part two

If demand pessimists are correct, future increases in the price of crude could be damped as weaker consumption stretches world oil supply by billions of barrels. Various analyst estimates maintain that the roughly 2% a year average growth rate in world oil consumption seen earlier this decade -- the biggest reason for crude prices hitting a record $147 a barrel last year -- may turn out to be an anomaly and that annual growth in the neighborhood of 0.5% to 1% is more the norm.

Still, a lot more energy, including nuclear power and raw crude, will be needed to power rising economic activity in China, the world's second-biggest oil consumer after the U.S., and other markets.

Cost savings gleaned from more-efficient products and processes may yield more commerce and, thus, more demand for oil. And there is this: The world has seen previous periods of energy-efficiency gains almost vanish after new oil supply hits the market and pressure prices lower, as happened in the 1990s.

Some analysts believe crude could rise to $200 a barrel within a few years from today's $79 level. They say a speedier-than-expected economic recovery could make open consumers' wallets to higher crude prices. Still, price increases are bound to reinforce conservation.

"There is a market assumption today that we will head back to the old days of rapid oil demand, but we think we are heading into new days," in which the growth in consumption will be more subdued, said Dan Yergin, chairman of IHS Cambridge Energy Research Associates.

Mr. Yergin says several factors are prompting companies and consumers to make the most of their energy dollars. Among them: the sting of record oil prices in recent years, the threat that political obstacles in many oil-producing states will slow delivery of new barrels to the market, and the battle against climate change.

The energy-research group said last month it thinks oil consumption in the industrialized world peaked in 2005. Mr. Yergin believes the same will probably happen globally in two decades.

Deutsche Bank says global demand will peak by 2016 as consumption reaches around 90 million barrels a day, versus about 85 million currently, due to efficiency gains and technology improvements in electric vehicles.