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Blah Blah Land Heat Budget

  1. Apr 24, 2008 #1


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    Let's say you are the Good King of Blah Blah Land, a cloudless tropical nation populated by honest-working and Earth-loving people. Your beautiful country is powered by a highly efficient and clean combined cycle natural gas power plant (60% efficiency). The aged power plant is very good but you really want to do the Earth a favor, so you replace it with a solar farm.

    Your country has a desert covered with white quartz sand (50% reflectance). Your extraterrestrial-based national advisor provides you with several square kilometers of solar panels (10% reflected, 80% becomes heat, 10% becomes electricity) shipped from Altair IV. Highly-paid union workers installed the panels in the desert in record time without any labor dispute and job injury.

    Let's say your citizens need 1 unit of energy per day (they sleep all night and work all day). Your gas plant needs to consume 1.6 unit of energy to output 1 unit of energy. 0.6 unit of energy is released as waste heat. The unused desert absorbs 5 units of energy as heat.

    Now to provide as much energy, your solar farm dissipates 8 units of waste heat ... At least you emit no CO2.

    Will your good intention make the world an even hotter place? What would replacing our power system with solar updraft systems do? What role do greenhouse gases provide? Is this a very very silly story that really does not make sense? The estimations of solar cell do not make extra room for future increases in efficiency.
  2. jcsd
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