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Venkat Viswanathan, a professor at Carnegie Mellon University, discusses how batteries are used to power drones and how battery innovation can improve drone function.
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A Lithium-Air Battery Based on Lithium Superoxide from Argonne National Laboratory
Rechargeable Lithium-Air Batteries from Pacific Northwest Laboratory
Battery Charge Depletion Prediction on an Electric Aircraft from the National Aeronautics and Space Administration
Transcript
HOST: Have you ever wondered how drones are powered? On this week’s Energy Bite, Venkat Viswanathan, a professor at Carnegie Mellon University, has some answers.
VENKAT: Drones are typically powered by lithium polymer batteries, similar to the lithium-ion batteries that are used in laptops, mobile phones, and other electronic devices. Drone batteries do not last long only providing about 25 minutes of flight time and a short lifetime.
HOST: Can drones be powered by something other than lithium ion batteries?
VENKAT: Yes, other options under exploration are gasoline used in a hybrid gas-electric engine and hydrogen fuel cells, which the manufacturers indicate can increase flight time to two hours. Lithium air batteries may also be an option in the future. You might be wondering why you just can’t add more lithium batteries to increase flight time. Adding more batteries, however, is not an option as then the drone is too heavy to fly.
HOST: Do you fly a drone? Would you like your drone to fly longer? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Venkat Viswanathan, a professor at Carnegie Mellon University, discusses why lithium ion batteries can catch fire and how these fires can be avoided.
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Making Lithium-Ion Batteries Safer from Lawrence Berkeley National Labaratory
Fire Hazards of Lithium Ion Batteries from the Federal Aviation Administration
PHMSA Issues Hoverboard Safety Advisory from the US Department of Transportation
Transcript
HOST: Have you ever wondered why batteries catch fire? On this week’s Energy Bite, Venkat Viswanathan, a professor at Carnegie Mellon University, has some answers.
VENKAT: The batteries in the news for catching fire are Lithium Ion batteries. These batteries are in many of the electronic devices we use including laptop computers, electric vehicles, and hover boards. Lithium ion batteries are safe when they are in environments with air temperatures ranging from 14 to 104 degrees Fahrenheit. The problem occurs when the battery is in very cold or very hot environments outside of this range.
HOST: How can these battery fires be avoided?
VENKAT: First, think about temperature when you are using a device with a lithium ion battery. Second, only purchase batteries with a failsafe mechanism from a high quality manufacturer, and use the recommended chargers for that battery. Don’t use batteries or chargers from “aftermarket” manufacturers producing lower quality inconsistent batteries. Third, consider using devices powered by nickel-metal hybrid batteries instead of lithium ion.
HOST: Have you ever had a battery catch fire? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Venkat Viswanathan, a professor at Carnegie Mellon University, discusses the current range of electric vehicles, how range can be improved with new battery technology, and what problems this new technology may introduce.
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Batteries for Hybrid and Plug In Electric Vehicles from the US Department of Energy
Rechargeable Lithium Air Batteries from Advanced Research Projects Agency- Energy
Hybrid and Plug In Electric Vehicles from the US Department of Energy
Transcript
HOST: Are you thinking about buying an electric car, but worried about how far it can go before it runs out of energy? On this week’s Energy Bite, Venkat Viswanathan, a professor at Carnegie Mellon University, has some answers.
VENKAT: Most electric vehicles today go about 200 miles on a single charge of a lithium ion battery. Consumers, however, want vehicles to go 300 to 500 miles before they are willing to purchase them. If you added enough batteries to a car so it could go 500 miles, however, the battery pack becomes more than half the weight of the car. This reduces the vehicle’s overall energy efficiency, and therefore the benefit of buying an electric car.
HOST: How can an electric vehicle’s range be increased?
VENKAT: One option is to switch from a lithium ion battery to a lithium air battery. These batteries can increase a vehicle’s range up to 500 miles without increasing the vehicle’s weight. The challenge with lithium air batteries is that these batteries do not do so well when you recharge them. These batteries can only last for 10s of cycles and we want the batteries to last much much longer than that.
