Energy Storage Technology Offers Solid Backup to Renewables

June 22, 2014

A thousand flowers blooming in the energy storage sector. This is one of them. Below, implications.

Roy Hales in The Eco Report:

Between 1 pm and 2 pm on Friday, June 6, Germany’s solar photovoltaic systems generated a record 24.24 GW. The real peak came three days later, when they provided 50.6% of the nation’s electricity. That shows this technologies potential. The current reality is solar contributed only 6% of the nation’s during the first five months of 2014. This will change. Increased Storage will unlock Germany’s Solar Potential.

Instead of relying on the grid, some solar users store energy and only feed the excess to the grid. They only draw upon the grid when their batteries are depleted.

Close to 7,000 battery systems were installed in 2013.

Tobias Rothacher, renewable energies expert at Germany Trade & Invest, expects to see more. Battery sales will increase as their price falls. Once battery-parity is achieved, possibly “within the next two years,” the majority of pv sales will probably be in conjunction with battery.

He explained, “Since the cost of electricity from PV is significantly lower than buying energy from the grid (~EUR 0.15 PV vs. ~EUR 0.30 utility), customers want to use as high a proportion of electricity from their PV systems as possible. If they were to feed the electricity into the grid, they would only receive a feed-in tariff of around EUR 0.13 – meaning that self-used energy from PV is worth twice as much as energy fed into the grid.

Rooftop solar solars with “PV-only” systems only obtain around 30-35% of their energy from solar and their excess ends up on the grid.

Add a battery system to this equation and they can obtain twice as much electricity (60-70%) for a household’s annual consumption.

“From now on, every new solar system that is installed in Germany increases the need for electricity storage solutions,” Rothacher said. “The cost of storage systems is forecast to drop in the coming years and this means that storage is not only becoming more necessary – it is becoming more attractive from a financial point of view as well.”



21 Responses to “Energy Storage Technology Offers Solid Backup to Renewables”

  1. ubrew12 Says:

    This video was great until around 3:50: “Support for the development of this technology… was provided by the U.S. Dept of Energy, Office of Electricity, Energy Storage Program” As any Koch-brothers acolyte will tell you, Big Government can only fund horrible bureaucratic boondoggles, whereas our glorious ‘free market’ capitalism is responsible for REAL innovations like Mortgage Derivatives, Credit-Default-Swaps, Happy-Meals and so many others!

    • dumboldguy Says:

      Yep, but do remember that one of Solar Roadway’s selling points is that they were the recipient of some sort of government grant also, and SR does look to be a boondoggle that the free-market is not picking up.

      • ubrew12 Says:

        SR is so radical it HAS to be a boondoggle, there is no other choice. That doesn’t mean that, down the road, it won’t find applications. Everything (that matters) is a boondoggle, in its infancy, including Pennsylvania Oil, which appeared ridiculous compared to the fine whale oil everyone was using everywhere else, at the time. Not in a million years would I expect the ‘free market’ to engage in the long term thinking needed to see whether a Hoover Dam, an Interstate System, an Iron-Vanadium storage unit, a solar cell, or a Solar Roadway is a worthy ‘investment’. It’s too busy selling itself, and others, on the ‘next, new thing’!! “Track your calories on your Smart Phone!” is surely a billion dollar idea!! Or, hey, the Go-Pro!! Its a camera that, like, is waterproof!! And you can take with you on your adventures!! And it’ll record them!! Wow!!

        • dumboldguy Says:

          The only “application” Solar Roadway will ever have is as a means of separating fools from their money, and transferring it to the “inventor”. Anyone who thinks anything else is either self-deluded or seriously science-knowledge-deprived.

        • Phillip Shaw Says:

          I think people are being overly harsh on the Solar Roadway concept. I don’t know whether it will ultimately be a successful innovation (many innovations never pan out). But I can see a number of niche applications for the SR pavers – not for major interstates, granted, but certainly in urban and suburban settings.

          First, pavers, bricks and cobblestones have been used successfully for roadways and walkways for millenia – far, far longer than asphalt paving has been around. You can go to Europe and find paving laid down by the Romans that is still in good shape and in daily use. Here in the US, many cities and towns use bricks and pavers for crosswalks and sidewalks. On a cost/benefit analysis SR pavers will be competing with conventional pavers, not with asphalt. (And have you ever seen an asphalt sidewalk? ‘Butt ugly’ is too weak a description.)

