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From the power plant to your home: How Iowa’s energy works
Iowa’s energy crosses an enormous power grid before it turns on your lights.
The power grid is whizzing all around you, whether you know it or not.
Any time you flip on a light switch in your Iowa home, you’re drawing energy from a carefully managed and incredibly complex power grid. The web of power lines stringing through the Midwestern skies or buzzing beneath your feet is long enough to encircle the entire Earth two-and-a-half times.
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The network that powers Iowa stretches across the continent and creates a thrumming international power grid. But how does that energy get from its source to your home — and how dependable is it? Here’s what you need to know about your energy, where it comes from and how reliable it is.
Strength in numbers
Iowa lies in the middle of the Eastern Interconnection — one of two major power grids across North America — which spans east of the Rocky Mountains. Iowa’s energy, along with that of 14 other states and a Canadian province, is managed within that grid by Midcontinent Independent System Operator, or MISO.
MISO stretches from central Canada down to Louisiana and is split up into north, central and south zones. In 2020, it managed more than 180,000 megawatts along with 65,800 miles of power lines. This energy serves around 42 million energy consumers. Since they have access to energy generation across 15 states, they benefit from more reliable and cost-effective power.
As the regional grid operator, MISO is tasked with making sure the right amount of electricity is generated across its various zones. That energy can then be sold and transmitted between its member utilities that distribute the power to their customers.
“If a big generator goes out in Florida, there’s a ripple that goes all the way to Iowa,” said Ian Dobson, an engineering professor at Iowa State University. “It’s all spinning together — humming together.”
The electricity buzzing throughout the grid travels extremely fast — sometimes just under the speed of light. It is made and consumed at the same time. Thus, the energy put into the grid must equal the energy pulled from it, Dobson said, especially with the lack of storage within the system.
That means the energy industry must ensure that the energy generated must meet demand, and that energy must be correctly transmitted to where it’s needed.
“Think of MISO as the air traffic controller of our regional grid system,” said Geoff Greenwood, spokesperson of MidAmerican Energy, which operates within MISO. “MISO makes sure there’s enough power available throughout the region, and that the power on the system gets to wherever it needs to go, whenever it’s needed.”
Each MISO region has its own energy capacity requirements. But they still can experience energy shortfalls, like the projections for this summer.
During these situations, zones can lean on their neighbor’s energy. An intricate web of contracts gives MISO access to generators elsewhere that can provide needed power. Different factors — such as weather patterns and availability of standby infrastructure — determine how much zones can depend on each other.
“People do cooperate,” Dobson said. “I mean, because the institutional structure is so complicated, it's amazing how well people cooperate.”
The protection is in the projection
The amount of energy on the power grid at any given time is referred to as an energy load. That load varies every day, Dobson said, often peaking in the evening.
To make electrical ends meet, the industry attempts to forecast these needs, particularly when there may be peaks in electricity usage, like in the hot summer months when air conditioning is used more frequently.
Projecting energy usage isn’t an exact science — so forecasters cushion their predictions with margins of error. That way if the actual energy demand surpasses the projected demand, the system won’t fail, Dobson said.
“Every day, they kind of ‘fly’ the system like someone pilots a plane,” he said. “They increase the generation, follow the load, and then go down again at night. And then, they do the same thing again every day.”
The calculations for these projections are complex, especially since it’s difficult to predict in advance how much wind and solar energy can be expected.
The resulting safety cushion determines the fate of the region’s energy in the face of emergencies. Its size is under frequent discussion, burdened with the push-pull of demands for cheaper energy yet increased reliability, which requires funding for increased generation and transmission. And when federal regulators think that cushion growing too small for their liking or is experiencing not-normal conditions, they can raise the alarms.
Emergency conditions for the power grid
Rolling blackouts — which are involuntary outages — are every utilities’ worst fear. But these emergency events are exceptionally rare. In fact, not including outages from destructive and unforeseen natural disasters, MISO has only been impacted by blackouts during the 2003 Northeast blackout.
Before MISO even transitions to emergency operations, it calls for conservative operations during times of severe weather, heat or cold spells or geomagnetic disturbances. Utilities suspend equipment maintenance during these conditions, and personnel in affected areas are on alert.
If conservative actions aren’t enough, MISO will call for emergency operations. These take place in a series of five steps, ending with controlled energy outages called load shedding as the last resort. Some steps may be skipped during emergency situations. Blackouts, the worst-case scenario, go beyond these steps.
MISO posts its real-time operations alerts and declarations on its website.
MISO emergency event levels and what they mean
Step 1: All available resources are in use, including emergency-only generation.
Step 2: MISO is energy-deficient and needs to decrease demand, like through a public appeal to curtail customers’ energy usage.
Step 3: Operating reserves are depleted, and operators should continue actions to decrease demand.
Step 4: Emergency energy needs to be purchased from other regions, if available.
Step 5: Controlled power outages should be implemented.
Brittney J. Miller is an environmental reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.
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