Harvest electricity from evaporating water

harvest electricity from evaporating water

harvest electricity from evaporating water

Scientists in the US have shown that evaporating water could be an abundant new source of clean, renewable energy, and it’s already powerful enough to light up a small LED and power a miniature car.

With around 70 percent of the planet covered in water that’s constantly evaporating into the atmosphere, the new technology has huge potential to help us power our homes, transportation and industries, without producing greenhouse gas emissions.

 “Evaporation is a fundamental force of nature,” lead researcher Ozgur Sahin from Columbia University said in a press release. “It’s everywhere, and it’s more powerful than other forces like wind and waves.” If the technology can be scaled up, his team believes we could one day place giant floating power generators on top of lakes, dams and rivers.

Although scientists have long known that evaporation was a constant and powerful force, they’ve struggled to find a way to use this energy to generate electricity. But last year, Sahin made a seemingly unrelated discovery – that when common soil bacteria spores shrink and swell as a result of changing humidity, they can push and pull other objects with surprising force.

With this in mind, Sahin and his team stuck Bacillus subtilis spores onto thin strips of tape, similar to cassette tape. This made the tape contract when the air surrounding it was dry, and expand when it was humid. “Several of these strips together can contract with enough force to lift small weights of 0.2 lbs to 0.7 lbs [0.09 to 0.3 kg] – 50 times the weight of the strips themselves,” writes Kiona Smith-Strickland for Discover magazine.

The researchers then used these strips – which they’re calling hygroscopy driven artificial muscles, or HYDRAs – to build a shuttered structure that floats on water. The humidity produced by the evaporating water causes the tape to expand, opening up the shutters and causing the device to dry out. As the tape shrinks again in the dry air, the shutters are pulled shut, which allows the humidity to build up again, repeating the cycle.

“When we placed water beneath the device, it suddenly came to life, moving on its own,” said Xi Chen, a postdoctoral fellow in Sahin’s lab.

The team used this opening and shutting as a rudimentary piston and linked it to a generator, producing enough electricity to cause a small LED light to flash on and off.

“We turned evaporation from a pool of water into light,” said Sahin. Chen speculates, “that an improved version with stickier plastic tape and more spores could potentially generate even more power per unit area than a wind farm”.

They also created a ‘Moisture Mill’ – a plastic wheel covered in the spore-covered tape, which is half covered in a humid environment, and half exposed to a dry environment. This change in moisture causes the tabs to curve and straighten, producing enough force to turn the wheel continuously.

Using the system, the team was able to make a small toy car weighing 0.1 kg roll forwards on its own. Sahin suggests that a larger version of this mill could produce as much electricity as a wind turbine

The research has been published in Nature Communications, and the team is now focussing on scaling up the devices and investigating other ways that the technology can help generate electricity. “Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment,” they write.

In the meantime they’ve put a call-out for other researchers to take their idea and run with it. Fingers crossed that further experiments confirm that the technology is as powerful as it seems, because this idea could be an exciting contender in the renewable energy space.

 

Source:  sciencealert.com

Wal-Mart’s water scam: Making $600 on $1 it spends in California

Walmart Scam

Walmart Scam

According to a report from Sacramento CBS affiliate, Walmart has been bottling its water from a Sacramento water district during California’s historically devastating drought– and it’s making a grotesquely large profit off of it.

CBS 13′s Adrienne Moore reports:

Sacramento sells water to a bottler, DS Services of America, at 99 cents for every 748 gallons—the same rate as other commercial and residential customers. That water is then bottled and sold at Walmart for 88 cents per gallon, meaning that $1 of water from Sacramento turns into $658.24 for Walmart and DS Services.

For comparison, the city of Sacramento says the average family uses 417 gallons of water a day.

The news comes shortly after California Governor Jerry Brown signed an executive order mandating a one-quarter reduction in urban water use state-wide.

Starbucks recently was criticized for bottling its Ethos water in drought-stricken California — so it stopped. Walmart would be wise to adopt the same policy.

 “It’s certainly leaving a bad taste in everyone’s mouth when you can’t fill up a swimming pool, if you’re building a new home in West Sacramento; you can’t water your lawn if you’re living in this region,” said public relations expert Doug Elmets. “And to find out they’re making a huge profit off of this, it’s just not right.”

A spokesperson from Walmart said the company is “tracking [the drought] closely.”

“Our commitment to sustainability includes efforts to minimize water use in our facilities. We have and continue to work with our suppliers to act responsibly while meeting the needs of customers who count on us across California.”