          Second, making pavers out of glass is neither new nor radical. Glass is a remarkably versatile material. Google “recycled glass pavers” and educate yourself about the spectrum of products already on the market. The infrastructure to produce the SR glass tiles already exists and any SR production is simply added jobs and revenue.

          Third, according to the data specs, each SR paver will incorporate an Enphase ( microinverter so the power produced by the SR is grid compatible AC. If you are familiar with microinverters, shading is not an issue as it is with conventional PV installations where strings of PV modues feed a central inverter. Scalability is a breeze and there is no single point failure issue. You will get clean AC from one SR paver, or ten thousand SR pavers.

          As I mentioned above, I see SR as a niche application. There are many sites where conventional PV modules aren’t a good option. My house is one of them so I’ll briefly describe the situation and show why I could use SR pavers today if they were available. My house is shaded by three large centuries-old oaks so only a small part of the roof is open to the sky and that part faces east – so conventional rooftop PV modules aren’t a full solution. But I also have a 19 by 35 foot driveway with good sun exposure. Room enough for a 6 kw PV carport – except that HOA rules forbid carports of any kind (gotta love HOAs). However, I could pave the driveway with SR tiles (and the HOA blessings). SR is less efficient than most PV so I might only produce 2 to 4 kw of power, but that’s more than I can generate with any other product on the market today. If I could also pave the sidewalk in front of my house with SR tiles that would double the power produced, essentially making me grid neutral, which is my goal. So when and if SR pavers hit the market I’ll probably be an early adopter.

          The Solar Roadway concept may never amount to anything but it is worthy of serious consideration. The majority of comments I’ve seen even on this forum just seem small-minded and thoughtless. It takes intelligence and vision to see the potential in nascent technologies. The past century of innovation (flight, television, cell phones, home computer, and so on) should have taught us that it’s rarely wise to sneer at new edeas just bethey’re new.

          • Gingerbaker Says:

            On the other hand, it is quite possible that the main utility of SR is its ability to derail blog post commentary. 😀

          • Gingerbaker Says:

            And, btw, I don’t sneer at the new idea of SR because its new, I sneer at it because I think it is stupid. Really really stupid in fact. But that’s just me……………. wait, it’s not just me.

          • dumboldguy Says:

            Phillip is being overly naive in his mindless enthusiasm for the Solar Roadway concept. He talks of others’ comments being “small-minded and thoughtless”, “unintelligent” and “without vision”, and says that all the sound reasoning as to why Solar Roadways is a bad idea is mere “sneering”.

            He says this because he is woefully ignorant in his understanding of the physics, chemistry, engineering, materials science, economic principles,and just plain common sense underlying why Solar Roadways is a bad idea and not worthy of serious consideration. He he sees himself as a visionary, and will be a joyful “first adopter” of Solar Roadway if and when they actually begin to produce it. He confuses past “new” ideas that WERE workable and produced benefits with something that is NOT workable on anything other than a small scale and will never make economic sense.

            Phillip displays the level of his self-delusion with “But I can see a number of niche applications for the SR pavers – not for major interstates, granted, but certainly in urban and suburban settings”. Of course, he has forgotten that “urban” settings implies tall buildings closely spaced, and a lot of SHADOWS.

            Phillip goes on at length about “pavers, bricks and cobblestones have been used successfully for roadways and walkways for millenia”, and neglects mentioning that those “bricks and cobblestones” are NOT made of glass, which is a very different (and unsuitable) material when compared to brick, stone, concrete, or easily recyclable asphalt.

            Phillip prattles on with, “On a cost/benefit analysis SR pavers will be competing with conventional pavers, not with asphalt”, without giving any thought to the fact that Solar Roadway will be WAY more expensive than ANY kind of paving, and is simply uncompetitive by any measure.

            Phillip asks and states, “And have you ever seen an asphalt sidewalk? ‘Butt ugly’ is too weak a description”. Really? I guess “visionary first adopters” have a different standard of beauty than us common sense folks. I myself find a material that can be tinted many colors and that can be made to flow “organically” in the landscape to be far more attractive than the rigid geometry and “techie” appearance of something that is simply utilitarian.

