More disruption in the electricity grid from all that solar output

Curtailed electricity in California during 2016 was greater than the output from any one of those towers. Photo by James Ulvog.

The routine surge of electricity during the late morning and early afternoon in California is disrupting the electricity system. Matching the excess production of electricity during the day with highest use in the evening is going to be expensive for consumers.

The underlying issue is solar is neither reliable nor dispatchable.  The issue is beginning to be a problem and will get far worse.

3/5/17 – Wall Street Journal – How California Utilities are Managing Excess Solar Power – There is so much solar power in California that when the sun is bright, there is too much electricity and it must be sold cheaply just to get rid of it. Then, when the sun goes down and demand goes up after people get home from work, there isn’t enough electricity and the spot price goes sky high.

Article says that during the day, the wholesale spot price of electricity frequently shrinks to zero. Occasionally the wholesale spot price can hit $1,000 a megawatt-hour after dark. That would be about a dollar a kilowatt. $1.00.

At the end of the article there is a comment that on 178 days in 2016 the wholesale price went negative. The spot was below zero. The solar plants in California had to pay someone to take the excess electricity. I wonder what that does to the bottom line at Ivanpah? (That is a rhetorical question. – Impact on them is zero because I think they are on a multi-decade fixed price contract.)

Huge battery plants can store electricity during the day and discharge at night. That is expensive. Article says the price ranges from $285 up to $581 a megawatt-hour, which is in contrast to a natural gas peaker at $155 to $227 a megawatt-hour. That is around twice as expensive.

3/18/17 – David Danelski of Press-Enterprise at Daily Bulletin – Here’s how California ended up with too much solar power – The amount of solar power now online in California is so high that it is disrupting the electricity market.

The impact of so much solar capacity shows up at two times during the day.

First, in late morning and early afternoon when there is high output from solar but most people aren’t home and thus aren’t running their air-conditioners. This is most pronounced in spring when people are not running air-conditioners anyway.

Second disruption is in the early evening when output from solar panels is falling fast and demand for electricity is rising fast because people are getting home, washing clothes, turning on TVs, and running air-conditioners.

The impact is visible from several directions, according to the article:

  • Spot prices during the day are dropping, as mentioned in the first article above.
  • Some power plants are being shut down during the day, which kills their revenue and results in increased costs as plants are spun back up.
  • Curtailment of electricity, meaning the electricity is dissipated unused.

The amount of curtailment is increasing rapidly. In 2016 there were 305 GW hours of electricity that was curtailed. This is from both solar and wind sources. Since capacity of unreliable energy sources is expressed in terms of houses it could be powered, this is an amount that would have provided all the electricity needs of 45,000 homes. That is a fair amount of wasted capacity. (implicit ratio is 6.8 MWh per house)

Let’s put that wasted 305,241 MWh into context.

According to data at Wikipedia (which data is sourced to the Energy Information Administration in cited footnotes 74, 75, and 76 in case you wish to check the data, which I won’t) the combined output of all three towers was 653,122 MWh in 2015 and 703,039 MWh in 2016.

So, here is a calculation for you:

  • 305,241 MWh – curtailed in 2016
  • 703,039 MWh – total output from Ivanpah in 2016
  • 43.4% – curtailed electricity in California during 2016 expressed as percent of Ivanpah’s actual output

The amount of solar and wind electricity wasted in 2016 is equal to about 40% of the annual output from Ivanpah.

For context, that means the capacity of one-half of a facility the size of a massive Ivanpah plant cannot be used because of the mismatch between when electricity is needed and when it is produced.

The problem is going to get worse fast. According to the article, the portion of electricity in the California grid coming from solar has been:

  • 6.4% – 2014
  • 9.0% – 2015
  • 11.9% – 2016

The goal is 50% by 2030 as dictated by the state legislature. Imagine how much curtailment will be needed then.


The article outlines several strategies possible to reduce the amount of wasted electricity. Consider in the back of your mind that the likely result of each of the strategies will increase electricity cost to consumers.

Time of day pricing will be here soon. Those of us getting our electricity from SCE will start to see that in 2018 according to the article. This means you will pay a higher price for electricity in the evening than during the day. The theory is this will push people to run washing machines and dishwashers during the day or late at night.

To assess the impact of this concept, keep in mind most people aren’t home during the middle of the day to run washing machines and dishwashers. Everyone who wants to start running your laundry at 9 p.m., raise your hand. Anyone?

