Category Archives: Science

Calculating my home’s energy inputs and outputs.

I’ve been wondering what the inputs and outputs are of my home energy usage. For some months now, I’ve used a CurrentCost Envi to track my house’s energy usage, so I know the numbers in kilowatt hours: 8,166 kWh in the past 12 months, an average of 680 kWh/month, with a low of 454 kWh (September 2010) and a high of 1,180 kWh (January 2010). But what does that mean?

My power comes from approximately an equal mix of coal and nuclear, according to Dominion, my power company. Let’s start with coal.

Although not all coal is created equal, it basically takes one kilogram of coal to generate two kilowatt hours of electricity. Coal itself contains rather more power, but a lot is wasted as heat in the generation process, and still more is lost in the distribution process. Of my 8,166 kWh, about 4,093 kWh came from coal. That means that 4,511 pounds of coal were burned to power my home in the past year. The pollution side of coal is rather worse. Each unit of coal results in the emission of 2.93 times as much CO2 by weight (assuming 80% carbon coal), a result of carbon emissions bonding with oxygen. The coal burned to power my home, therefore, resulted in 13,217 pounds—six and a half tons—of CO2 to be emitted.

Nuclear is rather different, at least by weight. Uranium produces 360,000 kWh per kilogram, meaning that the 4,093 kWh of nuclear power for my home required 1.2 grams of uranium, which is approximately half of the weight of a penny, and slightly more than a paperclip. The amount of waste is similarly minute, in quantity. Uranium generates 3 milligrams of waste per kilowatt hour, or the size of a standard-issue snowflake. For my home’s usage in a year, that’s 12 grams of nuclear waste, the weight of two quarters. Of course, a straight comparison of uranium to coal by weight isn’t particularly meaningful.

None of this considers the mining or transport of that coal or uranium, the storage of the waste, etc. But I find it useful to know that powering my house for the last year required a over two tons of coal, a single gram of uranium, and produced north of six tons of CO2 and twelve grams of nuclear waste.

For the record, I participate in Dominion’s Green Power program, meaning that I pay 1.5¢ extra per kWh to offset 100% of my power use via renewable sources. But those very electrons don’t travel to my home—they just get mixed into the regional grid. So while I can feel good that I have prevented all of the enumerated energy sources and pollution from being used and emitted on my behalf, I’m not kidding myself—it’s 98% coal and nuclear power that’s coming into my home.

(Previously: “Rethinking Virginia’s energy infrastructure” and “Degree days and energy usage.”)

McDonnell doubts global climate change exists at all.

Bob McDonnell just doesn’t think that people have anything to do with global climate change, and the AP’s Bob Lewis asked him some hard questions about it. Climate scientists are unanimous: the temperature is going up, and human are doing it. But McDonnell says he merely “thinks” that global climate change is real, but says that “there’s some debate” over that. (There’s not.) Lewis asked him if carbon emissions have anything to do with it, and McDonnell said, terrifyingly, that “it’s not going to affect my policy decisions.” (Yes, we know it’s not—that’s the problem.)

Two points to the first reporter who asks McDonnell whether a) evolution exists b) humans have evolved and c) there’s scientific consensus that evolution exists. I’ve got a strong suspicion that his answers will make for some good copy.

Giant puffball mushrooms.

We’ve got some giant puffball mushrooms growing here.

Annie Encounters a Puffball

Here’s a photo of a cluster of them with a penny set on top for scale.

Giant Puffball Mushrooms

When I saw them, I wondered why there were a bunch of volleyballs scattered around. Calvatia gigantea turns out to be relatively common and, according to several sources, edible and tasty. Once you’ve verified that the interior is firm and white, it can be battered and pan fried, or used like tofu. It smells strongly like your standard grocery store issue mushrooms. Which, unfortunately, I detest, so no giant puffball will be appearing on the household menu anytime soon.

A chemist has demonstrated how RNA developed.

The big mystery of evolution is how it all began. We know how life got more complex, but how did it start? An English chemist appears to have figured that out, having demonstrated how a base, ribose, and a phosphate group would join together to form RNA. The key appears to be exposure to ultraviolet light. Most impressively, this theory supports not the more recent theories of life’s origins—that it would have begun around in the extreme conditions around deep sea vents—but Charles Darwin’s 1871 theory, that life started “in some warm little pond, with all sorts of ammonia and phosphoric salts.”

Oil industry knew in 1995 that they were causing climate change.

Oil companies concluded in 1995 that “the scientific basis for the Greenhouse Effect and the potential impact of human emissions of greenhouse gases such as CO2 on climate is well established and cannot be denied,” but decided it was best to ignore conclusions and continue to claim that there was no correlation. Many of those oil companies continue to pretend otherwise, though some (Exxon Mobil) have recently admitted that humans are causing global climate change and stopped funding the groups that claim otherwise on behalf of the oil industry.

At this point being surprised by this is a bit like being surprised that the tobacco industry long ago knew that cigarettes are deadly.

Friendship extends lifespan.

For the New York Times, Tara Parker-Pope explains that friends are good for your health:

Last year, researchers studied 34 students at the University of Virginia, taking them to the base of a steep hill and fitting them with a weighted backpack. They were then asked to estimate the steepness of the hill. Some participants stood next to friends during the exercise, while others were alone.

The students who stood with friends gave lower estimates of the steepness of the hill. And the longer the friends had known each other, the less steep the hill appeared.

Flickr is auto-IDing astronomical objects.

Astronomy photos on Flickr are automatically being analyzed and labelled with constellations, planets, and other objects. The group doing the IDing then has a big corpus of astronomical images, which has got to be valuable. Man, that is so cool. The physical coordinates and the timestamp go a long way towards providing the basic data necessary to do the math on this, but some clever image recognition and computation has to be necessary to pick out individual objects and label them. I’ve only posted a few astrophotos that I’ve taken, but I intend to post a lot more now. (Via Slashdot)

The false hope of vitamin supplements.

In the New York Times, Tara Parker-Pope looks at the (possible) false hope of vitamin supplements. Vitamins are essential—we’d quickly die without them. But it’s looking increasingly likely that vitamin supplements—vitamins in pill form—are significantly less effective than vitamins that occur naturally, in food. Vitamins may be what allow our bodies to avoid the sorts of diseases that occur in their absence (scurvy and rickets, for example), and are likely help for people who lack the ability to produce or process vitamins in food, due to age or ailment. But they’re apparently useless in preventing cancer, heart disease, etc. And they can even be harmful. A massive dose of vitamin C does nothing to prevent colds. High rates of beta carotene are correlated with lung cancer. People’s faith in vitamins exceeds the science.

The moral of the story? Get your nutrition from food. If you think you need vitamin C, have an orange. Need some beta carotene? Eat a carrot.