If It Quacks Like a Duck...

Strap in for a short but important ride along the ‘Duck Curve’…
The electrical grid is basically a network of power generators that supply power to a network of loads that consume the power.

Generally, the power being generated needs to be balanced to the load being used. In periods of rapid load increase, power plants need to ramp up power production.
Likewise, when load demand decreases, the power plants have to ramp down power production.

Turns out, we have a lot of history regarding the daily pattern of load demand through the day and how seasonality affects it. We also know a thing or two about how winter storms or summer heat waves can affect it as well.

More or less- the demand is lowest at night when people are sleeping and starts increase as they wake up and peaks around the time they get home and cook their dinner- roughly.

That’s a pattern the grid operators know about and have been managing by starting and stopping additional generators as needed to keep a reasonable balance between generation and demand.

The problem is- solar is so effective that during the peak sun hours it provides so much power that the ‘net load’ the power plants see drops to levels below their minimum load levels.

Minimum load levels is a bit complex, but it isn’t really o.k. to just run a generator on the grid without a load on it for many reasons. Not just the financial aspect of keeping an entire power plant running just to sell a trickle of power.

The next problem is rapidly rising demand is difficult to keep up with and causes excessive churn on the power plant equipment with the rapid starting of new generation equipment.

Solar power comes on rapidly as the sun rises, draws down the net load on the power plants and as the sun sets, rapidly drops off in production. This rapid drop off in production happens exactly during the same timeframe of the peak load demand- which makes a very rapidly increasing demand on the power plants.

Instead of a smooth rise and fall in demand, solar can have the effect of making the net load curve much steeper. This in turn causes a more rapid action necessary to start/stop generation units- which causes operational stress on the personnel and equipment.

Here’s a quick explanation that might help visualize the duck curve:

https://www.youtube.com/watch?v=KwA44fr7apw

As you can see, solar is working so well to produce power that it is disrupting how we have traditionally operated the grid. Some might be pleased with that, but- this has ramifications for us as home owners that we should be aware of.

Like it or not, there is a minimum base load (not based on profits but on how the equipment operates) that the power plants need. Finding ways to keep that from happening is becoming more of a pressing matter- and it seems that charging for sending power to the grid during that time is one method that appears to be effective.

So, those of us without batteries that send excess power to the grid for credit to be used during the evening hours- that situation isn’t going to last. It is becoming increasingly clear that over production during solar hours is only growing.

More-
The ramp up period is also a major issue and one fairly effective strategy is to reduce demand during that time. One of the most effective actions to reduce demand? Raise the prices.

So again, for those of us who have solar without a battery who shift to the grid as solar production dies off- will encounter increased prices during those peak hours.

Hawaii and California are two states with a very large solar adoption rate and they are suffering the consequences of the impact it is having on their demand curve. As home owners, it would do us good to keep an eye on what and how those two states do with net-metering and power pricing strategies.

One major strategy on both single home and large grid scale applications is to store the energy produced from solar and use it during the peak demand period. On the scale of the grid- this would flatten the load curve keeping it from dipping below minimum load levels and making the rise into peak demand less steep and more manageable.

For a home owner, storing the excess power produced from solar in their own battery and using it as needed during non-solar production hours allows them to solve this problem on their own and therefore limit exposure to extreme pricing schemes.

The good news is this scenario hasn’t gone much further than Hawaii and California, for now. A rooftop solar system without a battery isn’t needed yet (well, I think in California rooftop solar only makes sense with a battery at this point- but that is my unqualified opinion).

Still more-
A home owner who does not have solar will soon be faced with even higher ‘peak pricing’ schemes as well as the coming carbon tax… For those folks, the time to look into solar is now.

If you are looking into rooftop solar I am sure you will be interested in my upcoming book. Click here to be notified when Tucson Solar Insider Desk Guide for Buying Solar is released.

Be Good!
Curtis