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  • 1.  Battery Storage System

    Posted 04-22-2021 12:04 AM
    Everyone wants to know about battery storage, it's the hot topic on the lips of everyone with even a passing interest in renewable energy. There's no doubt that battery technology is the way of the future and the next major step towards home energy independence from the grid.

    Solar Battery Systems work by storing excess solar power produced during the day for later use in the evening. More cost-effective than selling it back to your retailer during the day at a cheaper rate, this allows you to use more of your system's production and further reduce your reliance on the grid, saving you more than you would otherwise. 

    With battery storage, you're able to:

    • Store excess solar production during the day for use at night

    • Manipulate time-of-use tariffs (TOU) to buy power at off-peak rates when it's cheaper, and store it for peak hours

    • Provide backup power to your home

    • Sell energy back to the grid at peak times for a premium rate


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    Felix Okene
    QA/QC Engineer
    najiteokene@gmail.com
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  • 2.  RE: Battery Storage System

    Posted 04-22-2021 10:13 PM
    Edited by william fitch 04-22-2021 10:19 PM
    Hi: Battery tech is hot, you are right. Many changes coming especially with LiS regarding energy density, cost reduction and light weight. I would just caution regarding certain phrases like, "major step towards home energy independence from the grid." Allot of people translate this to mean dump the grid and be off grid. This is by no means a panacea from a reliability perspective or as an opportunity to get the maximum amount of power that the panels and inverter are capable of producing. In fact the only way to get the maximum power and best EROI is when you are grid tied. Second regarding TOU, on average at present the cost of Li batteries when compared to Lead is anywhere from 5 to 10 fold more expensive per KWH capacity per equal longevity. There are certain benefits Li gives you over Lead, some of them very nice, however, 5 or 10 fold more is still 5 or 10 fold more. If you can afford it that's great, if not.... The weakness of batteries is of course charge/discharge coupled with DOD (Depth of Discharge) regarding life. The TOU differences needed to ACTUALLY create a savings using even the cheapest type of battery is difficult to say the least, especially at a small residential level. Bigger systems (Commercial/Industrial) are easier in reaching a break even point, as often happens. Li is making a big push for the fixed market. One must remember that the main plus for Li is its light weight which has a critical factor in mobile use like transportation (EV's), but in most fixed circumstances has a smaller value (Lighter racking and less space) once positioned.
    Personally I think the best use of battery tech and virgin inverter chargers is backup power when the grid goes down. It is still more expensive than the usual propane gens, but it is RE and clean and does not require fuel to recharge the batteries, just clean solar energy... etc.. Maximum life is also obtainable under the backup scenario because the batteries spend most of their time floating, unless you live in a really BAD grid area for power reliability.
    I wanted to bring these factors out because I remember when small wind got under the publics skin (15 or 20 years ago) and everyone thought, "I can install a small wind turbine (Like Skystream) in my back yard and be energy free." Lets just say there were allot of inflated expectations and disappointments in the end. A different set of failings but the end result is the same.


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    william fitch
    Owner
    www.WeAreSolar.com
    fcfcfc@ptd.net
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  • 3.  RE: Battery Storage System

    Posted 04-23-2021 06:05 AM
    This only works where your local utility offers time of use (TOU) rates.  Unfortunately, those aren't offered in most places right now, including where I live in NE Ohio.  Also, my battery is primarily for backup power.  Using it in a TOU scenario would severely reduce its service life, and I don't believe the savings would offset the cost of replacing it sooner than I would have to otherwise.  
    41 kwh (20 kwh usable) flooded lead acid (FLA) deep cycle renewable energy battery.


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    Mike Curran
    Retired from (dare I say it?) Fossil Plant Mgt.
    joacchim57@gmail.com
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  • 4.  RE: Battery Storage System

    Posted 04-24-2021 12:41 PM
    There are many analyses published about battery storage for residential PV systems. The overwhelming consensus is that if you are doing it for backup when the grid goes down - OK. If you are doing it to maximize your system's impact on the environment - OK.  If you are doing it as a financial investment then it is a poor choice.  Lazards did a good study in 2018 on batteries for residential solar including both lead acid and lithium ion (https://www.lazard.com/media/450774/lazards-levelized-cost-of-storage-version-40-vfinal.pdf) and found that the unsubsidized cost of the battery storage averaged about $0.60 a KWhr. Battery storage is coming down in price but it has a long way to go. Many other publications conclude the same.

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    Thomas Grant
    Director
    XanaduEnergy
    Fairway KS
    tjg4@aol.com
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  • 5.  RE: Battery Storage System

    Posted 04-26-2021 11:35 AM
    Thomas has excellent points on the WHY of battery systems.

    Newer Wood-Mackenzie data than the 2018 Lazard shows exponential growth in batteries at the rooftop and utility scale. FERC order 2222 is unlocking the potential for virtual power plants - the aggregation of many residential batteries to provide monetizable grid services like frequency regulation, load balancing, and energy arbitrage.


     
    Andrew Stone
    Commercial Solar Lending

    Renewable Energy Industry Association board member
    NM Solar Energy Association board member
    National Community Solar Partnership member









  • 6.  RE: Battery Storage System

    Posted 04-26-2021 12:43 PM
    Edited by william fitch 04-27-2021 08:56 AM
    All of that requires control behind the meter. As a residential producer, I do not want the "power company" under the current monetized environment, to be able to decide when I can take and give power. My batteries are for standby only, so in my case my batteries would be unaffected. But, the entire power paradigm would have to change SIGNIFIGENTLY before I would consider that, and maybe not even then. When their current attitude is about putting special tariffs against distributed solar producers, etc.. altering rate costs to negativity benefit solar producers and a multitude of other highly questionable "RULES".., I don't think in the near future I will be trusting them to control my inverter or anything else. Their problem is demand destruction, which is totally bonafide under a profit model. If you get enough RE on line, their cash flow for "sold" electrons goes down the toilet. The bottom line, to have a grid that is a majority of distributed RE with no RE limits on production, a Capitalistic model will not work. The structure must be Socialistic.

    FYI: Here is a cheat sheet link for FERC 2222 relating to Wholesale markets....

    https://www.ferc.gov/media/ferc-order-no-2222-fact-sheet
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    william fitch
    Owner
    www.WeAreSolar.com
    fcfcfc@ptd.net
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  • 7.  RE: Battery Storage System

    Posted 04-29-2021 03:06 PM
    Andrew, thanks for your reply.  I read your link about the concept of Virtual Power Plants. Interesting and I agree it could be a factor in the future of behind-the-meter residential battery storage, but many of the Virtual Power Plant applications, such as the Utility accessing the energy storage of your electric vehicles, are only conceptual today. I tried to get the Wood-McKenzie report that you referenced, but it is for sale at a very large price, and beside it only addressed Front-of-the-Meter situations. As far as I know, the 2018 Lazard study is the most definitive study on the cost of electricity from residential battery storage. I note that even the 2020 IRENA study uses the 2018 Lazard study as a their reference on battery storage costs (if anybody has better cost estimates I would appreciate it). I agree that battery costs are dropping and have shown remarkable growth. I am aware of FERC orders encouraging battery storage, but even with Li ion batteries which are projected to drop 50% in price in a decade, that means the price of residential battery storage electricity would only be about 30 cents/KWhr in 2030. I pay 11 cents/KWhr from the utility in Kansas now. My point is that if you are considering residential battery storage to save you money, then that may come about some day, but my advice is to wait for that day before investing.

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    Thomas Grant
    Director
    XanaduEnergy
    Fairway KS
    tjg4@aol.com
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