More Progress on Battery Storage

February 23, 2019


The energy market in the Southwest has hit a turning point, with battery prices falling so low that the technology is now the least expensive way to provide customers electricity, according to officials from Arizona Public Service Co.

To take advantage of the historic shift, the state’s biggest electric company will spend hundreds of millions of dollars to add large, building-size batteries to the power grid across Arizona.

APS will use the batteries to soak up surplus energy on the grid early in the day when solar power plants across the region are pumping out more electricity than the homes and businesses require.

The batteries will then discharge that power in the evening, when the sun sets, solar panels power down for the night, and customers turn on their lights and need the energy.

The 850 megawatts of batteries planned by APS will make better use of the solar already on the grid. They will allow for more people to add solar panels to their roofs and utilities to build more solar power plants without creating problems on the grid, officials said.

“Eight-hundred fifty megawatts shows you how incredibly transformational what we’ve seen happening on the grid is and how quickly that has been evolving,” APS President Jeff Guldner said.

“The holy grail in the industry right now is trying to figure out how we capture solar energy during the day when there is tons on the system and then use it later when the sun goes down,” he said.

The amount of batteries APS plans to add by 2025 is more than the 338 megawatts of batteries the entire U.S. utility industry added last year, based on estimates from the Edison Electric Institute.

APS does not offer cost estimates for the entire project because of proprietary information from its construction partners and because not all the work has been put out to bid.

But in general, 100 megawatts of battery capacity with four hour of storage runs about $120 million, APS officials said.

That would put the total cost of the projects at more than $1 billion. APS will own some of the projects and purchase power from others.

The batteries will displace traditional power plants, particularly natural-gas-fired generators, and increase the amount of renewable energy APS uses.

APS today gets about 14 percent of its power supply from renewable sources like solar and wind. That’s well ahead of an incremental state rule that requires the utility to get 9 percent from those sources today and 15 percent by 2025.

The batteries will increase the number of renewables in APS’ power supply by another 3 to 4 percent, officials said.

Guldner cited the many days during the year — 81 in 2018 — that APS is actually paid to take surplus solar power from California because it is more economical for that state’s utilities to keep its power plants running than to shut them down midday and then restart them when demand picks up.

When APS accepts that power, it often curtails its own solar power plants because the energy isn’t needed at those times. That’s especially true in the spring and fall when the sun shines bright but few people are running air conditioners or electric heaters.

With a place to store that surplus midday energy, more of the power can be used to serve APS customers with solar after dark, he said.



21 Responses to “More Progress on Battery Storage”

  1. redskylite Says:

    It seems that energy companies should not fear taking the plunge in configuring large storage devices into their grid layouts. It has been a great “cost-effective” success down under.

    In its first annual revenue declaration, made after its stock exchange listing late last year, the Paris-based Neoen says the performance of what is officially known as the Hornsdale Power Reserve was ahead of expectations “owing to its technical characteristics,, particularly its highly responsive approach.”

    The performance of the 100MW/129MWh lithium-ion battery – still the world’s biggest – has surprised all, and delighted many, with its speed, accuracy, and versatility, and has earned the praise of the Australian Energy Market Operator, which sees it as a valuable resource in maintaining grid security and reliability.

  2. redskylite Says:

    Nuclear, hydro, marine and geothermal still need to be on the menu in replacing fossil fuels . . .

    100% Renewable Energy Needs Lots of Storage. This Polar Vortex Test Showed How Much.

    and we still keep our fingers crossed for the elusive El Dorado. . .

    Machine 3 has now been fully commissioned and its creators say it is now the biggest pulsed power machine in the world dedicated to researching fusion energy.

  3. Gingerbaker Says:

    Arizona alone could power the entire world with solar. And soon enough, it’ll be so hot there there will be nothing else will be fun to do there anyway.

  4. Terry Donte Says:

    850 MW of batteries is simply not large enough to make a difference. They will be discharged in a few hours at most so cannot make up for other sources of power. If the plant is say 1000 MW and the power demand is 1000 MV than one needs at least 15 times 1000 MW of battery storage for one days operation. You can run the numbers around all you want but Solar is simply not delivering power from around 4 or 5 PM to 10 to 12 PM when power is at the highest levels which people home , cooking dinner, watching TV, heating water and running the air conditioner. To get that stored power one needs a power plant at least 3 times the evening power demand plus the storage for that power plus backup from somewhere.

    • Sir Charles Says:

      Add some wind energy and you get a very different picture.

      With capacity factors of more than 60% offshore wind turbines deliver reliable power.

    • Greg Wellman Says:

      You’ve got the units wrong. The original article didn’t exactly help with that either, but it *sounds* like their capacity might be 4 hours at 850 MW … so 3.4 GWh.
      I don’t know what sort of evening power demand they need to cover, but if they can import enough wind power to get the demand for the battery down to 400MW, then it will last 8 hours.

