�鶹ӰԺ

To limit global warming to above pre-industrial levels, a threshold needed to avoid the irreversible effects of climate change, the world needs to slash greenhouse gas emissions to nearly zero by 2050. To reach this goal, technological innovations that can help reduce emissions from the source or absorb emitted warming gasses are crucial, scientists say. 

Here's a look at four innovations CU �鶹ӰԺ researchers are working on today.

Image: Lucy Pao at the NREL Flatirons Campus in Colorado next to hurricane-resistant wind turbines (Credit: Kelsey Simpkins/CU �鶹ӰԺ) 

1. Offshore wind turbines that might survive hurricanes 

Lucy Pao, a professor in the Department of Electrical, Computer and Energy Engineering, and her team are designing lighter-weight wind turbines with softer blades that are potentially more resistant to hurricanes. 

Setting up wind turbines off the United States’ thousands of miles of coastline could provide up to a quarter of the country’s electricity demand in 2050–a potentially crucial piece of the U.S. government’s pledge to produce 100% clean energy by 2035. But much of that potential remains untapped. Currently, there are only seven offshore turbines in the U.S., whereas more than 2,500 turbines sit off the coast of the United Kingdom alone.  

Hurricanes remain one of the main challenges to building offshore wind farms in the U.S., especially along the East Coast. These strong storms, which have become more frequent and intense due to climate change, can easily damage the turbines. 
 
The turbine design by Pao and a multi-disciplinary team of collaborators is inspired by palm trees, which can survive hurricanes because of their flexibility. 

“The goal is to have these blades not fight against the wind but rather go with the flow, so that there is less stress to the blades when hurricanes hit,” Pao said. 

These blades also require fewer materials to build, decreasing the price of turbines and, eventually, the cost of wind power.

Learn more about Pao’s wind turbine technology

Image: Smoke rising from chimneys of a paper mill in Sweden. (Credit: Daniel Moqvist/Unsplash)

2. Pulling CO2 from the air

Some carbon emissions will inevitably still wind up in the atmosphere. Oana Luca, an assistant professor in the Department of Chemistry in the College of Arts and Sciences, is designing a new tool to capture CO2 from the air and use it to produce fuels and cement.

Some common methods of carbon capture use chemical solutions to absorb CO2 gas. During the process, CO2 binds to molecules in the solution. Those bonds are so tight, however, that chemists and engineers need to heat the solution to really high temperatures to release the trapped CO2 and convert it into useful materials. The approach is energy-intensive.  

To address the problem, Luca and her team have designed molecules that they can activate with electricity to attract CO2. Scientists can then release the CO2 by simply giving the molecules another zap. 

“I think about our work as enabling a battery-like device,” Luca said. “In the charge cycle, the device loads up with CO2, and in the discharge step, it releases CO2.”

Luca said that the team could also power this process using a renewable power source like solar, making the process even more sustainable.

She envisions that in the future, scientists could place these devices on top of buildings in cities where they would absorb CO2 emissions from sources like cars and trucks.

Read more about Luca’s carbon capturing research

Image: Alexis Templeton visits a "hyper-alkaline" spring in Oman where hydrogen gas bubbles up to the surface. (Credit: Alexis Templeton)

3. Coaxing green energy from rocks

The next green energy revolution could begin below our feet.

That’s the idea behind a new research project led by Alexis Templeton, professor in the Department of Geological Sciences. She explained that deep below the Earth’s surface, water mixes with iron-rich minerals to produce large deposits of hydrogen gas—a possible clean energy source that doesn’t produce greenhouse gases when burned.
 
Over the next three years, Templeton and her colleagues will explore whether they can give these reactions a kick. The team plans to drill boreholes and inject water deep underground to try to coax rocks to make even more hydrogen than usual.
 
The team will carefully monitor its results to make sure these reactions don’t lead to any unintended consequences. The project is supported by a grant from the Grantham Foundation for the Protection of the Environment.
 
“We’re asking: Is geologic hydrogen really a viable source of energy?” Templeton said. “And if it is, how can we go about continuously producing it?”

Read more about Templeton's hydrogen gas research

Image: A concrete cube made from algae-grown limestone. (Credit: Glenn Asakawa/University of Colorado)

4. Zero-emission buildings made possible by algae  

Wil Srubar, an associate professor in the Department of Civil, Environmental and Architectural Engineering, and his team grow tanks of algae that can produce a key cement ingredient with carbon dioxide.

The cement industry is responsible for 8% of global carbon emissions. Yet cement is also a key ingredient in making concrete, the most used material in the world after water and the building blocks of houses, factories, skyscrapers, and more. To make cement, producers need to burn limestone at a very high temperature, which releases a large amount of CO2. 

Coccolithophore, a type of algae widely found in the oceans, could help. These algae can produce a hard shell made of calcium carbonate, which is essentially limestone, using sunlight, seawater and CO2. 

In Srubar’s lab, researchers feed giant tanks of coccolithophores with CO2 and harvest pieces of calcium carbonate the algae produce. These algae-grown limestone have a negative carbon footprint, because algae absorb CO2 during the production process. Engineers can then add this limestone to cement production to offset a quarter of its carbon emissions. 

“Even if the cement plants are still emitting, we're capturing the carbon somewhere else. It could effectively close the loop,” Srubar said. 

The team is working on finding the most productive species of coccolithophores and will scale up algae limestone production through a spin-off company called Minus Materials.

Learn more about Srubar’s living building research

Image: A laser emitter sits at the top of a tower at a natural gas facility in Colorado. (Credit: Casey Cass/CU �鶹ӰԺ)

5. Stopping methane leaks in their tracks

Engineers at CU �鶹ӰԺ and the Colorado-based company LongPath Technologies are employing specialized lasers originally developed for research in quantum physics to do something surprising: They’re sniffing out natural gas, or methane, leaking from pipes at oil and gas facilities around the American West. 
 
Methane is a powerful greenhouse gas, capable of trapping nearly 80 times more heat in the atmosphere than carbon dioxide.
 
To plug methane leaks, Greg Rieker, associate professor in the Paul M. Rady Department of Mechanical Engineering, and his colleagues have turned to a technology called dual frequency comb laser spectrometers. 

These lasers are so accurate that they can detect whiffs of methane in the air at concentrations of just a few parts per billion. In 2017, Rieker co-founded LongPath, which has deployed the tools at numerous facilities—where they can scan over several miles of terrain 24/7, then alert operators if they spot a leak. 
 
“This is a technology that was developed for something completely different—for creating better atomic clocks and other tools for quantum research,” he said. “Now, we’re making an impact on climate change.” 

Learn more about Rieker's research