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Are There More Blackouts in California’s Future?

Rising electricity demand from air conditioning will exacerbate problems during heat waves.

The Bay Area has definitely felt dystopian recently. Our Covid cases are high, we’ve had heat waves and rolling blackouts, wildfires are only partially controlled, our air quality is bad, our roads are terrible – the list goes on. I’m lucky enough to be healthy, I haven’t had to evacuate and I didn’t experience an outage. But, it’s uncomfortable in my house when the air quality is bad and it’s hot outside. I don’t have air conditioning, so if I open the windows, it gets really smoky inside, but if I keep them closed, our house really heats up.

So, is this the new normal? We’re all hoping Covid fears go away soon, but what about some of the other things? Are they here to stay?

With power outages and heat waves, I fear that the answer is yes, this is likely the new normal. As climate change leads to more heat waves and people like me eventually get air conditioning – both because it is hot and because the outside air is bad – heat waves will lead to higher and higher peak electricity demand. So, unless California regulators step up their games to do something about this, we will have more outages.

Mid-August Outages Exacerbated by Air Conditioning Load

As Severin mentioned last week, California suffered rolling blackouts on August 14 & 15. The short summary is that we didn’t have enough supply to meet demand. We had a heat wave (95 degrees in Berkeley is HOT!) and a lot of Californians turned on their air conditioners. That’s not super unusual, but what pushed California’s system to the brink was the fact that the heat wave extended throughout the West, so California couldn’t import as much power from other Western states as it usually does. Usually when there’s a heat wave in California, the Pacific Northwest or Arizona has a bit of spare power to send our way, but this didn’t happen two weeks ago. 

So, as the sun began to set, the rooftop and grid scale solar stopped generating, driving supply down. Meanwhile, air conditioners kicked into high gear, sucking up electricity to try to cool the homes that had been baking in the sun all day, driving demand up. 

Californians Are Going to Buy More Air Conditioners

As much as air conditioning drove the blackouts, it seems that there are a good number of Californians in the same boat as me – we don’t own air conditioners, at least not yet. Nationwide, 87% of households own air conditioners, while in the Pacific area, including Alaska, California, Hawaii, Oregon and Washington, this number is considerably lower – only 66% of households do (both stats are from the EIA). I haven’t found recent estimates from California, but this paper uses the relationship between temperature and load shapes to infer which households have air conditioning, and puts the estimate at 69% for Los Angeles.

You’ve heard the Twain-ism about cold summers in San Francisco, so historically we haven’t really had much of a reason for AC. With climate change, though, our weather will look more like other parts of the country. Research that I’ve done with Lucas Davis, Paul Gertler and Stephen Jarvis, indicates that higher incomes and hotter weather are big drivers of air conditioning adoption. Median Californian incomes are quite high, so as climate change leads to more frequent and more intense heat waves, more of us will invest in air conditioning.

This is on the residential side. I have not found statistics on the commercial side, but I know of at least one non-residential establishment that does not currently have air conditioning: UC Berkeley. I have heard that is likely to change in the coming decade, and, as I recall from pre-COVID days, when I used to teach and try to do work in hot buildings, there were more and more days when it was pretty uncomfortable. 

Zooming out, research by my colleague Max Auffhammer and Energy Institute alums Patrick Baylis and Catie Hausman shows that increasing temperatures associated with climate change will lead to higher peak demands. While they are not implicating air conditioning directly, it must be the biggest driver of peak electricity demand.

For my household, the main driver to get air conditioning is likely to be poor air quality. Until last week’s series of days with 150-plus Air Quality Index days (“unhealthy”, if you don’t know AQI’s intuitively), I had been lobbying my husband for a whole-house fan to suck in the cool evening air. If that air is smoky, though, we might as well get air conditioning so we can keep our windows closed and rely on the AC’s filters. I suspect that my preferences are more general, but I have not seen research to support that conjecture. This paper suggests that people in Singapore use more electricity when pollution levels are high, although it addresses use rather than adoption of new air conditioners. 

So, I see more AC units in California’s future.

