Electricity Flow Diagram  

Lou Grinzo has a look at the sources of electricity generation in the US and where the power is consumed (or wasted) - GOTW: Electricity Flow Diagram.

When the US Dept. of Energy recently released the latest edition of its Annual Energy Review, that naturally included updated versions of their “flow diagrams”, which are still the most useful set of graphics I’ve seen for understanding the sources and uses of all energy, coal, petroleum, natural gas, and electricity in the US.

This time around, let’s do electricity...

You can find links to all of the flow diagrams from the Annual Energy Review on the AER’s home page, in HTML and PDF format.

The things I find most interesting in this one include:

The relative sizes of the sources. Coal really is about half, as much as we wish it were otherwise, and oil is a barely perceptible sliver (don’t tell the media; they still love their decades-old conviction that the US still generates a sizable portion of its electricity with oil). Renewables, while still smaller than we’d prefer, is mostly conventional hydroelectric power.

Conversion losses practically leaps off the screen. This is (mostly) the energy lost in burning fuel to heat water to make steam to spin a turbine to pump electrons. When I show this chart to middle school students and tell them what “conversion losses” means, they give me the most withering, “Just how stupid are all you adults, anyway???” look. Aside from those awkward moments, it’s a good reminder that we decide things like how to generate electricity via economics, not energy or natural resource conservation.

Transmission and distribution losses are tiny. The almost universal misunderstanding among mainstreamers is that T&D losses are a huge factor in their electricity costs, when it just isn’t so. By comparison, conversion losses are 24.8 times higher.
The relatively even balance between residential, commercial, and industrial consumption. My guess is that while the commercial and industrial sectors are hardly paragons of environmental concern or even conservation purely for the sake of saving money, they’re probably on the whole much better than the residential sector. If my guess is right, then the low-hanging fruit for electricity conservation is in our homes and not at our jobs.

Transportation’s share of consumption is so tiny you almost need a magnifying glass to see it. How much do you think that will change, on a percentage basis, in the next ten years?

Not bad for one diagram, eh?