Stories tagged energy

This kid is contributing to alternative energy development: In his own way.
This kid is contributing to alternative energy development: In his own way.Courtesy jellywatson
I guess that the guy who invented the Super Soaker squirt gun is also kind of an all-around engineering genius. His company is currently developing a new kind of solar panel that converts heat (instead of light) into electricity. It could be a really big deal, or it could be slightly misplaced enthusiasm (see the "Bloom Box".)

In any case, read about it here. It's sort of exciting technology, and the inventor, Lonnie Johnson, has an interesting story.

Oct
11
2010

I don't know: I just assumed that a stupid car would have its tongue hanging out. Like my dog.
I don't know: I just assumed that a stupid car would have its tongue hanging out. Like my dog.Courtesy IFCAR
We talk about alternative fuels and energy use and transportation pretty often on Science Buzz, so when news about the Chevy's upcoming car, the "Volt," and it's 230 mpg efficiency, came out last year, I thought that was pretty neat. (Admittedly, I was also sarcastic about it's price, but whatevs.)

Well, car magazines are finally getting a look at the Volt, and they're finding that its mileage is way less than 230 mpg. Like way, way less. 30 - 40 mpg, maybe. Also, it doesn't work how they said it would. It's more like a plug in hybrid car than an electric car with a gas generator, and once its low-range battery runs down, it's not a very good hybrid. But I guess it's still an intermediate step to more efficient transportation*. Just kind of a disappointing one.

*Almost a third of the energy we use in this country goes to transportation, and the vast majority of that is from non-renewable sources, so improving efficiency in this sector is a big deal.

Sep
22
2010

NREL's membraine: There's so much science in his head it's projecting colorfully out into the air as a graph.
NREL's membraine: There's so much science in his head it's projecting colorfully out into the air as a graph.Courtesy NREL
You’re worried about the future again, aren’t you? You’re afraid that everything will taste like cardboard, and that most people will be robots, and that the robots will be too cool to hang with you, and that our trips to the bathroom with be confusing and abrasive, and something about bats, and that you will be hot all the time, even in your own homes.

And I wish I could tell you otherwise. But I can’t. I just don’t know enough about the future. Except on that last point—it looks like air conditioning may yet be an option in a necessarily energy efficient future.

Air conditioning can use up a lot of energy. An air conditioning unit typically cools air by blowing it over a coiled metal tube full of a cold refrigerant chemical. The refrigerant absorbs heat from the air in your house, and then it passes through a compressor, which squishes the refrigerant down, making it hot so that it releases heat outside your house. And then the refrigerant expands, and cycles back into the cool tube. (Here’s the explanation with some illustrations.)

Other cooling systems rely on evaporation. So called “swamp coolers” pull hot, dry air from outside, and blow it over water (or through wet fabric pads). The water evaporates to pull heat out of the air, so what is blown into your house is cool, humid air. Swamp coolers are more efficient, but they only work in very dry environments.

And then there’s another way to control your indoor climate: desiccant cooling. A lot of what makes warm air uncomfortable is the amount of moisture it can contain. Normal AC units remove moisture from the air, but they use a lot of energy in doing it. Another way is to use chemicals called desiccants. Desiccants suck up water. The little packs of “silica gel” crystals you might find in a new pair of shoes are full of desiccants. Blowing humid air over desiccants will result in the chemicals sucking the moisture out of the air, making it more comfortable.

Figuring out how to use the desiccants has been a challenge, however; desiccant chemicals can be corrosive to building materials, so they, and any dripping water, need to be contained. With this in mind, US government researchers at the National Renewable Energy Laboratory have developed a membrane for desiccant cooling systems that allows the water vapor in humid air to pass through it one way, but does not allow the liquid water removed from the air to pass back.

The researchers claim that this air conditioning process is up to 90% more energy efficient than standard AC. Every so often, the desiccant chemicals need to be “recharged” by heating them up so they release the trapped water (outside), a job that can be done by electric heating elements, or with a solar thermal collector. The University of Minnesota used a desiccant cooling system for their entry into the Solar Decathlon competition. Their system didn’t rely on a membrane—rather, humid air was pumped up through a drum of liquid desiccant—but they did recharge the desiccant using heat from solar thermal panels (which are basically big, flat, black boxes that collect heat from sunlight).

It’s reassuring to know that in the future, even as we’re covered in flesh eating bacteria, and spam advertisements for Spam are being beamed directly into our brains, we’ll at least be able to relax in pleasantly dry, cool air, without worrying too much about the energy we’re using to do it.

