Stories tagged Flow of Matter and Energy

Mar
14
2011

The Fukushima plant: Before the earthquake.
The Fukushima plant: Before the earthquake.Courtesy KEI
Ok, well, there isn’t really such a thing as a nuclear earthquake. “Nuclear Earthquake” just sounds impressive. And I suppose “impressive” is one way to describe what’s happening in Japan right now.

I suppose you’re all aware of the 8.9 (or possibly 9.0) rated earthquake that hit Japan last week (if you aren’t, check out this post), and that the Fukushima nuclear power station there has been severely damaged.

While the country is still trying to put itself together, officials are still trying to get the power plant under control. So what happened, what’s happening, and what’s (probably) going to happen?

Well, a nuclear plant like Fukushima basically operates by using radioactive uranium to boil water. The uranium is always decaying—the number of protons and neutrons it has isn’t stable, so neutrons fly off, causing heat. If the neutrons hit other neutrons in the uranium, they fly off too, causing even more heat. If there’s too much of this neutron-on-neutron action, the uranium will get too hot, melt everything around it, and it’s a disaster. This is what happened at Chernobyl.

To prevent the neutron reaction from getting out of control, and to make sure the uranium produces just the right amount of heat, “control rods” are inserted in with the uranium fuel. The control rods absorb some of the neutrons to keep the reaction under control. When the right amount of heat is being produced, the water around the fuel boils, turns to steam, and spins electric generators. It works out pretty well.

At Fukushima, the control rods were inserted into the uranium as soon as the earthquake started, and they did work—the uranium reaction was shut down. But the decaying uranium had already produced other elements, elements with a lot of heat of their own. So there was a lot of residual heat in the power station.

Normally, water would keep circulating around the hot core, carrying away the residual heat (and turning it into electricity). But between the earthquake and the ensuing tsunami, the power to the water pumps was shut off and the backup generators were disabled. The pumps had backup batteries, but eventually those ran out. That means there was still a lot of heat in the core, but no fresh water to carry it away. The water that was there would continue to heat up until the steam was vented or the vessel containing it simply burst.

Unfortunately, both of those things sort of happened. While purposely venting some of the steam, an explosion happened in the building surrounding one of the cores. According to this site, this is probably because some of the vented water vapor had separated into hydrogen and oxygen, which built up in the building and ignited. This whole situation (the venting and the steam) was radioactive, but not that bad as those things go—the radioactive elements decayed and became stable in a very short time.

The next problem was that with all the venting, the water level around the cores was slowly falling. Without water to take away their heat, the cores could overheat, and eventually melt down. This started to happen, and some more dangerous radioactive products of the uranium started to mix with the remaining water and steam, so officials decided to start pumping seawater into the core. Seawater can get more radioactive than clean water, but it would keep the core cool and under control. And it did.

Today, there was a second explosion at the plant, however. I’m not totally sure what caused this, but it looks like it was again from the accumulation of hydrogen in one of the buildings.

With the uranium reaction under control and the cores under water, the residual heat should eventually dissipate. But the explosions have further damaged the cooling systems, and keeping the multiple cores at the station submerged in seawater has been a challenge. The longer the cores are exposed, the harder it is to control radioactive material already produced by the cores, and the greater the chance of a meltdown occurring at the plant.

Approximately 200,000 people living in the region of the nuclear plant have been evacuated, and it’s still unclear what will happen there. Nothing good certainly, but a meltdown isn’t a sure thing at this point, and even if a meltdown were to occur (again, a meltdown happens when there’s too much heat in the core, and everything around the radioactive fuel melts), the Fukushima plant was built to much higher safety standards than Chernobyl was, and it should contain the damage much more effectively. At Chernobyl, explosions sent radioactive material into the atmosphere and over the surrounding area. At Fukushima, as I understand it, the radioactive products of a meltdown would be contained inside extremely thick, tough containers, which, so far, have not been damaged by the earthquake or the explosions.

