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Solar Power At Night | Earth Wise

March 16, 2023 By EarthWise Leave a Comment

The use of solar power has grown tremendously in recent years as it has declined in price and become far more competitive with other forms of electricity generation. Its fundamental drawback, of course, is that it only works when the sun is shining. Solar panels don’t produce any power at night. That is, until now, apparently.

A team of engineers at Stanford University have developed a new kind of solar cell that is capable of generating at least some electricity at night. Published in the journal Applied Physics Letters, the research describes a device that can be a continuous renewable power source for both day and nighttime.

The device incorporates a thermoelectric generator that produces electricity from the small difference in temperature between the ambient air and the solar cell itself. The amount of power produced is far less than the solar cell generates from sunlight, but the device can provide nighttime standby lighting and power in off-grid and mini-grid applications.

Mini-grid applications are independent electricity networks that are used for small populations that may be too isolated to be connected to the main power grid. Nearly 600 million people in Africa currently live without access to electricity, primarily in rural areas. A standalone solar system operating independently of any power grid can meet many electricity needs such as phone charging and lighting, but such systems may not be able to handle large electrical need such as powering machinery and agricultural equipment. Mini-grids are larger installations that can provide power to a small rural community.

With innovations like the new Stanford device, a solar mini-grid may be able to keep running at some level even at night.

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Solar panels that can generate electricity at night have been developed at Stanford

Photo, posted December 15, 2021, courtesy of Pete via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Solar-Powered Target Store | Earth Wise

April 26, 2022 By EarthWise Leave a Comment

Many companies have made sustainability commitments of various types. Environmental organizations have urged big-box and grocery stores to install solar panels on their rooftops and parking lots thereby reducing their energy usage and expanding the country’s supply of renewable energy. These places occupy large areas and therefore are capable of supporting large solar arrays.

According to a report by two environmental advocacy groups, rooftop solar panels on retail stores could generate enough electricity to power the equivalent of nearly 8 million U.S. homes.

Target Stores are one of the retailers that has been making an effort to be a greener company. Target has installed solar panels on about 25% of its approximately 1,900 stores. The Target store in Vista, California, about 40 miles north of San Diego, is the company’s most sustainable store. It already had solar panels on its rooftop, powering a portion of the store.

But now it has installed massive carports topped with solar panels high above its parking lot. With these panels, this Target can now produce enough renewable energy to power the entire store, from its refrigeration to its heating and air conditioning. Adding in some of the other energy-saving features of the store, Target expects to produce 10% more energy than the store needs, which it will return to the local power grid. This is Target’s first net-zero energy store.

Target is not the only big retailer going solar. Home Depot, Lowe’s, and Walmart all have been installing solar panels on some of their rooftops. Even some restaurants are trying to reach sustainability goals with solar panels. This is a trend that hopefully will continue to grow.

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Target looks to massive solar panels in a California parking lot as a green model to power its stores

Photo, posted June 30, 2014, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s The Best Way To Reduce Emissions? | Earth Wise

April 1, 2021 By EarthWise Leave a Comment

A carbon tax is a fee imposed on the burning of carbon-based fuels, like coal, oil, and gas. It’s one way to make the users of carbon fuels pay for the climate damage caused by releasing carbon dioxide into the atmosphere.

According to a new study by researchers at Ohio State University, putting a price on producing carbon is the cheapest and most efficient policy change that legislators can make in order to reduce climate change-causing emissions.

The case study, which was recently published in the journal Current Sustainable/Renewable Energy Reports, looked at the impact that a variety of policy changes would have on reducing carbon dioxide emissions from electricity generation in Texas. The researchers found that assigning a price to carbon, based on the cost of climate change, was most effective.

The study did not look at how policy changes might affect the reliability of the Texas power system, an important consideration after the failure of the state’s power grid following winter storms in February.

But the study did examine other policies and found that they were either more expensive or not as effective, including mandates that a certain amount of energy in a portfolio come from renewable sources. Subsidizing renewable energy sources was also found to be less effective.

According to researchers, market-based solutions have previously proven effective combating environmental issues. For example, a cap-and-trade approach was used to reduce levels of sulfur dioxide, one of the chemicals that causes acid rain.

For the sake of the climate, we should probably tax carbon.

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Want to cut emissions that cause climate change? Tax carbon

What’s a carbon tax?

Photo, posted June 5, 2011, courtesy of John Englart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Solar Fuel Farms

September 20, 2019 By EarthWise Leave a Comment

Limiting global warming will require a massive reduction in CO2 emissions from fossil fuel burning. Renewable energy sources are playing a growing role in the power grid and electric cars are becoming increasingly popular. Despite all this, carbon-based liquid fuels will continue to dominate our energy use for the foreseeable future.

Researchers in Norway and Switzerland have described a potential scheme that would help remove CO2 from the atmosphere and produce a valuable liquid fuel.

The idea is to create floating islands containing large numbers of solar panels that convert carbon dioxide in seawater into methanol, which can fuel airplanes and trucks.

A combination of largely existing technologies would be the basis of these floating islands, which would be similar to present-day floating fish farms. The researchers envision clusters each composed of 70 circular solar panels that in total cover an area of roughly half a square mile. The solar panels would produce electricity, which would split water molecules and isolate hydrogen. The hydrogen would then react with carbon dioxide pulled from seawater to produce usable methanol.

The technology already exists to build the floating methanol islands on a large scale in areas of the ocean free from large waves and extreme weather. Suitable locations are off the coasts of South America, North Australia, the Arabian Gulf, and Southeast Asia.

A single floating solar farm could produce more than 15,000 tons of methanol a year – enough to fuel a Boeing 737 airliner for more than 300 round-trip flights across the country. Floating energy islands would not be a magic bullet for limiting the effects of climate change, but they could well be an important part of an overall strategy.

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