The North Carolina Senate will soon consider a bill that would impose a moratorium through 2020 on approval of permits for new wind facilities sought since last year, a move its backers say is necessary to allow further study of potential operational hazards posed by turbines near military installations in the state.

The measure was added this week to a bill already approved by House of Representatives that would require Duke Energy, the state’s dominant electric utility, to utilise more biomass, solar and other alternative power.