“Energy transitions” encompass the time that elapses between an introduction of a new primary energy source oil, nuclear electricity, wind captured by large turbines) and its rise to claiming a substantial share (20 percent to 30 percent) of the overall market, or even to becoming the single largest contributor or an absolute leader (with more than 50 percent) in national or global energy supply. The term also refers to gradual diffusion of new prime movers, devices that replaced animal and human muscles by converting primary energies into mechanical power that is used to rotate massive turbogenerators producing electricity or to propel fleets of vehicles, ships, and airplanes. There is one thing all energy transitions have in common: they are prolonged affairs that take decades to accomplish, and the greater the scale of prevailing uses and conversions the longer the substitutions will take. The second part of this statement seems to be a truism but it is ignored as often as the first part: otherwise we would not have all those unrealized predicted milestones for new energy so.
The scale of transition needed for electricity generation is perhaps best illustrated by deconstructing Al Gore’s July 2008 proposal to “re-power” America: “Today I challenge our nation to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years. This goal is achievable, affordable, and transformative.”
Let’s see. In 2007 the country had about 870 gigawatts (GW) of electricity-generating capacity in fossil-fueled and nuclear stations, the two nonrenewable forms of generation that Gore wants to replace in their entirety. On average,these thermal power stations are at work about 50 percent of the time and hence they generated about 3.8 PWh (that is, 3.8 x 1015 watt-hours) of electricity in 2007. In contrast, wind turbines work on average only about 23 percent of the time, which means that even with all the requisite new high-voltage interconnections, slightly more than two units of wind-generating capacity would be needed to replace a unit in coal, gas, oil, and nuclear plants. And even if such an enormous capacity addition—in excess of 1,000 GW—could be accomplished in a single decade (since the year 2000, actual additions in all plants have averaged less than 30 GW/year!), the financial cost would be enormous: it would mean writing off the entire fossil-fuel and nuclear generation industry, an enterprise whose power plants alone have a replacement value of at least $1.5 trillion (assuming at least $1,700/installed kW), and spending at least $2.5 trillion to build the new capacity.
But because those new plants would have to be in areas that are not currently linked with high-voltage (HV)transmission lines to major consumption centers (wind from the Great Plains to the East and West coasts,photovoltaic solar from the Southwest to the rest of the country), that proposal would also require a rewiring of the country. Limited transmission capacity to move electricity eastward and westward from what is to be the new power center in the Southwest, Texas, and the Midwest is already delaying new wind projects even as wind generates less than 1 percent of all electricity. The United States has about 165,000 miles of HV lines, and at least 40,000 additional miles of new high-capacity lines would be needed to rewire the nation, at a cost of close to $100 billion. And the costs are bound to escalate, because the regulatory approval process required before beginning a new line construction can take many years. To think that the United States can install in 10 years wind and solar generating capacity equivalent to that of thermal power plants that took nearly 60 years to construct is delusional.
Monday, December 15, 2008
Why We Will Be Using Fossil Fuels for Decades to Come
From Vaclav Smil's essay in the American, "Moore's Curse and the Great Energy Delusion":