Where Battery Storage Will Provide Most Peaking Capacity

November 16th, 2014 by Roy L Hales

Coal-fired power plants have been the backbone of US electricity production for decades, but 25% of them will be retired by the end of this decade. Some of their replacements will be fueled by LNG. Others will make way for a disruptive technology that can “switch from charging to discharging in less than 1 second” and has a “significantly higher capacity use factor.” Paul Siblerud, VP Marketing at ViZn Energy Systems, explained where battery storage will provide most peaking capacity in the future.

His company just commissioned a study, entitled GUIDE TO PROCUREMENT OF FLEXIBLE PEAKING CAPACITY: ENERGY STORAGE OR COMBUSTION TURBINES?, that predicts battery storage will take over many of the functions currently performed by peaker plants. They already outperform conventional plants in several areas, but need to be more competitively priced.

Chet Lyons wrote that, “Storage will be a disruptive winner against simple cycle gas-fired CTs at that point, assuming a typical mid-range cost for competing fossil-based CT generation resources.”

As the scale of ViZn Energy Systems’ manufacturing increases, the cost per unit will drop. By 2017, they expect the cost of their 4-hour battery storage unit to be roughly competitive with mid-ranged combustion turbines. By 2018, ViZn should be competitive with a simple cycle peaker.

“We have a shot at becoming the lowest cost solution,” said Siblerud. “We are not expecting to displace all peaker plants, but our strong play is when you have a feeder line for a utility or a microgrid that has a fair amount of renewables tied to it.”

Lyon’s report mentioned California’s adoption of large amounts of renewable energy, which would require an additional 4,600 MW of capacity. Lyons wrote that the “limited speed” of fossil fuel powered plants is “less suitable for … stabilizing distribution circuits negatively impacted by high penetration solar PV. [However] … with the availability of new energy storage technologies, in particular flow batteries, utilities have the means to economically meet the increasing need for flexible peaking capacity using 2 to 6 hours of storage.”

“In those circumstances, battery storage is a viable alternative to peaker plants,” said Siblerud. “Flow batteries, specifically alkaline based flow batteries like ours, can do 3 to 4 hours,” he said. “That’s the key peak time that you usually have to deal with and now you can do that economically and safely. We have an opportunity to take some of that market.”

Using a 30 MW wind farm as an example, he said generation doesn’t usually “just drop to 20 MW. It’s pretty messy on its way down and vice versa on its way up.” There are usually peaker plants idling for occasions like this and they can usually ramp up in 3 to 5 minutes. Then you kick on the other plants and that can take up to 20 minutes.

“You are burning a lot of fossil fuels” to keep this system going.

“That is an area where batteries are superior,” said Siblerud. “They are available in a millisecond, or as fast as the inverter can switch.”

Can battery storage shave off enough peak demand so that utilities no longer have to buy peaker plants that are only needed a few times a year?

“Distributed networks, in general, have the potential of an integrated battery storage for peak shaving. In many cases, a properly sized battery can handle the load very nicely,” said Siblerud. “However, in many projects, it is economically more viable to run a combination of peaker and battery.”

If everything was working in concert, utilities could shut down their “chillers” when there is a peak. This could drop the demand by a third, or whatever is necessary to stabilize the grid. After the peak was over — in maybe fifteen minutes — they could turn the chillers back on.

“Unfortunately, right now there is not a lot of coordination between load and generation,” said Siblerud. “We are having to create little distribution networks, microgrids, that just handle their own visibility.

“That’s a good start, but there are some good options between batteries that have faster response and longer energy capacity in concert with peaker plants.”

Flow batteries like ViZn Energy Systems’ zinc/iron redox flow battery, are designed for applications where they might do two or more full discharge cycles a day.

“A flow battery needs to be used. It has some parasitic losses intrinsic to the battery itself,” said Siblerud. “The chemistry is constantly flowing. You need pumps to pump this chemistry through. If that battery just sits there charged through a seven day period, you’re going to have losses on the system. A major benefit of flow batteries is that there is no material loss if you are running a punishing duty cycle or deep discharging all the way down to a zero state of charge. You can make a complete charge or discharge as many times a day as you want. A flow battery can run at full-power for 3 to 4 hours or nominal power for 8 hours or more. It likes to be used a lot and in those applications is far superior to UPS or back-up systems.”

