Batteries not included


Almost a hundred million dollars of new investment in battery technology has been announced in the few days: first, Boston Power announced that it had received $55M in a fourth round of funding for their Sonata lithium-ion battery. The Sonata is advertised to have a very long lifetime, a quick charging cycle and makes a variety of environmentally friendly claims.

Next, GM announced that it will spend $30M on an assembly plant for the batteries for their up-and-coming Volt electric vehicle. This followed an announcement that Tesla would begin to manufacture batteries for other electric vehicles as well as their own Tesla Roadster.

These announcements reinforce just how important energy storage will be with the advent of new renewable energy technology.

Drivers, homeowners and businesses need power all the time. But America’s wind farms, solar arrays and electric cars can’t simply make electricity around the clock. Because renewables are a small enough piece of the US energy pie (7% in 2006, less than half a percent if you exclude hydro and biomass), the rest of the grid buffers periods of up and down time.

But as we approach the levels of renewable electricity generation that many environmentalists hope for, we will have to solve the issue of delivering constant supply from intermittent generation. Batteries are a great solution for the likes of electric and hybrid cars but how might you store energy from a large solar array or a massive wind farm?

Fortunately some very smart people are thinking about that very question. One interesting possibility that has recently been getting some press is compressed air energy storage technology. In this approach wind energy is used during periods where energy is readily available and the wind is blowing (at night) to compress air and force it underground. During times of peak demand the compressed air is then used to generate electricity for the grid.

There has also been interesting work done on pumped storage, where off peak electricity is used to pump water up to a storage reservoir and then during peak hours its flow back downhill is used to generate hydroelectricity.

It has been great to see so much investment into new, renewable energy generation technologies, but all this battery talk should serve as a strong reminder of just how far we have to go before we can fully implement a renewable energy system for the US. If you’ve heard of any other large-scale chemical or physical energy storage technologies leave a comment, we think all of this stuff is pretty neat.

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  1. Jay

    I read an article recently on a power-plant-sized vanadium-ion battery deployed in Japan. Wikipedia has a good explanation of the technology.
    A123systems is also experimenting with large storage batteries. See the article on the H-APU at
    Distributed storage in EV batteries is a good idea, but it requires lots of new infrastructure to get there, so it’s a ways off yet.

  2. David Bryant

    The previous post mentions VRB which are a type of flow battery. This is currently available technology with high potential for load leveling in a variety of transient power source like wind and solar.

  3. Jeffrey E. Anthony

    Hey, guess what ? We do not need energy storage anytime soon. There is this myth out there that we somehow need energy storage RIGHT NOW to integrate the variable-output electricty from wind and solar power. Wrong. Numerous studies have been performed by electric utilities and grid operators in the U.S. and ALL of these studies have found that the existing grid, and the resources that already exist, are the most effective and the cheapest way to integrate wind and solar power. And these studies show this consistently for increasing levels up to 20$ — where we would get 20% of our electricity from wind and solar, which won’t happen for many years.
    Turns out the flexibility in our grid today, which allows system operators to already match the variability inherent in our demand for electricity, which changes minute-to-minute every day, is well-suited to accommodate the variability of wind and solar output, too. And when combined with advanced wind forecasting techniques, operators need only make some changes to how they operate the grid to accommodate increasing levels of wind and solar power. The National Renewable Energy Lab (NREL) is also leading two major studies in the west and in the eastern part of the US right now to study even higher levels of wind and solar power use.
    But for now, energy storage is NOT needed — and since using energy storage is VERY expensive, the R&D phase for energy storage technologies will need to continue for several years. Someday, energy storage may play a bigger role — but not anytime soon — not until the costs of energy storage technologies drop dramatically.

  4. Ralph Wheeler

    Pump water up hill during excess energy times and run the water downhill through a generator during energy lows.
    Create hydrogen during excess energy times and burn it during energy lows.

  5. Dan Davis

    The posts about the fungibility of the grid are true that for now operators can bring other power sources (like gas turbine generators) up and down as needed. However this is inefficient and requires these generators to operate at part load during low demand and lose considerable efficiency – up to 50%, so keep up the search.
    As well the grid loses about 50% of it’s energy just to “push ” the power around, so we must begin to think of smaller and more efficient generators closer to the demand to minimize transmission losses and need for new lines.
    Also in upstate NY, northern Catskills, southwest of Albany, there is a pump storage facility that pumps water up at night and releases it back during peak times. The electric-hydro pumps at night are reversed and become the hydro-generators in the day. I don’t know if it is still in use, but surely must be. I believe it used to be owned by Niagra-Mohawk utility – if they still exist.
    What about capacitors, which are efficient energy storage devices, I believe more efficient than batteries, for the resourcs used.