There’s more to be said about what will happen, and how this might affect the world’s attitude toward nuclear power, and whether that’s a good thing or not … but that will have to wait for another post.

Update: A Third Explosion at Fukushima
A there's been another explosion at the Fukushima nuclear plant. Now three of the four reactors at Fukushima have experienced an explosion. The previous two explosions were probably caused by a buildup of hydrogen, but it isn't certain whether that was the cause of this explosion as well.

The vents that emergency workers had hoped to use to flood the reactor chamber with seawater were malfunctioning, meaning that the core was dry (and un-cooled) for several hours. The vents finally started working in the early morning, but the chamber wasn't filling with water the way they had hoped, perhaps because of a leak.

A meltdown is still possible, but while radiation levels in the area are considered "elevated," they are low enough that it's very unlikely that the vessels that contain the reactor cores have been breached.

3/15/11 Update: Fire at 4th reactor
Shortly after the explosion at reactor 2 (the third explosion), a fire started at reactor 4. Between the fire and the explosion, radiation levels at the site briefly spiked to about 167 times the average annual dose. Reactor 4 actually wasn't producing power when the tsunami hit, but it did contain a cooling pool for spent fuel assemblies.

Nuclear fuel that has decayed to the point where it's not useful for sustaining a nuclear reaction still produces a lot of heat, and so it's stored in a pool of water for years to deal with the heat and radiation. Reactor 4 at Fukishima has one of these pools, and—just like with the active reactors—it looks like the cooling system was malfunctioning, which allowed the water in the pool to boil away, exposing the spent fuel. The spent fuel likely heated up until it ignited, or caused a fire in the building.

Authorities are now warning people living as far as 20 miles away from the plant to stay inside to avoid any radioactive fallout. As for the emergency workers at Fukushima, CNN's expert says, "Their situation is not great. It's pretty clear that they will be getting very high doses of radiation. There's certainly the potential for lethal doses of radiation. They know it, and I think you have to call these people heroes."

Update: 2 Reactor containment vessels probably cracked
Japanese officials think that the spike of radiation around the Fukushima plant last night might have been associated with a cracked containment vessel in one of the reactors. Today, they think a second container might be cracked as well, and leaking radioactive steam.

Mar
04
2011

This started as a reply to Bryan's comment on the Freaky Frogs post, but it quickly turned into its own blog entry...

Here's Bryan's comment:

I thought the whole BPA freakout was an interesting look at how we think about environmental and personal contaminants like this. People seemed to get all up in arms about BPA in water bottles and bought tons of new plastic or aluminium vessels to replace them. But that switch over raised some questions for me.

Where did all those old bottles go? In the trash?

How much energy does it take to make those aluminium bottles? Is it lots more than the plastic ones?

How many bottles can you own before it'd just be better to use disposable paper?

Bauxite: It takes a lot of energy to get the aluminum out of this rock to make a can.
Bauxite: It takes a lot of energy to get the aluminum out of this rock to make a can.Courtesy US Government

And my response...
It took some searching, but I did find one article discussing a life cycle analysis from Australia which showed that, in a comparison between aluminum, stainless steel, and plastic, plastic has the smallest carbon emissions footprint, uses the least water, and produces the least manufacturing waste. However, it was unclear whether this comparison included recycled metals in its evaluation. Steel and aluminum are 100% recyclable (vs. plastic, which loses quality every time it's recycled), so over time and on a large scale, their use would lead to less material waste.

Steel plant: This place is probably recycling steel RIGHT NOW.
Steel plant: This place is probably recycling steel RIGHT NOW.Courtesy Matthew Baugh

It's also interesting to note that recycling metals uses significantly less energy vs. what it would take to smelt "new" metal. To paraphrase this reference, recycling steel and aluminum saves 74% and 95%, respectively, of the energy used to make these metals from scratch. As it turns out, we recycle about half the steel we use in a year in the US, and so almost all the steel we use contains recycled content. In contrast, we recycle just 7 percent of the plastic we use.

