Nathan Lewis’ “Powering the Planet”

“Powering the Planet” By Nathan S Lewis, Caltech Argyos Professor and professor of Chemistry

“The currency of the world is not the dollar, it’s the joule ….   Energy is The Single most important technological challenge facing humanity today. Nothing else in science or technology comes close in comparison. If we don’t invent the nano-widget, if we don’t cure cancer in 20 years, like it or not the world will stay the same. But with energy, we are in the middle of doing the biggest experiment that humans will have ever done, and we get to do that experiment exactly once. And there is no tomorrow, because in 20 years that experiment will be cast in stone”  Nate Lewis, Caltech, ‘Powering the Plant’ 2007

This is a summary of highlights of Nate Lewis’s presentation, “Powering the Planet”.  It’s an enlightening and insightful understanding of the perilous position we and or planet Earth is in. I’m doing this in bullet point as I hope this is clearer and more succinct.

1. The currency of the world is not the dollar it is the joule
2. Humanity’s current energy consumption is 13 trillion thermal watts, or 13 terawatts (a watt = joule per second)
3. The US consumes a quarter of the worlds energy or approximately 3.3 terawatts
4. 85% of all global energy consumed come from fossil fuels (i.e. coal, natural gas, and oil)
5. Most of the cheapest oil has been discovered
6. The world population is projected to be 9-10 billion by 2050 and with a conservative estimated GDP growth of 1.6% this means energy demand will triple by 2050.
7. Keeping this “business as usual” trajectory requires finding 10 terawatts of new carbon free energy, and this would not stabilize C02 levels (as CO2 emissions are cumulative). 10 terawatts means a 1 one-gigawatt reactor has to be built everyday somewhere for the next 50 years.
8. The current mechanized industrialized western agricultural system is highly energy intensive. That is, to run a farm and grow the food and transport it to the supermarket and put it in the refrigerator uses 10 to 20 times the energy content of the food itself
9. All this extra energy implies extra CO2
10. CO2 atmospheric levels have been between 200-300 part per million by volume (ppmv) for the last 670,000 years.
11. Current CO2 levels are 380 ppmv
12. Melting permafrost has not been incorporated into climate models. As it melts, less light is reflected and more is absorbed melting more permafrost.
13. There is enough CO2 and methane trapped in permafrost for greenhouse gas levels to go up by a factor of 10. When this last happened  250m years ago 90% of species went extinct.
14. To stabilize the CO2 at 550 ppmv will require 15-20 terawatts of carbon free power by 2050
15. It’s much cheaper to save a joule of energy than it is to make it, because the saving covers the losses along the supply chain, a joule saved at the end is equivalent to 5 joules at the source.
16. The payoff of energy efficiency (LEDs, “green buildings”, fuel cells..) is much faster than new clean energy supplies
17. Of all the renewable energies, hydro, wind, biomass, solar.. ,  relative to the scale and quantum needed based on projections only solar could be a solution
18. 120,000 terawatts of solar energy hits the earth. More solar energy hits the earth in an hour than the world consumes in a year.
19. A 10% efficient photovoltaic system on 400 square kilometres could  supply all the US energy needs, and six similar solar fields spread across the planet could power Earth
20. Currently solar power is expensive. 10-50 cents per kilowatt hour (from complex solar thermal systems to more standard PV systems) when the current rate (from fossil fuels) is about 4 cents per kilowatt hour.
21. Methods of storing energy are equally a challenge. Using solar energy to electrolyse water to make Hydrogen currently seems most promising yet a long way off

In summary, there is a huge and monstrous energy deficit that needs to be filled. Carbon free energy sources need to fill the gap to avert cataclysmic climate change. On a global scale, solar is the only solution that can satisfy but its costs need to come down and some form of energy storage is still needed. Reducing consumption, saving energy and being more efficient does a multiplied saving effects at source.  (My quick comment.. when you look at the energy embedded in food especially meat, it reinforces the profound effects reducing meat or being vegetarian can have on the climate and environment)