A substantial increase in the amount of electricity produced from renewable energy would require building a transmission system that would carry a price tag of up to $100 billion, according to a new study.

The new system would be needed because the existing eastern grid couldn't handle the volume of power coming from the wind-producing states. In addition, the new grid would need to be able to handle the fluctuating nature of wind power, which can surge at some moments and drop sharply at others.

There...