Part II has covered the energy scene from fossil fuels through all the renewables. Part III is on policy, both for the United States and internationally. However, policy has to be based on reality, so I want to summarize the important technical points. I have tried in Part II to present all the facts without prejudice, but here I will let my own opinions shine through and end this chapter with a repeat of the energy scorecard shown earlier.

We are in a race to reduce global emissions of greenhouse gases while energy demand is going up fast, driven by two things: a projected 50% increase in population, and an increase in world per capita income. Continuing on our present course, world primary energy demand is expected to double by 2050 and double again by 2100. There is enough fossil fuel to let the world do that at least through 2050, but beyond then the supply of fossil fuel is not so clear. It is not just climate change that should be moving us away from our dependence on fossil fuels.

There are three roads to reduced emission: doing the same with less (efficiency), capturing (putting the emission away somewhere else than the atmosphere), and substitution (replacing fossil with non-emitting or low-emitting fuels). We need to use all of them and remember that the goal is emissions reduction, not merely replacing fossil fuels with the limited collection of things that are called Renewables.