Blowin' in the wind

The US nuclear industry is getting a long-overdue boost.  Declining supplies of natural gas (accounting for 18% of US generation; stats) plus stiffening prices for coal (which supplies roughly 50%) have driven a surge of interest in new plants.  While coal plants are going to come on-line earlier, nuclear is zero-emission and will be in great demand in a future where the control of greenhouse gases is recognized as a crucial element of ecological, foreign and economic policy.

But the next generation of nuclear plants will not begin delivering power until around 2018, and some parts of the country long ago turned away from coal to reduce pollution.  What's left?  Fortunately, it's the fastest-growing source of electricity in the world:  wind power.

Wind capacity is growing exponentially, and manufacturers are moving aggressively to expand manufacturing.  Installed capacity in the US grew by 35% in 2005, or 2431 megawatts; world capacity grew nearly as fast, with total capacity growing by 25% and installations up 43% over 2004.  Total installations were approximately 11.8 GW; at 30% capacity factor, the new turbines represent about 3.5 GW of average production.  This is small compared to other additions, but the rate of expansion is faster than anything else on earth and the resource is 3 orders of magnitude away from any intrinsic limits.

At the typical 30% capacity factor, the US will receive roughly 740 MW from last year's turbine installations; that's about 3/4 of a large nuclear plant.  But that rate of growth is going through the roof, as both the number of turbines installed and their size increases every year.  If total capacity continues to rise at a compounded 35% per year, the 2006 additions will equal 1 nuclear plant, 2009's will equal 2.5, and the sum from 2006 through 2018 will equal 136 GW of average production or 136 large plants.  By the time the first third-generation nuke comes on line, wind power could be delivering more electrical power than all the nukes currently on the US grid; they would be supplying roughly 30% of 2004's total consumption (up from 0.36%).

But can that rate of growth be maintained at such capacity?  If the only limit on expansion is the capacity left untapped, the future looks quite rosy for at least the next 20 years.  The logistic curve stops accelerating at 50% of its asymptotic value, and 50% of the limit for the continental US is a mighty big number.  The wind potential from the top 20 US states averages about 1.2 TW (may be an underestimate).  At an average production of 139 GW, the US would only be about 12% of the way to full use of the resource.  The logistic curve would still be accelerating strongly at that point, and even at a 35%/year base rate of increase it wouldn't hit the turnover point for another five years or so.

Making effective use of this energy could become a bigger task than generating it.  Piling on another 120 GW of capacity (36 GW average production) each year might be more than either transmission could move or demand could absorb.  This would allow fossil-fired plants to be retired and other users to switch from fossil fuels to electric power during periods of surplus.  Demand-side management is bound to play a huge role over the next couple of decades, coming to be more important than peaking generation.  One of the consequences is likely to be a flattening of the electric price curve, making the off-peak generation of base-load plants even more valuable.  By the time that the new nukes flip on their switches, the world will be a very different place.

¶ 3/11/2006 10:27:00 PM