And then there's glass--we have lots of options, really.

Bottled water: Probably the least efficient option all around.
Bottled water: Probably the least efficient option all around.Courtesy Ivy Main

I can't speak to how much material was wasted when people discarded all those bottles (I think I recycled mine?). Personally, I do think that making reusable bottles in general uses less energy than is needed to make all those disposable plastics and recycle them--at least in terms of lifetime footprints. Of course, when it comes to a strict comparison between reusable bottles, switching to a new bottle will always consume more energy than just sticking with your old one.

Unfortunately, it turns out that most plastics, even the ones labeled BPA-free, leach estrogen-mimicking chemicals. So if you're looking for a long term solution, it may be best to just avoid plastics altogether. This does seem to be one of those cases where we have to consider our own health vs. the environment and pick our battles wisely. If people want to switch once to avoid health problems, at least they're still sticking with reusable bottles. Readers, do you agree?

Ice cold water: Wait, what's in here?
Ice cold water: Wait, what's in here?Courtesy Clementina

Of course, it would be great if choosing a water bottle were the only drinking water issue we faced. The other day I read about a study by Environmental Working Group, which found that the carcinogen chromium-6 contaminates tap water throughout the US. Are we exposing ourselves to this toxic metal by drinking tap water instead of pre-bottled water? Or is chromium in the bottled water, too? What about other unregulated pollutants in our water?

I guess my point of going into all this is that it's complicated to make these decisions, and we'll probably never be able to avoid every single toxic substance. But does that mean we shouldn't try to make drinking water safer?

For now, I'm gonna stick with the steel and aluminum bottles that I already have and try to get the most out of them. Luckily, I live in the Twin Cities, which don't rate high on EWG's chromium map. Every day, I learn more about my health and the health of our environment, and hopefully by searching, I'll find a direction that hits on a fair compromise.

Feb
23
2011

We've written about freaky frogs on the Buzz Blog before, but some recent news may shed new light on our abnormal amphibians. Until recently, researchers thought that atrazine, an agricultural pesticide, was the sole cause of sexual deformities in frogs. Unfortunately, it's not so simple.
UT OH: What lurks in me waters?
UT OH: What lurks in me waters?Courtesy Mike Ostrowski

An ecologist at Yale University, David Skelly, sought to test assumptions about atrazine by studying the frequencies of frog deformity in different land types--agricultural, suburban, urban, and forested. Skelly expected to find the highest rates of deformities in agricultural areas, which would be consistent with atrazine being the main cause. Curiously, he found the highest rates of deformity in urban and suburban areas--places we wouldn't expect to find much atrazine. So what's going on?

It turns out that what makes atrazine so dangerous is that it mimics estrogen and binds to estrogen receptors in frog cells. Because estrogen impacts sexual development and function, so too does atrazine. But atrazine isn't the only estrogen-mimicking compound out there--there's a whole class of chemicals that mimic estrogens, including those found in birth control pills and plastics (BPA). And these chemicals are found in droves in cities and surburban areas--they're flushed into the sewage, but aren't filtered out during water treatment.
Birth control pills: Estradiol, a synthetic estrogen, helps prevent pregnancy in women. But much of it is excreted in urine and eventually makes its way into various water sources.
Birth control pills: Estradiol, a synthetic estrogen, helps prevent pregnancy in women. But much of it is excreted in urine and eventually makes its way into various water sources.Courtesy Ceridwen

So why do we care? Besides the fact that frogs are just awesome little creatures and important parts of their food webs, they have something in common with humans--estrogen receptors. The same chemicals that impact frogs can impact us. So how do we humans keep our sexual development and functioning intact?
BPA-free: This Sigg bottle is made from enameled aluminum, and it's an example of a BPA-free bottle.
BPA-free: This Sigg bottle is made from enameled aluminum, and it's an example of a BPA-free bottle.Courtesy Bucklesman

Skelly had a great idea to filter this stuff out of the water at the treatment plant, so that it won't get into our bodies from drinking water. He also suggested that regulatory changes would help so that when new chemicals are developed, they're scrutinized for unintended side effects. And of course, we can make choices that reduce our exposure, such as by buying BPA-free plastics, or using stainless steel and glass containers. And of course, increased awareness is always a good idea.

