Archive for the ‘Energy’ Category

Scientific American

Today, this flue gas wafts up and out of the power plant’s enormous smokestacks, but by simply bubbling it through the nearby seawater, a new California-based company called Calera says it can use more than 90 percent of that CO2 to make something useful: cement.

It’s a twist that could make a polluting substance into a way to reduce greenhouse gases. Cement, which is mostly commonly composed of calcium silicates, requires heating limestone and other ingredients to 2,640 degrees F (1,450 degrees C) by burning fossil fuels and is the third largest source of greenhouse gas pollution in the U.S., according to the U.S. Environmental Protection Agency. Making one ton of cement results in the emission of roughly one ton of CO2—and in some cases much more.

While Calera’s process of making calcium carbonate cement wouldn’t eliminate all CO2 emissions, it would reverse that equation. “For every ton of cement we make, we are sequestering half a ton of CO2,” says crystallographer Brent Constantz, founder of Calera. “We probably have the best carbon capture and storage technique there is by a long shot.”


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Science Daily:

“This is the nirvana of what we’ve been talking about for years,” said MIT’s Daniel Nocera, the Henry Dreyfus Professor of Energy at MIT and senior author of a paper describing the work in the July 31 issue of Science. “Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon.”

Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera’s lab, have developed an unprecedented process that will allow the sun’s energy to be used to split water into hydrogen and oxygen gases. Later, the oxygen and hydrogen may be recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night.

The key component in Nocera and Kanan’s new process is a new catalyst that produces oxygen gas from water; another catalyst produces valuable hydrogen gas. The new catalyst consists of cobalt metal, phosphate and an electrode, placed in water. When electricity — whether from a photovoltaic cell, a wind turbine or any other source — runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.

Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water splitting reaction that occurs during photosynthesis.

The new catalyst works at room temperature, in neutral pH water, and it’s easy to set up, Nocera said. “That’s why I know this is going to work. It’s so easy to implement,” he said.

“This is just the beginning,” said Nocera, principal investigator for the Solar Revolution Project funded by the Chesonis Family Foundation and co-Director of the Eni-MIT Solar Frontiers Center. “The scientific community is really going to run with this.”

Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electricity-by-wire from a central source could be a thing of the past.

This project was funded by the National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make the large scale deployment of solar energy within 10 years.

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The Economist (requires subscription)

The brain behind this idea is Donald Highgate, a polymers expert, who made his name in the 1970s by developing soft contact lenses. The polymer he has come up with this time is used to make what are known as proton-exchange membranes. These, depending on how the device containing them is set up, can act as the guts of a fuel cell or as its opposite, turning water and electricity into hydrogen and oxygen.

That process is known as electrolysis, and normal commercial electrolysers are chunky units placed next to power stations to produce industrial quantities of hydrogen for the chemical industry. They rely on platinum, a metal that costs twice as much as gold, to catalyse the reaction.

Existing fuel cells intended for cars are not quite so greedy.

Making hydrogen at home, using one of these membranes, gets around the problem of a lack of hydrogen filling stations. In effect, hydrogen becomes a way of storing off-peak electricity. The result can be pumped into your car and run through a fuel cell—or even burned in a conventional internal combustion engine.

Sounds great to me. What’s one of those thingies gonna cost me and how many uses do I get out of it?

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Checking Consumer Reports for mileage stats on the most fuel efficient cars on the market has me shaking my head. The Toyota Yaris Base with manual transmission at 26/44 mpg is apparently the most fuel-efficient non-hybrid car on the road. The best rating overall went to the Toyota Prius Base, at 35/50 mpg.

What bothers me is that I remember when Pop brought home our brand new 1984 Toyota Tercel. The drunk friend of a neighbor’s teenage son had plowed into the family car parked in front of the house in the middle of the night, totaling the brown 1978 Ford Fairmont that lives in many of my early childhood memories. I was only 11, but I still recall Pop boasting about the stripped-down Tercel’s fuel economy. He didn’t go for a single non-standard feature. I had to poke around for mileage ratings because, based on the 2008 offerings I see, I was sure my memory was betraying me. It wasn’t.

According to the folks at MPG-O-Matic, the base model 4-speed Tercel got a neat 39/50. Even more disturbing was seeing that over 30 models available that year offered even better milage than the ’84 Tercel! Compared with today’s most fuel efficient cars, this didn’t seem possible.

