The wonder of petroleum comes from its physical properties. At standard atmospheric temperature and pressure, this largely benign liquid flows with little extra effort. Because of this, we can easily refine it into petrol and have it readily available throughout a vast transportation network.
With the waning reserves of petroleum, we are devising different methods to produce this versatile store of energy. Joules Unlimited Inc. created an organism that secretes fuel. They estimate that their process is capable of producing 25 000 gallons of ethanol per acre per year (4.9e8 J/sq.m./a). This is quite impressive when considering that after 4.5 billion years of natural selection the best ecosystem, a tropical rain forest, has a net primary productivity of 3.8e7 J/sq.m./a.
Eventually brewing our own energy reserves will occur. But, with the Joules Unlimited rate, humanity’s current annual energy consumption of 4e20 J necessitates the allocation of 8e5 sq.km to energy production. This is about four times the area of the 250 largest cities on Earth. Where will we get the space, when will we start the effort?