HOST: Would the range of an electric vehicle influence your decision to buy one? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Meagan Mauter, a professor at Carnegie Mellon University, discusses the role of water in the energy industry as well as the various technologies being developed to treat wastewater to minimize energy and environmental impacts.
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Quantity, Quality, and Availability of Waste Heat from United States Thermal Power Generation from the American Chemical Society
Water Treatment Capacity of Forward-Osmosis Systems Utilizing Power-Plant Waste Heat from the American Chemical Society
Effluent Guidelines from the Environmental Protection Agency
Transcript
MODERATOR: Have you wondered why coal-fired power plants are often near water? On this week’s Energy Bite, Megan Mauter, a professor at Carnegie Mellon University, has some answers.
MEAGAN: In previous Energy Bite episodes, we’ve talked about the water-energy nexus – how water is often essential to energy production. Coal-fired power plants use water for a number of in-plant operations including cooling, boiler make up water, and sometimes for removal air pollution like sulfur dioxide. As the water is used for these operations, it can gather salts and metals naturally present in coal, including mercury, arsenic, boron, selenium, and chlorides.
Until recently, much of this water was discharged to the environment without treatment. Upcoming US Environmental Protection Agency regulations, called Effluent Limitation Guidelines or ELGs, will require that the water is treated prior to discharge.
MODERATOR: Are there any disadvantages to treating this water?
MEAGAN: Water treatment processes consume both energy and chemicals. So treating this water may reduce the efficiency of electricity generation and increase air pollution emissions associated with auxiliary power consumption and chemical manufacturing. At Carnegie Mellon, we are working to develop water treatment technologies that use waste heat available at coal fired power plants to minimize this potential adverse environmental and energy impacts.
MODERATOR: Are you concerned about the wastewater discharged from coal power plants? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Meagan Mauter, a professor at Carnegie Mellon University, discusses the possibility of desalinating water to increase the water supply of areas experiencing drought conditions.
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Saline Water: Desalination from the United States Geological Survey
Desalination of Ground Water: Earth Science Perspectives from the United States Geological Survey
Antifouling Ultrafiltration Membranes via Post-Fabrication Grafting of Biocidal Nanomaterials from the American Chemical Society
Transcript
MODERATOR: Can we desalinate water to increase our water supply? On this week’s Energy Bite, Megan Mauter, a professor at Carnegie Mellon University, has some answers.
MEAGAN: We often hear about drought conditions in states like California and Texas that have ready access to salt water on their shores. In these areas, water desalination – the removal of salt from water—may be an important stopgap technology for providing freshwater when other resources and conservation measures have been exhausted.
In the most common way to desalinate water, reverse osmosis, salt water is passed through a semi-permeable membrane that retains salt, but allows water to pass through. This membrane is made from a very thin layer of polyamide polymer.
Unfortunately, the water desalination process is both expensive and consumes a lot of energy — on the order of 3-4 kWh per cubic meter, or the amount of electricity it takes to keep your iPhone powered for a full year.
MODERATOR: Can we do something about it?
MEAGAN: The lower the concentration of salt in your feed water, the less energy is needed to produce fresh water. So one way to reduce energy consumption of water desalination is to treat less saline water sources. Many reverse osmosis water treatment facilities use wastewater or low-salinity brackish water as the source water.
MODERATOR: Would you drink desalinated wastewater? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Meagan Mauter, a professor at Carnegie Mellon University, discusses how wastewater from hydraulic fracking could potentially cause earthquakes and how these earthquakes could potentially be prevented.
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Risks and Risk Governance in Unconventional Shale Gas Development from the American Chemical Society
Investment optimization model for freshwater acquisition and wastewater handling in shale gas production from the American Institute of Chemical Engineers
Transcript
MODERATOR: Does hydraulic fracturing cause earthquakes? On this week’s Energy Bite, Megan Mauter, a professor at Carnegie Mellon University, has some answers.
