By: Naga Srujana Goteti, Rochester Institute of Technology; Eric Hittinger, Rochester Institute of Technology, and Eric Williams, Rochester Institute of Technology

Carbon-free energy: Is the answer blowing in the wind? Perhaps, but the wind doesn’t always blow, nor does the sun always shine. The energy generated by wind and solar power is intermittent, meaning that the generated electricity goes up and down according to the weather.

But the output from the electricity grid must be controllable to match the second-by-second changing demand from consumers. So the intermittency of wind and solar power is an operational challenge for the electricity system.

Energy storage is a widely acknowledged solution to the problem of intermittent renewables. The idea is that storage charges up when the wind is blowing, or the sun is shining, then discharges later when the energy is needed. Storage for the grid can be a chemical battery like those we use in electronic devices, but it can also take the form of pumping water up a hill to a reservoir and generating electricity when letting it flow back down, or storing and discharging compressed air in an underground cavern.

(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.

(more…)

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.

(more…)

A new water-based air-conditioning system cools air to as low as 18 degrees Celsius (about 64 degrees Fahrenheit) without using energy-intensive compressors and environmentally harmful chemical refrigerants.

This technology could potentially replace the century-old air-cooling principle that is still used in modern-day air-conditioners. Suitable for both indoor and outdoor use, the new system is portable and can be customized for all types of weather conditions.

The team’s novel air-conditioning system is cost-effective to produce, and it is also more eco-friendly and sustainable.

(more…)

A team of researchers from the University of Toronto is looking to give wasted materials new value by developing a new catalyst that could help recycle carbon dioxide into plastic.

According to a new study, the researchers have successfully used a new technique to efficiently convert carbon dioxide to ethylene, which can then be processed to make polyethylene, the most common plastic used in making packaging, bottles, and toys.

By using a copper catalyst, the team was able to achieve the desired result of ethylene production. However, controlling the catalyst was one of the technological challenges the team had to overcome.

(more…)

Superior high-voltage performance of Li-ion full cell with Li-rich layered oxide cathode prepared with fluorinated polyimide (FPI) binder, compared to the cell with conventional binder PVdF. (Click to enlarge.)
Image: Seung Wan Song

In order to increase the driving range of electric vehicles, researchers across the globe are working to develop lithium-ion batteries with higher energy storage. Now, scientists at Chungnam National University and Kumoh National Institute of Technology in Korea are taking a step toward that goal with their development of the first high-voltage cathode binder for higher energy Li-ion batteries.

Today’s Li-ion batteries are limited to charge to 4.2V due to the electrochemical instability of the liquid electrolyte and cathode-electrolyte interface, and loosening of conventional binder, polyvinylidenefluoride (PVdF), particularly at elevated temperatures. The fabrication of Li-rich layered oxide cathode with a novel high-voltage binder, as the research team demonstrated, can overcome these limitations.

Charging the batteries with Li-rich layered oxide cathode (xLi₂MnO₃∙(1−x)LiMO2, M = Mn, Ni, Co) to higher than 4.5V produces approximately doubled capacity than those with LiCoO₂ cathode, so that doubled energy density batteries can be achieved.

(more…)

One year ago, the Chinese government’s energy agency made a long-term commitment to the development of renewable energy sources, investing more than $360 billion in an effort to shift away from coal-powered energy. Now, the country is following through on those promises, paving the way to becoming the global leader in the overall development of clean energy technology.

According to a new report from the Institute of Energy Economics and Financial Analysis (IEEFA), China has continued to grow its clean energy sector in 2017, installing over 50 GW of solar-powered generation.

“The clean energy market is growing at a rapid pace and China is setting itself up as a global technology leader while the U.S. government looks the other way,” said Tim Buckley, co-author of the report. “Although China isn’t necessarily intending to fill the climate leadership void left by the U.S. withdrawal from Paris, it will certainly be very comfortable providing technology leadership and financial capacity so as to dominate fast-growing sectors such as solar energy, electric vehicles, and batteries.”

(more…)

Water-based rechargeable batteries could be one step closer to commercial viability, thanks to research from Empa. According to a new report, a team of researchers has successfully doubled the electrochemical stability of water with a special saline solution.

Energy storage is the backbone of many technological innovations. As researchers explore new ways to develop low-cost, safe batteries, the research team from Empa is looking to water to function as a battery electrolyte.

While a water-electrolyte offers many potential benefits such as low cost and high availability, it does have at least one major drawback: low chemical stability. At a voltage of 1.23 volts, a water cell supplies three times less voltage than a typical lithium-ion cell. While water-based batteries may not see an application in such technologies as electric vehicles, the team of researchers at Empa believe they could be utilized for stationary electricity storage applications.

(more…)

Nitrogen-doped carbon nanotubes or modified graphene nanoribbons could be effective, less costly replacements for expensive platinum in fuel cells, according to a new study.

In fuel cells, platinum is used for fast oxygen reduction, the key reaction that transforms chemical energy into electricity.

The findings come from computer simulations scientists created to see how carbon nanomaterials could be improved for fuel-cell cathodes. Their study reveals the atom-level mechanisms by which doped nanomaterials catalyze oxygen reduction reactions (ORR).

Doping with nitrogen

Boris Yakobson, a professor of materials science and nanoengineering and of chemistry at Rice University, and his colleagues are among many researchers looking for a way to speed up ORR for fuel cells, which were discovered in the 19th century but not widely used until the latter part of the 20th. Fuel cells have since powered transportation modes ranging from cars and buses to spacecraft.

(more…)

Many areas of the United States are at risk for nitrate and nitrite contamination of drinking water due to overuse of agricultural fertilizers. Click to enlarge.
Image: USGS

Researchers have found a catalyst that can clean toxic nitrates from drinking water by converting them into air and water.

“Nitrates come mainly from agricultural runoff, which affects farming communities all over the world,” says lead study scientist Michael Wong, a chemical engineer at Rice University.

“Nitrates are both an environmental problem and health problem because they’re toxic. There are ion-exchange filters that can remove them from water, but these need to be flushed every few months to reuse them, and when that happens, the flushed water just returns a concentrated dose of nitrates right back into the water supply,” he explains.

Wong’s lab specializes in developing nanoparticle-based catalysts, submicroscopic bits of metal that speed up chemical reactions. In 2013, his group showed that tiny gold spheres dotted with specks of palladium could break apart nitrites, the more toxic chemical cousins of nitrates.

(more…)