Lead acid or lithium-ion batteries are well suited to handle periods of peak demand. They typically cannot discharge as deeply as flow batteries or be charged up and down 3 or 4 times a day, however, and they require thermal controls and protection. However, they can also sit idle for long periods without losing much charge.

It is difficult to give a rough figure for the amount of energy companies can save using battery storage to shave peak demand. Depending on their individual circumstances, he has seen it range anywhere from 10% to 60%.

Battery storage is currently more expensive than peaker plants, though it is also faster, environmentally sustainable, and more efficient for certain applications.

“At the end of 2016-2017, when we get down to the $250 kWh range, we will be very competitive and in some cases replace peakers completely,” said Siblerud.

All graphs taken from GUIDE TO PROCUREMENT OF FLEXIBLE PEAKING CAPACITY: ENERGY STORAGE OR COMBUSTION TURBINES?; headshot is Paul Siblerud, VP Marketing at ViZn Energy.

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Tags: ViZn Energy Systems

About the Author

Roy L Hales is the editor of the ECOreport (www.theecoreport.com), a website dedicated to exploring how our lifestyle choices and technologies affect the West Coast of North America and writes for both Clean Techncia and PlanetSave. He is a research junkie who has written hundreds of articles since he was first published in 1982. Roy lives on Cortes Island, BC, Canada.

Viswavarma Kanithi

energy efficiency of generation of electricity is to be considered.about 2.5 times energy is to be spent in the convertor for charging the storage batteries. they also have some efficiency to deal with.—it is not that straight forward way
http://fractalicious.ca/ Adam Grant

Now where in the mix will supercapacitors fit? Probably something on a pretty short time scale.
JamesWimberley

Can anybody tell me who is using 18GW of electricity in California at 3 a.m? If there is really something deserving the name of baseload demand, it has a face and identifiable users.
- spec9
  
  Well, some 40 million people live here.
- Jan Veselý
  
  It is mostly the result of the “social engineering” provided by utilities. In other words, baseload demand is artificially produced for better utilisation of big thermal plants and the grid.
  - GCO
    
    Please elaborate or give us example(s) of such “social engineering” and/or “artificially produced” demand…
    - Jan Veselý
      
      My brother-in-law works in the foundry which is using electric arc furnaces. They are allowed to use these electricity guzzlers only during night time (utility rules). So they do the casting at 3 a.m. paying extra fees for night shifts to their employees.
      I think it was in Belgium where were developed a special tariff for domestic electric resistance heating with accumulation. Electricity was for free during night, it was cheaper than turning off some nukes.
- Calamity_Jean
  
  “Can anybody tell me who is using 18GW of electricity in California at 3 a.m?”
  
  Hospitals, police stations, fire stations, 24 hour businesses, insomniacs, TV stations, street lighting, traffic signals. Security lighting, water heaters, freezers and refrigerators. And probably more that I can’t think of just now.
  - Bob_Wallace
    
    I’ve seen one claim that we’ve got 100,000 plug-ins on our roads. That would use up a little of the 18 GW.
  - GCO
    
    …like, most of the office equipment, which none bothers to turn off, or configure to go to sleep/standby after prolonged inactivity.
- Ronald Brakels
  
  Generally electricity is cheap at three in the morning so that industry will use it and electricity produced by coal and nuclear plants won’t go to waste. I assume this is the case in California. I tried to look up off peak power in California but I got confused. But yeah, the drop in evening electricity consumption does happen very late. It’s like Japan, I guess. People stay up late chewing power.
  - GCO
    
    There is virtually no coal left, and little nuclear, in California. It’s mostly NG, which I assume is pretty flexible so production should be able to follow demand quite well… http://www.eia.gov/state/?sid=ca#tabs-4
    - Ronald Brakels
      
      Thanks for that link. With that generating mix it looks like California can handle all additional wind and solar capacity that gets plugged in. That 12% or so of electricity coming from hydro will be very handy with integrating more renewables.
Kyle Field

It feels like a counterpoint to net metering might be mandating residential battery storage be installed alongside a residential solar system. Centralization might be a better solution…ie, mandating this for commercial scale installations (over 1mw) but not for residential installations.

