Wednesday, July 14, 2010

Have Solar Panel. Need Batteries.

I'm on vacation in the east coast of the US for the week and the sun has been relentless. I can only hope to have clouds and maybe a shower or two to cool things down.

But mention clouds and the solar photovoltaic folks start to go berserk. Apparently solar panels have a hard time being of any use when there is no sun! An hour of clouds and your power generation tanks. Two days of rain can make dependance on renewable electricity seem like a return to the dark ages.

Enter batteries. Why not store the electricity during the times we generate it and use it in the night/when there are clouds etc? Sounds like a great idea, but the problem is... you guessed it... those batteries!

Anyway, long story short there are some batteries (different from vehicle batteries) that have the hope of being very useful for these sort of renewable storage applications. We are talking about MWh of storage (the M is for mega, so... big). There are a lot of batteries that are needed for this application, but the cost of these batteries is a problem and so is the lifetime. A third problem is that the energy efficiency of these batteries is not that great (maybe 50-70%). When someone tells you that the energy efficiency is 50% it means that you use twice the energy to charge the battery than you get on discharge. So 50% of your solar panels are a waste (great for the solar panel maker. Bad for the customer).

ARPA-E, the new kid on the DOE block, came up with a solicitation looking for ideas to fix these problems. This week, they announced a bunch of awards for some interesting new technologies that promise to solve these problems. One of the awards went to your faithfully (that would be me) along with two of my colleagues from LBNL- Vince Battaglia and Adam Weber. For the project we assembled a team consisting of Robert Bosch, DuPont, and 3M. We also had Proton Energy has a partner to help with some designs. Its an amazing team that beings together knowledge of electrochemistry, catalysts, membranes, and balance of plants to work on a battery called a "flow battery".

I will try to expand on what we proposed in the near future. If we (and any of the others funded) are successful, then we can get a step closer to having a more efficient grid. Click here for the list of awardees.

Till now, my blog has concentrated on vehicle batteries. I think its time I expanded into grid electricity. This is another big problem and something that needs attention.

In the meantime, for all your solar enthusiasts that complain about your batteries. Hold on... hold on. Give us a few years and we hope to have something for you.

Venkat

12 comments:

  1. Flow batteries and PbA batteries have lousy coulombic efficiency. Why not focus on NiMH (OK) and LiFePO4 which has >>95% round trip efficiency? Flow batteries are poorly suited to distributed applications and the challenges with central utility scale installations mean that they'll take forever to put in place. Plus, for Solar, it easily makes the most sense to perform generation to storage in the DC domain rather than moving energy across an AC grid and incurring 4 different conversion losses plust transmission loss...

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  2. Did you see this?
    http://challenge.ecomagination.com/

    via http://www.greencarcongress.com/2010/07/ge-20100714-1.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+greencarcongress%2FTrBK+(Green+Car+Congress)&utm_content=Google+Reader

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  3. Fantastic, it'll be great getting your insight on both markets. Thank you, and good luck!

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  4. Venkat SrinivasanJuly 15, 2010 at 4:38 AM

    Anonymous:
    The problem for NiMH and Li-ion is the cost. With most batteries costing more than $500/kWh, the feeling is that its hard to make much of an inroad. I think Na-S is the system to beat, not NiMH!

    One of the requirement of the ARPA-E proposal was >80% energy efficiency. Couloumbic efficiency is not the issue; its the energy that matters.

    Venkat

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  5. I think solar might not be suitable for national grid at the moment since you loses some during transport, and solar technology still needs to be more efficient from what I understand. It's probably more viable locally.

    Actually, to talk about the 2 technologies, solar and batteries, can someone talk about the numbers side by side? It's hard for anyone not working in the field to imagine in terms of energy can generated/stored.

    Solar has on-off times (day-night), so question is how much energy can it generate on AM1.5 per hour per square meter for say, 8 hours? And how much battery materials are needed to store that same amount using current commercial oxide or phosphate batteries?

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  6. What is your opinion of bipolar batteries in general? And, more specifically, the batteries from Altraverda, Axion, and Nilar?

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  7. I'm discouraged at this discussion of batteries. There is a world of applications going begging because the world isn't perfect. During the past 30 years, I've run TV's, radios, batt powered razors, lights, chain saws,welders,computers, mixers, ice makers, annnd battery chargers.
    This solar system is stored on 6 volt, 12 volt, used, discarded, new, series, parallel, C,D,AA, and AAA storage devices where and when I found them. Any is better than none.

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  8. At the heart of any modern residential solar power system are the PV solar panels.

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  9. Learning to make solar energy and specifically, home solar panels is not necessarily an easy task and a lot of people might not really

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  10. Use of renewable energy has depicted in form of solar devices like solar panels, solar water heaters, solar cookers, solar calculators etc. These small devices using which solar power be harnessed. Also set up solar electricity at home instead of electricity from government. For this just need roof to install solar panel.


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  11. Anon, why do you think Vanadium Flow Redox batteries are poor choices for distributed generation? Sure they have poor energy density, but they are very easy to scale to fairly huge capacities.

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  12. Solar panel uses photons, or light energy from the sun, to generate electricity through the photovoltaic effect. These not only help the environment but solar panels can provide huge savings on our electric bills.

    ReplyDelete