Who says water and electricity don't mix? South Carolina lake has role in state's solar future
PEAK - Look closely at the highway bridge crossing the Broad River, and you can just make out a sign of how much electricity South Carolina used this morning. The river is running low, far below the high-water mark stained on the pilings. But a few inches above the surface, the bridge is still damp.
From article, (When South Carolina Electric & Gas has more power than it needs, it uses the excess to pump water from a river-fed reservoir into Lake Monticello. When demand surges, it sends the water gushing back out, spinning turbines and generating electricity as it flows.
That's what happened on a recent morning. It was chilly, so South Carolinians turned on their heat pumps, SCE&G produced more electricity, and downstream, the reservoir and the Broad River slowly rose.
Lake Monticello has quietly performed this ebb-and-flow role for more than four decades — storing and delivering electricity again and again.
For most of that time, the work of the "pumped-storage plant" named Fairfield has been tied to big power plants that burn natural gas and coal, letting them run at full throttle and storing the excess.
At night, when electricity demand tapers off, the pumps on Lake Monticello spin into action to prepare for the morning surge.
Federal regulators are taking a fresh look at the hydroelectric project before its license runs out in the summer of 2020. SCE&G says that getting that license extended is "critical" to the future of South Carolina's electric grid.
That's because solar energy is making up more and more of the utility's electric generation base. For the most part, solar power isn't stored, so its output can't be controlled.
Which is to say, it would be helpful to have a giant battery of sorts that keeps electricity production steady as solar power fades in and out with the sun.
In SCE&G's words, Lake Monticello is becoming an "important asset for grid stability, reliability and power quality."
Rather than just fill the body at night, the company says excess solar capacity would enable it to also pump water in while the sun is out and release it when people get home from work and start fiddling with their thermostats.
Big energy storage systems have become increasingly important in the utility industry as renewable power has become more prevalent.
Utilities are experimenting with all sorts of concepts that would let them tap electricity when it's needed rather than when it's created. Among them: giant banks of batteries, vats of molten salt, caverns filled with compressed air. Each performs essentially the same task that the Fairfield project does.
But the old standby has been reservoirs like Lake Monticello. The U.S. has about three dozen of them, most of them built 40 to 60 years ago.
Utilities are interested in building more, mostly out West: So many projects are in the pipeline now that if they were all completed they could nearly double the nation's pumped-storage capacity, according to the Federal Energy Regulatory Commission.
South Carolina has the second-most pumped-storage capacity in the country, including a lake that reaches into North Carolina. They were built in a different energy era, when virtually all the state's electric generation came from fossil fuels and nuclear reactors that are difficult to shut down and crank up.
The projects planned elsewhere are geared toward solar and wind power, which face similar challenges: Utilities can't control how much electricity they produce at any given moment. That's led to renewed interest in building hydro plants that they can control with the flick of switch.
To be sure, storing renewable energy hasn't been much of an issue in South Carolina because until recently, there hasn't been much renewable energy to keep around.
Solar power began taking off only in the last few years in the Palmetto State, now home to one of the fastest-growing solar industries in the country.
But by the end of the year, the sun is expected to produce as much electricity in South Carolina as a nuclear reactor. And that power will have to be stored somewhere if it's not used immediately. )
For More Info
No comments:
Post a Comment