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When you flip a light switch, you expect it to work right?

All of your appliances work, because your power company has electricity ready to transmit.

For a lot of customers.

And utility companies have gotten really good at anticipating that demand.

But a rise in solar energy production is making their jobs a bit more complex.

Here's a chart that explains why.

It's showing demand for electricity at any given time of day.

The power companies supply the least amount of power overnight.

Then, it ramps up in the morning.

Everyone's woken up and business gets going.

Then at sunset, energy demand peaks.

Utility companies will update models like this to operate as efficiently as possible.

But the introduction of renewable energy, particularly the solar energy, has started

causing problems in these demand curves.

In 2010, solar panel deployment really started taking off.

Most of those installations took place in California, so researchers there started looking

into it.

They found that the sun produces the most energy at mid-day.

And when you factor in that new mid-day production, your demand curve changes like this.

Every year means new solar capacity, which makes mid-day demand dip lower and lower.

Researchers call this drop in demand the "duck curve."

From the grid managers' perspective, the people whose job it is to constantly balance generation

and demand, it looks like a drop in demand.

That drop in demand creates two problems.

The first has to do with the intense ramps in the new chart.

As the sun sets, solar energy production ends just as the demand for energy typically peaks.

Power plants then have to rapidly ramp up production to compensate for that.

Which is kind of hard to do with the current fleet of power infrastructure.

The second problem is economic.

Say you have a couple of nuclear and coal plants.

Those plants are only economic when they are running all the time, basically.

They run around the clock.

And if you have to turn them off at mid-day, it completely screws up their economics and

plus lots of utilities just have contracts with those power plants to keep them running

all the time.

So that creates sort of an artificial floor.

If solar generates too much power and there's no use for it, there's no one to consume it,

then grid managers just have to turn some solar panels off.

If they didn't, we could risk overloading or even damaging the power grid.

So we throw away some of that extra solar energy.

Effectively, what's happening is that solar power is being wasted.

That waste, curtailment, is the big challenge moving forward for solar energy.

If you want solar, eventually to power everything or close to everything, you've gotta figure

out some way of shifting it to the night time.

Cause the sun's down during the night time.

The more power that can be stored, the more you can sort of let solar rip.

While the grid managers figure out how to serve this new supply and demand, this duck

is the greatest challenge facing renewable energy.

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