Do you take extra steps to avoid things like BPA? What are they?

Jan
25
2011

Bloom Energy is a CA business that has developed a fuel cell called the Bloom Box. The Bloom Box is a self-contained source of energy. So far its on-site application has been cost prohibitive for the mainstream. To make the Bloom Box more accessible, Bloom Energy is rolling out a system that enables corporations to derive power from the Bloom Box without actually buying it.

The Bloom Electrons Program details

The Bloom Box is something that Bloom Energy got to the clean energy industry. The Bloom Box is an "energy server" that produces electricity with a chemical response and extremely low carbon footprint. Want to understand the price of a Bloom Box? Over $700,000 is the cost. The price has caused the number of Bloom Energy consumers to be pretty low. Corporations consist of B of A, FedEx, eBay and Google. To increase demand for Bloom Boxes, Bloom Energy partnered with Credit Suisse and Silicon Valley Bank to create Bloom Electrons. Bloom Electrons is a financing business that offers 10-year contracts for electricity from on site Bloom Boxes at a fixed rate.

Powering Bloom Electrons with clean power

There are not upfront costs for businesses to use Bloom Box meaning the companies can go off the grid with Bloom Electrons. Companies that have already purchased Bloom Boxes up front expect to recoup the cost of the unit anywhere from three to six years after they're installed. With Bloom Electrons, Bloom Energy said businesses can start saving up to 20 percent immediately on what they're paying in CA. At present, Bloom Electrons only pencils out in California. It's about ten cents per kilowatt-hour within the U.S. for average electricity. About 14 cents per kilowatt-hour is what Bloom boxes do. This is a different price. Bloom Electrons power comes down to about 7 cents per kilowatt-hour with the California subsidies and federal clean power incentives.

The whole world getting Bloom Box soon

Bloom Energy said the Bloom Box will offer businesses a competitive energy advantage without the need for subsidies in three to five years. The first thing the company is worried about is meeting demand for the Bloom Electrons system. The production will need to go up. If you look back 2 years, Bloom Energy was not very fast. About one Bloom Box a month was made. When it comes to shipping Bloom Boxes, the business has gotten faster. It can do one a day now. If Bloom Energy can decrease the production price along with increasing production, it could eventually meet its goal of supplying clean power to the creating world.

Citations

Business Week

businessweek.com/technology/content/jan2011/tc20110120_212633.htm

TechCrunch

techcrunch.com/2011/01/20/bloom-launches-financing-service/

Reuters

reuters.com/article/idUS9777404420110120

Jan
18
2011

If you're a total Buzz nerd like JGordon, you may have noticed a number of posts with the tag "Future Earth" over the last couple of years. They started when the folks here at the Science Museum of Minnesota began researching a new permanent exhibit called Future Earth, opening Fall 2011 at SMM. This exhibit will ask, "How do we survive and thrive on a human-dominated planet?"

EarthBuzz: This new branch of the Buzz focuses on Future Earth topics.
EarthBuzz: This new branch of the Buzz focuses on Future Earth topics.Courtesy SMM

This is a different question than we're used to asking, but it's a vital one. Understanding the answer means studying more than just global warming, rising sea levels, and population growth--we also have to think about energy production, agriculture, retreating glaciers, transportation, hunger, poverty, development, and the list goes on. It turns out that because all of these issues are interrelated, we can't study or address any one of them in total isolation.

This new way of understanding is what inspired the Future Earth exhibit. Future Earth will look at environmental issues with a fresh perspective, explore the ways we study and understand our impacts on the environment, and shed light on projects that offer innovative solutions to complex problems, such as this one we hope to implement at Science Museum of Minnesota. The goal is to foster understanding, hope, and action.

