Welcome to Superoceras, a blog about science and natural history, slightly biased towards paleontology and zoology, but inclusive of all sciences. Started in October of 2009, my goal is to communicate scientific knowledge (and the occasional piece of nonsense) in an informative and entertaining manner. Feel free to contact me with questions, comments, concerns, or criticism at superoceras(at)gmail(dot)com, and follow me on Twitter @Superoceras for all that and more in 140 characters or less!

Sunday, May 27, 2012

Things I Learned This Semester #15 - 21: Energy Edition Part I

And now, as promised, it's time for some very "non-avian content".  This semester I took a course on the physics of energy, and the science behind the technologies that power our every day lives.  Natural history may be where my heart lies.  But life isn't all trees, birds, and fossils.  So recently I've been interested in learning more about other aspects of the world we live in, and how our actions as a species impact it.  Energy use is one of the big ones.  Where do we get our energy from?  What impact is that having on the rest of the world?  Is there anything we can do about it?  These are big questions.  And there are no simple answers.  But I learned a few things this semester that, if nothing else, have made me a more informed decision maker when it comes to my energy use, and the politics and science behind it.  I thought I'd share a few of those things with you all.

#15 - Getting down to basics, energy is the ability to do work.  Like mass it can neither be created nor destroyed.  But it can be transformed, from one kind of energy into another, or from energy into matter. Energy can be measured as a physical quantity, and is done so in joules (J) in most of the world (here in the United States, we measure energy in kilowatt-hours).  Energy is different from power, which is a measure of energy used per unit of time (the rate at which energy is transferred).

#16 - In 2009 the world population (around 6.8 billion people) consumed 516.95 x 1018 J of energy.  About 20% of that energy was used by the United States alone.  To provide a frame of reference for these numbers, a very common two-patty, "special" sauce covered burger  is 550 calories (another unit used for measuring energy), which is about 2.3 MJ. So throw in a little math, and it turns out that the world population of 2009 consumed 224.76 trillion "burgers" worth of energy.  That makes the 550 million burgers that were actually sold that year pale in comparison.

#17 - This world population is growing every second. Net population growth (birth rate minus death rate) is around 2.5 people a second. As our populations grow exponentially, our resources grow linearly.  And energy is no exception.  As we generate and consume more and more energy to meet the needs of this population, we are experiencing a "tragedy of the commons" on a global scale; a scenario in which shared limited resources are depleted due to individuals acting in self-interest, when the end result is a net loss for everyone. Some of our current energy sources are finite, and if not managed properly, could be easily depleted by this expanding population.

#18 - The majority of global energy (around 82%) comes from fossil fuels: petroleum (oil), coal, and methane (natural gas).  Oil is the largest source, with coal and natural gas coming in second and third.  Smaller quantities of energy come from nuclear, hydroelectric, and other renewable sources.  Fossil fuels, by nature, are non-renewable, as they take millions of years to form, and we are using them at a much higher rate at than they are being created.

#19 - The phrase "energy independence" is a hot one today, and more and more we hear people talking about our dependence on foreign oil.  A dependence on oil, particularly foreign, is bad for our economy and the environment.  But this is something that our political leaders have known for a long time.  Most oil reserves can be found in the Middle East, and so, that is where most of our oil comes from.  There are some to be found domestically, and the United States.  And we have a ton of coal under our feet as well.  But these resources won't last forever.

#20 - There are some sources that would last "forever", if our current technology was up to speed.  My money has always been on renewables such as solar.  Solar power, after all, has always powered everything on Earth.  If you get your energy from fossil fuels, that comes from the solar power originally harvested by organisms that locked it up as carbon in their bodies.  If you get your energy from wind, it comes from the absorption of solar energy across the surface of the globe.  Even the energy in your bodies from the food you eat comes from solar.  Using solar power to meet our current energy needs seems like a no brainer.

#21 - Unfortunately, as I mentioned above, there are some problems with trying to rely solely on solar or other renewable resources.  With solar specifically, you can only harvest this energy when the sun is out.  So what happens when people want to use energy at night, or when it is overcast?  You would need some  kind of storage system for the energy produced during peak times. And while that battery technology exists, it is fairly expensive to produce and purchase on a large scale.  Solar photovoltaic cells also produce electricity in direct current, which has to be converted to alternating current for everyday use.  Add the cost of an inverter to your solar system, not to mention the cost of rebuilding and implementing this infrastructure across the country, and this energy source is almost always more expensive than the current alternative. That's a darn shame, but there will come a point in the future where this is no longer the case, and grid parity (the point at which solar electricity costs as much as grid power) is reached.

And on that optimistic note, I'll break here for the moment, but part two will be up later today.


Lathrop, Daniel P. 2012. Personal communication in PHYS105, University of Maryland, College Park. 

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