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Ararat Rock Solar farm in Mount Airy, North Carolina. NARENCO

Solar Battle Continues as Duke-Backed Energy Bill Passes North Carolina House

By Molly Taft, Laura A. Shepard and Monika Sharma

Alongside Highway 401 in northern North Carolina is a 21st-century twist on a classic rural scene. A few miles outside of Roxboro, sheep graze among 5,000 panels at the Person County Solar Park, keeping the grass tidy on the rural installation.

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Ready to Purchase Solar Power Right From Your Neighbor's Roof?

By Jeremy Deaton

In Brooklyn, you can buy honey collected from an urban bee hive. You can buy lettuce grown atop an old bowling alley.

And now, you can purchase free range, gluten free, fresh, organic solar power right off your neighbor's roof.

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Indiana Governor Deals Death Blow to State's Solar Industry

By Jeremy Deaton and Laura A. Shepard

In Indiana, solar employs nearly three times as many people as natural gas, according to the Department of Energy. You might think, given the numbers, that legislators would want to protect the state's nascent solar industry.

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The Autopsy Is in: Natural Gas Killed Coal

By Courtney St. John

In case anyone doubts the death of coal, experts just issued the autopsy.

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The Smoky Hills Wind Farm in Kansas. Photo credit: Drenaline

Will Wind in Kansas Leave Coal in the Dust?

By Molly Taft

When President Trump signed his executive order targeting Obama-era climate policies in March, he made sure to get the optics right. "You're going back to work," he promised the coal miners surrounding him. "We will produce American coal to power American industry."

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Solar panels in Shanghai. Photo credit: Shutterstock

5 Ways China Is Becoming the Global Leader on Climate Change

By Bridgette Burkholder

Last week, the U.S. Environmental Protection Agency (EPA) chief Scott Pruitt called the Paris agreement a "bad deal." He claimed China has made no significant efforts to curb carbon pollution, while the U.S. has sacrificed jobs to meet the terms of the pact.

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Renewable Energy

From Steel City to Sun City: Colorado Town Turns to Clean Energy

By Laura A. Shepard

Working-class homeowners in Pueblo, Colorado have struggled to keep up with their sky-high electric bills. Locals said rampant shutoffs have plunged entire city blocks into darkness and sent power-starved families to motels and homeless shelters. Senior citizens have given up television and unscrewed refrigerator lights in an attempt to save money. And local businesses have grappled with electric bills as high as their rents.

Frustrated by bloated power bills and frequent shutoffs, citizens of Pueblo have lobbied the city council to abandon natural gas and switch to more affordable renewable energy.

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New Technology Uses Food Waste to Make Tires

By Marlene Cimons

Some day you may discover tomato peels and eggshells where the rubber meets the road.

The environment—not to mention your tires—will be better for it.

Researchers at Ohio State University have discovered that food waste, specifically tomato peels and eggshells, makes excellent filler for rubber tires, with tests showing they exceed industrial standards for performance. Filler is combined with rubber to make the rubber composite used in tires. Food waste could partially replace carbon black, the petroleum-based filler long used in tire manufacturing, which has become increasingly hard to come by.

This approach to manufacturing more environmentally-friendly materials complements ongoing efforts to develop sources of clean fuel. Using tomato peels and egg shells as tire filler could help reduce the nation's dependence on foreign oil, keep food waste out of landfills and make the production of rubber items—especially tires—more sustainable, according to Katrina Cornish, who holds an endowed chair in biomaterials at Ohio State University.

"If we hit a real shortfall in carbon black, we'll have to use something else," Cornish said. "You could use some nice eggshells. Many companies would like to have a green position and this is a good way to do that."

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Food accounts for around one-fifth of the waste sent to landfills, according to the U.S. Environmental Protection Agency. Finding ways to keep food waste out of landfills not only saves space, but also helps in the fight against climate change. Bacteria turn food and yard trimmings found in landfills into methane, a potent greenhouse gas.

When properly processed, food waste can be used to generate energy, enrich the soil as a fertilizer or serve as a food source for animals. Now, it also could prove valuable in tire manufacturing.

