Archive for the 'Water and Energy' Category

Evaporation as a renewable energy source

Researchers at Columbia University, led by biophysicist Ozgur Sahin, have developed an “evaporation engine” that uses bacterial spores that expand in the presence of humidity and contract when the humidity is low.

While this technology was first described in a 2015 paper in Nature, the group recently made headlines again when they wrote a paper describing the potential for natural evaporation from U.S. lakes and reservoirs to generate 325 gigawatts of power!  That represents nearly 70 percent of the electricity currently generated by the United States. Their analysis, published in Nature in Sept 2017, revealed that the energy potential available from evaporation is comparable to that of wind and solar power but unlike wind and solar is characterized as low-intermittency. According to the authors, these findings “motivate the improvement of materials and devices that convert energy from evaporation.

This is the just kind of innovation that I believe needs to make its way into classrooms to inspire the next generation of scientists and engineers.  This new technology also provides an opportunity to invite your students to evaluate the challenges that will need to be studied in order to use this technology on large bodies of water. For example, the authors cite that “using evaporation driven materials and devices on lakes or reservoirs could affect freshwater resources” but that this technology could reduce evaporative losses in regions characterized by water stress and scarcity.  The authors conclude that “these materials and devices could potentially contribute toward solving energy and water related challenges.”

Below I have listed some classroom-ready resources should you want to introduce this technology to your students:

Renewable Energy from Evaporating Water (5 minute video with Ozgur Sahin)

Evaporation-powered devices in action (4 minute video)

A miniature car driven by evaporation (Under 1 minute video)

ScienceTake | The Spore Machine (1:36 minute video from the New York Times)

Engineering Evaporation (6 minute conversation between Ozgur Sahin and Ira Flatow on NPR’s Science Friday)

Evaporation could power most of the U.S. — study
Greenwire, September 26, 2017

Water evaporation could be a promising source of renewable energy
The Verge, September 26, 2017

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Guest Post: How much energy is in your water bottle? by Ryan Kingsbury

We don’t often think about the energy it takes to satisfy our thirst, but where we get our drinking water has huge consequences for how much energy is needed. In many parts of the world, fresh water sources like lakes or aquifers are becoming scarce, forcing residents to settle for supplies that aren’t as clean. And the dirtier the water, the more energy it takes to purify.

Salt is especially hard to remove. In desert or coastal regions with limited sources of freshwater, residents must use a process called desalination to turn salty groundwater or seawater into drinking water. We’ve already covered how mixing saltwater with freshwater releases a lot of energy,  so, to do the reverse– to remove salt from water– consumes a lot of energy.

Exactly how much energy is required depends on the method of desalination. Distillation (which involves boiling)  is a simple way to desalinate water, but it’s also one of the most energy-intensive. By using a technology called reverse osmosis, we can desalinate water using about 1/10th as much energy as distillation. So compared to boiling the water, using reverse osmosis is much more efficient. But reverse osmosis still requires about 100x more energy than treating fresh surface water or groundwater. In fact, you could charge your smartphone with the energy it takes to desalinate just 1 gallon of seawater!

Despite its energy demands, desalination is widely used around the world. There are more than 18,000 desalination plants in 150 countries, including about 250 in the U.S. About half of these plants use reverse osmosis, and about a third use distillation.

In the U.S., most plants are located in Florida, Texas, and California (shown on this cool map), but there are about a dozen here in North Carolina. If you’ve ever visited the Outer Banks, your drinking water probably came from a reverse osmosis desalination plant.

There are so many reverse osmosis plants in the world, that together they produce 4x as much water in one year as refineries do oil! But virtually all of these plants were built as a “last resort,” in areas where there simply isn’t enough freshwater to meet the needs of consumers, industry, and agriculture. When it’s available, treating freshwater is always preferable to desalination.

The more we have to rely on seawater and other salty water resources, the more energy it will take to slake our thirst. So next time you take a drink of water, remember that you’re not just drinking ounces, you’re drinking watts.

Want to learn more about reverse osmosis desalination? Check out this animated video from the Seven Seas Water Corporation.

Ryan Kingsbury, P.E., is a PhD student at the University of North Carolina at Chapel Hill where he is a member of the Coronell Research Group.  Orlando Coronell, PhD, and his research team study membrane-based processes for water purification and energy production and storage, with applications in municipal, industrial, and household systems. Ryan studies salinity gradient energy which you can read more about here.