Future Earth is part of a larger effort taking place at SMM, the University of Minnesota's Institute on the Environment, and a team of other institutions called the Future Earth Initiative. Funded by the National Science Foundation, FEI aims to raise awareness and offer workable solutions for life in a human-dominated environment. Given adequate time and resources, these solutions could help reduce our negative impacts on the environment while providing us all with the energy we need to live. Think of it as saving two birds with one…thing that you save birds with…

Dec
29
2010

What what?
What what?Courtesy Public Domain
For those of you who want to choose the most environmentally friendly shaving solution, Slate's Green Lantern just did a column about the carbon footprints of different shaving options. Disposable or electric? Which is "greener"?

As with everything else in the future (where we live), even this little question is complicated. But the author seems to do a pretty good job unpacking it—you have to consider energy used in the process, whether for hot water or to run a small electric motor, as well as manufacturing costs and each product's useful lifetime.

The long and the short of it, depending on your shaving habits, is that electric razors are ultimately more energy efficient than plastic disposables. But just barely. According to the Green Lantern's calculations, you save about 15 pounds of carbon dioxide by using an electric shaver. And, as the author puts it, you would have to shave with a disposable razor for more than 350 years to equal the amount of greenhouse gases produced by one cow in a single year. (I don't think a cow produces 5200 pounds of greenhouse gas a year by itself. That figure might be taking in to consideration the gases produced by growing feed and processing the animal as well, or it might account for the greater potency of methane—which cows produce—as a greenhouse gas over carbon dioxide.)

In any case, this assumes that you shave your face at all. You might wear a beard, or you might be what I like to call "a female." Or you might take advantage of one of the many other shaving options: some men use old-fashion safety razors and straight razors; Crocodile Dundee finishes his shaves with a bowie knife; I cover my face in high-proof grain alcohol and set it ablaze (it's invigorating, but I can't maintain eyelashes well this way); I have friends who let cats lick away their stubble.

So this isn't the be-all-end-all. But it's like David Schwimmer says.

Dec
09
2010

Surveying Microbes at Sea
Surveying Microbes at SeaCourtesy C-MORE
There are microbes…and then there are micro-microbes. Oceanographers on C-MORE’s BiG RAPA oceanographic expedition are finding bacteria the size of one-one-millionth of a meter in the oligotrophic (low nutrient), open-ocean of the Southeast Pacific, far from the productive waters off the coast of Chile. But that’s not all; some scientists are looking for the even smaller marine viruses in gallons of filtered seawater. Meet some of these micro-microbes in these video reports:
Prochlorococcus
ProchlorococcusCourtesy Dr. Anne Thompson, MIT

  • Microbe Diversity, Part 1: Prochlorococcus, the most common bacterium in the world’s oceans; nitrogen-fixing bacteria that provide a usable form of nitrogen “fertilizer” for other photosynthesizers
  • Microbe Diversity, Part 2: picophytoeukaryotes with different colored pigments; viruses, which are parasites on other living things

Yes indeed, microbial oceanographers are taking home quite a collection from the South Pacific Ocean. In less than a week the good ship RV Melville will arrive at Rapa Nui (Easter Island), and scientists will step onto land for the first time in almost a month. They and their oceanographic samples will return to C-MORE laboratories around the U.S. The oceanographers are also returning with new hypotheses buzzing around in their heads. Now it’s time for them to take the next step in the Scientific Method: data analysis!

Dec
01
2010

The University of Minnesota's Institute on the Environment has made some great movies examining what they call "big questions."

Big question: Feast or famine?
IonE's first Big Question asks: How do we feed a growing world without destroying the planet?

Big question: Is Earth past the tipping point?
Have we pushed our planet past the tipping point? That's a critical issue the IonE explores in our second Big Question video.