Stretching the Duck’s Neck 

The thing about air conditioning demand is that it ramps up late in the afternoon, just as solar electricity is fading away. The graph below, from the wonderfully titled paper on, “Stretching the Duck: How Rising Temperatures will Change the Level and Shape of Future Electricity Consumption,” makes this point for Ontario, Canada. As more and more people get air conditioning in response to climate change, by the end of this century the projected daily minimum demand will go up by less than 10%, but demand at 6PM at night will go up by almost 25%.

Source: Shaffer and Rivers, Stretching the Duck: How Rising Temperatures will Change the Level and Shape of Future Electricity Consumption


A stretched out duck’s neck – if we take the analogy too seriously – starts looking like a swan, graceful and serene. But California with more heat waves and more air conditioning will be anything but. 

This is not an insurmountable problem. Air conditioning load can be flexible, for example, and with time-varying pricing, as Severin was advocating for, customers would have an incentive to pre-cool their homes. But, California regulators will need to closely monitor and anticipate these trends and act before outages become a normal part of California’s summers.

Keep up with Energy Institute blogs, research, and events on Twitter @energyathaas.

Suggested citation: Wolfram, Catherine. “Are There More Blackouts in California’s Future?” Energy Institute Blog, UC Berkeley, August 31, 2020,…lifornias-future/

Catherine Wolfram View All

Catherine Wolfram is Associate Dean for Academic Affairs and the Cora Jane Flood Professor of Business Administration at the Haas School of Business, University of California, Berkeley. ​She is the Program Director of the National Bureau of Economic Research's Environment and Energy Economics Program, Faculty Director of The E2e Project, a research organization focused on energy efficiency and a research affiliate at the Energy Institute at Haas. She is also an affiliated faculty member of in the Agriculture and Resource Economics department and the Energy and Resources Group at Berkeley.

Wolfram has published extensively on the economics of energy markets. Her work has analyzed rural electrification programs in the developing world, energy efficiency programs in the US, the effects of environmental regulation on energy markets and the impact of privatization and restructuring in the US and UK. She is currently implementing several randomized controlled trials to evaluate energy programs in the U.S., Ghana, and Kenya.

She received a PhD in Economics from MIT in 1996 and an AB from Harvard in 1989. Before joining the faculty at UC Berkeley, she was an Assistant Professor of Economics at Harvard.

48 thoughts on “Are There More Blackouts in California’s Future? Leave a comment

  1. Catherine,

    Nice article, thanks. I have three thoughts.

    1) You don’t need air conditioning to get whole-house air filtering. An option is to run your forced-air furnace fan. Mine has a 25x20x1 inch filter. I replace it every three months during the heating season, so once in Sept. and then again in January. But I just went to my local hardware store and bought a new filter rated at 3M 2200/MERV 13. According to Consumer Reports tests, 1-inch filters do a pretty good job, but not as good a thicker versions. If I am using the fan-only mode, I will crank up the thermostat and run the furnace briefly every few weeks to burn off any slight accumulation of dust. Then I replace the filter in Sept. Seems to help, but I’ll have to spring for a Purpleair indoor monitor to know for sure.

    2) As for nuclear power. Sigh. Back when we had two operating nuclear power plants in California, San Onofre and Diablo Canyon, each with two reactors pumping out 1,100 megawatts, we had a total of 4,400 megawatts of carbon-free power. Severin Borenstein, in the article you link to above, said peak demand recently was more than 40,000 megawatts. Nuclear power could have been supplying at least 10 percent of that. Carbon free. But San Onofre has already been decommissioned, and Diablo Canyon will shut down in the next few years. Sheer madness.

    3) The gird instability calls into question the wisdom of Berkeley’s plans not to put natural gas lines in new construction. I have a friend in Marin with an electric car, who was without power last fire season for several days. If she lived in an all electric house she would have had no heat, no hot water, no stove and no easy way to recharge the automobile. OTOH, My natural gas water heater and stove don’t require electricity, and I could modify my wood-burning fireplace insert (which I never use) to run on gas. I can run the fan with a marine deep-cycle battery and inverter for several hours. I do have Sonic fiber-optic internet with a UPS (uninterrupted power supply), so with my laptop on battery I can still use the internet for several hours. And in emergencies my old-fashioned phone works with Sonic’s VOIP. I agree that all-electric houses and autos are the wave of the future, but when that future finally arrives, I just have to walk out to my gas meter and turn the knob to the off position.

