They've realized that with oil being cheap, the non-oil energy sources margins are too thin, or at a loss. With an USA oil tax at the pipe line, or from imports at oil carrier ship (unless the importing country has already taxed it), would then increase oil prices, and the market would then put more money non-oil energy sources.
Higher fossil-fuel prices will also assist in reducing the numbers of old, sick, and poor (especially the poor) through attrition as the prices for heating and A/C go higher and higher and more and more deaths from heat/cold exposure and starvation (many will have to choose between food and heat/AC). Luckily it won't much affect those that matter...the rich and the politically-connected who can easily afford outrageously high energy costs.
Increasing energy costs have a very real and serious affect on the lives of people, and price increases are extremely regressive as they hurt the poorest first and worst.
Can't we come up with a solution that doesn't involve forcing poor, sick, and elderly people to die of exposure?