Source:  salon.com

Earth’s Water Is Older Than the Sun

 

 Earth’s Water Is Older Than the Sun

Earth’s Water Is Older Than the Sun

 

Much of the water on Earth and elsewhere in the solar system likely predates the birth of the sun, a new study reports.

The finding suggests that water is commonly incorporated into newly forming planets throughout the Milky Way galaxy and beyond, researchers said — good news for anyone hoping that Earth isn’t the only world to host life.

“The implications of our study are that interstellar water-ice remarkably survived the incredibly violent process of stellar birth to then be incorporated into planetary bodies,” study lead author Ilse Cleeves, an astronomy Ph.D. student at the University of Michigan, told Space.com via email. [Theories on the Origin of Life]

“If our sun’s formation was typical, interstellar ices, including water, likely survive and are a common ingredient during the formation of all extrasolar systems,” Cleeves added. “This is particularly exciting given the number of confirmed extrasolar planetary systems to date — that they, too, had access to abundant, life-fostering water during their formation.”

Astronomers have discovered nearly 2,000 exoplanets so far, and many billions likely lurk undetected in the depths of space. On average, every Milky Way star is thought to host at least one planet.

Water, water everywhere

Our solar system abounds with water. Oceans of it slosh about not only on Earth’s surface but also beneath the icy shells of Jupiter’s moon Europa and the Saturn satellite Enceladus. And water ice is found on Earth’s moon, on comets, at the Martian poles and even inside shadowed craters on Mercury, the planet closest to the sun.

Cleeves and her colleagues wanted to know where all this water came from.

 

Source:  livescience.com

TEPCO might freeze the exploded nuclear reactor

TEPCO estimated that between 20 trillion and 40 trillion becquerels (units of radioactivity representing decay per second) of radioactive tritium have since leaked into the ocean:

 

In lieu of the Japanese government doing the right thing and finally coming clean about the epic environmental catastrophe that is Fukushima, which it hopes to simply dig under the rug even as the inconvenient reality gets worse and thousands of tons of radioactive water make their way into the ocean, one is forced to rely on third-party sources for information on this tragedy. We present a useful primer from Scientific American on Fukushima “water retention” problem and “what you need to know about the radioactive water leaking from Japan’s Fukushima nuclear plant into the Pacific Ocean.”

Radioactive Water Leaks from Fukushima: What We Know

Scientists on both sides of the Pacific have measured changing levels of radioactivity in fish and other ocean life since the March 2011 earthquake and tsunami triggered a nuclear meltdown at Japan’s Fukushima Daiichi nuclear plant. On Aug. 2, 2013, when Japan’s Tokyo Electric Power Co. (TEPCO) gave its first estimate of how much radioactive water from the nuclear plant has flowed into the ocean since the disaster, the company was finally facing up to what scientists have recognized for years.

“As an oceanographer looking at the reactor, we’ve known this since 2011,” said Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institute in Woods Hole, Mass. “The news is TEPCO is finally admitting this.”

TEPCO estimated that between 20 trillion and 40 trillion becquerels (units of radioactivity representing decay per second) of radioactive tritium have leaked into the ocean since the disaster, according to the Japanese newspaper Asahi Shimbun. The Fukushima plant is still leaking about 300 tons of radioactive water into the ocean every day, according to Japanese government officials. [Infographic: Inside Japan’s Nuclear Reactors]

Japan is haunted by two lingering questions from this aftermath of the disaster: First, how the radioactivity might seriously contaminate ocean life that represents a source of seafood for humans; second, whether it can stop the leaks of radioactive water from the Fukushima plant.

Radioactivity is not created equal

The Fukushima plant is leaking much less contaminated water today compared with the immediate aftermath of the nuclear meltdown in June 2011 — a period when scientists measured 5,000 to 15,000 trillion becquerels of radioactive substances reaching the ocean. Even if radioactivity levels in the groundwater have spiked recently, as reported by Japanese news sources, Buesseler expects the overall amount to remain lower than during the June 2011 period.

“The amount of increase is still much smaller today than it was in 2011,” Buesseler told LiveScience. “I’m not as concerned about the immediate health threat of human exposure, but I am worried about contamination of marine life in the long run.”

The biggest threat in the contaminated water that flowed directly from Fukushima’s reactors into the sea in June 2011 was huge quantities of the radionuclide called cesium. But the danger has changed over time as groundwater became the main source for leaks into the ocean. Soil can naturally absorb the cesium in groundwater, but other radionuclides, such as strontium and tritium, flow more freely through the soil into the ocean. (TEPCO is still coming up with estimates for how much strontium has reached the ocean.)

