This is what the engine of our economy looks like. The width of the colored flows is proportional to the amount energy conveyed. Very small flows have been removed for clarity.
- Hydro, other renewable energy sources (solar, wind, geothermal, etc.), and nuclear power are only a small portion of the US energy mix.
- Most of our electricity is produced from coal.
- Very little oil goes to non-fuel uses like manufacturing plastics (petrochemical feedstocks). Asphalt for roads is another big component.
- Most of our oil is imported. (The US used to be the world’s largest oil producer.)
- Transportation is entirely dependent on oil.
Between 1949 and 2002
- population doubled
- energy consumption tripled
- GDP grew six fold in chained dollars, 39x in nominal dollars
The diagram is based on this one developed by Energy & Environment Directorate of the Lawrence Livermore National Laboratory for the US Department of Energy. The raw data is here (PDF, yearly data from 1949 to 2002).
Here’s a similar diagram with more information. Click the thumbnail for a reasonably sized view or go to the original source for a giant-size version.
Very revealing information. I did ‘t know, for instance, how little oil went to plastics. I also didn’t know coal was the main source of electricity. (I assumed oil was somehow bigger there.)
One possible clarification. Though from 1949 to 2002 pop doubled and energy consumption tripled, this is probably total energy consumption which is the product of per capita consumption and population size. Most likely, per capita energy consumption didn’t triple, though I don’t have the data in front of me. In a key article in 1991 (Population and the Energy Problem), John Holdren calculated that population and per capita energy consumption had risen (over some multiple decades) similarly. I think per capita consumption had just a slight edge. But in some categories population was the bigger factor. Yet, some folks try to use the total consumption figures to argue consumption is a bigger problem than population. Unfortunately, pop can’t be let off the hook that easily. I know you know that. Just wanted to mention it.
It is a beautiful diagram, isn’t it? Someone at Lawrence Livermore had a great idea for conveying a lot of useful information in a small picture. I removed some of the clutter to make it more accessible.
On the consumption/population issue, I think (as you have written before) it is not meaningful to look at one to the exclusion of the other, but it’s very important to look at regional differences. In the US, although our population growth has been a serious contributor, since pop growth is slowing it makes sense to emphasize consumption. In the developing world, most of which is experiencing relatively high population growth, the increasing number of people all wishing for a much higher standard of living, the emphasis can almost be reversed.
1949 to 2002 pop doubled and energy consumption tripled, this is probably total energy consumption which is the product of per capita consumption and population size
One way to think about this is if you use 1949 as a baseline for per capita energy consumption (one person consumes 1X unit of energy) then in 2002 that number is 1.5X, per capita consumption has risen by 50%. Given that energy efficiency has improved across the board — cars, power plants, homes, and manufacturing — the amount of useful energy consumed per person has gone up even more which I would guess accounts for much of the great increase in GDP over the last 50 some years.