  6. Ron Proctor

    Utility scale solar thermal installations in Arizona are considering using molten salt for heat storage.

  7. Russ in San Diego

    Indeed, we will need efficient power storage mechanisms in significant quantity, within the comind decade.
    Pumped storage (hydro, pneumo) are possibilities. I’m pretty sure pumped hydro storage is already in use. The problem is that it ties up valuable resources (real estate and fresh water).
    Capacitors are indeed efficient — but they sport extraordinarily low energy density. You could probably fill a small closet with supercapacitors and achieve the same energy storage as a AA battery. On the other hand, if you apply a direct short-circuit to that same capacitive battery, well, let’s just say your neighbors will know about it right away!

  8. Chad

    Yes, Russ, there are hundreds of pumped storage facilities all across the country, including some which exceed a gigawatt. We don’t need some radical new technology. We already have it and have been using it for decades to provide peak power.
    Here’s a link to the one of the largest ones, in Ludington Michigan.

  9. rpn

    that was a very perceptive comment re the capacity of the grid to move power to balance supply. the “grid problem” is a red herring. we can do alternative production with little change to the present system.
    in response to storage:
    1. there are existing large format, high voltage battery systems the primary purpose of which is to smooth both peak demand and power quality.
    2. a large supplier of electrical power in southern cal is considering a plan for distributed storage in local battery systems.
    3. please note, though, central to all the schemes for storing electricity — water, air, chemical — is a sophisticated energy management and control system. this principle is particularly important in electrochemical storage because the potential of the energy is always “on” and release is instantaneous. finally, a useful and safe battery system is not a trivial matter of bolting together a bunch of batteries in a box.

  10. rpn

    [No problem, rpn, your comment has been updated — Ed.]

  11. disdaniel

    I take exception with your headline terminology “inconsistent renewables”.
    Inconsistent makes renewables sound like the underlying technology doesn’t work right.
    Solar, wind, geothermal, hydro etc are very consistent as long as the underlying resource is available…sun, wind, groundheat etc. Granted these resources may fluctuate leading to intermittent power generation depending on locatation.
    But as J Anthony (#3) points out, demand is just as intermittent as renewables for any near future renewable generation scenarios. Heck even coal plants and nuclear plants shut down now and then for maintenance etc…

  12. Dan McDonough

    Ron Proctor’s Comment about molten salt heat storage refers to a form of solar technology known as “Solar Thermal.” ST uses parabolic-reflector concentration of sunlight to collect heat, which is then used to power a conventional steam generator. It’s an extremely promising technology that was gaining in popularity in the late ’80s before the dramatic drop in oil prices that drove much of the cheap energy “SUV culture” of the ’90s and early ’00s.
    This is a system that we could use now to augment electricity supplies in the existing grid; of course it does work best in hot, sunny climes, but being essentially a passive technology (as opposed to PV), it could be ready to go in a very short time.
    Wikipedia article is here:

  13. Matt

    Why worry about storage at this point? Even if renewable are at 6%, the intermittant ones like wind & solar are only 0.5%.
    Denmark gets >20% of their electricity from wind. Germany gets close to 10%.
    Why do we need to worry about it now?

  14. tony marmont

    We make about 50,000 kwhrs of renewable power per year from Wind , Solar PV, Hydro, and it is intermittent,so we started with a set of 200 kwhr storeage batteries, but then realised it was not big enough, so we started making Hydrogen with the spare power in times of high production then using it through two fuel cells when there was a shortage, this worked , we have a store of H2 equivalent to 3.8 MWhrs of power if converted back to eletricity.Now we have discovered a way of combining the H2 with CO2 (abstracted at low cost), from the air and making liquid fuels gasoline , deisel and Jet A1.
    see our web site

  15. David Bryant

    Indeed Jeffery, we do not need energy storage to begin the build out of wind, solar, tidal and other renewable energy sources. While wind is indeed the most variable it has been observed to be on line 85% of the time, which is comparable to gas turbine peaking plants. Except that gas is available on demand and wind is unpredictable. However with sophisticated ARIMA modeling methods ( and current weatehr predictions we can successfully integrate wind power availability with very high confidence. Ain’t science groovy? 🙂