    • “OTOH, My natural gas water heater and stove don’t require electricity”

      Only if these are very old and very inefficient. Same with your gas furnace. Your Internet also will be down without electricity, so no VOIP.

      One of the points of going with new all electric houses for now is to avoid the high installation costs of natural gas infrastructure, which can cost several thousand dollars per house.

      • You might want to check out whether your natural gas stove and water heater can operate without electricity. Natural gas stoves and water heaters use electronic ignitions and many natural gas water heaters use electronic thermostats. Some older models of natural gas stoves can manually ignited by using matches or lighters. Tankless water heaters need electricity to operate.

  2. More AC mostly means retrofits. Ductless systems provide a “newer” option that is intermediate between window units and whole-house retrofits. Perhaps this will further drive adoption.

    We have used a whole-house fan at night for 30 years. It helps, but it’s no longer enough, even in coastal San Diego.
    San Diego has time of use prices, but they are fixed years in advance, and therefore not fully matched to actual weather/load. Peak price is $.50/kWh, 4pm to 9pm, 7 days a week, 7 months/year.

    • “San Diego has time of use prices, but they are fixed years in advance, and therefore not fully matched to actual weather/load.”

      Roger, you hit the nail on the head! The fundamental problem with TOU rates is that they are static and unresponsive to actual power system conditions.

      When I was at the US Department of Energy back in 1978 TOU rates were innovative; today they are dinosaurs. It is interesting that progressive California is first now adopting TOU rates.

  3. As more electric cars are introduced will allowing them to both charge from and into the grid help? In Japan the Nissan Leaf can be plugged into the grid though a home “vehicle to home” and used to power the home. This is described here:
    and Tesla apparently has this capability but doesn’t seem to have advertised it yet, see:
    The cheapest battery storage right now is a used Nissan Leaf. They are available for around $4,000 with 10-14 kwh usable capacity of the battery, considerably less than a similar capacity Tesla Powerwall We have a 2011 Leaf with 9 bars left on the battery that based on our watt meter appears to have a capacity of 12 kwh from 20-80% battery capacity. We only use the Leaf for short local trips so it is frequently home after 5pm with 7 or more kwh available. This would be enough to power our home with AC (with some pre-cooling before 3pm) until 9pm or later, getting us over the main power use. Since we charge the car curing cheap rates from 12M to 3pm this would provide very low cost battery storage to flatten demand after 5pm. It may even pay for itself in reduction in expensive electriciy use 3pm to 12M.
    An electric car like a Tesla with a 75 kwh battery would be much more flexible with potentially much more surplus storage available If the retail price of electricity is variable to perhaps the minute then electric cars plugged into the grid have the potential to charge during low cost electricity and supply during high cost electricity. I can see a future where an electric car owner plugs the car in when they get home and specify they need a minimum 30 kwh available on the car at all times and 50 kwh in the morning. If going on a longer trip they would specify 75 kwh. Then the car could supply and charge from the grid as the price varies. Now that cars are connected to the internet and might be plugged in at both home and place of work, in the future this might supply the electrical storage capacity California will need to flatten the daily demand curve. Electric car might even pay for themselves being able to supply high priced electricity when demand is high.
    Is there any research on how many electric cars and what battery capacity would have to be plugged into the grid to make a difference?

    • Unfortunately the push for carbon free supply combined with existing mandates to increase electric vehicles not only contributes to the demand-supply imbalance, but suggestions to use electric vehicles as backup power will almost certainly then result in more blackouts and a disabled transportation network. This problem is not difficult to resolve, it just requires a reconsideration of nuclear and hydro.