Sep
02
2010

Electricity in the air: Some of our energy needs may someday come from the atmosphere.
Electricity in the air: Some of our energy needs may someday come from the atmosphere.Courtesy wvs (Sam Javanrouh)
In a paper delivered at the 240th National Meeting of the American Chemical Society in Boston, a researcher envisioned a time in the not-too-distant future when houses and buildings outfitted with the proper equipment would be able gather electric energy stored in humidity in the atmosphere that could be used to fill a community’s electrical needs.

The concept isn’t new; electrical wunderkind Nikola Tesla had a similar idea more than a century ago.

Science has long sought the answer to how electricity builds up and discharges in the atmosphere, and whether the moisture in the atmosphere could even hold an electrical charge. But Fernando Galembeck, a professor at Brazil’s University of Campinas, claims he and his research team have successfully shown that it can, and by using special metal conduits to collect that electricity, it could allow homeowners and building managers to gather and store the electricity as an alternative energy source.

”Just as solar energy could free some households from paying electric bills, this promising new energy source could have a similar effect,” Galembeck said. He terms the new method “hygroelectricity” which means “humidity electricity”. Galembeck's research could also add to our understanding of how thunderstorms form.

In their laboratory experiments, Galembeck’s research team created a simulated atmosphere densely saturated with water (humidity), which they seeded with silica and aluminum phosphate, two chemical compounds commonly found in air. As water droplets formed around the tiny, airborne chemical substances, the researchers noticed the silica took on a negative charge while the aluminum phosphate droplets held a positive charge. The charged water vapor readily condenses upon contact with surfaces such as a cold can of soda or beer, and on the windows of air-conditioned buildings or vehicles. In the process, energy is transferred onto the contact surface.

“This was clear evidence that water in the atmosphere can accumulate electrical charges and transfer them to other materials it comes in contact with,” Galembeck said.

Just as solar panels convert energy from sunlight into a usable power source, the researchers think water vapor in the atmosphere could someday be harvested for its hygroelectric energy. The rooftops of buildings in regions of high humidity and thunderstorm activity could someday be fitted with special hygroelectric panels that would absorb the charges built up in the humid atmosphere and funnel the energy to where it can be utilized, and at the same time reduce the risk of lightning forming and discharging. The technology would be best suited to regions of high humidity, such as the tropics or the eastern and southeastern U.S.

SOURCES
ScienceDaily story
Wired story
Green Diary story

Thunderstorm over Lake Harriet in Minneapolis; Could this be a new source of energy for the Upper Midwest?

Aug
16
2010

Another tidal generator: But this one is hiding underwater. This is why I didn't know what they look like.
Another tidal generator: But this one is hiding underwater. This is why I didn't know what they look like.Courtesy Fundy
Along with wind and solar, harvesting power from tidal forces comes up a lot in discussions of alternative energy sources.

Was that a horrible sentence? I think it was. What I meant to say is this: we can generate electricity from tides, and lots of it. "Tidal power" is often brought up alongside solar power and wind power, but while I can easily picture windmills and solar panels, I'm not always sure what sort of device we'd use to harness the power in the tides.

This sort of device! For those of you too afraid to click on a strange link (who knows... I could be linking to an image like this!), the article depicts something that looks sort of like a thick, stubby windmill, with blades on its front and back. It's a tidal turbine, and at 74 feet tall and 130 tons it's the world's largest. It should be able to supply electricity to about 1,000 households. Pretty impressive.

Tidal turbines, apparently, are so productive because water is so much denser than water, and so it takes a lot more energy to move it. An ocean current moving at 5 knots (that's a little shy of 6 miles per hour, for the landlubbers) has more kinetic energy, for example, than wind moving at over 217 miles per hour.

At least according to that article, the United States and Great Britain each have enough tidal resources (areas where this kind of generator could be installed) to supply about 15% of their energy needs.

More info on the tidal turbine, which I am calling "the Kraken," because it's big, underwater, and will occupy your mind for only a very short time.

Polar Home: This guy does not look like he minds his cool digs, but I think I am going to turn down my A/C now.
Polar Home: This guy does not look like he minds his cool digs, but I think I am going to turn down my A/C now.Courtesy thecourtyard

In a news release this past week, the University of Minnesota, led by professors Pat Huelman and John Carmody, has announced being chosen by the U.S. Department of Energy to "Build America."

The research group, the NorthernSTAR Energy Efficient Housing Research Partnership Team, will be developing cheap solutions to home energy efficiency in cold climates. For me and you, that means more comfortable and eco-friendly Minnesota winters to come! Pretty cool, huh?

For more information, check out "Polar Energy", an article in the Institute on the Environment's Momentum magazine, winter 2010.

Jul
27
2010

The Smartypants Grid

The smart grid is actually a futuristic collection of technologies that manage electricity distribution. Ultimately, they are "smarter" (more efficient) at generating, distributing, and using electricity than the current industry standards.

