If the last post was hopeful, this one is more depressing. Every year, Lawrence Livermore National Laboratory updates the Sankey diagram of energy flow in the US. The flow chart may be a little confusing at first, but it traces all sources of energy (left) to the users (middle and right). The width of each line is proportional to the energy flow. The reason the chart is such a downer is that the lines for renewables are so much smaller than the fossil fuel lines. The yellow line for solar is basically invisible at the reduced image size below. There is a long way to go.
Just to end on a better note, the diagram also shows a huge opportunity – the gray bar on the right labeled, Rejected Energy. About 60% of all the source energy is lost during processing and use as waste heat. This can’t be completely eliminated (I won’t get into the thermodynamics of it), but there is plenty of room for greater efficiency and energy re-use that can shift the loss ratio.
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