MEAGAN: In the major US shale gas plays, there is no strong evidence that hydraulic fracturing causes earthquakes directly. Instead, many of the earthquakes reported around Oklahoma, Texas, and Ohio stem from injecting high volumes of hydraulic fracturing wastewater in disposal wells.
In earlier Energy Bite episodes, we explained that the wastewater produced from hydraulic fracturing operations is often very salty, and therefore difficult to treat. When this water is injected into disposal wells, it is being pushed into many tiny holes within porous geological formations. If the injection rate is too high, then the formation becomes stressed and can result in an earthquake.
MODERATOR: What can be done to prevent these earthquakes?
MEAGAN: By maximizing the reuse of wastewater in subsequent hydraulic fracturing operations, we minimize the amount of water sent to these injection wells. We can also develop new water treatment technologies that remove all contaminants from this water and allow us to safely discharge clean, fresh water into streams. More research and development will help respond to concerns some have about hydraulic fracturing operations and related activities.
.MODERATOR: Are you concerned about earthquakes that may result from the disposal of hydraulic fracturing wastewater? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Episode 149: What practices are available to better manage the wastewater from hydraulic fracturing?
Meagan Mauter, a professor at Carnegie Mellon University, discusses how new technologies for wastewater management can be beneficial both economically and environmentally.
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Expert Elicitation of Trends in Marcellus Oil and Gas Wastewater Management from the American Society of Civil Engineers
Water Management Challenges Associated with the Production of Shale Gas by Hydraulic Fracturing from Elements
Natural Gas Extraction from the Environmental Protection Agency
Transcript
MODERATOR: How is wastewater from hydraulic fracturing, managed? On this week’s Energy Bite, Megan Mauter, a professor at Carnegie Mellon University, has some answers.
MEAGAN: In a previous Energy Bite episode, we talked about how water is used to fracture shale and release natural gas. Water that returns to the surface has a high concentration of salt and dissolved organics, requiring careful wastewater management. In Pennsylvania, this wastewater is either reused to fracture another well, transported to a treatment facility, or trucked to a deep well injection site.
Recent technical improvements have allowed companies to reuse more of their high salinity wastewater at subsequent hydraulic fracturing sites, but there is still a wide variation in how much wastewater companies reuse. Our research finds that companies who drill wells in spatial-temporal clusters are more likely to find water reuse easier and more cost effective.
MODERATOR: What happens when the water is trucked off-site for deep well injection?
MEAGAN: Since Pennsylvania has so few injection wells, these trucks often have to travel to Ohio and West Virginia. All of this trucking is expensive for companies and can have negative consequences for air emissions, roadway wear and tear, and vehicular accidents. Another issue is that injecting this water may be increasing earthquakes in these regions, which we will discuss in a future episode.
MODERATOR: Are you concerned about these wastewater management methods? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Meagan Mauter, a professor at Carnegie Mellon University, discusses how water is used as part of the hydraulic fracturing process, how much is used, and possible implications of that use.
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The Hydraulic Fracturing Water Cycle from the Environmental Protection Agency
Regional Variation in Water-Related Impacts of Shale Gas Development and Implications for Emerging International Plays from the journal Environmental Science & Technology
Risks and Risk Governance in Unconventional Shale Gas Development from the journal Environmental Science & Technology
Transcript
MODERATOR: Is it true that hydraulic fracturing, commonly known as fracking, uses a lot of water? On this week’s Energy Bite, Megan Mauter, a professor at Carnegie Mellon University, has some answers.
MAUTER: Yes, hydraulic fracturing uses quite a bit of water. This water carries sand and chemicals to the shale layer, helping to fracture the shale and release the trapped natural gas.
Unconventional hydraulic fracturing uses as little as one million gallons or as many as six million gallons per well depending on the type of fracturing technology, the horizontal length of the well bore, and the specific location of the well.
