In doing so, however, it ran up against a 51-year-old state law that requires cities to use the least expensive source for a commodity.

This makes inductively coupled plasma a rather expensive source.

The iron mine was abandoned after losing advantages over other less expensive sources.

Coal power plants are generally one of the least expensive sources of electricity by this measure, at around $2.10 a watt.

Production ended in 1920 when magnesite again became available from less expensive sources.

Equity is an expensive source of funds that is based on an entity's growth prospects.

As in other projects, on-shore sand availability was limited, forcing consideration of more expensive offshore sources.

New York City's energy policy is to seek the least expensive, environmentally sound sources of power.

Nuclear power has also proved to be a very expensive source of energy.

"It's an expensive and unreliable source of critical liquid fuel and chemicals."