Build wind and solar closer to urban centers. Must admit that I don’t get this. How building a several hundred acre solar plant in the heart of the San Fernando Valley instead of the pristine desert will change the disruption equation is not immediately apparent to me.

Solar powered vehicles being charged during the day is another way to use that curtailed electricity.

All that will be needed is to build a massive number of charging stations, replace the lines going into businesses so the increased draw from the charging stations won’t fry power lines, put in new transformers throughout cities to handle the increased use, increase subsidies for EVs so people who don’t otherwise want to buy one will get one anyway, and get enough people rich enough that they can afford a not-for-family-use car that won’t go more than 80 miles before spending hours to recharge.

Sell surplus electricity outside the state. First sobering piece of information from the article is that rules in the state don’t allow more than minor amounts of electricity sales outside the state. The proposed solution here is to sell surplus electricity into other markets.

Downside is this will dump excess electricity into other markets driving down prices in their markets. Of course that will have the impact of appearing to reduce our curtailment here in the state and would put a bit more money into the pockets of producers here. That would be at the cost of reduced revenue for power plants in other states. I believe this is called externalization – making someone else bear the cost for your problems.

Battery storage, as always, is the most touted solution to the imbalance between when solar electricity is produced and consumed.

A demonstration project in Ontario, run by SCE, uses “powerpack” storage units from Tesla. The 1.5 acre facility can store enough power to feed 15,000 homes, but only for about four hours. That would actually be enough capacity to cover the peak use in the evening for those 15,000 homes.

Let’s ponder this for a moment and do a few calculations.

I’ve previously pushed around some numbers on what it would look like to get enough solar installed at my home to get off the grid. A few of my posts are:

What with the need to be sure to store enough for the months of heavy use and the need to avoid drawing batteries down more that 70% (taking them to zero occasionally will shorten their lives), I’m guessing it would take about 7 batteries to power my home.

The cost for the batteries alone, apart from installation and permits and the solar panels and the inverter and insurance, would be $3500 at list price.

That would be about $24,500 just for batteries.

Let’s discount that by 50% as an assumption for the better price in an industrial setting.

That leaves the cost at about $12,500.

Amortize that over a useful life of about 15 years gives an annual cost of somewhere around $830.

Compare that to my electricity costs in 2013 and 2014 which averaged $1,700 a year.

That means that the batteries to store enough electricity to cover my use in the evening would increase my costs by 49%.

If you have seen some industrial scale numbers to replace my wild guesses above, please point me to the appropriate public information.

Until there is an awesome breakthrough in battery technology comparable to what petroleum wizards have done with fracking and horizontal drilling in the oil patch, the cost of battery storage to solve the problem with solar power will increase costs to consumers rather severely.

1/21/17 – David Danelski of Press-Enterprise at Daily Bulletin – Ivanpah solar plant built to limit greenhouse gases is burning more natural gas – In 2015 Ivanpah emitted 60,676 metric tons of carbon. That is a 48% increase from 2014.

Ironically that is double the cut off which requires a commercial facility to participate in the cap-and-trade program.

Expect the carbon output to increase in 2016, since the article cites data showing consumption of natural gas was up 7% in the first nine months of 2016 compared to 2015, according to the EIA.

Article cites a government fact sheet that the facility is expected to prevent “up to” 500K tons of carbon a year. Article says the fact sheet doesn’t specify whether that is net of the carbon output generated by the facility. Note the “up to” qualifier. That is the theoretical amount so actual will likely be less. My guess is that is a bit of puffery based on the face plate capacity, not the expected actual capacity. I’ll also guess it is gross, not net of the carbon generated by the plant. Does anyone have better information than my wild guesses?

Article provides more background for me.

Electricity consumption per home

The announced target for the wing-toasting facility is eventually to get up to 940,000 MHw output a year, which is quoted as providing enough electricity to power 140,000 homes.

Thus the consumption factor is 6.7 MHw per home per year. That is consistent with the calc made earlier in this post.

In 2016, the facility was up to 74.8% of theoretical annual output.

No discussion in the article of the birds incinerated per megawatt metric at expected capacity.

Amount of carbon output is a surprise

Article suggests people are surprised at the amount of carbon output from the Ivanpah facility. After reading the article, it looks to me like the massive amount of carbon spewed into the air was fully expected by the facility’s owner and government regulators but they kinda’ sorta’ forgot to mention that to the public.


Recap at end of the superb article: subsidies at the federal level were $0.6B tax credits and $1.6B loan guarantee.

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