So let me get this straight:
1. It took us 150 years to build the first 14 TW of energy infrastructure (along with the rest of our industrial infrastructure).
2. In 50 years we will roughly double our energy demand (assuming life continues as normal).
3. In 50 years it will be impossible for rapidly growing renewable energy infrastructure to overtake demand?
32% of planned capacity increases in 2007 come from renewable sources
The next few years have a lower percentage because companies are waiting on Congress to act on tax/energy policy legislation.
The existing infrastructure isn't going away any time soon so our concern is with meeting new demand. Over time, we can take coal and natural gas plants offline as the gap is filled with less-polluting forms of energy production.
In 2007, 17,552 Megawatts of new capacity were adding to an existing capacity of around 1,075,000 Megawatts. This represents a 1.6% increase in capacity.
I'm going to take that % as a given. Electricity consumption must increase at 1.6% a year from now until 2050 or else the US economy will collapse. (I only have data for the US so I'm only going to outline the US scalability of renewables).
A 1.6% year over year increase compounded over 43 years gives us a rough doubling (1,075,000MW to 2,127,000MW).
Renewable energy capacity in 2006 was 26,470MW.
We added 5,714MW of capacity in 2007. That represents a growth rate of 21.6%.
Now that's an unrealistic rate of growth because by 2050, renewable energy production would exceed demand by 66,000%
So let's say that every 2 years, the rate of growth drops by a full percentage point until it hits say, 4% a year. This would be a realistic result of the law of diminish returns.
Just as oil supply growth slowed down in the 1970s, surely wind/solar/whatever supply growth would slow down over time.
In the first scenario (steady exponential growth) the result is rather absurd. Demand isn't even visible on the chart because after renewable supply exceeds demand in 2026 in sky rockets off the chart:
In the second scenario, a rapidly decelerating growth rate for renewables, we crossover into 100% renewables (excluding nuclear and conventional hydropower, mind you) by about 2047. Looks like we get "saved" just in time. Moreover, we don't have to decrease our future energy demand by a single light bulb.
Efficiency and conservation would make demand growth slow down considerably and the graph would look quite different.
Blue is demand.
Red is supply of renewables.
The scale on the bottom is years since 2007.
The scale on the right is Megawatts of US electricity demand.
Sorry, Microsoft decided to change excel dramatically for its new Vista operating system and I haven't figured out the charts perfectly yet.