      • How will using EVs as back disrupt the transportation system? Cars are parked 95% of the time, and the fleet will have at least 3 times the capacity needs for reliable back up. Such a broad assertion requires much more analytic backup.

        • Richard
          I’ll assume the pricing, communication, and software issues necessary to compensate and use electric vehicles as a backup power source are resolved. Now imagine the difficulty in determining how much power to drain from an electric vehicle, given the difficulty in also determining how long supply any given shorage may last, and initially how to account for electric vehicle batteries in resource adequacy. The complexity of this problem is magnitudes greater than anything the CAISO or any utility currently deals. The consequences of a mistake will not only not prevent blackouts and leave the grid short of supply but cars short of battery charge. Now depending on the cause of supply shortages (weather, fires or other natural diasters) you will incur outage costs magnitudes more serious than from a faulty forecast. While toying with electric car batteries as supply, why not extend this dispatch concept to personal and computer system battery backup systems, business onsite generation, and residential battery systems?

          • You’re imagining a centrally controlled grid that controls every resource asset. But that’s not what’s going to happen. The EV manufacturers have already resolved most of these issues with the V2G systems. Another poster gave a great example of how this system will work, with each EV owner setting their parameters for how much storage is available at any time. And since a 100% EV fleet will provide more than 3 times the needed capacity, no one EV needs to be called to provide what’s needed–there will be at least 3 available to supply the output. We have already extended this approach to ACs and other demand management technologies. This is really isn’t much different than how the Internet works by splitting, sending and reassembling packets.

            And in fact, this is MORE reliable than the current system. The rolling blackouts in August were caused at least in part by two large single contingency power plants being unavailable unexpectedly. With millions of small resources instead, supply diversity will provide BETTER reliability because we can statistically predict what will be available with substantial accuracy.

          • Richard
            Wishful thinking won’t run an air conditioner. A 100% EV fleet raises far too many unresolvable environmental, mining, manufacturing, and distribution system cost issues than even you are capable of addressing.

          • That’s only your assertion. The fact is that many people are already addressing those issues. And compared to extracting fossil fuels and uranium, mining issues for storage are relatively small.

    • Paul,

      Your suggested solution is a good one. Real time pricing at the retail level would provide the right price signals needed to determine when the EV should charge vs. supply energy. All that would be needed is the software and control equipment that reads the real time prices and directs the operation of the EV battery. However, feeding energy back into the distribution could cause flow limits or voltage limits to be violated so that’s another problem to be concurrently solved.

    • For a few years now, some have said that the electricity industry could face a disruption similar to what has occurred in communications networks. The reply has been “but electricity is different.” EVs are looking like the “cell phone” of the electricity industry, and solar panels are the “ISP” that allows us to “cut the cable wire.” Have you seen any cut rate long-distance calling plan ads lately? Neither have I.

    • Shame on Californians charging their cars when they get home. They need to be charging their cars at work at school off solar panels. Then at home set the charging to come on at midnight. If they cared at all they would do this. Apparently Californians like rolling blackouts. Come on people get with the renewables program.

  4. BTW,

    It’s time to reconsider the decision to retire Diablo Canyon, which appears to be politically driven.

    • No, retiring Diablo Canyon was justified on an economic basis. As I have said repeatedly, PG&E found that it would cost $120/MWH to run after relicensing. No alternatives are that expensive given that the unit has to run 24/7 as designed.

  5. Gene,

    How about adding 16 times the solar and just curtail the excess solar energy in the Summer months? Studies show that it is far cheaper than accommodating the seasonal variation with just storage. Marc Perez showed that in his research.

    • Hi Bob, my comment was to generate the total energy needed from solar, not curtail it. Im not suggesting we do this. Im just trying to suggest the amount of solar needed. The solar currently in CA is pathetically small to satisfy the total energy needs. You dont dump excess solar of this magnitude, but you have to store it. The cost of storage is greater than the cost of new nuclear.

      • “The cost of storage is greater than the cost of new nuclear.”

        If that’s true, why are vendors adding storage to solar projects for less than $40/MWH while new nuclear is costing $100/MWH?