      The idea is that if we connect up large enough areas with HVDC backbone, it’s always windy somewhere, and as Sir Charles points out, offshore is very reliable. Then batteries only need to provide *some* evening power, not all of it.

      • Brent Jensen-Schmidt Says:

        Just to rain a bit on the parade. If you think there will always be some wind somewhere, let me introduce the great god Sod and his law giving first son Murphy. There will always be wind somewhere except when you really need it. Alternatively, someone somewhere else gets it. These highs and lows will exaggerate, a lot, with the increasing use of renewable s. Problems to be solved. Also, the wind has a tendency to stop at dawn and dusk.

        • Sir Charles Says:

          “wind has a tendency to stop at dawn and dusk”

          Never heard that before. Does daddy wind sing a lullaby for kiddy winds every eve?

          • Brent Jensen-Schmidt Says:

            You mentioned the reliability of off shore wind. Normal situation is, during the day land heats up, pressure rises relative to colder sea creating offshore wind. At night the reverse is the case causing onshore wind. Round dawn and dusk there is a period of quiescence while the wind decides which way to go. Have you never experienced the ‘Dawn Stillness”, or the ‘Quietness of dusk”? Just around the low output of the Duck Curve. Lesson for the day Chas, aren’t you pleased?

          • Sir Charles Says:

            Ireland’s renewable electricity comes mainly from onshore wind. Although we cannot see any correlation between time of the day and generation in the charts. Magic?

        • Sir Charles Says:

          Have a look here and click at “Actual and Forecast Wind”. Now tell me there’s any correlation with the time of the day. There isn’t any.

          • Brent Jensen-Schmidt Says:

            Did see at end of May into June a full fortnight straight of NO wind worth mentioning. Dam, need fourteen straight days of storage.
            I am a proponent of renewable s, but the world does not have time for wishful thinking.

          • Sir Charles Says:

            Can’t see a whole fortnight with “no wind”. But I’m sure. That’s the time of the year where Ireland needs most energy 🙄

            Nonetheless, Ireland’s electricity comes at 30% from wind (even mostly onshore). That’s my lullaby.

          • Brent Jensen-Schmidt Says:

            28 May to 12 June.

          • Sir Charles Says:

            BTW, that 30% is working perfectly without any additional storage.

      • rhymeswithgoalie Says:

        The trade-offs vary around the planet. Here in Austin we have a sweet deal where our max air-conditioning load is about 4-5pm when we get the max power supply from West Texas solar farms. On islands or in mountains where the greatest fuel-transport expenses are, squeezing out as much as possible from wind and solar is the most cost-effective. And, of course, utilities can continue using load-shifting programs for local industries in exchange for off-peak discounts.

    • J4Zonian Says:

      Donte’s as bad at math as she is at everything else–and of course as always, malevolently so. One needs what one needs locally, and that varies. But nowhere near as much as Donte claims, which is why she neglects to back her assertions with any citations. One needs enough storage to meet whatever demand there is beyond what everything else supplies at the time that gap is biggest. Demand of course, is also variable and malleable–targeted efficiency, wiser lives, and demand response can all be bent to reduce its peaks, match it to supply, and time-shift it, as other time zones’s resources time-shift supply. (Solar to the west can provide power to flatten ducks to the east, as California’s does, and could more, for Arizona, New Mexico, Utah, and Wyoming, Montana, Colorado, and parts of Idaho, Kansas, Nebraska, North Dakota, Oregon, South Dakota, and Texas).

      In coastal areas, for example, offshore and coastal onshore wind can supply quite a bit mornings and evenings as water and land heat and cool at different rates. In winter and spring, enough wind can be built to supply what peaking hydro, micro hydro, solar, etc. don’t; in summer, there’s often less wind and hydro, but more solar PV and storage, 24/7 solar thermal (CSP), and whatever else exists in the area–geothermal, some waste biomass, wave, tidal, OTEC… In inland areas, whatever isn’t supplied by all that will be supplied by storage from peak PV including EV batteries. Year round, clothesline paradox solar will do what it does–reduce demand without being recorded as doing it, including solar cooking, passive and active solar heating and cooling with built-in rock, water or eutectic salt storage; Annual Cycle Energy System (geothermal that’s not geothermal), district heating, cogeneration and other methods.

      All these systems can be harmonized, the cheapest expanded til its niche is filled and any more will cause grid problems or curtailment, and then others expanded to fill their niches. Adding each may add more space for others (adding solar adds space for batteries, and often wind; adding batteries may create space for more solar and wind, and so on, the whole mix creating the potential for more and more renewable energy up to 100% when the right combination is found.
      How to choreograph high-renewables electricity systems www[DOT]youtube[DOT]com/watch?v=MsgrahFln0s

  5. doldrom Says:

    Mentioned by Sailrick 14 December, but I recently read an article about it here in national daily newspaper. MIT initiative to store solar energy using molten silicone (sun in a box).

    See for instance:

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