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The award-winning Phase Change Matters blog tracks the latest news and research on phase change materials and thermal energy storage. E-mail tips and comments to Ben Welter, communications director at Entropy Solutions. Follow the blog on Twitter at @PureTemp. Subscribe to the monthly PCM newsletter. Or join the discussion on LinkedIn.




Clean energy now provides 94.5% of Uruguay's electricity

Ben Welter - Wednesday, December 09, 2015

Ramon Mendez, Uruguay's head of climate changeUruguay's head of climate change policy says renewables now provide 94.5 percent of his country's electricity.

In less than 10 years, Ramón Méndez says, Uruguay has slashed its carbon footprint, adding wind turbines, biomass and solar without government subsidies. And prices are lower as well.

"There are also fewer power cuts," the Guardian reports, "because a diverse energy mix means greater resilience to droughts." Uruguay's hydroelectric system, which continues to generate much of the country's electricity, is dependent on seasonal rainfall. 

But the work is not complete. At the climate conference in Paris, Méndez committed his country to an ambitious pledge: an 88% cut in carbon emissions by 2017 compared with the average for 2009-13.

N.Y. conference on renewable energy set for Sept. 24-25

Ben Welter - Wednesday, July 22, 2015

Registration is open for the REV4NY conference and expo in New York City Sept. 24-25. 

"Reforming the Energy Vision" – REV – is New York State's effort to pave the way for utilities, homeowners and businesses to adopt renewable energy technology more easily.

The conference agenda and list of speakers are still in flux, but Day 1 includes a session on integrating behind-the-meter storage with solar, EV and other technologies. Networking sessions and opportunities to explore partnerships are also on the agenda.

IRENA app helps identify potential locations for wind, solar, hydro and geothermal projects

Ben Welter - Thursday, June 18, 2015

The International Renewable Energy Agency's Web-based Global Atlas, a research tool that helps identify potential locations for wind, solar, hydro and geothermal projects, is now available as an app for mobile devices. The Global Atlas Pocket combines a thousand datasets, including 3Tier solar and wind data and GOCE gravity disturbance maps's Vince Font reports:

"Upon launch, the app pulls up a satellite view world map. Navigating to specific points on the globe can be accomplished manually via pinch and zoom or by typing the name of a location in the search box. Users can also launch their mobile device’s GPS to zero in on their current position.

"Once a geographical location has been selected, users can access a series of maps that produce visual overlays of existing renewable energy resources. Information returned includes such data as annual solar exposure and crop sustainability indexes based on average yearly rainfall. Personalized search and sharing capabilities are also included with the app, allowing a user to forward information via email and social media."

Global Atlas Pocket is a free download for iOS, Android, Blackberry 10 and Windows Phone devices. It's a great fit for tablets such as the iPad Air 2, but difficult to use on devices with smaller screens. And it consistently crashed on my Nexus 5 smartphone.

Department of Energy awards $3 million for power plant cooling research

Ben Welter - Thursday, June 18, 2015

The Electric Power Research Institute has won a $3 million award from the U.S. Department of Energy to develop a new dry-cooling technology for thermoelectric power plants. 

The new technology, which uses advanced phase change materials to improve heat transfer, is designed to significantly reduce fan power consumption and steam condensation temperatures. Existing dry-cooling systems use air instead of water to cool the steam exiting a turbine and can cut water consumption by more than 90 percent.

The nonprofit organization, funded by the electric utility industry, is teaming up with Drexel University, the University of Memphis, Evapco, WorleyParsons and Maulbetsch Consulting on the project. Their goal is to develop and manufacture a cost-effective, 50 kW indirect dry-cooling system with the potential for integration into existing power plants. 

"Successful scale-up and demonstration of this technology will help determine if it could be a competitive water conserving option for the next generation in power plant cooling,” said Sean Bushart, director of EPRI's generation environmental sciences department.$3-Million-Award-for-Power-Plant-Cooling-Research.aspx

Super smart grid could handle massive expansion of renewables, professor says

Ben Welter - Thursday, June 18, 2015

Prof. Sean Meyn, University of FloridaThe sun shines until clouds move in or night falls. The wind blows until it doesn't. How can utilities working to harness these sources of renewable energy account for their variability? 

The obvious answer is batteries. In a piece posted on, Sean Meyn, a professor of electrical and computer engineering at University of Florida, offers another approach: 

"California plans to spend billions of dollars for batteries to even out the flow of power from solar and wind, much the way shock absorbers smooth out bumps on the road. But do they need to? Not at all!

"In my research, I’ve found that we can accommodate a grid powered 50% by renewable energy without the use of batteries.

"Systems flexible enough to accommodate the ups and downs of solar and wind production can be made by adjusting the power at millions of homes and businesses on a minute-by-minute or even second-by-second basis. This approach requires no new hardware, some control software and a bit of consumer engagement."

