Energy Bite 
Casey Canfield, a recent PhD graduate of Carnegie Mellon University’s Engineering and Public Policy Department, discusses some of the social, economical, and environmental factors that influence people to power their home with solar energy.
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Planning a Home Solar Electric System from the Department of Energy
A Consumer’s Guide: Get Your Power from the Sun from the National Renewable Energy Labaratory
Solar Power for Your Home from the Federal Trade Commission
Transcript
HOST: Why do people decide to put solar panels on their home? On this week’s Energy Bite, Casey Canfield, a recent PhD graduate of Carnegie Mellon University, has some answers.
CASEY: You may think that people only consider environmental goals when they install solar panels, but other factors such as economics and appearance play a role. Some view it as a good financial investment, such as retirees who want to stabilize their electricity costs while on a fixed income. On the other hand, some may dislike the look of solar panels or may be overruled by their homeowner’s association.
HOST: What else influences consumers to adopt solar power?
CASEY: People are also influenced by their social network. When people see their neighbors getting solar panels, they may be more motivated to investigate getting solar panels themselves. People also prefer to get information from those who they trust. So…if their neighbor says that solar panels are a good investment, they take that information more seriously.
HOST: Would you install solar panels on your home? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Casey Canfield, a recent PhD graduate of Carnegie Mellon University’s Engineering and Public Policy Department, explains what the best way is to communicate electricity consumption on your bill.
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Perceptions of electricity-use communications: effects of information, format, and individual differences from the Journal of Risk Research
How is electricity used in U.S. homes? from U.S. Energy Information Administration
Transcript
How should your electricity bill show your electricity consumption?
HOST: How should your bill show your electricity consumption? On this week’s Energy Bite, Casey Canfield, a recent PhD graduate of Carnegie Mellon University, has some answers.
CASEY: When you look at an electricity bill, you probably want to know how much the bill is, but also how much electricity you consumed and how you could reduce your bill next month. How that information is communicated may influence the decisions you make.
HOST: So what’s the best way to communicate electricity consumption?
CASEY: We recently performed a study, which suggested that tables are better than graphs in this context. For reading specific values, such as how much electricity I used this month, a table is better than a graph. Graphs are more useful for understanding trends, but not everyone can interpret them. This means that if an electricity bill uses a graph, not everyone is able to understand what it means.
HOST: Do you think about your energy consumption when you look at your electric bill? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Casey Canfield, a recent PhD graduate of Carnegie Mellon University’s Engineering and Public Policy Department, explains how smart meters can be hacked.
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Electric Meters from the Department of Energy
Terrorism and the Electric Power Delivery System from the National Academies Press
Multi-vendor Penetration Testing in the Advanced Metering Infrastructure presented at the Annual Computer Security Applications Conference
Transcript
Can smart meters be hacked?
HOST: Are you worried about your smart meter being hacked? On this week’s Energy Bite, Casey Canfield, a recent PhD graduate of Carnegie Mellon University, has some answers.
CASEY: A smart meter, which is a device the electricity company can put in your home to record more information about how much electricity you use, can be hacked. Hackers may want to steal electricity or money or implement a large-scale attack on the grid. For some of these attacks, the hacker needs physical access to the meter, but in other cases they don’t. The worst-case scenario…malicious hackers could illegally access many smart meters at the same time and cause a large blackout.
HOST: Is there anything we can do about it?
CASEY: We can improve the security of smart meters both in terms of hardware and software. Some have talked about improving the resiliency of the grid. This means that instead of making the electrical grid impossible to attack, we want the grid to be quick to recover. Reducing the demand for electricity also reduces national security risk.
HOST: Do security concerns influence how you feel about smart meters? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Andrew Gellman, Lord Professor of Chemical Engineering at Carnegie Mellon University, explains how energy changes form when we use it for power or heat.
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Conservation of Energy from NASA
What is Energy? Explained: Laws of Energy from the US Energy Information Administration
Students’ Misunderstandings about the Energy Conservation Principle: A General View to Studies in Literature from the International Journal of Environmental & Science Education
Transcript
Where does energy go when we use it?
HOST: Have you ever wondered where the energy goes when we use it? On this week’s Energy Bite, Andy Gellman, a professor at Carnegie Mellon University, has some answers.
ANDY: You may have learned in a science class that energy is always conserved and never consumed. In other words, the total amount of energy in the universe does not change, it simply shifts from one form to another. For example, if you mix some hot water into some cold water, the energy in the hot water heats the cold water and you get warm water. The energy in the warm water equals the energy originally in the hot and the cold water.
HOST: In that case, what does it mean to ‘use’ energy?