Tritium represents the lowest radioactive threat to ocean life and humans compared with cesium and strontium. Cesium’s radioactive energy is greater than tritium, but both it and tritium flow in and out of human and fish bodies relatively quickly. By comparison, strontium poses a greater danger because it replaces the calcium in bones and stays for much longer in the body.

Not fishing for trouble
A number of fish species caught off the coast of the Fukushima Prefecture in 2011 and 2012 had levels of cesium contamination greater than Japan’s regulatory limit for seafood (100 becquerels per kilogram), but both U.S. and Japanese scientists have also reported a significant drop in overall cesium contamination of ocean life since the fall of 2011. The biggest contamination risks came from bottom-dwelling fish near the Fukushima site.

The radioactive groundwater leaks could still become worse in the future if TEPCO does not contain the problem, U.S. scientists say. But they cautioned against drawing firm conclusions about the latest impacts on ocean life until new peer-reviewed studies come out.

“For fish that are harvested 100 miles [160 kilometers] out to sea, I doubt it’d be a problem,” said Nicholas Fisher, a marine biologist at Stony Brook University in Stony Brook, N.Y. “But in the region, yes, it’s possible there could be sufficient contamination of local seafood so it’d be unwise to eat that seafood.”

The overall contamination of ocean life by the Fukushima meltdown still remains very low compared with the effects of naturally occurring radioactivity and leftover contamination from U.S. and Soviet nuclear weapons testing in the 1960s. Fisher said he’d be “shocked” if the ongoing leaks of contaminated water had a significant impact on the ocean ecosystems.

Source of radioactive water

TEPCO is facing two huge issues in stopping the radioactive water leaks. First, groundwater from nearby mountains is becoming contaminated as it flows through the flooded basements of the Fukushima plant’s reactor buildings. The water empties into the nuclear plant’s man-made harbor at a rate of about 400 tons per day — and TEPCO has struggled to keep the water from leaking beyond existing barriers into the ocean.

“This water issue is going to be their biggest challenge for a long time,” said Dale Klein, former head of the U.S. Nuclear Regulatory Commission. “It was a challenge for the U.S. during Three Mile Island [a partial nuclear meltdown in Pennsylvania on March 28, 1979], and this one is much more challenging.”

Second, TEPCO must also deal with contaminated water from underground tunnels and pits that hold cables and pipes for the Fukushima nuclear plant’s emergency systems. The underground areas became flooded with highly radioactive water during the initial meltdown of the Fukushima plant’s reactors, and have since leaked water into the ocean despite TEPCO’s efforts to seal off the tunnels and pits.

TEPCO has also been racing to deal with the problem of storing hundreds of thousands of tons of radioactive water from the Fukushima plant, said Hiroaki Koide, a nuclear engineer at Kyoto University in Japan. The Japanese utility is testing a water decontamination system called ALPS that can remove almost all radioactive substances except for tritium, but has put much of the contaminated water in storage tanks in the meantime.

“The tanks are an emergency solution that is not suitable for long-time storage,” Koide said. “Water will leak from any tank, and if that happens, it will merge with the groundwater.”

What must be done

So what solutions exist beyond building more storage tanks? Klein reviewed a number of possible solutions with TEPCO when he was picked to head an independent advisory committee investigating the Fukushima nuclear accident.

One possible solution involves using refrigerants to freeze the ground around the Fukushima plant and create a barrier that stops the inflow of groundwater from the mountains. TEPCO is also considering a plan to inject a gel-like material into the ground that hardens into an artificial barrier similar to concrete, so that it can stop the contaminated groundwater from flowing into the ocean.

Such barriers could help hold the line while TEPCO pumped out the water, treated it with purification systems such as ALPS, and then figured out how to finally dispose of the decontaminated water.

“My priority would be stop the leak from the tunnel immediately,” Klein said. “Number two would be to come up with a plan to stop the inflow and infiltration of groundwater. Number three is to come up with an integrated systematic water treatment plan.”

Meanwhile, both Japanese and U.S. scientists continue to gather fresh scientific data on how the radioactivity impacts ocean life. Despite low contamination levels overall, studies have shown great differences in certain species depending on where they live and feed in the ocean.

“The most straightforward thing the Japanese can do now is measure the radionuclides in fish tissue, both at the bottom of the ocean and up in the water column at different distances from the release of contaminated groundwater,” Fisher said.