In complete opposition to an earlier post from Justin, I would like to fight for the use of scientific energy units. I may have a different view on this, but when I read news articles stating that a new turbine or solar panel array can generate enough energy to power 1000 homes, I’m left in a blank. As a disclaimer, I do deal with energy measurements at my work, so I know things like a solar field generating 30 megawatts (MW) capacity is pretty big. And a solar field generating 1000 MW is REALLY big! So I understand that I may deal with these units a lot more frequently than most people. Truth be told, before I started working in energy, it took me a good week to understand the difference between a kilowatt and a kilowatt-hour. Okay, two weeks.
In a book I recently reviewed named “Sustainable Energy – Without the Hot Air,” author David JC MacKay outlines several annoying units and explains why they are inaccurate. One example he outlines is the use of “homes” as measurement indicators. For example, “a solar panel array that generates enough energy to power 2,500 homes.” The reason MacKay doesn’t like this unit is because everybody uses a different amount of energy in their homes. As he states in the book, the UK has determined that the energy consumption of the average British home is about 4,700 kilowatt-hours (kWh) per year. The average US home, according to the Energy Information Administration (EIA) uses about 11,496 kWh per year. Not only is this difference in consumption between these two countries shocking, but it shows how a reader could easily be left with a mistaken view on just how large an energy project really is.
Not only that, people may be mistaken that a project which powers 1,000 homes also covers the energy consumption of the occupants of those home. In reality, this amount is much, much larger than just what a home consumes. According to MacKay, if you include the energy consumption of the occupants of a home, that is commuting, heating, or other energy consuming activities of everyday life, you can increase the total consumption amounts by a whole 24 times as opposed to just the home by itself.
But certainly not all scientific units are all that helpful, either. One scientific unit I commonly had to deal with for a recent independent study was the BTU, or British Thermal Unit. Anyone using data from the EIA will find most of their data in BTUs, which I had to constantly convert into kilowatt-hours or gigawatt-hours. What is most annoying about BTU’s is just how tiny an amount of energy a single BTU is. For example, in the chart I linked to above, you can see the US consumed about 98 quadrillion BTUs of energy in 2010. Quick, try to picture that one in your head. It looks like this: 98,000,000,000,000,000 BTU. Converting this number to gigawatt-hours looks like this: 28,720,000 GWh. Or even simpler, the terawatt-hour looks like this: 28,720 TWh.
So I guess I will have to agree to disagree on scientific energy units. But care must be taken when explaining consumption and generation to the public, because there is already a huge lack of understanding about energy, and feeding the public inaccurate units isn’t going to help raise the level of understanding.