To run our world in 2005, all human activity consumed 13 terawatts — how much does this amount to for each global inhabitant, and why do we use so much energy?
Currently, there are roughly 6.6 billion humans on the planet and each of us has a basal metabolism of around 100 watts. Think of yourself as a bright lightbulb, so for the 6.6 billion humans, this amounts to only 0.66 terawatts versus the 13 terawatts total that is actually used. The other 12.34 terawatts (95% of our energy consumption) goes into producing a high standard of living— and quite a bit of waste!
- U.S. Energy Use by Sector
The U.S. population just passed 300 million (roughly 5% of the worlds population), and we consume roughly 25% of the total energy. Therefore, we consume roughly five times as much per inhabitant as the average global inhabitant.
There are many opportunities for energy conservation and improved efficiency, and we must pursue these opportunities to avoid causing environmental problems for our future inhabitants. The developing world is watching and emulating our pattern of energy consumption. Credible estimates suggest that the world's population will pass 10 billion by 2035, and if consumption patterns match ours in the U.S., global energy demand will more than double by 2030.
One area to consider addressing this problem is the largest one—in the industrial sector. Energy intensive production of commodities consumes much of the industrial sector energy. Indeed, thermally-driven separations such as distillation consumes up to 40-45% of this amount, so up to 15% of our energy budget is used for separations. If global commodity production grows as is projected, to provide higher living standards, within 30 years, separation processes alone will place an enormous load on global energy sources.
While separations processes create useful products ranging from drinking water to gasoline and polymers for clothing, it is reasonable to ask— is there another option? One of the key initiatives of the Strategic Energy Institute (SEI) at Georgia Tech is to provide such options. For instance, membrane processes already are saving huge amounts of energy for producing clean water from saline sources. Worldwide production of desalinated water is over 9 billion gallons per day, and half of this comes from membrane processes. There are active programs through the SEI to create more efficient separation processes to extend these efficiencies to include production of transportation fuels as well.
We can, of course, all assist by using our resources more efficiently, and using mass transit and carpooling are areas where we can each contribute to becoming a model for the rest of the world.