Perhaps Sustainability Starts with Energy, But It Certainly Doesn't End There
A reader notes: In 20 years or so, literally 1% of the land will be covered by PV.
I respond:
Even if we powered the whole world with solar, we wouldn’t need 1% of the Earth’s landmass to do it (though you’re at the right order of magnitude). 1% of the Earth’s surface is 1% (4 pi 4000^2) square miles ~ 2*10^6 square miles. The landmass is ~30% of that, or ~ 6*10^5 square miles ~ 1.5*10^13 square feet. At 20 watts/square foot and a 15% capacity factor, that’s ~ 4.5*10^13 watts = 45 TW which is ~ 3 times more than we’re using now globally.
In any case, no one is talking about powering the whole world with solar, for many reasons including the challenges associated with making that much PV; our current load (15 TW) is about 300 times our current annual output. What we need is a grid-mix that eliminates coal-fired electricity and relies on a blend of solar, wind, the other renewables, efficiency, storage, transmission, and natural gas back-up (as well as advanced nuclear when it’s ready to go, of course). We also need electric transportation for our cars and light-duty trucks, charged with the above-mentioned array of resources. If we can get there in 20 years, which I believe we can, we’ll have done about as much to reduce the damage we’re inflicting on the environment from our generation and consumption of energy as possible.
Of course, there is no reason to do any of this as long as we’re eating huge amounts of meat. If everyone on the planet ate like Americans, Earth’s food-production resources could support only about 2 billion people; if everyone ate like most Asians, those same resources would support 15 billion people. The most unsustainable thing we’re doing on this planet is pictured above.
Btw, I chose this picture to suggest, though to gloss over, the unbelievable level of cruelty associated with our meat-related processes. They say that a trip to the “killing floor” of a slaughterhouse is an experience that “sears the soul for a lifetime.” I don’t doubt that for a second; neither should you.
Craig,
You are off by a few orders of magnitude here.
The CIA world factbook gives the geographic land mass of the world at ~149 million km2, which would convert to ~57 million square miles… but I have trouble understanding large-scope issues in customary units.
At 149 million km2, assuming a yearlong average ~250 W/m2, you have a total insolation of ~894 trillion kWh/d. 1% of that would be ~8.94 trillion kWh/d. At ~20% efficiency, you get ~1.79 trillion kWh/d, or ~635 PWh/year. The U.S. uses ~4 PWh/year of electricity. I don’t remember right offhand what the entire world uses…. but even after factoring in heating, cooking, industrial needs, and transportation, I think the world would still be manyfold shy of 635 PWh/year.
🙂
I did my calcs in power rather than energy. The world power demand is ~ 15 TW. Are you sure I’m wrong?
And are you saying that the US uses 4 PWh/yr in electricity and the world’s total demand is more than 150 times that? That couldn’t possibly be correct.
I just noted your calc’s assumed ~2 million square miles. The real number is ~28 times that amount.
🙂
15 TW, assuming ~20% capacity factor, would be ~26 PWh/y.
As for the amount of electricity the U.S. uses, that I am sure of.
Our total electrical generation from all sources in 2014 was 4,093,606 GWh.
Obviously, our total energy usage was far greater than that, especially since coal averages 31% efficiency and NG averages 40%… plus all the NG and coal used for industrial and agricultural purposes, plus all NG heating, plus all oil used in transportation…
So if you’re talking about TOTAL energy used by a country, it’s higher, but much of that would be scaled down if you start with energy that has been converted to electricity.
Actually, 1% of the Earth’s surface areas is ~ 2 million square miles. 30% is land, giving 600,000 of land, which is ~ what I get by Googling it.
Oh… Ok.
I see what you did there.
🙂
We ended up quite close on the land total then, as it should be. I just misread your initial post.
Regarding meat production whilst I agree with you that industrial scale meat production is a serious issue in terms of both ethical and environmental concerns, I would say that the uncontrolled growth of Population is even bigger.
If population levels remain broadly stable, we have a good chance of developing a more sustainable way of living.
On the other hand, if the population continues doubling within an individual’s lifespan, then there is no chance to avoid an eventual collapse of ecosystems, economies, and population brought about by war, famine, climate change etc
Good points. Happy New Year to you, Gary. Thanks again for all your help and support.