Note that there certainly are many other battery technologies out there. GreenSpec lists products that are currently available and actively marketed in the U.S, so this blog was not intended to cover all them. For grid-tied applications where batteries have to communicate and have performance that are compatible with utility software, golf cart batteries just aren’t going to cut it. At the rate of change in the industry, I too would be very surprised to find lithium ion batteries still being sold in ten years. I expect we will see new and significantly better batteries long before then. We’re going to keep an eye on battery technology, and when consumers can purchase these new technologies we’ll get them into GreenSpec as soon as possible.
Blog Post
Smarter Batteries for a Smart Grid
Grid-tied solar could have a siginificant role in the smart grid--if we can get the lithium ion battery technology right.
People living off the grid using photovoltaics (PV) or other renewable energy to generate power typically depend on maintaining banks of lead-acid batteries and carefully managing the amount of energy they store and use as well as maintaining those batteries for long-term durability.
As the move toward renewable energy gains traction, especially in Europe, an intriguing possibility is beginning to take hold: the use of next-generation batteries in grid-connected systems to store and manage energy capacity.
Time-shifting for peak demand
In current grid-tied PV, any excess energy produced by a home or business PV array is sent back to the grid. This works well because demand for electricity is high during the sunniest part of the day, but it also has limitations since peak demand can occur in the early evening and so does not coincide with PV power generation.
Storing this power generated at mid-day would allow the power to be accessed, or "time shifted," for use later in the evening. A joint pilot project between the U.S. Department of Energy and the Sacramento Municipal Utility District (SMUD) is attempting just such a project, and at the heart of the system are lithium-ion batteries.
Bursting the lead balloon
Lead-acid batteries were invented in the mid-19th century, and flooded deep-cycle versions necessary for power storage continue to be the workhorses of off-grid PV installations. They are inexpensive and have established, reliable performance, but the mining, transport, and use of lead have significant environmental drawbacks. And lead-acid batteries have to be maintained and used in well-ventilated areas because they produce explosive hydrogen gas.
Lithium ion batteries use lithium salts and organic solvents rather than lead and acid to generate the electric charge. We have all used the consumer version of lithium ion batteries in laptop computers, cell phones, and even electric cars like the Tesla. These are the batteries we use when we need a long service life and better performance than alkaline or nickel cadmium can provide.
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See membership options »Deep-cycle versions are sealed and do not generate explosive gases; they're also lighter than lead (what isn't?), almost maintenance free, and companies estimate a 20-year lifespan (though the technology for PV applications is still new). On the down side, they require rare earth minerals, you have to have additional electronics to run them safely, and they are at least three times the cost of lead-acid.
GreenSpec shows the best of both battery worlds
But the advanced design and performance might just be worth it when it comes to grid-tied applications such as those run by SMUD, and the cost of these batteries should drop as demand increases and technology advances. GreenSpec lists a number of the best lead-acid and lithium-ion batteries.
One of the manufacturers we list has been making lithium iron magnesium phosphate batteries since 2002 and offering them for renewable energy systems since 2006. Another company's lithium-ion batteries are RoHS-compliant and can be equipped with energy management controls and designed for specific energy demands and uses, including 12-, 24-, and 48-volt options.
Though lithium ion battery technology is not new, its use in renewable energy storage is. If you are trying to avoid toxic lead, need a sealed system because of ventilation concerns, and are willing to pay the price, these are worth a look. Yes, it will take years for the performance and cost to balance out for most consumers, but if these prove successful in smart-grid applications, utilities might find subsidizing use of these batteries is less expensive than building additional power plants.
Published December 14, 2011 Permalink Citation
(2011, December 14). Smarter Batteries for a Smart Grid. Retrieved from https://www.buildinggreen.com/blog/smarter-batteries-smart-grid
Comments
Lithium-ion batteries already on the way out
Lithium ion batteries are not a good technology. While their use is still growing, they have already been replaced at the leading edge of the battery marketplace by other formulations, including the Lithium phosphate that you mention. I wouldn't be surprised if lithium ion batteries are hard to find within ten years.
There are better, cheaper, and more reliable battery technologies for solar that have been around for a long time, for example nickel-iron. These batteries have some features that disqualify them for many modern uses, such as a fairly low maximum discharge rate, slow recharge rate, and moderate energy density. This is not the battery for your laptop or cell phone, but none of these traits are a problem for solar installations. We know the sun isn't going to be four times as bright next week, we don't want to drain our battery bank in one hour, and we can tolerate a slightly larger battery room, especially since we can decrease the risk of explosion, toxic, and corrosive gases. Nickel iron batteries, among others, are tolerant of a larger (deeper) discharge cycle, and last much longer than either lead-acid or lithium ion. They have the potential to cost much less, both up front and long term. And they are comparatively low-tech, using few or no exotic materials.
It is sad that the market neglects excellent, older battery technologies that are very well-suited to solar and other uses. Although some of these battery types are more available in Europe, they are hard to find here, and cost more than they should, due to small market share. It is ironic that so many solar installations use golfcart batteries. The solar market ought to be thousands of times that of the golfcart market, and if we could get battery production focused on solar needs and strengths, we could have a superior product at a lower price.
Battery Recycling Opportunity
What about using old batteries from laptops and cars for building energy storage? This reduces the nead for mining rare earth metals and also helps address the disposal problem for all those batteries. Once a rechargable battery in an electric or hybrid car loses it's storage capacity, it's potential energy benefits are offset by the energy needed to drag around the dead weight of the battery. These used batteries might still have enough storage capacity to be useful in buildings where dead weight is less of an issue.
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