NEW YORK (Reuters) - The absence of clear carbon
emissions rules in the United States will prevent power
companies from building new coal or nuclear power plants for
the next several years, the head of Duke Energy Corp
said Tuesday.

Most power companies will instead build natural-gas fired
power plants, betting that new U.S. gas fields will keep
supplies of that fuel abundant, Jim Rogers, Duke's chairman and
chief executive, told Reuters.

Energy legislation being debated in the U.S. Congress
omitted regulations that would have established a market for
companies to trade the right to emit carbon dioxide.

"I think it puts on hold the building of any new coal
plants. It probably puts on hold the building of nuclear plants
because you don't have a price on carbon," Rogers said.

Duke Energy is one of several major U.S. power utility
owners that support a cap and trade system for carbon. It owns
20 coal fired-power plants and is also the nation's third
largest operator of nuclear power.

About 85 percent of the new power plants built in the
United States over the past decade have run on natural gas, he
said.

Coal-fired power plants produce about half the nation's
power, although natural gas power plants emit about half as
much carbon as the coal plants.

By leaving the future of carbon regulation uncertain, few
utilities are likely to risk investing hundreds of millions of
dollars in new coal fired power plants.

That will hurt coal companies in the long run, Rogers
said.

"I think from the coal industry perspective, they start to
go into what I call the valley of death," he said. "It's hard
to envision anyone getting the permitting and really going
through the process of building a coal plant in the next
decade."

In addition, as much as one-third of the 330,000 megawatts
of aging coal-fired electricity capacity will likely be shut
down in the next decade, he said.

Earlier Tuesday, Duke reported a second quarter net loss
as it wrote down the value of some of its Midwest power plants,
although its profits per share excluding the charge beat Wall
Street estimates.

Electricity demand from industrial customers has started to
rise, Rogers said, although it was coming from very low levels,
while household and commercial power demand in the second
quarter was flat.

"It'll probably be '14 to '15 before we get back to a 2007
(electricity consumption) level," Rogers said.

Rogers noted economic growth and power consumption are
typically correlated and, although fears of deflation in the
United States could push investors into utility stocks, the
company would be better off in a robust economy.

"Deflationary (pressure) would be great for utility stocks,
but bad for our country. I'd like to see our economy get going
and get our mojo back and a deflationary period doesn't allow
our economy to do that."
(Reporting by Matt Daily; editing by Andre Grenon)