Exploring the gospel principles of earth stewardship

Energy Visualization

I was excited to read that this month’s blogging topic would be energy conservation.  As an engineer, presently employed as a researcher within an energy conservation research group, I have lot to say about the subject.  The only challenge I had was deciding what to say.

Sitting here in my office, I needed only to spin my chair around and reach for a stack of government-produced pamphlets, research studies, peer reviewed journal articles and textbooks, to begin to bombard you with facts and figures.  Concerted energy conservation programs have been around since the dark days of the Second World War when fuel was being rationed.   However, most of the advice I can give has been around for a long time and boils down to – don’t waste energy.

The problem is that, despite our best efforts, per-capita energy use has been been increasing steadily for well over 100 years.  It is difficult to lay the blame on any one policy or technology, but it is easy to see how much of what we see as progress toward efficiency can be at fault.  More fuel efficient cars have not reduced consumption, they have simply enabled people to travel more.  Better insulated homes and smarter heating systems have allowed the square footage of homes to expand.  Allegorically, we have focused on cutting a thinner piece of pie whilst rapidly increases the size of the pie.

Part of this, I feel, has to do with the intangible nature of the energy we use.  Especially when it comes to gas and electricity.  Few people know how to quantify energy, fewer still can visualize it.  It is easy to imagine a gallon of gasoline or a hundredweight of coal.  How much is a kilowatt-hour of electricity, what does it look like?  What about a gigajoule of natural gas?  Better yet, how many buckets of coal were burnt to provide you with a tub of warm bathwater or keep your iPhone charged?

Given that a large percentage of the world’s electricity is generated from coal, about 42% of the electricity in the USA is produced by burning coal (82% of Utah’s generating capacity), I’d like to offer up a little challenge to the blog readers.  For the next month, I would like to help you visualize your energy use in terms of coal.  Give me a task that requires energy and I will tell you how much coal you’ll burn to do that – on a daily and annual basis!

Just leave your comment below and I’ll respond.  Feel free to make it as complicated as you wish 🙂

  • Eloise says:

    How much energy does it take to do six loads of laundry a week?  Just washing–not drying.

  • Peter says:

    Suppose a house (in Utah) uses an average of 300 kWh of electricity each month.  How much coal does it take to produce that electricity?  Bonus question:  What is the mass and volume of the CO2 produced by burning that much coal?

    • Steve Brogan says:

      Excellent question.  So I had to do a bit of homework for this question to increase the accuracy.  In Utah your power plant burns sub-bituminous coal, which has a heating value of about 21,000 kJ/kg.  Assuming a steam-electric generation plant with a median net fuel efficiency of 48% and line loss of 6.5%, one kilogram of coal will make about 2.209 kWh of electricity.

      So you ‘average’ house would burn around 790 lbs of coal each month to satisfy the electrical needs.  So to visualise that – you’re looking at about 16 half hundredweight bags!

      Now getting to your bonus question, that’s actually easier, but a little more of a simplification.  Because gasses have different volumes at different pressures and temperatures, it’s a pretty rough guess.  Similarly, how the coal of burnt really makes a big difference in the CO2 output (direct or two-stage gasification).  I’ll have to dig into a couple of books here to get an average for you.

  • Alex says:

    The BBC did an excellent TV show depicting a human powered home refer  http://www.bbc.co.uk/programmes/b00p8469  Some segments are on Youtube