ANDY: When we use energy we simply cause it to change from one form to another. For example, when you burn natural gas it is transformed into carbon dioxide and water. These compounds contain less energy than the natural gas. The heat released is exactly equal to the energy difference between the gas being burned and the carbon dioxide and water being produced. This heat then cooks your food or powers a car. Although the energy is not lost, it changes form, and this transformation cannot be undone.
HOST: Do you ever think about what happens when you use energy? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Andrew Gellman, Lord Professor of Chemical Engineering at Carnegie Mellon University, discusses potential uses for shale gas beyond heating and cooking.
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Natural Gas Vehicles from the Department of Energy
Global Demand, Inexpensive Natural Gas are Increasing Domestic Plastic Production from the US Energy Information Administration
Natural Gas Explained: Use of Natural Gas from the US Energy Information Administration
Transcript
What are some of the options for using shale gas?
HOST: We are all aware of the relatively recent impact of shale gas on our energy economy, but did you know that shale gas can be used for products other than energy? On this week’s Energy Bite, Andy Gellman, a professor at Carnegie Mellon University, has some answers.
ANDY: The most common use of shale gas, also known as natural gas, is to burn it. Human beings and our evolutionary predecessors have been burning things for heating and cooking purposes for over 1 million years. Today, shale gas is burned in large scale power plants and the heat released is used to make electricity. In some places shale gas is used as fuel for transportation vehicles.
HOST: But shale can gas be used for more than this?
ANDY: Absolutely! Shale gas consists largely of methane, but with varying amounts of other molecules such as ethane and propane. In some shale gas regions, like the Marcellus region in Pennsylvania, the proportions of ethane and propane are quite high and have enormous potential value. By simply removing some of the hydrogen contained in these molecules one creates ethylene and propylene. These chemicals can then be used as the feedstocks for production of a wide variety of commodity chemicals ranging from fuels to textiles to plastics. The value of these goods is far more than the value of the methane itself.
HOST: Did you know that shale gas can be used for more than heating and cooking? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Andrew Gellman, Lord Professor of Chemical Engineering at Carnegie Mellon University, explains how material innovation will play a key role in the advancement of the energy industry.
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About the Energy Materials Network from the Office of Energy Efficiency & Renewable Energy
Accelerating Materials Development for a Clean Energy Future from the Department of Energy
Materials for Energy from the Argonne National Labaratory
Transcript
How are new materials important to our energy infrastructure?
HOST: Do you ever think how materials influence energy generation and use? If not, you should! On this week’s Energy Bite, Andy Gellman, a professor at Carnegie Mellon University, has some answers.
ANDY: The discovery and development of new materials has improved our standard of living continuously from Stone Age times, into the semiconductor age. New materials are important in energy technologies because they can reduce the amount of energy that we consume. For example, developing lightweight aluminum or carbon- based materials strong enough for use in cars and airplanes can significantly reduces energy consumption for transportation.
HOST: How do materials influence energy generation?
ANDY: The turbines used for coal and natural gas power plants must operate for years at temperatures approaching 1000 degrees centigrade and without corroding. Increasing turbine efficiency requires operating at even higher temperatures and, as a result, requires the development of new steels or entirely new alloy materials for these turbines. Solar photovoltaics that convert sunlight into electricity use materials like silicon that are semiconductors. Much of today’s energy research is developing new materials such as lithium for batteries or absorbent materials for hydrogen storage in order to enhance our ability to store energy. These types of materials will enable us to store solar and wind energy when the sun does not shine and the wind does not blow.
HOST: Did you know how important new materials are in meeting our energy needs? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Andrew Gellman, Lord Professor of Chemical Engineering at Carnegie Mellon University, discusses how solar thermal power can be used and some of the challenges that are associated with it.
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Solar Explained: Solar Thermal Power Plants from the US Energy Information Administration
Solar Thermal Electricity from the California Consumer Energy Center
Residential Solar Thermal Plant from Lawrence Livermore National Labaratory
Transcript
How is solar thermal power generated and used?
HOST: You have probably heard of solar panels, but do you know there are other ways to generate solar power? On this week’s Energy Bite, Andy Gellman, a professor at Carnegie Mellon University, has some answers.
ANDY: Although solar panels that generate electricity for local and residential use have received a lot of attention, they are not the only means of extracting useful energy from sunlight. The energy of sunlight can be collected as heat to be used for many purposes that would otherwise require electricity. This is called solar thermal power. For example in many parts of the world roof tops are commonly used to house solar hot water heaters, and they work remarkably well.
HOST: What are the challenges in using solar power?
