Solar Power World spoke with Carl Mansfield, VP of system solutions for NantEnergy, about the company’s attempt to take zinc-air batteries mainstream. NantEnergy, which acquired Sharp’s energy storage division and its lithium know-how last year, is improving a zinc-air/lithium hybrid storage system for the C&I and microgrid markets. Mansfield said that finding the perfect cost-effective, long-duration chemistry setup will be key to energy storage deployments taking off even more.
SPW: What energy storage offerings does NantEnergy have available?
Mansfield: Our primary in-house product is the zinc-air rechargeable battery. That solution is already deployed around the world in about 3,000 operating systems. Most are in remote microgrid deployments, electrifying rural areas. We have a lot of systems deployed in Indonesia. In Central America, we have a lot of the hybrid systems, which combine zinc-air with small amounts of lithium, that are deployed at telecom applications. Zinc-air’s sweet spot really is long-duration resilience or as an off-grid system. It’s very competitive in price against lead-acid and also against diesel generation.
We also are working on some new chemistries that are better suited to shorter duration. Last fall, my group, which was originally part of Sharp Electronics Corporation, was acquired by NantEnergy. We brought Sharp’s behind-the-meter commercial and industrial energy storage solution (SmartStorage), and we’re continuing to promote and sell our C&I behind-the-meter product, which is designed for economic ROI to the system owner based off utility savings and other revenue opportunities. So we have a variety of battery chemistries that we’re supplying. We’re targeting C&I and microgrids.
SPW: What is the configuration for NantEnergy’s hybrid zinc-air/lithium batteries?
Mansfield: You can combine the battery cells at a rack-level. We’re shipping a single rack that has lithium and zinc-air inside it, and it behaves like a single 48-volt battery rack. Or, if the system is large enough, you can also have a dozen zinc-air racks and a half-dozen lithium racks integrated through inverters at the AC level. There are a number of different architectural options. Most of what we’ve shipped historically in Central America is through the telecom market and is integrated at the rack level.
SPW: What is contributing to increased interest in energy storage in the United States?
Mansfield: There are three major factors. The first is the fundamental cost of the battery technology itself has been coming down so dramatically in the last three to five years that the cost effectiveness is becoming much stronger. The second is that the capital providers who finance projects are starting to become a little bit more familiar with the technology, more comfortable with it. The third is end-customers are also starting to become more comfortable with the applications and the value that these systems provide. If you look in the C&I segment, historically most commercial customers had a sense of how solar delivered but didn’t really know what a battery would do for them in terms of saving energy bills. I think that’s starting to become a little bit more understood by more and more commercial businesses.
SPW: What needs to change to promote further energy storage deployments?
Mansfield: If the technology improves, that always helps. We’re gradually getting to the stage where more longer duration battery storage is required both for energy savings as well as backup. What’s key right now to helping the market grow is getting a very cost-effective, longer duration storage. Lithium battery storage is still relatively expensive. Going from a two-hour to a six-hour installation substantially increases the cost. We believe that our longer duration (zinc) technology coupled with some of the shorter durations like lithium and others can be quite effective at getting over that hurdle. Although the market is starting to become more familiar with the technology, there’s still a ways to go in terms of marketing and educating the market to these type of products.
SPW: Will residential or large-scale storage lead the charge?
Mansfield: Residential has always been kind of slow and a bit of a niche. I think the problem with residential is that until the residential systems can pay for themselves in savings they generate, it’s always going to be a niche driven by consumers who are concerned about outage protection. The U.S. grid is so stable in general that even though people are concerned about that, it’s something they can live with. A couple of short outages a year are not really a major burden. Residential has potential, but I think it’s going to continue to be slow until the prices improve.
Commercial and industrial — right now we can get, in some cases, less than a two-year payback period. The economics are really strong. I think we’re going to see more regions of the United States beyond California and the Northeast open up with very favorable economics. We’re going to see a trend toward systems of longer duration that can provide economic benefit as well as a backup function to allow business-critical systems to continue to operate during an outage.
I see large-scale deployment of distributed storage becoming longer and longer duration on the utility side. Many of these large multi-megawatt-hour installations are going to continue to be deployed. After a while, it’s going to become problematic with citing from a transmission interconnection point of view. Our vision for the U.S. is fairly widespread deployment of storage across buildings on the distribution system with many applications ranging from energy saving to critical backup to powered emergency response centers to telecom backup.
SPW: Will lithium still be the dominant chemistry?
Mansfield: I think lithium will be one of the dominant chemistries. Lithium has two major challenges. One is the fire hazard. There are still concerns in certain regions with the potential of runaway fires with this technology even when it’s deployed very safely and most likely won’t have issues. If you look at New York in particular, lithium is still not able to be deployed in many of the buildings [because of] the fire hazards. The second issue is it needs to be cooled. The cost to maintain the batteries in the most favorable operating temperature can be fairly significant. As energy costs rise, that’s going to be become more of a factor. Our zinc-based battery systems don’t require active cooling, so they don’t have those disadvantages. And then recycling is going to begin to rear its head. Many of the large-scale grid-interconnected lithium batteries are not even close to end-of-life yet, so the start of the recycling hurdles for them is going to come in a few years.
That said, there’s huge investment behind lithium. [Being] a primary battery type used in electric vehicles is helping the innovation and the cost reduction [efforts]. So with all those factors, I think lithium will continue to be a major player, but we’re pretty confident that zinc-based chemistries can break in as a major player as well.