Reducing CO2 concentrations and air pollution in the atmosphere
f we’re going to limit global temperature increases to 2 degrees above pre-industrial levels, as laid out in the Paris Climate Agreement, it’s going to take a lot more than a transition to carbon-neutral energy sources such as wind and solar. It’s going to require carbon-negative technologies, including energy sources that actually reduce carbon dioxide levels in the atmosphere.
While most climate researchers and activists agree that carbon-negative solutions will be needed to meet the terms of the Paris Agreement goal, so far most of these solutions have been viewed as impractical in the near term, especially for large, coal-reliant countries like China.
Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences and the Harvard-China Project on Energy, Economy and Environment, in collaboration with colleagues from Tsinghua University in Beijing and other institutions in China, Australia and the U.S., have analyzed technical and economic viability for China to move towards carbon-negative electric power generation.
The research is published in the Proceedings of the National Academy of Sciences.
“This paper is making a bold suggestion that not only can China move towards negative carbon power but that it can do so in an economically competitive way,” said Michael McElroy, the Gilbert Butler Professor of Environmental Studies at Harvard and a senior co-author of the paper.
“The system we describe not only offers a carbon-negative alternative to generate electricity in the long run but also brings significant near-term co-benefit to reducing air pollution in China,” said Xi Lu, Associate Professor in the School of Environment at Tsinghua University and first author of the paper. Lu is also a former SEAS graduate student and postdoctoral fellow.
The strategy McElroy, Lu and their colleagues lay out involves the combination of two forms of green energy: coal-bioenergy gasification and carbon capture and storage.
Bioenergy one of the most important tools in the carbon-negative toolbox.
Bioenergy comes from the best CO2 scrubbers on the planet — plants. As most of us learned in grade school, plants use photosynthesis to convert CO2 into organic carbon and oxygen. The carbon stored in plants can be converted back into energy through combustion (a.k.a., fire); fermentation, as in the production of ethanol; or through a process known as gasification, which converts carbon-rich materials into carbon monoxide, hydrogen and carbon dioxide for fuels and industrial chemicals.
The process of converting biomass into energy and then capturing and storing the waste CO2 is one of the most talked-about strategies for negative carbon power. It’s known as BECCS, bioenergy with carbon capture and storage. The problem is, in most applications BECCS is not very efficient and requires massive amounts of land to grow the plants needed to power the planet, which would likely result in global food and water shortages.
But what if there was a way to make the process more practical and efficient?
Lu, McElroy and their international team turned to an unlikely solution for green energy: coal.
“If you try to do this with biofuel alone, it’s not very effective,” McElroy said. “The addition of coal provides an energy source that is really important. If you combine biofuel with coal and gasify the mixture, you can essentially develop a pure source of hydrogen in the process.”
By modeling different ratios of biofuel to coal, the researchers found that as long as at least 35 percent of the mixture is biomass and the waste carbon is captured, the power generated would actually reduce CO2 in the atmosphere. At that ratio, the researchers found that the levelized cost of electricity would be no more than 9.2 cents per kilowatt hour. A carbon price of approximately $52 per ton would make this system cost-competitive with current coal-fired powerplants in China.
A key component to this strategy is the use of crop residue — the remains of plants after fields have been harvested — as biofuel.
Seasonal agricultural fires, when farmers set fire to their fields to clear stubble after a harvest, are a major source of air pollution in China. Collecting that stubble and using it as biofuels would not only reduce CO2 but significantly improve air quality in the country. Gasification also allows easier removal of air pollutants from the waste stream.
The researchers acknowledge that developing a system to collect the biomass and deliver it to powerplants will take time but they argue that the system doesn’t need to be implemented all at once.
“Because we’ve investigated the whole range of coal-to-biomass ratios, we’ve demonstrated how China could move incrementally towards an increasingly carbon-negative energy source,” said Chris P. Nielsen, Executive Director of the Harvard-China Project and co-author of the study. “First, small amounts of biofuel could be used to reduce the net positive carbon emissions. Then, the system could grow toward carbon neutrality and eventually to a carbon-negative system. You don’t have to accomplish everything from the get-go.”
“This study provides critical information for policy makers seeking to implement carbon-negative energy opportunities in China,” said Lu.
Learn more: Carbon-negative power generation for China
The Latest on: Carbon-negative power source
via Google News
The Latest on: Carbon-negative power source
- Student project adds solar power to Warrenton High Schoolon August 26, 2019 at 3:26 pm
WARRENTON — It took on average 873 kilowatt-hours of electricity a day to power Warrenton High School over the past ... energy and other sustainable technologies to make his home carbon-negative.
- The Promise of Direct Air Capture: Making Stuff Out of Thin Airon August 23, 2019 at 7:00 am
Mimicking what already occurs in nature, DAC essentially involves industrial photosynthesis, harnessing the power of the sun to draw carbon ... In success, these conversion products are ...
- FuelCell Energy Celebrates 9 Million MWH of Clean Power Generationon August 5, 2019 at 11:18 am
SureSource™ fuel cells are a clean energy solution for the need for baseload power ... cases carbon negative, by regulatory authorities due to the renewable nature of the biogas fuel source.
- Study shows China can be carbon-negative in an economically competitive wayon April 19, 2019 at 9:35 am
It’s going to require carbon-negative technologies, including energy sources that actually reduce carbon dioxide ... viability for China to move toward carbon-negative electric power generation. The ...
- Carbon-Negative Power Generation for Chinaon April 9, 2019 at 2:06 pm
Nielsen, and Michael B. McElroy. 2019. “Gasification of coal and biomass: a net carbon-negative power source for environmental-friendly electricity generation in China.” Proceedings of the National ...
- Carbon-negative power generation for Chinaon April 8, 2019 at 6:54 pm
"The addition of coal provides an energy source that is really important ... Paulson School of Engineering and Applied Sciences. (2019, April 8). Carbon-negative power generation for China: Reducing ...
- Carbon-negative power generation for Chinaon April 8, 2019 at 12:03 pm
It's going to require carbon-negative technologies, including energy sources that actually reduce carbon dioxide ... viability for China to move towards carbon-negative electric power generation. The ...
- Lancium Announces Strategic Investment from SBI Holdingson July 26, 2018 at 1:00 am
This unique "win-win" solution supports the development of new renewable energy resources, while providing an exceptionally cost effective and carbon negative power source for distributed, ...
- Can we build power plants that actually take carbon dioxide out of the air?on March 11, 2015 at 9:17 am
much further than that by simply adding a few carbon-negative biomass plants to the mix. In the most optimistic case, power plant emissions could fall 145 percent below 1990 levels by 2050: It all ...
- Carbon-negative energy, a reality at last -- and cheap, tooon October 18, 2013 at 9:00 pm
is the origin story of a company that now produces what it says is the world's only carbon-negative power source. Located in one of the grittiest areas of town, where train tracks, garbage, and broken ...
via Bing News