Announcing an Interactive Energy Game from the US EPA

The US EPA has just released an interactive board game developed by physical scientist Rebecca Dodder, PhD, in collaboration with classroom teachers and others at the EPA, and this is a game that teachers are going to love incorporating into their instruction!  The Generate! Game lets participants engage in friendly competition while conducting a  simulation that enables them to examine the costs and benefits of using varied fossil and renewable energy sources to power their electrical grid.

Each team is given a game board which represents their power grid.  Every team has same size grid and thus can generate the same total amount of energy, but teams do not have the same mix of energy sources. Each team assembles a portfolio of energy sources for their grid under constraints provided by the facilitator – which group can come up with the least expensive energy portfolio?  Which group can come up with a portfolio that generates the least amount carbon dioxide emissions? Which energy portfolio utilizes the least amount of water and would presumably be more resilient during a drought?  How does the addition of energy efficiency measures impact costs? emissions?Game-in-playI have seen this game played numerous times, both with high school students and teachers and it is always well received. In fact, most people want to keep playing the game as each round brings an improved understanding of the kinds of decisions that must be taken into account when choosing which energy sources will be used to provide electricity. This game is a very effective instructional tool that cultivates critical thinking about the energy sources used to generate electricity both now and in the future.

Materials for making your own Generate! game are now available along with a PowerPoint slide set for introducing the game to students and a teacher’s guide for both middle school and high school teachers. Once you conduct this game with students, you will find that students are more prepared to thoughtfully engage in a discussion about the future of electricity generation and to grapple “with the complexities of our energy challenges.”

Have fun!

 

WFAE’s Charlotte Talks examines Fracking in NC

When I lived in Charlotte one of my favorite programs to listen to during my commute was WFAE’s Charlotte Talks with Mike Collins and so I am looking forward to listening to a two part discussion on fracking in North Carolina that aired on September 3rd and 8th, 2014.

Fracking in NC| Sept 3rd program with featured guests:

  • Christopher Hardin, P.E. – Senior Project Director, CH2M HILL
  • Franklin H. Yoho – Senior Vice President – Chief Commercial Officer, Piedmont Natural Gas
  • Dr. Andy Bobyarchick – Associate Professor of Earth Sciences, Department of Geography and Earth Sciences at UNC Charlotte

Fracking Part 2| Sept 8th program with featured guests:

  • James Womack – Commissioner for the Mining & Energy Commission
  • Dr. Andy Bobyarchick – Associate Professor of Earth Sciences, Department of Geography and Earth Sciences at UNC Charlotte
  • Cassie Gavin – Director of Government Affairs with Sierra Club’s NC Chapter

You can listen to each segment online and find links to related content from WFAE.

Energy, Water and Land: National Climate Assessment

The National Climate Assessment “provides an in-depth look at climate change impacts on the U.S. It details the multitude of ways climate change is already affecting and will increasingly affect the lives of Americans.”  Chapter 10 of the report is devoted to exploring the connections between energy, water and land as understanding these connections “can improve our capacity to predict, prepare for, and mitigate climate change.”

The report is organized around three key messages:
1. Energy, water, and land systems interact in many ways. Climate change affects the individual sectors and their interactions; the combination of these factors affects climate change vulnerability as well as adaptation and mitigation options for different regions of the country.
2. The dependence of energy systems on land and water supplies will influence the development of these systems and options for reducing greenhouse gas emissions, as well as their climate change vulnerability.
3. Jointly considering risks, vulnerabilities, and opportunities associated with energy, water, and land use is challenging, but can improve the identification and evaluation of options for reducing climate change impacts.

Each chapter of the report includes interactive graphics as well as figures and graphics that can be downloaded for use in the classroom.  Check out the interactive version of Figure 10.4 that shows the energy production by source, amount of water withdrawn by key sectors and land cover type for each region of the US along with projected climate change impacts. This figure provides an at-a-glance view of water, energy and land use that can be used by students as they consider how projected climate impacts might influence each of these sectors in their region.

The report also includes examples of energy, water and land connections by exploring the following technologies and the corresponding energy-water-land tradeoffs in more depth:

  • shale gas and hydraulic fracturing
  • solar power generation
  • biofuels
  • carbon capture and storage

So the next time you ask students to critically evaluate the various energy sources used by society, encourage them to also consider the role of water and land in the mining and acquisition of energy sources, the generation of electricity, and the manufacture and delivery of transportation fuels.

