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Power DesignLine Blog

Wake up and smell the numbers

Bill Schweber

6/18/2010 10:41 AM EDT

There's a lot of talk about "alternative" energy sources and techniques these days; you'd have to be living in a cave to not know that. But I am also impressed (yeah, right :-) by the pundits who talk about alternative sources without first getting some semblance of real data on our present sources and these proposed alternatives.

Unfortunately, doing this sort of homework gets in the way of whatever argument they are trying to make. So for starters, here are some data points I urge anyone looking at various energy sources to check out. (No, I am not doing your homework for you; you'll need to get the numbers yourself, sorry.)

The numbers are available from a variety of reputable sources. I suggest you start with these, and ignore cost for now, just stick to the incontrovertible physics:

  • Energy density (watt-hours/weight and volume) for gasoline
  • Same data for hydrogen gas and for hydrocarbons such as natural gas, ethanol, propane and others of your choice (in gas and liquid phases)
  • Maximum solar radiation (watts/meter2) on the Earth's surface, under best-case conditions
  • Mean solar radiation at different locations on Earth
  • Energy density for various battery technologies, again with respect to both weight and volume
  • Maximum energy capture for wind power under ideal conditions (watts per land area and wind speed)
  • Realistic energy capture for wind power
  • Energy-capture density for biomass such as corn, stalks, wood, among others (watt-hours/land area)
  • Muscle power from human effort (such as pedaling)
  • Power and energy for water power (various ways to assess this)
  • Nuclear power (what non-cost metrics would make sense here?)
    • The list goes on, but these are just some to start with, as you try to figure out what is viable for your project or dream, and what steps you need to take to make it happen.

    Next, you'll have to account for inefficiencies along the way, whether it is in transforming the initial stored energy and power into a more useful form (such as solar to electrical) or in converting the stored energy into mechanical power (such gasoline into mechanical energy, in an internal combustion engine).

    Cost comes into the picture too, but any cost-related numbers have lots of assumptions, variability, and dependencies. At least the solid, physics and chemistry-based numbers will define an envelope.

    Only with this sort of solid data can you start to make meaningful statements about energy alternatives. . . . unless, of course, you are a professional media pundit or talking head. ♦



    green_is_now

    7/9/2010 6:29 PM EDT

    why not list links to these type of numbers.
    critisizing pundits for not having facts investigated but not providing any facts oneself seems a little hippo-critical.

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    Engbob

    7/15/2010 12:50 PM EDT

    Bill, Are you trying to scare us? The chemical storge and efficiency to do work of Gasoline (and coal..) are so many times everything else it is depressing to think about.

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