The long-haul. That’s what private investors face to develop merchant high-voltage interstate bulk electric transmission for wind in the US.
No energy infrastructure – hydroelectric dams, natural gas pipelines, nuclear plants, offshore oil platforms – takes longer to permit. A decade or more is not unusual versus two or three years to build a project, and failure to obtain a single permit can cripple it.
Indeed, the ratio of development cost to construction cost is higher for non-utility transmission than for any renewable or fossil fuel technology – 40%, even 50%, versus 4-5% for a typical wind or solar farm.