 

 

“Algae”, biofuels and carbon capture

Photo credit: NREL

I was excited to see cyanobacteria (blue-green algae) featured in a recent energy-related article in the News and Observer.  Asheville entrepreneur aims to harness cyanobacteria’s photosynthetic prowess details the work of Phytonix, an Asheville-based company that has  engineered cyanobacteria to use carbon dioxide and sunlight to produce n-butanol instead of sugar! According to the article, “current methods of producing butanol use petroleum as a feedstock and emit carbon dioxide in the process. Because the Phytonix approach uses carbon dioxide as a feedstock, it removes carbon dioxide from the atmosphere.”

Thus, in addition to producing biofuels, these microscopic photosynthetic organisms also serve to capture carbon from the atmosphere or other concentrated source. The scientist behind Phytonix, Bruce Dannenberg, is said to envision his “facilities being located near sources of carbon dioxide, such as ethanol refineries, oil and gas production plants, cement factories or breweries.” And power companies like Duke Energy are also turning to photosynthesis  and exploring technologies to capture CO2 from the flue gas of coal-fired power plants. 

There is an algae-based system for CO2 capture at Duke Energy’s East Bend Power Plant (a coal-fired power plant) located in Kentucky along the Ohio River. This project is a collaboration between the University of Kentucky Center for Applied Energy Research and the University of Kentucky Department of Biosystems and Agriculture Engineering.  According to Duke Energy, “while the primary focus of the project is to demonstrate how to use algae to reduce CO2 emissions produced by coal-fired power plants, the project also focuses upon studying the production of biofuels and other bioproducts from the algae to demonstrate the economic feasibility of using algae to capture CO2.”  

A two part video about algae CO2 capture and this Duke Energy project was produced by the University of Kentucky Center for Applied Energy Research and Reveal: University of Kentucky Research Media:

Algae CO2 Capture Part 1: How it Works (5 minutes)

Algae CO2 Capture Part 2: Imagining the Future (5 minutes)

A Photo Gallery is also available.

Here is some additional reading related to Duke Energy’s East Bend Power Plant photobioreactor:

CO2 recycling using microalgae for the production of fuels, March 2014
This article from the journal Applied Petrochemical Research describes the demonstration project at Duke Energy’s East Bend Power Plant.

Duke, UK use algae to eat CO2 and make new stuff, Nov 8, 2013
This article is not available in full but this link includes access to a 1 minute video titled “Algae Eat Emissions at East Bend Power Plant.”

CAER Scientists, Duke Energy Demonstrate Algae-Based Carbon-Capture System, Nov 2013
This article is from University of Kentucky News.

Ky. power station to implement algae carbon capture project, Dec 2011
This article is from Biodiesel Magazine.

 

 

 

 

 

2014 World Water Day: Water and Energy

Photo of Kerr-DamnThe theme of the 2014 World Water Day on March 22 is water and energy. As a teacher, you may be interested in seeing how many of the event’s key messages, designed to raise awareness about water and energy, are relevant to your teaching and perhaps that you are already incorporating into your instruction.

In recognition of World Water Day, today the United Nations released the 2014 World Water Development Report (pdf) that is divided into two volumes – Volume 1 – Water and Energy and Volume 2 – Facing the Challenges, which includes thirteen case studies from around the globe that illustrate “that an array of opportunities exists to exploit the benefits of synergies, such as energy recovery from sewerage water, the use of solar energy for wastewater treatment, and electricity production at ‘drinking water power plants’. These examples also showcase alternatives to fossil fuel-based energy production, including hydropower development, geothermal energy, solar power and biogas.” There is one US case study about Austin, Texas, which is at “the centre of energy-rich and water-stressed Texas” that highlights the city’s water and energy conservation programs, including a reclaimed water program. These case studies are brief and reader friendly and could be useful to students seeking not only to understand the interplay between water and energy but also to examine innovative solutions for conserving water and energy around the globe.

Information briefs to accompany 2014 World Water Day are also available and may be useful as you seek to update your instruction about the water and energy connection:

Water and Energy (pdf)
Water and Energy Efficiency (pdf)
Water and Energy Sustainability (pdf)

There is also a useful list of additional documents and information resources, which includes links to related infographics, activities for youth, and articles. Facts and figures from the 2014 report are also available.

I’d love to hear how you use any of this information with your students!



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