The Einstien Meter: Smart meters are a component of the smart grid infrastructure.  They provide the two-way communication between electricity consumers and providers with the goal of enabling consumers to manage their electricity usage and spending.  The utility providers also benefit by experiencing fewer demand spikes.
The Einstien Meter: Smart meters are a component of the smart grid infrastructure. They provide the two-way communication between electricity consumers and providers with the goal of enabling consumers to manage their electricity usage and spending. The utility providers also benefit by experiencing fewer demand spikes.Courtesy Duke Energy

Some people are getting excited about smart grids because cutting back on electricity usage is cutting back on fossil fuel consumption which is cutting back on human-driven causes of global climate change. (Are you still with me or did I lose you there?) Other people are looking forward to smart grids because they should decrease the number of brown- and blackouts experienced in the country, which improves the region's health and economy. Still more people are pumped for the smart grid because it could mean lower electricity bills for their homes.

When will the smart grid reach your hometown? That depends. Some cities already have smart grid technology, but regional adoption is set to take place on a rolling basis during the next five years and is largely dependent on whether the American people get on board.

Scientific American: How Will the Smart Grid Handle Heat Waves?

"Pretty well, once the technology to automatically respond to peak demand and store renewable energy matures."

Smart grid test cites in Harrisburg, PA, Richland, WA, and Boulder, CO have their work cut out for them this week as people across the nation crank down the A/C to battle the heat wave covering most of the continental United States. According to the Scientific American article, a regional smart grid should have the potential to excel under stressful heat wave conditions. In the meantime, utility companies and academics are working toward developing a method to better store electricity when supply exceeds demand thus creating a stockpile of electricity for times of scarcity.

Explore More:

Check out SmartGrid.gov for all things smart and grid-y. Or, if you're looking for something more technical, the Department of Energy's other smart grid website.

If you're looking for a more interactive learning experience, check out General Electric's smart grid webpage complete with narrated animations.

Of course, if you're looking to hear from academics or industry experts themselves, the Initiative for Renewable Energy and the Environment in conjunction with the University of Minnesota's Institute on the Environment and St. Anthony Falls Laboratory, are hosting Midwest's Premier Energy, Economic, and Environmental Conference, E3 2010, at the St. Paul River Center (right across Kellogg Blvd from the Science Museum) Tuesday, November 30.

Jul
13
2010

…of climate control systems...

Ever notice the plumes of smoke rising from many buildings, factories, and power plants on a cold day? That smoke is actually water vapor, which still contains usable energy, muahahahaha! Our buildings use lots of energy. Electricity, for example, powers everything from lights to computers to copy machines to coffee makers. Electricity eventually degrades into heat—you can feel that heat coming off of electric appliances. Current building energy management systems expel this excess heat energy instead of using it for other purposes, such as building the ultimate tilt-a-whirl of doom. Dave Solberg, an energy miser and consulting engineer-ahem-secret advisor, wants to change all that using the concept of exergy. He envisions a future where energy is used as efficiently as possible, and he has been working with Xcel Energy and organizations in the St. Paul area to re-engineer buildings.

We all know that mad scientists with plans for world domination need money and power. Well, current climate control systems are expensive to build and operate, and they're bad for the environment. But retrofitting old buildings and creating the infrastructure to support Solberg's systems has a higher up-front cost than following the status quo. If Solberg can demonstrate the effectiveness and cost savings of his plan below at SMM, your regional science museum will become a model for climate control systems all over the world--I mean it will take over the world! HAHAHAHAHAHA!

At Science Museum of Minnesota, Solberg wants to make two big changes in the way we use energy:

Solberg's Plan - Phase 1
Like all large buildings, SMM takes in outdoor air, cools it to dehumidify it, then reheats the air and sends it throughout the building to control the climate. Unlike most buildings, which use giant air conditioners and boilers, SMM uses hot and cold water piped in from Saint Paul District Energy to do that job. You can learn more about District Energy in an outdoor exhibit to the left of SMM's main entrance--and you can see the building right next to us!

District Energy burnin' the biomass
District Energy burnin' the biomassCourtesy Andrew Ciscel

The first change Solberg proposes is to re-use the waste heat that SMM generates from cooling down fresh outside air. Currently, SMM's ventilation system cools outside air down to about 50 degrees F with cold water from District Energy, dehumidifies it, and then reheats that air back up to a comfortable indoor temperature with hot water from District Energy.

Solberg would have us cool the air with cold District Energy water, then use that same water (now warmer) to reheat the air back up to 65 degrees F on its way to the ventilation ducts. This change would eliminate the need to use hot water from DE to reheat air, and it would reduce use our demand on DE’s cooling system, because we would send water back to their chilled water plant at a lower temperature than we currently do.

