Sustainable Energy Without the Hot Air by David MacKay

What does a world without fossil fuels look like?  There are lots of different options, but none of them look much like the rich developed nations of the world today.  David MacKay’s approach in Sustainable Energy Without the Hot Air is to hold our rate of energy consumption constant, and explore the kinds of carbon-free energy systems that could satisfy that demand.  The uncomfortable conclusion he comes to is that if we want to run our world on renewables, the energy farms have to be comparable in scale to nations.  Comparable in scale to our agricultural systems.  This is because all renewable energy is very diffuse, and we use a whole lot of energy.

SunPower's Bavarian PV Installation

Just as an example, of all the renewable power sources solar is the most concentrated, and PV farms like the ones cropping up in Bavaria because of Germany’s generous feed-in tariff average about 5W/m2.  With better siting (the Sahara, Arizona) you can do a bit better, and there’s a little more efficiency to be eked out of the panels, but for large scale deployments, you’re not going to get above 10W/m2.  If you’re an average citizen of the EU or Japan, your 5kW of power thus demands 500m2 of land.  Multiply that by 700 million people in the EU, and you get the total area of Germany.  An average North American’s 10kW requires 1000m2.  Multiply that by 300 million people, and you get an the entire area of Arizona.

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Why Urban Farming is an Awful Idea

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Boulder County is looking at some kind of county-wide sustainability program, with an associated tax which will be on the ballot this fall.  The City of Boulder is revising its Climate Action Plan, looking toward a goal of climate neutrality in 2050.  An extension of the tax which supports our climate work will also be on the ballot in the fall.  One thing that none of that money should go toward?  Urban farming.

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Empirical Investing

In my previous post I described the stock and bond markets by analogy with a casino, but you might reasonably question the validity of that analogy.  Are market returns really as unpredictable as coin flips?  The real payoff probability distributions obviously aren’t binary; what do they actually look like?

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Links for the week of November 20th, 2009

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Shared Links for Jun 26th – Jul 7th

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