            Sorry, Phillip, but making pavers out of glass IS not happening. Glass is NOT a remarkably versatile material, and that’s why it hasn’t happened. The pavers you reference are 3/4 CONCRETE, and only incorporate small amounts of glass, mainly as a gimmick and not because of its superiority as a material. The infrastructure to produce the SR glass tiles does NOT exist—it is a far different process from what is used to produce simple “pavers”.

            Phillip closes with “So when and if SR pavers hit the market I’ll probably be an early adopter”. Good luck, Phillip. Some folks like to gamble on horse races or sporting events, others like to buy penny stocks in hopes that some of them will greatly appreciate (remember the frenzy?). Others have called SR a “stupid” idea. It may be “stupid” from the technical standpoint, but it’s actually a very clever and appealing pie-in-the-sky concept that will separate many ignorant suckers from their $$$$. The inventors have done a great job of producing marketing materials, and can probably find enough suckers to make a good living off SR for years to come.

    • Sir Charles Says:

      Well. And Germany is a socialist state where Honecker is still in power…


  2. mbrysonb Says:

    I’d love to see some numbers here– say, $/kilowatt-hour of storage. (I gather from elsewhere that $100/ KWh is an important target for car batteries…)

    • ubrew12 Says:

      Solar Photovoltaics were once so expensive they were used only on Satellites, where no other power source was available. I’m sure you would love to see some numbers. It’s just that they wouldn’t mean anything…

    • Okay. Balqon. 34kwhr. 12k dollars. About $300/kwhr, installed first cost. Thats for a DC DC converter from solar, all the BMS for the batteries, and an inverter to 120VAC. Given there must be a profit, the raw cost of the batteries is much lower than $300/kwhr. If you keep max charge and DoD in the 70% range, you can get greatly extended life.!/~/product/id=12477202
      8000 cycles at 70% DoD for the 40Ahr cell.

      If you get 8000 daily cycles at 70% DoD, you have 0.7 x 34kwhr x 8000 = 1.9e5 kwhr stored over the lifetime.
      Now this calculation does not include the interest cost, so it is not strictly accurate, but…

      $12,000/1.9e5 kwhr = $0.06/kwhr.

      The lifetime cycled daily would be 365 x 20 or about 7200 cycles.
      Properly done, a modified calculation might look at annual storage over a twenty year period, only looking at annual periods, rather than computing the daily interest. The calculation should yield similar results. Despite the crudeness of the calculation, it appears clear that storage costs are well under $0.20/kwhr, even if the storage unit only gets 4000cycles, something easy for it to do. Thats why Hawaii is ripe for grid defection. Its utility rates are 0.40/kwhr.

  3. Interesting that you’d choose “A thousand flowers blooming in the energy storage sector” given the rather sordid origins of that expression:

    But never mind, it’s the technology that counts. If solar energy wants to be a serious alternative to fossil fuels or nukes, cost-effective energy storage has to become widely available.

    Wikipedia has a decent write-up on Vanadium-redox batteries:

    I was surprised to see that the technology has been around in usable form since at least the 1980s. It does seem to have some advantages over lead-acid batteries, not the least of which are less toxicity and easier maintenance. I’m still not sure of costs. A significant drawback seems to be it’s relatively low energy density, though Wiki gives the impression that this is improving. If they can be made practical enough for use in motor vehicles, that would give this tech a big boost, since motor vehicles are currently the largest market for battery storage.

    At the moment, most people with solar installations and battery back-up rely on lead-acid batteries, which are high-maintenance, short-lived and toxic (though can be recycled). I would be happy to experiment with a vanadium-redox battery, if they can be manufactured at competitive cost.

  4. Gingerbaker Says:

    I would just like to point out the monumental inefficiency of the needless duplication inherent to millions of rooftop PV systems now dramatically increased by the idea of millions of needlessly duplicated battery systems.

    Granted, millions of needlessly duplicated control panels, inverters, charge control components, wiring harnesses, and now battery control systems and huge battery modules maximize manufacturing costs and profit margins for the companies and huge corporations that are riding the crest of this technology, but is nobody interested in the economics of this?

    Can anyone tell me – within an order of magnitude! – how much enough solar to actually run our country will cost if we do it on rooftops vs doing it in huge arrays in the American Southwest deserts?

    And if you can’t tell me, don’t you think these figures are something we probably should know?

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