My personal direction is to obtain residential power storage as soon as it’s realistically available from a reputable Lion provider. I’m sure there are solutions are out there today but I want something more stable, less bleeding edge.
BillW

“Coal-fired power plants have been the backbone of US electricity production for decades, but 25% of them will be retired by the end of this decade. Some of their replacements will be fueled by LNG. Others will make way for a disruptive technology that can “switch from charging to discharging in less than 1 second” and has a “significantly higher capacity use factor.””

This paragraph implies that these battery systems will be used to replace coal plants. As the rest of the article goes on to point out, they’ll really replace gas peaker plants. My understanding is that there are no coal peaker plants, because it takes too long to change the generation level (stoke or unstoke the fires, I’d guess) at a coal plant. Coal is generally used for so-called “base load” power. The key to our future is to replace as much of that as possible with renewables.
- Bob_Wallace
  
  Batteries are part of the combo of wind, solar, storage and dispatchable generation that will replace coal plants.
  
  When the Sun is shining or wind blowing we’ll use that power direct from the source. As storage prices drop we’ll store more wind and solar. Then when we don’t have wind, solar or stored power we’ll fire up the dispatchable generation. Dispatchable can be natural gas, bio gas, bio fuel, or hydro.
  
  As storage becomes cheaper and gets built out we’ll use gas less and less.
  - Ronald Brakels
    
    I’m looking at taking my parents off grid or alternatively leaving them on grid but not actually drawing grid power except under unusual circumstances using lead gel batteries in mostly coal powered Queensland. My parents are kind of perfect for home energy storage as they have plenty of roofspace for extra solar panels, they don’t use air conditioning, my father wakes up at dawn which limits their night time electricity use, and they have money sitting in the bank that gives them a low cost of capital. (I hope they have money sitting in the bank.) I don’t think battery storage will pay for itself just at the moment for people currently on the grid, but it will be interesting to see how close things are in Australia at the moment.
    - tibi stibi
      
      good plan. funny how investments in solar need a payback time. when your parents go on a holiday for fun they don’t calculate the payback time? when they want energy independents for fun they also don’t need a payback time do they?
      
      i need a fence on my roof, i can make it from aluminium bars or from solar panels. cost more but it will make me energy independent
      - Ronald Brakels
        
        I think I follow you, but too much energy independance is not necessarily seen as a good thing here. Ideally we’d like our excess solar energy to be fed into the grid so our massive collective can benefit from low emission energy.
      - tibi stibi
        
        thats also true!
    - GCO
      
      If your goal is to displace as much coal as possible, wouldn’t it make more sense to stay on-grid? That way, any extra PV capacity you might install can always find a use, instead of being mostly wasted during the sunny season.
      Additionally, you could save some or all of the cost and environmental burden of the batteries…
      - Ronald Brakels
        
        I need to work out the point at which the cost of going off grid saves enough money to pay for enough additional on grid solar PV to compensate for the solar electricity that’s being lost by taking my parents off grid. But this is just for personal interest. Currently my parents’ electricity bill is about 40% services charges which is a strong incentive to go off grid, but those charges will start to disappear once people start dropping off the grid on account of how the electricity distributors would prefer to have some of the money rather than none of the money,
- Joseph Dubeau
  
  “Some of their replacements will be fueled by LNG.” this is base load.
  
  “Others will make way for a disruptive technology that can “switch from charging to discharging in less than 1 second” — flow battery station.
  
  The batteries solve this problem. They can buy the power at a lower wholesale prices and dump on the grid during peak.
Joseph Dubeau

Good article on Peak shaving with zinc/iron redox flow battery.