chance of limiting future sea-level rise to one meter, the high emissions scenario would threaten the survival of some coastal cities and low-lying islands," says Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research. "From a risk management perspective, projections of future sea-level rise are of major importance for coastal planning, and for weighing options of different levels of ambition in reducing greenhouse-gas emissions."

Projecting sea-level rise, however, comes with large uncertainties, since the physical processes causing the rise are complex. They include the expansion of ocean water as it warms, the melting of mountain glaciers and ice caps and of the two large ice sheets in Greenland and Antarctica, and the pumping of ground water for irrigation purposes. Different modeling approaches yield widely differing answers. The recently published IPCC report had to revise its projections upwards by about 60 percent compared to the previous report published in 2007.

Wednesday, November 20, 2013

Can individual action save the day?

At a major United Nations climate summit in Warsaw this week, a plan is being hammered out (in the 19th annual effort) for negotiations on a new climate treaty to be finalized in Paris in two years’ time. Delegates from 195 nations are also seeking to obtain commitments from countries to limit their greenhouse-gas emissions between now and 2020.

The moot question : will it make any difference? The path ahead is rife with disputes between rich and poor countries over funding, and how to allocate and enforce emissions reductions. The conference aims to outline the schedule and to set parameters for negotiations ahead of the next major climate summit in Paris in 2015, when countries hope to forge a treaty to follow the 2009 agreement settled on in Copenhagen. At Copenhagen, negotiations over a formal treaty broke down, but eventually resulted in a set of non-binding pledges — the Copenhagen Accord — for emissions reductions until 2020. The accord also blurred the distinction between developed countries, which were bound by the 1997 Kyoto Protocol to reduce emissions.

The Warsaw talks are split into two main tracks. One focuses on the architecture of a new global climate treaty that would take effect after 2020, when the current Copenhagen commitments expire. The second examines what can be done to strengthen commitments between now and 2020 to increase the chance of limiting global warming to a target of 2
°C above pre-industrial temperatures (see ‘Emissions up in the air?’).

Indigenous leaders from across North America met half a world away and offered a prophecy: The solution will never come via the UN talks. Tribal elders from the United States, Greenland and Mexico spoke of the need for individual action rather than government edicts, and of the difficulty – and urgency – of replacing economic questions with moral ones.

A return to the "old values:" Respect, concern for the future, and sharing – alone can help the world they believe. But as one elder pointed, it is a colossal task to get people to change. “How do you instruct 7 billion people as to their relationship to the Earth?" he asked. "It's very difficult – when you're struggling to protect your people and you're hanging by a thread – to instruct other people."

Friday, November 15, 2013

Solar bonanza

A new solar cell material has properties that might lead to solar cells more than twice as efficient as the best on the market today. The material—a modified form of a class of compounds called perovskites, promises to be a good choice though not experimentally used.

Researchers are making new perovskites using combinations of elements and molecules not seen in nature; many researchers see the materials as the next great hope for making solar power cheap enough to compete with fossil fuels. Perovskite-based solar cells have been improving at a remarkable pace. It took a decade or more for the major solar cell materials used today—silicon and cadmium telluride—to reach efficiency levels that have been demonstrated with perovskites in just four years.

The perovskite material described in the latest Nature has properties that could lead to solar cells that can convert over half of the energy in sunlight directly into electricity according to the center for energy innovation at the University of Pennsylvania.

That’s more than twice as efficient as conventional solar cells. Such high efficiency would cut in half the number of solar cells needed to produce a given amount of power. Besides reducing the cost of solar panels, this would greatly reduce installation costs, which now account for most of the cost of a new solar system.

Unlike conventional solar cell materials, the new material doesn’t require an electric field to produce an electrical current. This reduces the amount of material needed and produces higher voltages, which can help increase power output. While other materials have been shown to produce current without the aid of an electric field, the new material is the first to also respond well to visible light, making it relevant for solar cells.

The researchers also showed that it is relatively easy to modify the material so that it efficiently converts different wavelengths of light into electricity. It could be possible to form a solar cell with different layers, each designed for a specific part of the solar spectrum, something that could greatly improve efficiency compared to conventional solar cells.

Friday, November 8, 2013

Aluminum to the rescue

When it comes ot fuel cells , the challenge of storing the hydrogen has been vexing. Lightweight interstitial hydrides -- compounds in which hydrogen atoms occupy the interstices (spaces) between metal atoms -- have now been proposed as a safe and efficient means for storing hydrogen for fuel cell vehicles. And fuel cells are what many see as the future.

Hydrides using magnesium, sodium and boron have been manufactured, but so far, none have proven practical as a hydrogen repository. An aluminum-based alloy hydride offers a more viable candidate because it has the desired traits of light weight, no toxicity to plants and animals, and absence of volatile gas products except for hydrogen.

Until now, however, only complex aluminum hydrides -- unsuitable for use as a hydrogen storage system -- have been created. In a recent paper in the AIP Publishing journal APL Materials, a joint research group with members from the Japan Atomic Energy Agency (Hyogo, Japan) and Tohoku University (Sendai, Japan) announced that it had achieved the long-sought goal of a simple-structured, aluminum-based interstitial alloy.

“Although its synthesis requires very extreme conditions and its hydrogen content is low, our new compound showed that an aluminum-based alloy hydride is achievable," said Hiroyuki Saitoh, lead author of the APL Materials paper. "Based on what we've learned from this first step, we plan to synthesize similar materials at more moderate conditions -- products that hopefully will prove to be very effective at storing hydrogen."