Lead engineers, Xiaobo Yin and Ronggui Yang.
Image credit: Glenn Asakawa/CU-Boulder

According to Forbes, engineers at the University of Colorado Boulder have created a new material that works like an air conditioning system for structures—cooling rooftops with zero energy consumption.

The material, about the same thickness as aluminum foil, is rolled across the surface of a rooftop, reflecting incoming solar energy back into space while simultaneously purging its own heat. Adding to its appeal, the material is adaptable and cost-effective for use in large-scale residential and commercial applications, as it can be manufactured on rolls. (more…)

New energy system prototype from Chalmers University that can store the sun’s energy for up to 18 years. Image by: Chalmers University of Technology

According to Science Alert, scientists have recently figured out a way to store solar power for up to 18 years.

It’s made possible with a specialised fluid, called a solar thermal fuel, that’s catching the attention of numerous investors, according to the research team at the Chalmers University of Technology working on the project. (more…)

By: Joshua M. Pearce, Michigan Technological University

Falling costs for solar power have led to an explosive growth in residential, commercial and utility-scale solar use over the past decade. The levelized cost of solar electricity using imported solar panels – that is, the solar electricity cost measured over the life of the panels – has dropped in cost so much that it is lower than electricity from competing sources like coal in most of America.

However, the Trump administration on Jan. 22 announced a 30 percent tariff on solar panel imports into the U.S. This decision is expected to slow both the deployment of large-scale solar farms in the United States and the rate of American solar job growth (which is 12 times faster than the rest of the economy). The tariff increases the cost of solar panels by about 10 to 15 cents per watt. That could reduce utility-scale solar installations, which have come in under $1 per watt, by about 11 percent.

The tariffs may lead China and other countries to appeal the move with the World Trade Organization. But could innovations in solar power compensate for tariffs on panels?

In my research, I have found that one solar technology – previously largely ignored because of low-cost photovoltaics, or PV, panels – could make a comeback: the humble mirror, or booster reflector, as it is known in the technical literature.

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By: Joshua D. Rhodes, University of Texas at Austin

Editor’s note: On Jan. 22, 2018, the Trump administration announced plans to impose punitive duties on solar panels imported from abroad. This decision came in response to a complaint filed by two solar companies, but much of the industry opposes the action, which trade groups say will increase the cost of solar projects and depress demand. To illustrate what’s at stake, energy scholar Joshua Rhodes provides some context on the U.S. solar industry and its opportunities and challenges.

How big is the U.S. solar industry, and what is its growth trajectory?

The U.S. solar industry generated US$154 billion in economic activity in 2016, including direct sales, wages, salaries, benefits, taxes and fees. Its revenues have grown from $42 million in 2007 to $210 million in 2017.

About 25 percent of total new power plant capacity installed in 2017 came from solar. Total installed U.S. solar capacity is over 50 gigawatts – the equivalent generating capacity of 50 commercial nuclear reactors.

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Engineers working to make solar cells more cost effective ended up finding a method for making sonar-like collision avoidance systems in self-driving cars.

The twin discoveries started, the researchers say, when they began looking for a solution to a well-known problem in the world of solar cells.

Solar cells capture photons from sunlight in order to convert them into electricity. The thicker the layer of silicon in the cell, the more light it can absorb, and the more electricity it can ultimately produce. But the sheer expense of silicon has become a barrier to solar cost-effectiveness.

So the engineers figured out how to create a very thin layer of silicon that could absorb as many photons as a much thicker layer of the costly material. Specifically, rather than laying the silicon flat, they nanotextured the surface of the silicon in a way that created more opportunities for light particles to be absorbed.

Their technique increased photon absorption rates for the nanotextured solar cells compared to traditional thin silicon cells, making more cost-effective use of the material.

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Researchers have developed a new kind of semiconductor alloy capable of capturing the near-infrared light located on the edge of the visible light spectrum.

Easier to manufacture and at least 25 percent less costly than previous formulations, it’s believed to be the world’s most cost-effective material that can capture near-infrared light—and is compatible with the gallium arsenide semiconductors often used in concentrator photovoltaics.

Concentrator photovoltaics gather and focus sunlight onto small, high-efficiency solar cells made of gallium arsenide or germanium semiconductors. They’re on track to achieve efficiency rates of over 50 percent, while conventional flat-panel silicon solar cells top out in the mid-20s.