Cal Poly's Solar Decathlon entry uses biobased PCM to reduce heating, cooling costs

Ben Welter - Wednesday, June 10, 2015

California Polytechnic's entry in Solar Decathlon 2015 features an open design that takes advantage of the mild climate on the Pacific Coast. Team member Lisa-Marie Mueller describes INhouse as a "coastal home that is true to that climate and the very unique indoor-outdoor living that we have here year-round."

The house, now under construction in San Luis Obispo, uses a variety of energy- and space-saving techniques:

• A 15-foot glass wall separating the living room and deck can be folded back to create an indoor-outdoor living space.

• Two-sided photovoltaic panels serve as an awning above the deck, providing shade and capturing 30 percent more energy than a single layer of PV.

• Biobased phase change material is used in the home's ductwork to reduce heating and cooling costs.

The Solar Decathlon, sponsored by the U.S. Department of Energy, will take place Oct. 8-18 in Irvine, Calif. Entries will be judged on energy efficiency, design, affordability and consumer appeal.

Researchers outline ambitious plan to run U.S. economy entirely on renewable energy

Ben Welter - Wednesday, June 10, 2015

Would it be possible to run the U.S. economy entirely on renewable energy by 2050? A team of researchers led by Dr. Mark Z. Jacobson of Stanford says yes, and lays out an ambitious and detailed state-by-state plan.'s David Roberts explains:

"The core of the plan is to electrify everything, including sectors that currently run partially or entirely on liquid fossil fuels. That means shifting transportation, heating/cooling, and industry to run on electric power.

"Electrifying everything produces an enormous drop in projected demand, since the energy-to-work conversion of electric motors is much more efficient than combustion motors, which lose a ton of energy to heat. So the amount of energy necessary to meet projected demand drops by a third just from the conversion."

The study, published in Energy & Environmental Science, also sees a role for thermal energy storage, including ice, water and phase change materials, and time-of-use electricity rates that encourage off-peak energy consumption.

Economist says energy efficiency is overlooked factor in measuring productivity

Ben Welter - Tuesday, June 09, 2015

Greentech Media's latest "Energy Gang" podcast includes a segment with Skip Laitner, an economist who says we've been measuring energy productivity all wrong. As measured by all energy available for use, he said, the U.S. economy is running at only 15 percent efficiency. 

Economist Skip Laitner"Whether it's light, whether it's thermal energy, an industrial process, whether it's powering up the Internet or maintaining a cold beer in the refrigerator, what is actually going on as work, to provide the cooling, to provide the heat and provide the light?" said Laitner, right. "When we [measure energy productivity] that way we find that we're wasting more than 80 percent of that energy, and that's nothing but a set of costs that really clamp down on the economy."

In another segment, starting at 25:30, the group talks about the Energy Storage Association's expo in Dallas last month. Among the takeaways: Ice-based storage and phase change material are gaining traction in the discussion of energy storage.

"Storage is everything from batteries all the way through ice storage and thermal storage units, all the way through to some of these phase change materials and other things," said energy futurist Jigar Shah. "I was pitched a couple times by folks who had much different definitions of storage, which I thought was fascinating."

Solar Decathlon entry uses rainwater to shift cooling to off-peak hours

Ben Welter - Friday, June 05, 2015


Builder Online takes an in-depth look at NexusHaus, one of 20 entries in the U.S. Department of Energy's Solar Decathlon 2015. Net zero energy use and water conservation are integral to the house, a co-production of a team of students from the University of Texas, Austin, and Technische Universitat Munchen, Germany. One goal is to reduce peak energy consumption by 80 percent through thermal energy storage. In summer, a rainwater-collecting tank will serve as a thermal storage unit for a system that will shift cooling to off-peak hours. 

"The home will capture enough rainwater to supply all of its potable water needs, although it will be connected to the municipal water supply for backup during long dry spells," Builder Online reports. "Rainwater will hit the 2,000-square-foot canopy between the home's two modules and flow down a system of gutters into under-deck bladder tanks that can hold up to 5,000 gallons. Before being used in the house for drinking, bathing, and clothes and dish washing, the rainwater will be run through a two-state filtration system: a carbon filter for particulates and a UV light filter to treat it to the National Sanitation Foundation's Standard 61 for potable water."

The Solar Decathlon will take place Oct. 8-18 in Irvine, Calif. Entries will be judged on energy efficiency, design, affordability and consumer appeal.

Advanced energy storage market expected to reach $6.93 billion by 2022

Ben Welter - Friday, May 29, 2015

The global market for advanced energy storage systems is expected to reach $6.93 billion by 2022, according to Grand View Research.

"Rising electricity consumption on a daily basis coupled with increasing energy supply-demand gap has resulted in high need for storage capacity additions," according to the report. Thermal energy storage technology, which now accounts for more than 40 percent of capacity, will continue to dominate the market, "owing to high effectiveness in energy capturing and storing temporarily for use after a stipulated time period."