        • Nowhere in the world is storage capacity being added to solar projects for “less than $40/MWh”, and to compare the value of batteries to a nuclear plant you’d have to include the combined per/MWh cost of electricity from the grid mix that charged them. Otherwise, the comparison makes no sense.

          All storage in California is either 1) charging from a grid mix, or 2) charging from the direct output of a gas plant – 100% gas-fired generation. In either case at least 13% of stored energy is wasted in resistance and inversion losses; combined with grid inefficiencies batteries add at least ~200kgCO2e/MWh in emissions.

          Storage is built near solar/wind farms in California for appearance only – there’s no other reason than to give the false impression batteries can cure solar of intermittency.

          • Here’s two of many articles discussing solar + storage projects for less than $40/MWH:

            There are many direct charge solar to storage projects coming on line. It’s the easiest way to get the federal renewable tax credit. LBNL recently put out a report discussing these types of projects.

          • “Here’s two of many articles discussing solar + storage projects for less than $40/MWH…”

            You’re again confusing storage capacity with output capacity. Developers don’t get “solar + storage projects for less than $40/MWh”, wholesale customers pay $40/MWh of energy as part of a PPA. Big difference – if developers paid $40/MWh for a project, the entire 180-MWh battery would cost only $7,200.

            EIA’s most recent update (July 2020) says installed Li-Ion battery capacity, at capacity-weighted, average duration, costs $1,200/kWh ($1,200,000/MWh). A 180-MWh battery facility would cost 180 x 1.2M = $216 M.

            Obviously, investors have figured that over the course of the project’s lifetime they’ll come out ahead. But with existing nuclear power plants generating power at a marginal cost of $23.86/MWh – 41% less than solar + storage – there is no way storage can be competitive with nuclear, or any dispatchable source, on a level playing field. It’s pushed to the front of the loading order now because someone decided it was “renewable” – at the expense of California ratepayers.


            Those who believe the contribution of batteries might help to meet peak demand don’t know how infinitesimally small it is. On August 16, with outages already occurring in mid-afternoon, the peak power contributed by all batteries in the state was 80 MW, for a brief period before noon. Look at the graph below, can you see it? I can’t either – it’s so small it’s hidden behind the baseline on the graph.

            Click to access 8-16power1.pdf

            Batteries = just another in the litany of green power fictions that serve no purpose but to drive up rates.

        • Because new nuclear is not allowed. It could save us money over the solar panels plus batteries option. But the lowest cost is to use both, get about half your energy from nuclear and half from solar. This can be shown using the program on my web page . You need some hourly demand wind solar and hydro data to create the hdata.csv file though. Im going to be updating my web page today but the file is up to date for modeling ERCOT.

        • “ ‘The cost of storage is greater than the cost of new nuclear.’

          If that’s true, why are vendors adding storage to solar projects for less than $40/MWH while new nuclear is costing $100/MWH?”

          Richard, the amounts of storage being added in these hybrid offerings are far less than that needed to convert the solar resources into base load resources capable of producing continuous levels of energy output 24/8, which a nuclear units do.

          • We don’t that much continuous baseload generation. The diverse portfolio provided by wind and solar meets much of that. And if we build solar beyond meeting just peak demand as was done with hydro in the PNW then then solar+storage can meet the energy requirements. I’ve posted previously the calculations for what an all solar+storage system would look like.

          • Richard,

            “We don’t that much continuous baseload generation. The diverse portfolio provided by wind and solar meets much of that. And if we build solar beyond meeting just peak demand as was done with hydro in the PNW then then solar+storage can meet the energy requirements. I’ve posted previously the calculations for what an all solar+storage system would look like.”

            I you build enough solar the resulting Duck Curve can certainly eliminate the need for any baseload generation. But to do that you need enough storage to serve the load after the sun goes down. Then there is the seasonal variation in solar output that has to be solved. This system design is very expensive.

            Jessie Jenkins did some landmark work examining the use of renewable energy to achieve zero emissions and concluded that the cost of doing so with just renewables and storage is substantially more expensive than including some firm, low carbon generation, like nuclear. Here is a link to his work: .

