GELFAND’S WORLD-It's a rare moment when a student thesis gets worldwide coverage, but it happened a few days ago. The big hit was a picture of what it would take to provide all the world's electricity using solar power alone. The background is simple -- the energy hitting the surface of our planet from the sun is much more than what humans use.
So if we wanted to convert all of our electricity supplies to solar, we could potentially do so. It would take a square about 160 miles on a side from which to collect the total. Of course you don't take your solar power from a single place and try to feed it to the rest of the world. You divide it up into bite sized squares. In California, northern Mexico, and the rest of the great southwest, we have plenty of area from which to choose.
The article in Kos includes a little of the expected sappiness -- the world hasn't yet gone solar due to the political power of the big energy companies, and so on. It seems to me that this suggestion is a bit of a stretch, particularly when you look at increasing levels of solar power installations both here and abroad. It's more likely that we've not gone whole hog into solar as yet for the most obvious of reasons.
The first is that we already have a cheap and plentiful supply of fuel in the form of coal. It's been the fuel source for the industrial revolution, going back a couple of centuries. The second reason is that solar cell electricity (aka photovoltaic) is a newer technology that was once very expensive. It's only now, with the problems of global warming and rapidly dwindling supplies of petroleum, that we have to start thinking about alternative power.
Luckily, the world has not only been thinking about alternative energy, it has been doing something. What we've done so far is tiny in comparison to where we have to go, but it's a start. What's important is that we are gaining experience in using the alternative technologies such as wind power and photovoltaics. There are economies of scale that come into play at a certain point, particularly in the case of photovoltaics. That's because installed manufacturing capacity becomes a major part of price reductions. We can see that in the rapid fall in solar panels we have been seeing.
In addition, there are several experimental technologies for doing bigger and better solar cells, Eventually, one or two of these will hit big.
When we get into thinking about alternative energy -- or even non-alternative energy for that matter -- we have to recognize one sobering fact. No matter what kind of power plant or solar collectors you install, there is going to be environmental damage. That paragon of clean energy, hydroelectricity, generates power by the thousands of megawatts.
You only lose one thing when you install a hydroelectric dam. You lose the entire area of land that is destroyed when it is covered with water. It's the complete destruction of an entire habitat. There are still sad reminiscences about the destruction done by putting in the Glen Canyon dam on the Colorado River.
We don't have to talk about the environmental catastrophe that is coal. Burning it has already increased the level of carbon dioxide in the air by about one-third, much of that within our lifetimes. It also spews other kinds of air pollution, and coal mining has traditionally been one of the more dangerous occupations.
Now we are entering the age that will be characterized by that most coveted alternative energy supply, solar. Photovoltaic cells don't spew carbon dioxide or thorium, they just sit there, basking in the sun.
Another approach is to collect sunlight and use it to heat something, which is then used as the energy source to drive an electric generator. The graduate thesis that the Kos article cites goes in that direction.
But even then, there are environmental issues, and they go directly to that picture that was featured in Daily Kos.
The discussion excerpted by Kos mentions the total area that would presumably need to be covered by sunlight-collecting mirrors in order to generate the electricity that would supply the European continent. It comes to a square about 70 miles on a side (I've converted the kilometer values to miles for you).
The author goes into great detail about how to transmit electricity from North Africa to Europe, and the interested reader can go through the nearly 200 pages of the thesis for a very interesting discussion of transmission line characteristics and whether we should use AC or DC for long distance lines.
Theoretically, we could apply some of the same theories and calculations to our own situation. For example, the area of solar mirrors that would supply the nation of Germany is a square about 28 miles on a side, and which would be situated in the Sahara Desert. Since Germany has a population that is equivalent to most of our western states combined (and then some), we should be able to apply a similar approach to California and pretty much everywhere out to the Rocky Mountains.
We should be able to find those 800 square miles in our vast deserts. The Mojave Desert includes almost 50,000 square miles, and the Sonoran Desert is about twice that large. Of course there are large areas that we would really like to protect in those deserts, but we ought to be able to find places here and there that would be appropriate. Take two miles here and ten miles there, and eventually you have enough space.
There is one serious problem with this scenario. Solar panels and solar mirrors don't cover everything with water the way a dam does, but they do cover the ground with shadow. If photovoltaics were installed densely, they would also shade the land from what little rain it gets. And that little bit of rain is a required part of the desert ecology.
In short, covering greats swaths of land with densely packed solar panels or even mirror arrays is intensely damaging to the underlying life forms. Many of us have dedicated a considerable number of hours to gaining protection for endangered desert species. We should not stop now.
But perhaps there is an additional techno-fix for the problems coming from wide-array solar power. Suppose we were to make use of even more land, but site the solar modules in patches, with plenty of room left between them to let the sunlight and the rain come through. That would provide some habitat for the lizards and the cacti, and still allow for enough solar installations to make a dent in our needs.
There is another idea that has been getting a lot of press lately. An innovative couple came up with an idea for building a road surface that includes a fairly dense inlay of solar electric panels. Since we have already covered a large proportion of our land area with streets and highways, this would be a way to find the needed area in places that have already been covered over by civilization.
Since we have over 60,000 square miles of paved roads and parking lots in the U.S., perhaps we could find our photovoltaic spaces there. Imagine Palm Springs as an energy capital. Duluth? Not so much. But we can transmit it to them.
As engineering students learn, pretty much everything you do is a tradeoff. If we want cheap electricity and burn coal to get it, we pay the price in an increased risk of lung cancer, and other kinds of sickness among the miners. If we want to build wind farms to generate cleaner electricity, we end up killing some birds and offending some peoples' aesthetic sensibilities.
If we decide to cover enough land area with solar cells to supply our needs, then we have to be careful about where we put them, what land we are willing to destroy, and how we will protect endangered species which live in sensitive areas. Building solar power installations covered with collecting mirrors is probably even more directly destructive than covering everything with photovoltaics.
The point of this little essay is not to oppose the mass installation of solar electric panels, even to the level that would supply most of the world's energy needs. To the contrary. But the use of solar electric at this level is not magic, nor is it a panacea for the effects of an already overly large human population.
But we have to do it, because there really aren't a lot of better choices.
Addendum: I would be ducking if I failed to mention a previous article in which I quoted 4 scientists who believe that whatever else we do, nuclear power is going to be a required element in our electricity supplies for the near future.
I don't see any likely way out of that judgment, particularly if the human race wants to maintain its standard of living. Installed power plants provide what is called baseline power, which simply means that when the sun goes down and the wind dies off, there are 55 million people between here and the Colorado border who want to turn on their lights and cook dinner.
If we could find a way of storing all that solar electric power not just for an hour, but for weeks and months, then we could think about closing down the baseline plants. And you can't just wave the political version of a magic wand.
You have to think in terms of thousands of gigawatt hours -- how you generate them, how you store them, and how you get them out of storage. This is the root question for energy thinkers.
The idea of using solar energy to generate stored heat is worth considering. Some major breakthrough in the ability to store electric power will solve a lot of problems, not only for powering our cities, but for powering our cars.
(Bob Gelfand writes on culture and politics for CityWatch. He can be reached at [email protected])
-cw
CityWatch
Vol 12 Issue 53
Pub: Jul 1, 2014
