... A 'green power' program regularly invites customers to pay $4 to $10 extra per month to switch to clean energy.

VOA: standard.2010.03.23

It would have to climb higher to give consumers a financial incentive to switch.

VOA: standard.2010.02.23

That means they're expensive. Last year,citing the cost, the Pentagon canceled a $14 billion program to buy new helicopters for the rescue squadrons and switch the medical missions to less heavily armed Army helicopters.

VOA: standard.2010.04.27