Solberg's Plan - Phase 2
District Energy makes electricity by burning waste wood. DE then uses the heat energy still available after making electricity to produce hot and cold water, making District Energy 50% more efficient than coal-fired power plants. But at the end of the day, DE has 95-degree F water left over. Right now this excess heat is released into the atmosphere from cooling towers on top of the building (see the plume rising from the building in the image?), but that 95-degree water could meet most of SMMs heating needs. Solberg wants us to tap into that wastewater as our primary heating source, replacing the 180-degree water we currently get from DE. This would put an oft-wasted energy source to work, and it would allow the 180-degree water now being used by SMM to be used elsewhere within DE’s hot water distribution system.

This plan is so good it must be evil. In the long run, if the kinds of changes being pursued by SMM were replicated widely, they would amount to lower emissions and lower energy bills everywhere, which is ultimately healthier for our environment (not that mad scientists care about that sort of thing). In fact, we found out that if we had implemented this system when the current building was constructed, we could have saved $1.5 million in infrastructure (which we could have really used for that giant laser in the--end of message truncated--

Jul
13
2010

Brown gold!: This is actually the solid byproduct of a manure-to-methane operation. As you can see, it holds no fear for the owner of this bare hand.
Brown gold!: This is actually the solid byproduct of a manure-to-methane operation. As you can see, it holds no fear for the owner of this bare hand.Courtesy kqedquest
We’ve talked about the delights of cow feces before on Science Buzz, but mid-July always puts me in the mind of “brown gold” (coincidentally, the last occasion it came up was exactly four years ago today), and any time there’s talk of turning an animal into a fuel source, I get excited. (Remember that fuel cell that ran on the tears of lab monkeys? Like that.) Why not take another look?

So here you are: another wonderful story of cows trying their best to please us, before they make the ultimate gift of allowing their bodies to be processed into hamburgers and gelatin and cool jackets.

Poop jokes aside (j/k—that’s impossible), it is a pretty interesting story. The smell you detect coming from cattle farms is, of course, largely from the tens of thousands of gallons of poop the cattle produce every day. The decomposing feces release lots of stinky methane. (Or, to be more precise, the methane itself isn’t smelly. The bad smell comes from other chemicals, like methanethiol, produced by poop-eating bacteria along with the methane.)

Aside from being, you know, gross, all of that poop is pretty bad for the environment. The methane is released into the atmosphere, where it traps heat and contributes to global warming (methane is 20 to 50 times more potent than carbon dioxide as a greenhouse gas), and the poop itself is spread onto fields as fertilizer. Re-using the poop as fertilizer is mostly a good idea, but not all of it gets absorbed into the soil, and lots of it ends up getting washed away into rivers, lakes, and streams, where it pollutes the water.

Some farms have managed to address all of these problems, and make money while doing it.

Instead of spreading the manure onto fields right away, the farms funnel all the poop into swimming pool-sized holding tanks, where it is mixed around and just sort of stewed for a few weeks. All of the methane gas produced by bacteria as it breaks down the manure is captured in tanks. What’s left is a fluffy, more or less sterile, solid that can be used as bedding for the animals, or mixed in with soil, and a liquid fertilizer that can be spread onto fields.

The methane can then be used on-site to generate electricity, either by burning it in a generator, or using it in a fuel cell. (The methane is broken apart and combined with oxygen from the air to produce electricity, water, and carbon dioxide.) A large farm will produce enough electricity to power itself and several hundred other houses. (The extra electricity is just put back into the power grid and sold to the power company.)

Whether the methane is burned or used in a fuel cell, the process still creates carbon dioxide. However, CO2 isn’t nearly as bad as methane when it comes to trapping heat, and because the original source of the carbon was from plant-based feed, the process can be considered “carbon-neutral.” (Although one might argue that the fossil fuels involved in other steps of the cattle farming process could offset this. But let’s leave that be for now. It’s complicated.)

The downside is that setting up an operation to capture and process manure, and to generate power by burning it is expensive—it took about 2.2 million dollars to do it at the farm covered in the article, with about a third of that coming from grants. Still, the byproducts (electricity, fertilizer, soil/bedding) are profitable enough that the system could pay for itself over the course of a few years.

It’s amazing, eh? Out of a cow’s butt we get soft, clean bedding, liquid fertilizer, and electricity, all without the bad smell. What a world.

Naval architects believe that huge 5 megawatt wind generators could be mounted on three floating legs, much like a deepwater oil production platform.

Their paper titled WindFloat: A floating foundation for offshore wind turbinesis in the Journal of Renewable and Sustainable Energy.

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More info and a podcast can be found via Scientific American.