            Richard, the devil is in the details.

          • “We don’t [need] that much continuous baseload generation.”

            Nonsense. We need at least 20GW of continuous, carbon-free baseload generation if California expects to achieve 100% zero-carbon electricity by 2045. That’s not a projection, that’s a fact.

            “The diverse portfolio provided by wind and solar meets much of that.”

            The diverse portfolio of…two intermittent resources? However you add it up doesn’t matter: solar + wind + batteries will never be capable of providing a reliable supply of electricity to the CAISO grid or any other. Publicizing this specious marketing only makes a carbon-free grid harder to achieve.

            “I’ve posted previously the calculations for what an all solar + storage system would look like.”

            OK, but previously-posted calculations are worthless for the purposes of supporting your argument here. So I’m challenging you: put ’em up! Even the 100%-wind-water-sunlight (WWS) proposal of Jacobson doesn’t pretend solar + storage alone can power an electrical grid, and his was laid to waste by Clack et al in 2017. Though it included pages and pages of complex mathematical analysis – a technique commonly used by analytical hacks to conceal a fundamental flaw in reasoning – Clack and Company undertook the unenviable task of verifying it, and concluded

            “…their analysis involves errors, inappropriate methods, and implausible assumptions. Their study does not provide credible evidence for rejecting the conclusions of previous analyses that point to the benefits of considering a broad portfolio of energy system options. A policy prescription that overpromises on the benefits of relying on a narrower portfolio of technologies options could be counterproductive, seriously impeding the move to a cost effective decarbonized energy system.”


            If your previously-posted calculations presume to show an all solar + storage system capable of powering an electricity grid would be remotely affordable or practical, I will tear them to shreds (not that it will require much thought or skill).

  6. Typically even in Davis, we are able to precool our house with our whole house fan and avoid running the AC unless the temperature nears 100. But with the fires, the last 2 weeks we’ve run our AC continuously to filter the air. We can’t open up the house as we typically do.

  7. As a nation we are coddled and lazy. Not just millennials. Cannot stand discomfort. Almost always tackle the symptoms. A Tylenol for a headache, rather than perhaps a glass of water for the dehydration!! Having mac/peak capacity on standby is wasteful. We already mostly have smart meters; use that capability to convey realtime rate charges to customers if their demand exceeds a certain level. They can setup for higher base demand, and pay higher connection charge. Can do limits by individual consumption units – ie no cooking when running the AC!

    If you have a central heating system you already have a blower, use that to circulate inside air. If you want to get outside ‘fresh’ [smoky] air for cooling do that through a filter. Do not need AC.
    You cannot avoid outside air for too long.

    Simple architectural features have been used for cooling in the HOT central Asian lands for centuries. Here we may need intake filters [as above].

    Look for simpler solution. There are many options.
    Perhaps the hurdle is regulatory – fix those rather than build unsustainable capacity for the few-days-a-year high demand.

  8. You make several very good points about getting a more fundamental understanding of the future shape of the demand curve, and especially the need for “fixing the neck” of the duck, which I would say broke in mid August…. my “old school” brain says we need to rely on natural gas a bit longer while we learn the best way to serve the neck… batteries? new natural gas/?? extended life of existing natural gas capacity???

    My thought is that it makes the most sense to extend the life of the existing gas fleet until we KNOW that batteries, modified demand incentives as Severin advocated, and whatever else ends up being needed, are tested and shown to serve the demand of the neck…. as it evolves, which is what you expect. I think it makes sense to have an updated market where the “neck servers” are properly valued … and my expectation is that these extended life “old dogs” provide the most flexible option, with a year-by-year review to determine whether or not they are needed in the next year. If we build new capacity, that means a long-term commitment for the next generation of people. Once the batteries, updated demand reducing program, and other new ideas have been proven to work, then fully retire the old dogs.

  9. Yes there will be a continuous blackout if the nuclear plants are retired and not enough capacity is added. Add 8 times the solar you currently have an storage to turn that solar into 24/7 base load generation and then maybe you can retire the nuclear plants.

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