It’s no secret that energy storage is on the rise. This week, though, we saw several stories on innovative thermal storage solutions, everything from hot rocks to cool ice. Plus, member updates from SunPower (solar + storage!), Bloom Energy (whose secret IPO is not-so-secret anymore), and General Electric, which, at 124 years old, is looking pretty spry when it comes to advanced energy investment.

Our first story of extreme energy storage solutions comes to us from Hawaii. Kapolei, the “second city” of Oahu, where AEE member Stem has installed a 108-kW battery array at the Wet’n’Wild Hawaii theme park. Recently voted Honolulu Magazine’s “Best Family Attraction,” Wet’n’Wild Hawaii is participating in a three-year energy storage pilot program aimed specifically at 30 businesses on the three most densely populated islands: Oahu, Maui, and the Big Island. Together, these islands host more than 80% of Hawaii’s population. The Wet’n’Wild Hawaii installation is the largest project in the program, constituting about 10% of the overall battery capacity that will be installed.

Theme parks like Wet’n’Wild pose a particular challenge for energy managers: They have large peak usage spikes, often in the middle of the day. That makes them uniquely suited for energy storage projects. As Jerry Pupillo, the general manager of Wet’n’Wild said in a statement, the storage system will decrease that spike, which the park has “always battled.”

“This makes dollars and sense for us as a business as our peak use determines the rate we pay,” Pupillo said, adding that the utilities will see a benefit as well.

Meanwhile, AEE member Ice Energy is solving another challenge: residential storage. Set to launch in early 2017, Ice Energy’s Ice Cub, the adorably named offspring of the commercial and industrial scale Ice Bear, will help homeowners cool their homes just like a conventional air conditioner, but also allow them to store up to three hours of cooling power without drawing from the grid. The Ice Cub works a lot like a traditional AC unit, except that it also freezes water in an insulated tank in between cooling cycles. The unit can then switch from conventional air conditioning to using the ice for cooling for at least three hours.

As the advanced energy guru Andre 3000 once said, what’s cooler than being cool? Ice cold!

On the other end of the thermometer, AEE member Siemens is using hot rocks for another innovative form of energy storage. Come December, Siemens is planning to begin testing a system that uses a bed of heated rocks to store excess energy. It works like this. When wind turbines produce excess electricity, the system redirects it to power an industrial-scale heater, which then heats up the rocks—specifically a “packed bed of basalt rocks in an insulated container.” The rocks stay hot, storing the energy until it’s needed, at which point the system, much like your least favorite person in the sauna, throws water on the hot rocks and the resulting steam powers a turbine.

Siemens will be assembling test projects in Germany where, Greentech Media reports, 1,581 GWh of renewable energy was curtailed—most of that wind. The project will be complete in 2018 and the company plans to develop a commercial pilot in 2019.

Siemens is calling the system “Future Energy Solution,” even though it seems a little like something out of the Flintstones. The hot-rock system could be cheap as dirt, as well. Estimates for the Siemens system are as low as $111 per MWh. In comparison, Greentech Media points out that Lazard’s Levelized Cost of Storage analysis puts U.S. gas peaker costs between $165 and $218 per MWh, and pumped hydro at $188 per MWh.

If this keeps up, Robert Frost will be dead wrong: The world will end in neither fire nor ice. But those extremes may indeed suffice for energy storage, a long-sought solution we’ve seen go from pipe dream to advanced energy reality over the past 36 months.

According to Navigant Research, energy storage is on track for its best year ever. After 2015’s “banner year,” 2016 is shaping up to be even better. Policymakers are cottoning on to the idea, and have taken 89 state regulatory and legislative actions recently to capitalize on the benefits of storage.

Before we move on, here’s another example of our favorite advanced energy combo platter: storage + solar. Late last month SunPower announced that it was partnering with the Colton Joint Unified School District in California to install SunPower’s Helix carport systems at 28 schools within the district. The 6.1 MW project is expected to fulfill about 73% of the district’s electricity needs and save more than $35 million in electricity savings over the next 25 years. SunPower is also providing battery storage systems at seven schools to help manage peak demand.

Finally, some quick hits from our members. The Wall Street Journal (subscription required) broke the news of Bloom Energy’s no-longer-secret IPO. The company has fuel cells at more than 300 sites with more than 200 MW of combined energy capacity.

GE announced the purchase of LM Wind Power, one of the world’s largest wind turbine blade manufacturers, for $1.65 billion. According to Greentech Media, LM Wind Power will continue to operate as a standalone subsidiary, but the acquisition will allow GE to integrate the blade design into overall design of GE’s turbines.

Steve Patterson, executive director of AEE state partner Arkansas Advanced Energy Association, says that LM Wind Power’s factory in Little Rock is operating at “near-capacity” and employing about 450 workers. “Our Interstate highways are frequented by the spectacle of these long wind blades trucking along to wind farms in the southwest,” Patterson told Advanced Energy Perspectives in an email, “an ever-present reminder that Arkansas is part of the advanced energy marketplace.”

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