Energy Bite 
Have you ever wondered what exactly the metric “global warming potential” entails? On this week’s Energy Bite, Kelly Klima, a research scientist at Carnegie Mellon University, has some answers.
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HOST: Did you know that some greenhouse gases have more impact on climate change than others? On this week’s Energy Bite, Kelly Klima, a research scientist at Carnegie Mellon University, has some answers.
KELLY: The term “global warming potential” is one way to describe the impact of a gas on surface temperatures. Scientifically, global warming potential is the ratio of the amount of heat a certain mass of greenhouse gas traps in the atmosphere to the amount of heat trapped by a similar mass of carbon dioxide. If a gas has a positive global warming potential, it will warm the surface temperatures. On the contrary, if it has a negative global warming potential, it will decrease the surface temperatures.
HOST: What are the implications of global warming potential on climate change?
KELLY: Over the last century, people have been doing a lot of activities such as driving cars or flipping on light switches. Over a century, these actions net gases with a positive global warming potential, and consequently are warming the surface. Some activities, such as releasing natural gas, have a greater immediate warming effect than others, which leads scientists to wonder what energy sources might be best for the environment.
HOST: Does knowing about the higher impact of natural gas on climate change influence your decisions? (Yes, No, Maybe?) Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Kelly Klima, a research scientist at Carnegie Mellon University’s Engineering and Public Policy Department, discusses how energy use changes with a change in population.
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Fifth Assessment Report (AR5) by International Panel on Climate Change
Energy and Population by Joel Darmstadter, Washington and Lee University
International Energy Outlook by U.S. Energy Information Administration
Transcript
HOST: Does energy consumption change as our population changes? On this week’s Energy Bite, Kelly Klima, a research scientist at Carnegie Mellon University, has some answers.
KELLY: Historically, we’ve seen total global energy use increase as population increases; in other words, adding a person increases total energy use. However, this is uneven throughout the world. Specifically, inhabitants of wealthy countries enjoy a greater rate of energy use, on average, than in developing countries. So, adding a person in say, Africa, has very little impact on energy use compared to adding a person to the U.S., by a factor of 20.
HOST: I’ve heard that as population increases, people move to cities; does this have an effect on energy use?
KELLY: Urbanization, where people move from the country to the city, is increasing. Today…over half of the world’s population lives in cities, with estimates of as many as 80% living in cities in 2050. On average, people living in cities often use less energy than their rural counterparts, in part due to the close proximity of resources as well as smaller living space. While this will help reduce our demand for energy, energy usage is predicted to continue to increase as population increases.
HOST: Do you think energy use will increase or decrease as population increases? (Yes, No, Maybe?) Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Have you ever wondered what exactly is the “Food-energy-water nexus”? On this week’s Energy Bite, Kelly Klima, a research scientist at Carnegie Mellon University, has some answers.
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The Water-Energy Nexus: Challenges and Opportunities by the Department of Energy
Water, Energy and Food Security Nexus by Wikipedia
Nexus Food Water and Energy by GRACE Communications Foundation
Transcript
HOST: Have you ever wondered what exactly is the “Food-energy-water nexus”? On this week’s Energy Bite, Kelly Klima, a research scientist at Carnegie Mellon University, has some answers.
KELLY: You may have heard folks use the term “food-energy-water nexus.” This means that food, energy, and water are inextricably linked and that actions in one area often have impacts in one or both of the others. These connections have always been present, and growth of the global and U.S. population has placed an ever-increasing stress on these resources. We heard before from Dr. Jared Cohon on the link between water and energy; today…let’s explore the other links. For instance, agriculture is currently the largest user of water at the global level and the food production accounts for a large part of energy consumption.
HOST: Can you provide an example of these linked resources, and how they affect me?
KELLY: Think about how a slice of pizza gets to your plate. The ingredients probably all came from a farm, which uses water to feed the crops and livestock, and energy to harvest the ingredients. Then…the ingredients had to be transported to the pizza shop, which might require energy input. Finally…the pizza was assembled and cooked in an oven, which requires energy to operate. So, without water and energy, your food – the pizza – would never have made it to your plate.
HOST: Will knowing about the food-energy-water nexus influence your behavior? (Yes, No, Maybe)? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
We get our electricity from lots of different sources, like coal, natural gas, wind, and nuclear. Which are the cheapest? On this week’s Energy Bite, Nathaniel Horner, a researcher for Carnegie Mellon University’s Engineering and Public Policy Department, has some answers.
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Levelized Cost of Energy by U.S. Department of Energy
Levelized Cost of Energy Analysis 9.0 by LAZARD
Electricity Pricing that Reflects its Real-Time Cost by The National Bureau of Economic Research
Transcript
HOST: We get our electricity from lots of different sources, like coal, natural gas, wind, and nuclear. Which are the cheapest? On this week’s Energy Bite, Nathaniel Horner, a researcher at Carnegie Mellon University, has some answers.