ANDY: Two of the primary limitations on our use of solar photovoltaic electricity are the cost of the materials and the vast quantity of land that we would need to cover to meet the United States’ energy needs. Efforts to minimize these include research on the development of new materials that have higher efficiencies than silicon. However, even at 100% efficiency, solar photovoltaic cells and solar thermal power stations will require the use of vast amounts of land located in regions with a lot of sunshine.
HOST: Would you consider putting a solar water heater on your house? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
Andrew Gellman, a Lord Professor of Chemical Engineering at Carnegie Mellon University, explains how photovoltaic cells function to generate solar electric power.
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How do Photovoltaics Work from NASA
How Solar Works from Go Solar California
Solar Energy Basics from the National Renewable Energy Labaratory
Transcript
How is solar electric power generated and captured?
HOST: Have you ever wondered how energy is generated from sunlight? On this week’s Energy Bite, Andy Gellman, a professor at Carnegie Mellon University, has some answers.
ANDREW: Solar electric power is generated by materials called photovoltaics. When sunlight hits a thin wafer of silicon, a photovoltaic, the solar energy separates positive and negative charges near the surface so that the silicon wafer behaves like a battery. The photovoltaics cause the negatively charged electrons to go to one side of the wafer, which becomes the negative terminal of the battery. The positive charges go to the other side, which becomes the positive terminal.
HOST: How does using the different materials used as photovoltaics influence their ability to convert sunlight to energy?
ANDREW: The light from the sun has a spectrum of colors that we see in the rainbow; red through yellow to purple, and colors like infrared that we cannot see. Photovoltaic materials can only absorb light colors over a specific range. Those materials that absorb over a wide range of colors collect a greater fraction of the solar energy than those absorbing over a narrow range of colors. Ongoing research efforts aim to maximize the efficiency of solar energy conversion to electricity while also reducing the costs of solar cells.
HOST: Do you think the nation’s investment in solar energy research should be increased? 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 powering homes with batteries, whether they will save consumers money, and where they can best be used.
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Residential Solar Energy Storage Analysis from New York State Energy Research and Development
Battery Power for Your Residential Solar Electric System from the National Renewable Energy Laboratory
Is LG Attempting to Steal the Thunder from Tesla’s Entry into Home Battery Storage? from the Lawrence Berkeley National Labaratory
Transcript
HOST: Have you ever wondered if the home batteries in the news make sense for your home? On this week’s Energy Bite, Venkat Viswanathan, a professor at Carnegie Mellon University, has some answers.
VENKAT: Home batteries are typically used to store energy from a renewable source, such as a solar panel on your roof. When the sun is shining during the day, you can store the excess electricity generated for use later at night. You can also use home batteries to store electricity from the grid in case your power goes out. Current home batteries store about 2.2 kWh. Each battery provides enough power to run your television for about 5 hours. Multiple batteries could extend this time.
HOST: Should I buy home batteries now?
VENKAT: The cost for home batteries are prohibitively high for the average consumer. Two situations where batteries might make sense are for homes with solar power, and states like California and Hawaii where electricity is priced daily. Battery costs are dropping dramatically year after year and very soon, it might reach the price point where this is competitive for all consumers.
HOST: Would you buy a battery for your home? 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 how electric bikes work and what they can be used for.
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Intro to EBikes from Grin Technologies
AB-1096 Vehicles: electric bicycles from California Legislative Information
E-Bike Research at Portland State University from Portland State University
Transcript
HOST: Have you heard about electric bikes, and wondered how they work? On this week’s Energy Bite, Venkat Viswanathan, a professor at Carnegie Mellon University, has some answers.
VENKAT: Electric bikes are regular bikes that can operate in two modes — the normal pedal mode that a typical bike uses, and an assist mode where a battery can be used to help you pedal. You might use the assist mode, for example, when going up a big hill or windy conditions. These bikes may also be useful if you become injured or suffer from asthma in providing power when you can’t. E-bikes, as they are called, can go 15 to 20 miles in assist mode before the battery needs to be charged.
HOST: If I want to buy an E-bike, what factors should I consider?
VENKAT: There are two main considerations when you are buying an E-bike. First, how long can the e-bike operate in the assist mode, when the battery is being used. Second, how fast can the E-bike go in the assist mode. Just like pedal-only bikes, the price of E-bikes vary widely. On the low end, you can retrofit an existing bike so that it becomes an E-bike. On the high end are bikes that go really fast, which require use of a premium battery pack. E-bikes can also be rented instead of purchased.
HOST: Would you buy or use an E-bike? Take our poll, see the results, and ask your energy questions at Energy Bite dot org.
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