A blog entry linked in the comments section of the page cited a 2004 USA Today Article that yielded the answer:

Those were official figures, but they didn’t tell the whole truth. They didn’t reflect real-world driving in a variety of conditions. Actual mileage was less and, as USA Today reported:

“In 1984, responding to consumer complaints that its numbers didn’t match on-the-road experience, EPA cut 22% from its highway fuel-economy number and trimmed the city estimate 10%, starting with 1985 models.”

OK now we’re getting somewhere. A check over at http://www.fueleconomy.gov (which uses the EPA’s new mileage standards) shows the 1985 base model 4-cylinder 5-speed Honda Civic HF rocked at 40/48 mpg! This figure is down somewhat from its original sticker mpg rating of 49/54, but not by all that much, and still notably better than Japan or anyone else can come up with today for a street-legal non-hybrid internal combustion engine car in America.

The ’08 Yaris runs a 1.5L engine that boasts 106 hp compared with a 1.3L at 60 hp for the ’85 Civic HF. The ’08 manual transmission Yaris has it’s curb weight listed at 2,293 lbs. compared with 1,750 for the Civic HF.

So I guess that’s my answer: the most fuel-efficient gasoline powered car on the road today offers some 75% more horsepower to carry around about 30% more weight. And Pop’s ’84 Tercel sure wasn’t fun merging from those short entrance ramps onto Long Island’s Northern State Parkway, so I can imagine how an even less powerful vehicle would do. Regarding the extra weight, I couldn’t find a listing of standard features in the ’85 Civic HF but I recall that Pop’s base model Tercel did not have an air conditioner while in the Yaris the AC unit comes standard. The only other possibly weighty non-essential feature included in the base model Yaris that probably didn’t come standard in the ’85 Civic is power steering. So I imagine most of the 543 lbs or so of the Yaris’ extra weight is mostly made up in safety measures. But gasoline prices being what they are, it does stand to reason that stripped down, bare minimum cars like those mid-80s sub-compacts should be available to consumers today. Lots of commuters can’t get above 40mph during rush hour anyway and safety standards surely aren’t as important for people who rarely travel outside the city.

Still, it is rather disappointing that after 23 years, we cannot build a non-hybrid car with the curb weight and horsepower of the ’08 Yaris that can match the gas mileage of the 1985 Civic. Further, it’s highly disappointing that our modern and very expensive hybrid cars are just slightly more fuel-efficient than what must have been one of the least expensive cars you could buy in 1985.

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Popular Mechanics reviews Electroride’s zero emission commercial box truck:

The Specs
The Zero Truck is a Class 4 or 5 (depending on configuration) commercial truck based on the Isuzu NPR—one of the best sellers in the industry. The Zero Truck is an “Integration Package.” In other words, participating dealers receive the Zero Truck conversion components in a few very large crates and up-fit the trucks on site. To become a Zero Truck, the Isuzu’s gas or diesel powerplant is removed along with all the related hardware. In place of the internal combustion powertrain is a large, 100 kw, UQM liquid-cooled, DC brushless electric motor that receives juice from a 50 kw, recyclable lithium polymer battery pack that rides between the truck’s frame rails.

Zero Trucks actually retain the stock GM automatic transmission, thanks to a proprietary, patent-pending coupler (they wouldn’t tell us how it worked), so the driving experience is most like a conventional truck. The Zero Truck drive system adds roughly 600 pounds to the existing 7000-pound curb weight of a gas-powered NPR. The trucks come with an onboard charger and the battery pack takes 8 hours on 220 volts—or 12 hours—on 110 volts, for a complete charge.

The Bottom Line
So how long will that battery pack last? Electrorides says a full 10 years, assuming one charge/discharge cycle every day.

And now … the cost: $126,000. That’s about $100,000 more than the price of a normal Isuzu truck. About $50,000 of the cost, however, comes from the lithium polymer packs.

Expensive? Sure, but here’s how the math apparently works out. With an E-truck, Electrorides says, business owners can control their fuel costs. They say a typical monthly payment on an Isuzu NPR is around $850 or $900. And the typical monthly gas or diesel fuel bill for a truck could range from $1200 to $1800, if you include oil changes and assume 100 miles driven per business day. The Zero Truck can be leased for seven years at $1900 a month, for example. And the cost to charge one of the EV haulers is about $3 off-peak here in Southern California—not bad at all.

Electroride claims the charge lasts 100 miles, though the article doesn’t specify if that’s at the 4,000 to 6,000 lb maximum hauling capacity.

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