NATHANIEL: Nuclear and hydro plants are expensive to build, but, once running, they produce electricity very cheaply. Coal and natural gas plants are cheaper to build, but can have higher fuel costs. Wind and solar have no fuel costs, but they can’t run all the time. A nuclear plant might last 40 years, while a wind turbine might only last 10. Finally, fossil plants have health and environmental impacts, which are borne by the public. So the answer depends on what type of cost you care about.
HOST: Isn’t there a way to compare different technologies on similar basis?
NATHANIEL: Economists use a calculation called the levelized cost of electricity to adjust for these differences. Currently, natural gas, wind, and geothermal pencil out with the lowest levelized cost. Government subsidies are an important way to adjust levelized cost to account for things it doesn’t include, like impacts from power plant emissions.
HOST: Do you think about the emissions cost of the electricity you consume, or just the charges on your electricity bill? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Nathaniel Horner, a researcher for Carnegie Mellon University’s Engineering and Public Policy Department, discusses variable prices of electricity.
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An Introduction to Electricity Markets by Scientific American
Time Based Rate Programs by SmartGrid.gov
Electricity Pricing that Reflects its Real-Time Cost by The National Bureau of Economic Research
Transcript
HOST: Most of us pay a flat rate for our electricity. On this week’s Energy Bite, Nathaniel Horner, a researcher at Carnegie Mellon University, explains why the cost of electricity actually changes over the course of the day.
NATHANIEL: The electricity powering your coffee maker at 6 a.m. might come mostly from nuclear plants, which tend to run all the time and produce power cheaply. As we go to work and school and start to need more energy, more power plants need to brought online, so by noon, the microwave warming your lunch might use higher-cost electricity from plants running on natural gas or coal.
HOST: How might this affect my electricity bill?
NATHANIEL: If you’re a typical residential customer, it doesn’t: these variations get smoothed out on your bill into a single average rate. However, variable-price electricity has been available in some places since the 1980s. If you paid a price that changed from hour to hour, you would start to pay attention to when you used electricity. You would probably try to avoid using lots of energy when demand and prices are the highest, such as a hot summer day. In this way, passing variable prices on to customers can also help relieve stress on the electric grid.
HOST: Would you consider using a variable-price electricity rate schedule if your utility company offered it? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Nathaniel Horner, a researcher for Carnegie Mellon University’s Engineering and Public Policy Department, discusses if shopping online helps save energy.
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Known unknowns: indirect energy effects of information and communication technology by Nathaniel C. Horner, Arman Shehabi and Inês L. Azevedo
Is Online Shopping Really the Green Alternative? by Jennifer Konuik
What’s more energy efficient, shopping online or in stores? by Time De Chant
Transcript
HOST: Have you ever wondered if ordering something online instead of going to the store to buy it saves energy? On this week’s Energy Bite, Nathaniel Horner, a researcher at Carnegie Mellon University, has some answers.
NATHANIEL: It depends. If you usually drive to the store, ordering online might save energy, since a truck making deliveries to you and your neighbors on the same route consumes less fuel than if everyone drives individually to the store. But if you usually walk to go shopping, then having the truck drive to your house could use more energy. And you have to look at the entire system: how the product is manufactured, packaged, and shipped in each case.
HOST: It sounds complicated!
NATHANIEL: We haven’t even mentioned “ripple effects” yet! If the ease of buying online makes you buy more stuff, or you use the time it saves you to drive to a vacation spot, you might use more energy. But if you spend the time taking a nap, you could save energy on balance. Now think about the broad impacts of people and companies making these kinds of choices individually, and you get a sense of how hard it is to determine if e-commerce saves energy overall!
HOST: Does energy use inform your shopping habits? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Nathaniel Horner, a researcher for Carnegie Mellon University’s Engineering and Public Policy Department, discusses vampire electrical loads.
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4 Ways to Slay Energy Vampires this Halloween by the Department of Energy
What is Phantom Load? by Efficiency Vermont
Latest Research on Comatose Servers by Jonathan Koomey
Transcript
HOST: On this week’s Energy Bite, Nathaniel Horner, a researcher at Carnegie Mellon University, warns us about vampire electrical loads!
NATHANIEL: Vampire loads—also called phantom loads—are electrical appliances that consume electricity when they are not being used. Not to scare you too much, but they’re everywhere! Your cable box draws power when you aren’t watching TV, and your sleeping laptop and laser printer are quietly sucking power in the dead of the night. These phantoms aren’t just in your home. Legions of so-called “zombie servers” sit idling in data centers long after they should have been unplugged.
