By: David Roberts

Residents of Hammarby Sjöstad, a district on the south side of Stockholm, Sweden, don’t let their waste go to waste. Every building in the district boasts an array of pneumatic tubes, like larger versions of the ones that whooshed checks from cars to bank tellers back in the day. One tube carries combustible waste to a plant where it is burned to make heat and electricity. Another zips food waste and other biomatter away to be composted and made into fertilizer. Yet another takes recyclables to a sorting facility.

After they are done, district authorities hope Hammarby Sjöstad will produce about half its power independently, a task made easier by the fact that residents, thanks to a broad range of efficiency and conservation measures, will consume half the energy of the average Swede (who already consumes only about 75 percent as much as the average American). These intrepid Swedish urbanites are pushing the envelope on a phenomenon catching on in cities across the developed world: “distributed energy.”

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PEACHTREE CITY, GA. — Rinnai Corp. has extended the heat exchanger warranty on RC98HPe, RC98HPi, RC80HPe and RC80HPi condensing tankless water heaters used in recirculating applications from three years to 12 years. The new warranty pertains to recirculating systems that are controlled through an aquastat/thermostat, a timer or an on-demand system. The change means that Rinnai brand condensing tankless products used in qualified recirculating systems will now feature the same 12-year heat exchanger warranty as all residential installations.

“We originally implemented a reduced heat exchanger warranty on condensing units in recirculating systems due to the accelerated wear that results from use with a constantly running circulation loop,” said Joe Holliday, Rinnai’s director of product management. “However, we realize that advances in some recirculating systems have eliminated the need for constant recirculation. This, along with advances in the strength and durability of our heat exchanger design, allows us to offer the same warranty as traditional residential installations.”

The warranty change is effective immediately on all new Rinnai brand condensing tankless unit installations with qualified recirculation systems and is not retroactive.

by Todd Woody

Nipton, CA – The desert micropolis — population 38 — announced Thursday that it had installed a solar array that will provide 85 percent of the town’s electricity. (The population of this outpost on the edge of Mojave National Preserve spikes to 250 or so during tourist season.) The solar system is ground- rather than on rooftop-mounted, and only generates 82 kilowatts. But what is notable is the technology developed by Skyline Solar, a Silicon Valley startup I first wrote about for Grist last year.

The company’s power plants resemble solar thermal parabolic trough installations. They deploy long rows of mirrors which heat tubes of liquid that that suspended over the arrays. The heat turns the liquid into steam, which drives an electricity-generating turbine. Skyline’s system is purely solid state, however.

Each 240-foot-long trough row concentrates the sun on photovoltaic modules attached to the edges of the arrays. That boosts the solar cell’s electricity production as does a tracking mechanism that allows the arrays to follow the sun throughout the day. Such concentrating photovoltaic systems — which Skyline calls “high gain solar” — have been a niche market due to their relatively high costs. But as solar cell prices decline and solar thermal projects get bogged down in environmental disputes, they have become increasingly attractive as they can be built near utility substations and plugged directly into the grid eliminating the need for expensive new transmission systems.

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By: Priyanka Dayal

WESTBORO, MA — To some, it’s an eyesore. To others it’s art.

Walter “Jay” E. Johnson is one of the others.

Mr. Johnson paid more than $12,000 to have a big white cylinder erected in his backyard at 34 Eli Whitney St. He likes the way it looks, but he probably wouldn’t have paid quite so much for simply a lawn ornament.

The 30-foot-high structure is a Windspire, a vertical-axis wind turbine that spins with the wind and produces power. The turbine, which is connected to the grid, is expected to generate enough power to cover one-fourth of Mr. Johnson’s home energy use.

A tall, hollow cylinder sits atop a pole and spins horizontally. It starts generating power with wind speeds as mild as 8 mph but is built to withstand hurricane-caliber winds.

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By: Jonathan Hiskes

California’s largest electricity provider — Pacific Gas & Electric Co. — has gotten some understandable love from the environmental world recently. It’s part of the U.S. Climate Action Partnership, an enviro/business alliance calling for a national climate plan. It told off (and quit) the U.S. Chamber of Commerce for hating all over clean energy and climate science. And it announced a significant 500 MW solar project last spring.

As more and more companies speak up for clean-energy investment (GE, Google, PepsiCo, John Deere, and the big three automakers did so last week), it’s tempting to sort major corporations into “good guy” and “bad guy” camps. Or at least “gets it” and “doesn’t get it” camps.

PG&E, an investor-owned utility, shows why that doesn’t work. The northern California utility has spent a cool $46 million on a ballot initiative that would protect its market share from encroachment by municipally owned utilities. It’ll have the effect of blocking out power providers that want to make stronger renewable investments than PG&E’s admirable but modest steps.

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