[ASSURAS] The energy storage technology we just showed you isn't used by many wind farms, and that's a challenge for the folks who run the power grid. The wind can be fickle, so when those breezes blow, or don't, it takes quite a bit of juggling to make sure renewable energy doesn't get wasted and everyone's lights stay on.

"energyNOW!"'s Lee Patrick Sullivan got an inside look at the wind farms and control rooms that make it work, and spoke to some of the Midwesterners who are taking charge of their energy future.

[SULLIVAN] There's something sprouting above the cornfields of Minnesota.

[SHANELLE EVANS MONTANA] I think they're very majestic. No matter how many times I go through a particular farm, I still have to stop and say, "Wow! That's really amazing."

[SULLIVAN] Shanelle Evans Montana of enXco Energy is talking about four large wind farms, turning an area that grows nearly 10% of the country's corn into a source of more than 10% of Minnesota's electricity.

Now, when these massive turbines are way up in the air, it's hard to get a perspective of how big they are. But this is one of the blades. They're made out of a tough fiberglass, the same sort of stuff that boats are made out of. Montana took me into one of the sections of the tower. In about six months, it will be put upright and join the others in the Fenton Wind Farm in Chandler, Minnesota.

[MONTANA] We'll have three different tower sections and then a nacelle on top of that which contains the gearbox, and then the blades that are attached.

[SULLIVAN] But what's even more impressive is the amount of wind out here on the prairie. [Wind gusting] My God, it's windy here.

[MONTANA] It is very windy here. People don't associate the wind with Minnesota until you come here to southwestern Minnesota.

[SULLIVAN] Take that, Chicago -- this is the Windy City. Montana had a better idea -- seeking refuge inside this massive turbine.

[MONTANA] Yes, this is the inside, and as you can see, it's a lot more spacious than you expect.

[SULLIVAN] Yes. Now, how big is this thing?

[MONTANA] So, from the tip of the blade all the way down, it's about 400 feet, but the actual tower will go up about 80 meters.

[SULLIVAN] Meters? Are you Canadian? What is that in feet?

[MONTANA] We're very close to... [Laughs]

[SULLIVAN] This, right here, is what it is in feet.

[TEXT ON SCREEN] 262 feet

[SULLIVAN] All right. And you have people that will climb up there to turn a bolt. What would they do when they get up there?

[MONTANA] Our wind technicians are very special people.

[SULLIVAN] Is it a balanced level of stupidity and skill to want to go up that high?

[MONTANA] You would think, but it's a lot more skill, I think, than anything else.

[SULLIVAN] Those high-wire maintenance crews are part of a team of 60 full-time workers here at the Fenton Wind Farm, which is huge for this small town's economy.

This is the part where we walk out and go into the wind, and I don't want to go back out there.

The wind farm spans two counties, which, together, get $800,000 a year in taxes and fees from enXco. The roughly 150 property owners on this farm who lease their land to enXco get a combined total of about half a million dollars each year.

So, how much energy does one of these turbines produce?

[MONTANA] This would be about 1,500 homes for this one turbine. It's a 1.5 GE turbine.

[SULLIVAN] The entire wind farm produces enough electricity for 66,000 homes. Now, there are only 110 homes in the city of Chandler, so this energy needs to be sent somewhere else. Enter the Midwest Independent System Operator, or MISO for short. Cameras are rarely allowed inside this facility. The people who work here are like air traffic controllers for electrons. It's their job to move electricity around the power grid to where it's needed, when it's needed.

[RICHARD DOYING, VP, OPERATIONS, MISO] You can see that load would typically be very low, 5:00 A.M. It would increase during the day and it would peak here between 2:00 and 4:00 in the afternoon.

[SULLIVAN] It's Richard Doying's job to coordinate the delivery of electricity across 12 states.

[DOYING] Here is zero.

[SULLIVAN] In the last decade, he's been trying to get the most out of all the new wind farms connecting to the power grid.

[DOYING] Wind, typically, is highest early in the morning, late at night, and you can see it dropping off pretty quickly, so, 10:00 in the morning, we're at a fairly low level, relative to where we started and where we were during the early morning hours.

[SULLIVAN] And Doying says, that's the challenge with wind. It blows the hardest and produces the most electricity at night, when demand is low.

[CLAIR MOELLER, VP, TRANSMISSION, MISO] When you start to move renewable energy, particularly wind, into the system, that energy shows up when the wind blows, not when you may or may not need it.

[SULLIVAN] And when they don't need extra electricity from wind turbines, that puts the grid operators in a tricky situation.

[TEXT ON SCREEN] Take a tour of the MISO Control Room at energyNOW.com.

[SULLIVAN] To keep the grid stable, they have to perfectly balance the supply of electricity with demand. So making room for more wind means dialing back or shutting down other power plants. Otherwise, they would have to tell the wind farm operators to take their turbines offline.

[MOELLER] So, finding a place to put it is a much more desirable situation. So we work hard to try to make that come true.

[SULLIVAN] The scramble to find a town or city that needs the extra power from a wind farm also puts a strain on MISO's section of the power grid. MISO says the grid was really designed to move electricity between power plants and population centers that are pretty close together. With wind, sometimes the only place that needs electricity can be several states away from a wind farm. To get it there, the grid operator has to use backup transmission lines that weren't designed to carry large volumes of electricity.

[MOELLER] We're using that emergency backup system to move great blocks of energy all the time. So that's really, fundamentally, the problem.

[SULLIVAN] So you might think, with all these challenges, the folks at MISO would want fewer renewable resources like wind turbines plugging into the grid. Well, actually, they say, whatever the fuel mix of the future, they can make it work.

[DOYING] Whether it be 20% renewable, or whether it be what we have today -- coal, gas, nuclear -- in either case, our job is simply to keep the lights on.

[SULLIVAN] Back in Minnesota, Shanelle Montana is still enjoying what she calls "a nice breeze."

You're used to this wind. Did you ever think it would become an asset for the state?

[MONTANA] You know, I didn't. I think it's tremendous, and I'm glad that Minnesota's been a leader in this industry, because it has provided so much to this area.

[SULLIVAN] And Montana expects even more turbines to be sprouting up among the cornfields in the future. In Chandler, Minnesota, Lee Patrick Sullivan, "energyNOW!"

[ASSURAS] One reason wind turbines keep springing up in Minnesota is because it's one of more than two dozen states with a renewable energy mandate. The 2007 law requires Minnesota to get 25% of its electricity from renewable sources by 2025. The EIA says, this year, Minnesota ranks fifth in the nation in total electricity generated by wind, behind Texas, California, Iowa, and Washington state.