Cornish has long been interested in developing new sources of rubber, as well as ways to enhance rubber products. So, when she came to Ohio State in 2010, she looked to food waste as a potential tire filler.

"I wrote to every food processor in the state and said: 'if you've got waste, we'd like to look at it,'" she said. "We received 35 different types of waste: batter drippings, sauerkraut juice, milk dust powder, among them—and eggshells and tomato peels. I'd always wanted to look at tomato peels because I spent a lot of time in California and would see all those produce trucks loaded with tomatoes and knew they had to have thick, tough skins so the ones on top didn't squash the ones on the bottom."

Initially, Cornish had doubts as to how well eggshells would work. Eggshells are composed largely of calcium carbonate, which is used as an extender, rather than a reinforcer. The latter is more useful as tire filler. But Cornish discovered to her delight that her doubts were misplaced. Eggshells have a porous architecture that provides a larger surface area for contact with the rubber and proved to be reinforcing.

"We were very excited," she said. "It added considerably more value than expected." They also found that tomato peels are very stable at high temperatures and can generate material that performs well.

"Fillers generally make rubber stronger, but they also make it less flexible," said Cindy Barrera, a postdoctoral researcher in Cornish's lab. "We found that replacing carbon black with ground eggshells and tomato peels caused synergistic effects, for instance, enabling strong rubber to retain flexibility."

It also turned the rubber reddish brown—depending on the amount of eggshell or tomato in it—rather than the black appearance that results from using carbon black. About 30 percent of a typical automobile tire is made of carbon black, the cost of which varies with petroleum prices. American companies most often purchase carbon black from foreign sources, according to Cornish.

"The tire industry is growing very quickly and we don't just need more natural rubber. We need more filler too," Cornish said. "The number of tires being produced worldwide is going up all the time, so countries are using all the carbon black they can make. There's no longer a surplus…"

Particles of tomato peels and eggshells used by to make rubber composite. Katrina Cornish

Cornish and her colleagues' research on potential tire fillers has appeared in the Journal of Polymers and the Environment and elsewhere.

The U.S. produces around 80 billion eggs annually, according to the United Egg Producers. Cornish said that commercial food factories crack open half of them, then pay to send the remains to a landfill, where the mineral-loaded shells do not break down. "Nothing much happens to them in a landfill, since there are no calcium-eating animals," she said. "They are mostly rock."

The U.S. grows around 15 million tons of the ever-popular tomato, according to the Department of Agriculture. Most of that is canned or in processed products. When food companies make tomato sauce, for example, they peel and discard the skin, which is difficult to digest, she said.

Cornish is concerned about deforestation that results from planting new rubber trees and she has been researching rubber alternatives, including the rubber dandelion. While they are unmistakably dandelions, they are not the same as what many homeowners regard as annoying lawn and garden intruders.

Cornish explained that their leaves are thicker and bluer and the flowers are smaller. Most importantly, its taproot yields a milky fluid with natural rubber particles in it.

The rubber dandelion can be used to make tires. Biobased World

"The rubber dandelion comes from northwest China, Kazakhstan and Uzbekistan, but it can grow in snowy areas of Ohio," she said. "But it is not very sturdy, so we are trying to make it stronger and higher yielding." If successful, "it could grow as an annual crop and it could create many processing jobs," she added.

Meanwhile, Ohio State has licensed Cornish's technology for turning food waste into tire filler to her company, EnergyEne, for further development. Cornish stresses, however, that no one will start collecting "the eggshells from your breakfast," she said. "Kitchen waste is not going to go this way. So keep on with your compost piles. In fact, maybe you can use them to grow rubber dandelions."

Reposted with permission from our media associate Nexus Media.

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A rendering of Babcock Ranch. Photo credit: Babcock Ranch

America's Most Sustainable Town

By Marlene Cimons

It was love at first sight for Richard and Robin Kinley. But it took a sunset to seal the deal.

The Kinleys, both 59 and living in Atlanta, visited southwest Florida in January to look at Babcock Ranch, a planned community that could become the most sustainable town in America.

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