Several regions of the country were identified, but interest in developing them was lost as petroleum prices fell.

And now that petroleum prices are rising again, methanol is back in the news.

With petroleum prices increasing, researchers began to look elsewhere.

Crude petroleum prices fell 4 percent last month after an 11.9 percent June drop.

Only lately have they focused on why a doubling in petroleum prices has lost its kick.

This is amazing because despite all the news and views expressed, it seems that petroleum prices have been stable for an entire century.

But the strongest incentives are high petroleum prices and federal tax credits.

When petroleum prices rose, as they did from 1978 to 1981, overall fuel economy rose.

But when the oil shortage ended and petroleum prices fell, so did the hydrogen project.

Only gas was produced until the 1970s, when high petroleum prices encouraged limited oil production as well.