In the Marcellus shale play, where Pennsylvania’s shale gas comes from, about 5 million gallons is used to fracture each shale gas well over a couple of days – about the same water as in 7 and a half Olympic size swimming pools.
MODERATOR: What happens to all this water?
MAUTER: This varies. In Pennsylvania, most of the water stays underground with only about 20% returning to the surface. The water that does return to the surface has a high concentration of salt and needs to be carefully disposed of in specialized oil and gas wastewater disposal wells, reused in future fracturing activities, or treated. We’ll discuss more about this issue in a future episode.
MODERATOR: Do you think the amount of water used for hydraulic fracturing is a concern? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Nick Muller, a visiting professor at Carnegie Mellon University, responds to a listener who wonders if a carbon tax is a better solution than a cap-and-trade program.
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Market-based Emissions Regulation When Damages Vary Across Sources: What are the Gains from Differentiation? by Meredith Fowlie and Nicholas Muller
Location Key to Pollution’s Real Cost from the Journal of Yale School of Forestry & Environmental Studies
Evaluating the Policy Trade–Offs in ARB’s Cap–and–Trade Program from the California Legislative Analyst’s Office
Transcript
HOST: An Energy Bite listener asked the following question: Which is better, a revenue-neutral carbon fee-and-dividend price on carbon pollution or a cap-and-trade program such as is promoted by the EPA power plant rules? On this week’s Energy Bite, Nick Muller, a visiting professor at Carnegie Mellon University, has some answers.
MULLER: There are many factors that determine whether a carbon tax or a cap-and-trade program are preferred. With full information regarding the costs of pollution control, using either taxes or cap-and-trade makes no difference in terms of efficiency. However, it should be obvious that regulators do not have complete information on costs. These are a function of specific technologies used by firms as well as the costs of their inputs, like fuel and labor.
HOST: So, what happens when costs are not known?
MULLER: When costs are not known, the equivalence between taxes and cap-and-trade breaks down. Research suggests that damages increase very slowly with additional CO2 emissions. As such, the regulator should elect to use an emission tax. The additional benefit of an emission tax is the ability of the regulator to use tax revenue for productive purposes. One such purpose is rebates to low or middle income households to offset higher energy costs.
HOST: Do you prefer a carbon tax or a cap and trade program? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
ANNOUNCER: Energy Bite is a co-production between 90.5 WESA and Carnegie Mellon’s’ Scott Institute for Energy Innovation.
Nick Muller, a visiting professor at Carnegie Mellon University explains how environmental policies adversely affect firms that use coal.
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Environmental Accounting for Pollution in the United States Economy by Nicholas Z. Muller, Robert Mendelsohn, and William Nordhaus
EPA Regulations and Electricity from the U.S. Senate
Effects of a Carbon Tax on the Economy and the Environment from the U.S. Budget Office
Transcript
HOST: Why do environmental regulations tend to adversely affect firms that extract or use coal? On this week’s Energy Bite, Nick Muller, a visiting professor at Carnegie Mellon University, has some answers.
MULLER: Coal has a long history of use as a source of energy. Coal contains a variety of substances that make it a dirty source of energy. These include but are not limited to: sulfur, mercury, and carbon.
HOST: How does this impact firms that extract or use coal?
MULLER: Relative to the other fossil fuels (namely oil and natural gas) coal contains these substances in much higher quantities per unit of energy. Because of these differences in composition, most applications of coal as a source of energy produce more pollution per unit useful energy than the other fossil fuels.
As a result, when environmental policies are implemented that manage emissions of sulfur, soot, or carbon, these regulations will require greater compliance costs on the part of firms that burn coal than firms that employ other fossil fuels. Because coal contains more pollutants than other fossil fuels, firms that rely on this fuel tend to bear the brunt of environmental regulations.
HOST: Do you think coal is treated fairly when regulated for environmental reasons? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
ANNOUNCER: Energy Bite is a co-production between 90.5 WESA and Carnegie Mellon’s’ Scott Institute for Energy Innovation.
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