Big question: What is nature worth?
Plants, animals, even entire ecosystems are disappearing. So what? "What is Nature Worth" offers a three-minute look at what we’re REALLY losing – and what we can do about it.

Interesting problems, right? If you're intrigued, and want to know more about the folks posing the questions and trying to find the solutions, jump over to Future Earth.

Nov
26
2010

surveying microbes at sea
surveying microbes at seaCourtesy C-MORE
Dr. Dan Repeta from the Woods Hole Oceanographic Institution (WHOI) is C-MORE’s Chief Scientist on the BiG RAPA expedition, which is conducting research off the coast of Chile. Dr. Repeta and his team of scientists are sampling the underwater microbial environment using a variety of instruments, including a water collector called a CTD (see educational resource below). Two interesting results have turned up in the CTD data:

  1. chlorophyll -- The greatest amount of the green pigment, representing floating microscopic plants in the sea known as phytoplankton, was found about 30 meters below the sea surface. (That's where oceanographers expect the most chlorophyll. Perhaps phytoplankton living at that depth must produce more chlorophyll in order to capture the lower light intensities, just like leaves are usually darker green if they're growing on a land plant in the shade). However, a surprise awaited oceanographers at 60 meters. At that depth, they discovered an unusual “secondary, deeper chlorophyll max," something not seen many other places in the world.
  2. Oxygen -- This gas enters the ocean primarily at the surface, from the air and also from phytoplankton photosynthesis. Bacteria and other heterotrophs consume the O2 as they metabolize. Therefore, oxygen is expected to decrease with depth. At BiG RAPA's Station 1 oxygen not only fell; it fell all the way to near zero.

Dr. Angel White and the CTD
Dr. Angel White and the CTDCourtesy Eric Grabowski, C-MORE
"Sea It Live" in some BiG RAPA videos. Join Dr. Angel White from Oregon State University as she demonstrates the CTD rosette. Then join Dr. Repeta for his Chief Scientist Station 1 Update .
______________________
*Educational resource = C-MORE Science Kit Ocean Conveyor Belt's Powerpoint, "Lesson 3: Using Data to Explore Ocean Processes "

Oct
13
2010

Happy as a whale in: ... in whatever.
Happy as a whale in: ... in whatever.Courtesy Ineuw
We love whale poop around here. Love it love it love it. Can’t get enough. It’s fortunate for us that whales poop so much—if you were to get the planet’s daily supply of whale poop in one place, and if you were also in that place, you would suffocate. It’d be awful.

The reason we love whale poop so much is because of its role in what Elton John and I like to call “the circle of life.”

We’ve already discussed how sperm whales have a net negative contribution to atmospheric CO2, because of all the iron in their poop. (The iron rich waste feeds tiny sea creatures, which, in turn, suck up CO2.)

It turns out that whales and their poop are also vital for the nitrogen cycle. Nitrogen is a vital nutrient for ocean life. While some parts of the ocean have too much nitrogen—extra nitrogen from fertilizers washes out through rivers, causing algae to grow out of control and create a dead zone—other areas contain a very small amount nitrogen, and local ecosystem productivity is limited by nitrogen availability.

So what brings more nitrogen to these nitrogen-poor areas? Microorganisms and fish bring it from other parts of the ocean, and release it by dying or going to the bathroom. But, also… whales bring it. Whales bring it by the crapload.

Whales, it turns out, probably play a very heavy role in the nitrogen cycle. And because the nitrogen feeds tiny ocean creatures, and those tiny ocean creatures feed larger ocean creatures, and on and on until we get to fish, more whales (and whale poop) means more fish. And we (humans) love fish.

Commercial whaling over the last several hundred years reduced global whale population to a small fraction of what it once was, but even at their current numbers whales contribute significantly to nitrogen levels in some areas. More whales, the authors of a recent whale poop study say, could help offset the damage humans have done to the oceans and ocean fisheries, while relaxing restrictions on whaling could have much further reaching ramifications than we might expect.

See? Whale poop is the best! (Whales too, I guess.)