On February 8, 2021, Cotton, Minnesota was the
coldest place in the entire lower-48 states with a temperature of -43. Two
years ago, the same town saw a reading of -56. Now the state has just ended a stretch of
single-digit or lower temperatures that lasted 10 days and will go down in the
history books as one of the coldest February’s in 85 years.
Most of us never give the reliability of our electric
grid a second thought. We expect the lights to turn on whenever we need them. But,
the reliability of our electric system takes on a whole new meaning during
winters in the Upper Midwest when weather reports routinely include phrases
like “polar vortex,” sub-zero temperatures reflect the “high” temperature of
the day, or when dangerous wind-chill warnings of -50 or even lower are in the
forecast. These weather factors put a white-hot spotlight on the importance of reliability
in our electric grid.
Fortunately, we have a regional integrated electric
grid and a diverse energy resource mix that provides the safety-net we need
during such weather extremes.
public utilities commissions, the regional electric grid operator Midcontinent
Independent System Operator (MISO), and other regulatory bodies are responsible
for making sure electricity can be delivered to homes and businesses regardless
of what Mother Nature throws our way.
+ Transmission = Reliability
The recipe for success is to balance generation
resources with a robust transmission system, which will deliver the reliability
we all count on. And, diversity is the
name of the game. The old adage, “don’t put all your eggs in one basket,” holds
true for maintaining the reliability of our electric grid, too. A variety of generation
resources ensures we’re getting the most bang for our buck while meeting demand
at the same time. The Midcontinent Independent System Operator (MISO) and its
sister Regional Transmission Operators (RTOs or “grid operators”) like PJM,
SPP, ERCOT, and others are tasked with ensuring the lights go on 24-7-365 and
at the lowest possible cost.
Choosing from available resources, RTOs deploy
energy resources in least-cost order until the demand is met. Wind and solar,
because they are zero-fuel-cost sources, are most often chosen first to fill as
much of the demand as possible before calling upon other more expensive
resources to fill the gaps. With the cost of wind down 70 percent and solar
costs down 90 percent in the last decade, increasing the amount of renewables
we have available on the system makes good economic sense and can really help hold
down the cost of electricity. Currently, the United States has enough installed
clean energy to power 43
Technological advancements in forecasting and the
gradual nature of the changes in wind output enable grid operators to
accommodate the variability of renewable resources. In fact, the MISO
system already successfully manages 26,000 megawatts of wind capacity, and
another 1,000 megawatts of solar. On February 5, 2021, MISO reached another
historic wind peak of 20,348 megawatts on the system.
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While it’s true that renewable resources like wind
and solar are variable, additional “back-up” generation is not required. Transmission
and the integrated nature of our electric grid take care of the fact that no
energy resource is available 100 percent of the time. The diversity of our
grid operator’s geographical footprint also helps reduce the need for
additional assets for capacity reserves because resources can be shared. After
all, the wind is always blowing and
the sun is always shining somewhere!
The crisis in Texas in February is a case in point.
Extreme weather conditions taxed the delivery of virtually all available
sources of generation creating a perfect storm of failures. Nearly 30,000
megawatts of coal, nuclear and natural gas fell off-line as a result of extreme
temperatures in the entire state. Wind plant outages also reduced the
amount of generation on the system by up to 2,000 megawatts. The massive increase in demand was met by
catastrophic failures in the delivery system. Since Texas has its own electric power grid (ERCOT), it is more isolated from the rest of the country, making it
difficult to move power from other regions of the country to help fill the
In the Midwest, the polar vortex of 2019 also included
frozen piles of coal, snow on solar panels, low wind speeds, natural gas fuel
shortages and mechanical problems. But, because of the Midwest’s network of
transmission lines and an integrated regional electric system MISO was able to
import electricity from other RTOs to avoid widespread black-outs.
Planning and coordination at the RTO level,
combined with a diverse energy resource mix and transmission delivery system
are paramount for keeping the lights on and the home fires burning.
Fortunately, we have those systems in place and there’s still room to grow our
use of renewable energy.