HOST: Yikes! What can I do about these energy vampires, phantoms, and zombies?
NATHANIEL: The department of energy estimates vampire devices could suck one of every ten dollars you pay for electricity, so it’s worth taking action. Look for appliances that have ENERGY STAR ratings. Shut down devices completely rather than putting them in standby. You can also buy “smart” power strips that cut the power to your game console, DVD player, and cable box when your TV is turned off.
HOST: Do you exterminate vampire loads in your house? Take our poll, see the results, and ask your energy questions at Energy Bite dot org
Nathaniel Horner, a research associate of Carnegie Mellon University’s Engineering and Public Policy Department, discusses how much electricity is consumed by the data centers.
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Data Center Energy Consumption Modeling: A Survey by M Dayarathna and Yonggang Wen
Here’s How Much Energy Data Centers Consume by Yevgeniy Sverdlik
How A Data Center Works by SAP
Transcript
HOST: Have you ever wondered how much electricity is used to power the data centers that make your digital life possible? On this week’s Energy Bite, Nathaniel Horner, a researcher at Carnegie Mellon University, has some answers.
NATHANIEL: Very few of us make it through a day without using email, browsing the Internet, streaming a TV episode, or buying something online. None of this would be possible without large groups of computers called data centers to store, process, and exchange all of this digital information. As you can imagine, the amount of data center traffic grows exponentially! In the early 2000s, data center electricity consumption also grew very quickly, but, over time, growth has slowed. Data centers use just under 2% of total U.S. electricity.
HOST: How is it possible for data center electricity consumption to grow so much more slowly than the amount of data we use?
NATHANIEL: Industry leaders like Apple, Amazon, Google, and Facebook have improved the efficiency, design, and operation of their data centers. At the same time, more of our data is stored in huge, highly efficient data centers that make up “the cloud.”
HOST: Would you move your data to the cloud if it meant saving energy? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Julian Lamy, a recent PhD graduate of Carnegie Mellon University’s Engineering and Public Policy Department, discusses how coastal towns feel about offshore wind projects compared to onshore ones in their community?
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Offshore Wind Energy by Bureau of Ocean Energy Management
Onshore Wind Energy: What are the pros and cons? by The Guardian
Advantages and Challenges of Wind Energy by the Department of Energy
Frequently Asked Questions About Windy Energy by the Department of Energy
Transcript
HOST: Have you ever wondered how coastal towns feel about offshore wind projects compared to onshore ones in their community? On this week’s Energy Bite, Julian Lamy, a recent PhD graduate of Carnegie Mellon University, has some answers.
JULIAN: We found that residents of coastal communities strongly prefer having an onshore project in their town instead of an offshore project 5 miles at sea. We estimate that the value of this preference is equivalent to $5.6 million per year. The main objection to offshore was the changes to the ocean landscape, which many participants thought defined their community. This demonstrates the massive challenge that state governments will face when trying to build offshore wind projects, like Massachusetts which requires about 1,600 megawatts of offshore capacity in the next 10 years.
HOST: Does that mean that offshore wind development is doomed from the start?
JULIAN: No. A solution could be to locate offshore wind projects further from shore where they are not visible at least 30 miles out. Floating offshore turbines, as opposed to traditional turbines cemented to the seabed, could enable such projects. Our work suggests that the additional cost for floating offshore is worth it.
HOST: If you lived near the ocean, would you prefer an offshore or onshore wind farm? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Julian Lamy, a recent PhD graduate of Carnegie Mellon University’s Engineering and Public Policy Department, discusses where most people prefer to have wind energy projects located
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Siting wind farms requires choosing a proper location by American Wind Energy Association
Advantages and Challenges of Wind Energy by the Department of Energy
Frequently Asked Questions About Windy Energy by the Department of Energy
Transcript
HOST: Where do most people prefer to have wind energy projects located? On this week’s Energy Bite, Julian Lamy, a recent PhD graduate of Carnegie Mellon University, has some answers.
JULIAN: We systematically tested with surveys whether people care more about having a wind project in a distant town compared to in their community. Surprisingly, we found that most people prefer having a wind project in their town, so long as there are economic benefits such as reduced energy bills and increased tax revenue to the local government. There is however a slight preference to avoid living within 1 mile of the project, but otherwise, people seem OK with a project in their town.
HOST: What is the minimum safe distance from a house to a wind turbine?
JULIAN: In Massachusetts, we found that a wind project must be built more than 1000 feet from residential buildings. This is to prevent damage due to freak accidents. Furthermore, it’s required that noise from the rotating blades at nearby homes can’t exceed 10 decibels above existing ambient noise levels. To put this in perspective, 30 decibels is a like a quiet whisper in a library.
HOST: Do you prefer wind projects be located in a certain area? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
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