EGEB: Light control for solar breakthrough, widespread coal contamination, and more

Phil Dzikiy | Mar 7 2019 - 9:05 am PT

Today in EGEB, a discovery in controlling light from exotic crystal semiconductors could be a major breakthrough for solar and electronics. Analysis of coal industry data reveals widespread groundwater contamination. And a proposed solar farm would be big for Washington state.

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A new discovery in how to control light from exotic crystal semiconductors could open up an array of possibilities within the solar and electronics industries. The study comes from Materials Today and was led by Rutgers University.

Scientists found a way to control light emitted when crystals called hybrid perovskites are excited by a laser. With this breakthrough, “the intensity of light emitted by a hybrid perovskite crystal can be increased by up to 100 times simply by adjusting voltage applied to an electrode on the crystal surface.” Senior author of the study and physics professor Vitaly Podzorov said,

“To the best of our knowledge, this is the first time that the photoluminescence of a material has been reversibly controlled to such a wide degree with voltage. Previously, to change the intensity of photoluminescence, you had to change the temperature or apply enormous pressure to a crystal, which was cumbersome and costly. We can do it simply within a small electronic device at room temperature.”

Hybrid perovskites consist of interlocking organic and inorganic materials, and the crystals have great solar potential, as we’ve noted before. They’re also more efficient than standard silicon-based solar cells, and are both easier and cheaper to manufacture. Podzorov believes this study “could help lead to their widespread use.”

Coal Contamination

A study from the Environmental Integrity Project examined coal industry data that’s just been released to the public. What it found was widespread groundwater contamination.

An analysis found that 91 percent of U.S. coal-fired power plants with monitoring data are contaminating groundwater with unsafe levels of toxic pollutants. Groundwater near “242 of the 265 power plants with monitoring data contained unsafe levels of one or more of the pollutants in coal ash, including arsenic, a known carcinogen, and lithium, which is associated with neurological damage, among other pollutants.”

The EIP notes that “the rest of the coal plants have not posted groundwater data either because they closed their ash dumps before the Coal Ash Rule took effect in 2015, or because they were eligible for an extension or exemption.”

The Coal Ash Rule created a federal regulation for disposing coal ash. The rule also created groundwater monitoring requirements, and that data is now available for the first time.

Further details from the report, which also includes a list of the most contaminated sites in the country:

91 percent of coal plants have unsafe levels of one or more coal ash constituents in groundwater, even after we set aside contamination that may naturally occurring or coming from other sources.
The groundwater at a majority of coal plants (52 percent) has unsafe levels of arsenic, which is known to cause multiple types of cancer. Arsenic is also a neurotoxin, and, much like lead, can impair the brains of developing children.
The majority of coal plants (60 percent) also have unsafe levels of lithium, a chemical associated with multiple health risks, including neurological damage.
The contamination at a given site typically involves multiple chemicals. The majority of coal plants have unsafe levels of at least four toxic constituents of coal ash.

Billionaire businessman Michael Bloomberg recently announced he’d be expanding his support for the Beyond Coal campaign. The former New York City mayor has set a new goal for the movement to retire “every single coal-fired power plant over the next 11 years.”

Evergreen Solar

Portland-based Avangrid Renewables is looking to build a solar project that would put 500,000 photovoltaic panels onto 1,700 acres of private and public land in Washington’s Klickitat County, the Seattle Times reports.

The proposed 150 MW solar farm could supply an estimated 28,000 homes with electricity. This would appear to make the project the eventual second-largest in Washington state. Its capacity easily bests a 28-megawatt solar farm which came online last year, but ranks behind the in-progress 180 MW Tono Solar project.

Solar power lags behind the likes of wind and hydropower in Washington, but the Times says there’s now a “surge of interest in building solar farms in the Pacific Northwest.”