“Flat-panel silicon is basically maxed out in terms of efficiency,” says Rachel Goldman, a professor of materials science and engineering, as well as physics at the University of Michigan, whose lab developed the alloy. “The cost of silicon isn’t going down and efficiency isn’t going up. Concentrator photovoltaics could power the next generation.”

Varieties of concentrator photovoltaics exist today. They are made of three different semiconductor alloys layered together. Sprayed onto a semiconductor wafer in a process called molecular-beam epitaxy—a bit like spray painting with individual elements—each layer is only a few microns thick. The layers capture different parts of the solar spectrum; light that gets through one layer is captured by the next.

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Recent trends in solar technology have led to transforming mundane surface to energy harvesting powerhouses. First, Elon Musk proposed his new solar roof. Now, rural France is taking a page from that book with the recent paving of paths with solar panels.

The solar road is part of the Wattway projects, which aims to pave nearly 3,000 roadways with solar panel tiles.

According to reports, the 1 kilometer road will produce 767 kWh hours of electricity every day. Because the panels are flat, the amount of energy produced is limited. However, the energy generated is enough to power an average family home for one year.

“We are still experimenting with Wattway,” says Jean-Charles Broizat, CEO of Wattway, in a statement. “Building an application site of this magnitude is a real opportunity for our innovation. This application site has enabled us to improve our process of installing photovoltaic panels as well as their manufacture, in order to optimize our solution as best as possible.”

How solar panels can save everyone money

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When talking about the benefits of solar energy, one challenge always makes its way into the conversation: cost. While many see solar as a costly alternative to conventional means of generating electricity, a study out of Boston University is showing how solar not only saves those who own panels money, but even those who generate electricity conventionally.

According to the study, the 40,000 solar panels deployed in Massachusetts have effectively cut electricity prices for the nearly three million power users in the state (even those households and businesses not utilizing the panels).

“Until now, people have focused on how much was being saved by those who owned PV,” says Robert Kaufmann, professor of Earth and environment at Boston University. “What this analysis quantified was that it actually generates savings for everybody.”

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Image: Antalexion

With the increasing popularity of solar power and ongoing dialogue about the effects of climate changes comes inevitable discussions about the viability of renewable energy. While efficiency levels have grown tremendously over the years, many still worry about the feasibility of solar panels during inclement weather when the sun is not shining its brightest.

To address that issue, more attention has been focused on energy storage. However, a group of Chinese scientists are turning to the solar panels themselves to answer some of these questions.

In a recently published paper, scientist detailed a new way for solar panels to produce electricity from rain water. The way it works is pretty simple: researchers apply a thin layer of graphene to the bottom of the solar panel; when it rains, you simply flip the panel and allow the positively charged ions from the rain drops to interact with the graphene and produce electricity.

“Although great achievements have been made since the discovery of various solar cells, there is still a remaining problem that the currently known solar cells can only be excited by sunlight on sunny days,” wrote the researchers in the paper.

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MIT researcher have developed the first steps to creating the thinnest, lightest solar cell ever made.

Through a unique fabrication method, the researchers are moving toward the development of a solar cell so thin it could blow away. Instead of a solar cell’s typical makeup, the MIT researchers have opted for a unique fabrication of creating each layer at the same time.

This from Popular Science:

Solar cells are typically made up of layers of photovoltaic materials and a substrate, such as glass or plastic. Instead of the usual method of fabricating each layer separately, and then depositing the layers onto the substrate, the MIT researchers made all three parts of their solar cell (the cell, the supportive substrate, and the protective coating) at the same time, a method that cuts down on performance-harming contaminants. In the demonstration, the substrate and coating are made from parylene, which is a flexible polymer, and the component that absorbs light was made from dibutyl phthalate (DBP). The researchers note that the solar cell could be made from a number of material combinations, including perovskite, and it could be added to a variety of surfaces such as fabric or paper.

Read the full article.

To put the thinness of the solar cell in perspective, it is approximately 1/50th the thickness of a strand of hair. The light weight means that its power-to-weight ratio is particularly high, with an efficiency output of about 6 watts per gram (400 times higher than silicon-based solar cells).

The final trial for the researcher will be to translate the lab work to the real world, making it scalable and practical for commercial use.