Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Droughts boost emissions as hydropower dries up

21.12.2018

When hydropower runs low in a drought, western states tend to ramp up power generation - and emissions - from fossil fuels. According to a new study from Stanford University, droughts caused about 10 percent of the average annual carbon dioxide emissions from power generation in California, Idaho, Oregon and Washington between 2001 and 2015.

"Water is used in electricity generation, both directly for hydropower and indirectly for cooling in thermoelectric power plants," said climate scientist Noah Diffenbaugh, the Kara J. Foundation professor in Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth) and senior author of the study.


This photo is an aerial view of Folsom Dam and Lake in Sacramento County shows low water levels in January 2014.

Credit: Paul Hames/California Department of Water Resources

"We find that in a number of western states where hydropower plays a key role in the clean energy portfolio, droughts cause an increase in emissions as natural gas or coal-fired power plants are brought online to pick up the slack when water for hydropower comes up short."

The study, published Dec. 21 in Environmental Research Letters, shows emissions of sulfur dioxide and nitrogen oxides - air pollutants that can irritate lungs and contribute to acid rain and smog - also increased in some states as a result of droughts.

Some of the largest increases in sulfur dioxide took place in Colorado, Utah, Washington and Wyoming. The largest increases in nitrogen oxides occurred in California, Colorado, Oregon, Utah, Washington and Wyoming.

Challenges to going carbon-free

In total, the researchers found drought-induced shifts in energy sources led to an additional 100 million tons of carbon dioxide across 11 western states between 2001 and 2015. That's like adding 1.4 million vehicles per year to the region's roadways.

The power sector in California, which has a mandate to go carbon-free by 2045, contributed around 51 million tons to the total. Washington, where the legislature is expected in January 2019 to consider a proposal to eliminate fossil fuels from electricity generation by 2045, contributed nearly 22 million tons.

"For California, Oregon and Washington, which generate a lot of hydropower, the drought-induced increases in carbon dioxide emissions represent substantial fractions of their Clean Power Plan targets," said postdoctoral researcher Julio Herrera-Estrada, lead author of the study.

Enacted in 2015, the Clean Power Plan established nationwide limits on greenhouse gas emissions from power plants. The policy has been rolled back under the Trump administration, but according to Herrera-Estrada, it remains a valuable benchmark for targets that states or the federal government may eventually set for the electricity sector.

Western states in recent years have suffered the kind of intense droughts that scientists expect to become more common in many regions around the world as global warming continues. The new research suggests that failure to prepare for the emissions impact of these droughts could make achieving climate and air quality goals more difficult.

"To have reliable and clean electricity, you have to make sure you have an energy portfolio that's diverse, such that low-emissions electricity sources are able to kick in during a drought when hydropower cannot fully operate," Herrera-Estrada said.

Assessing the West

The western United States offers an ideal testing ground for understanding relationships between droughts and emissions from the power sector. In addition to plentiful data from recent droughts, the researchers could examine how emissions change with different types of backup power plants because states across the region have a wide variety of energy mixes.

Colorado, for example, tends to ramp up coal-fired power plants when hydropower dwindles, while California and Idaho increase generation from natural gas. Oregon, Washington and Wyoming tend to increase both. Wyoming and Montana increase coal generation in part so that they can export the electricity to surrounding states that are also experiencing declines due to drought.

"For decades, people have been looking at the impacts of droughts on food security and agriculture," Herrera-Estrada said. "We're less aware of exactly how droughts impact the energy sector and pollutant emissions in a quantitative and systematic way."

Previous efforts to understand how drought affects electricity have mostly relied on models of power plants, which require researchers to make assumptions about factors such as the plants' efficiencies and decisions about how water resources are allocated. For the current paper, the scientists analyzed statistics reported by the U.S. Energy Information Administration and the U.S. Environmental Protection Agency.

According to Herrera-Estrada, the new study can help validate existing models, which can then be used to gain a more complete picture of the risks associated with droughts and to inform efforts to tamp down drought-induced emissions.

Far beyond the American West, droughts may drive similar emission increases in places that normally rely heavily on hydropower and turn to natural gas, coal or petroleum when waterways run low.

"Other parts of the world depend on hydropower even more than the western U.S.," said Diffenbaugh, who is also Kimmelman Family senior fellow at Stanford's Woods Institute for the Environment. "Our results suggest that hydro-dependent regions may need to consider not only primary generation but also backup generation in order to meet emissions reduction targets, such as those in the UN Paris Agreement."

###

Diffenbaugh is also an affiliate of the Precourt Institute for Energy. Co-authors on the paper are affiliated with the International Institute for Applied Systems Analysis in Laxenburg, Austria, Princeton University and the University of Southampton, in Southampton, United Kingdom.

The work was funded by the NASA Earth and Space Science Fellowship, NOAA, the Department of Energy and Stanford University.

Media Contact

Josie Garthwaite
josieg@stanford.edu
650-497-0947

 @stanfordearth

https://earth.stanford.edu/ 

Josie Garthwaite | EurekAlert!
Further information:
http://dx.doi.org/10.1008/1748-9326/aaf07b

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

 
Latest News

Rising water temperatures could endanger the mating of many fish species

03.07.2020 | Life Sciences

Risk of infection with COVID-19 from singing: First results of aerosol study with the Bavarian Radio Chorus

03.07.2020 | Studies and Analyses

Efficient, Economical and Aesthetic: Researchers Build Electrodes from Leaves

03.07.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>