Duke Energy forecast shows slow demand growth, more solar power

Duke Energy Carolinas, in a 15-year planning forecast filed this week, projects slow growth in electricity use, more solar energy and investments to wring more energy from its biggest hydroelectric station.

The filing also repeats Duke’s interest in building a new nuclear power plant in upstate South Carolina. Duke expects to be awarded a construction license for the Lee plant by the end of this year, but hasn’t decided whether to move forward with the project.

Duke Energy Carolinas is the utility that serves Charlotte and the western Carolinas. Like other utilities, it’s required to update a 15-year forecast of power demand and generating needs once a year.

Among the utility’s key projections:

▪ Continued slow growth in demand for electricity – 1.1 percent a year, a tick down from the 1.2 percent growth estimated a year ago.

▪ A decision looms on whether to build the Lee nuclear plant in Cherokee County, S.C. Duke Carolinas projects a 33 percent increase in nuclear energy by 2031. Duke’s studies show new nuclear capacity could be needed as early as the mid-2020s.

But the Lee decision is complicated by several factors: Whether prices for a competing fuel, natural gas, stay low; the impact of environmental regulations such as President Obama’s carbon-cutting plan, now on hold; and whether federal regulators will let Duke extend the operating licenses of its current nuclear fleet.

▪ Solar capacity will nearly triple to more than 2,100 megawatts. The percentage of Duke Carolinas’ electric generation in winter from renewable energy, energy efficiency and demand-curbing programs rises from six percent in 2017 to 12 percent in 2031, slightly more than Duke predicted a year ago.

▪ Duke plans to spend $200 million on a 17 percent increase to the generating capacity of its 1,065-megawatt Bad Creek hydro plant in upstate South Carolina. Duke says it is part of a strategy to add capacity to its hydro stations to help offset the intermittent nature of solar energy.

Bad Creek uses an unusual design called pumped storage. Water in an upper reservoir is released into underground tunnels, through turbines connected to generators that make electricity, then flows into a lower reservoir. When demand for electricity is low, such as at night, water is then pumped back up to the upper lake for reuse.

▪ The fuel shift from coal to cleaner, cheaper natural gas will continue. Electric generation from natural gas will increase 36 percent by 2031, to 25 percent of the total. Coal will drop from 31 percent now to 21 percent in 2031.

This story was originally published September 2, 2016 at 5:31 PM with the headline "Duke Energy forecast shows slow demand growth, more solar power."