Guest Post by Willis Eschenbach
Encouraged by the response to my post on Adrian Bejan and the Constructal Law, which achieved what might be termed unprecedented levels of tepidity, I persevere. Here’s a lovely look at the energy use of the United States:
Figure 1. US 2002 Energy production and consumption by sector.
There are some interesting things which can be seen in this diagram.
1. Almost none of the power for electrical generation comes from oil. This means that even if the US could generate every Watt of electricity from solar/wind/whatever, it will not directly replace our consumption of oil.
2. Generation, transformation, and transmission losses eat up most of the energy used for electrical generation. Overall efficiency is 31%
3. Transportation is worse, with only 20% efficiency.
4. Nuclear is three times the size of hydro.
5. Wood, waste, alcohol, geothermal, solar, and wind electrical generation together are 3% of total energy use.
However, as interesting as I found those, that’s not the reason I started looking at energy use and GDP.
I was sucked into this subject by what I thought was an interesting quote from Adrian Bejan here (PDF, worth reading. My emphasis):
To summarize, all the high-temperature heating that comes from burning fuel (QH or the energy associated with QH and the high temperature of combustion; cf. Bejan 2006) is dissipated into the environment. The need for higher efficiencies in power generation (greater W/QH) is the same as the need to have more W, i.e. the need to move more weight over larger distances on the surface of the Earth, which is the natural phenomenon (tendency) summarized in the constructal law.
At the end of the day, when all the fuel has been burned, and all the food has been eaten, this is what animate flow systems have achieved. They have moved mass on the surface of the Earth (they have ‘mixed’ the Earth’s crust) more than in the absence of animate flow systems. The moving animal or vehicle is equivalent to an engine connected to a brake (figure 4), first proposed by Bejan & Paynter (1976) and Bejan (1982, 2006).
The power generated by muscles and motors is ultimately and necessarily dissipated by rubbing against the environment. There is no taker for the W produced by the animal and vehicle. This is why the GNP of a country should be roughly proportional to the amount of fuel burned in that country. (Bejan 2009).
I must confess, I had thought about GDP and energy before, but never from a thermodynamic standpoint. Here is a graph of per capita GDP and per capita energy consumption for a number of countries:
Figure 2. Per Capita Energy Consumption vs Per Capita GDP for Different Countries. PPP values are used. Image Source
OK, call me slow. I knew that depriving the developing world of affordable energy would impede development. But I had never realized that energy use is development, that there is a thermodynamic relationship between the two. I hadn’t noticed that if a country wishes to develop, it can only develop to the extent that it has energy, and no further. Lack of energy doesn’t merely hinder or slow or delay development of poor countries as I had thought.
It puts an absolute ceiling on development.
Given the number of people in the world living on a dollar a day or so, that’s a discouraging insight in the context of the current AGW war on fossil fuel energy.