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Your chariot awaits! Electric vehicles, mobile gadgets and the future of American energy use

Think about buying 100 old-fashioned 100-watt light bulbs. Imagine placing them in lamps, flicking all the switches on and leaving them burning bright for 24 hours a day. The amount of energy needed to do that is about equal to one American’s daily energy use, said Yip-Wah Chung, professor of materials science and engineering at Northwestern University.

That per capita energy use in America averages out to roughly 250 kilowatt-hours of energy per person, per day. That means every single person in your household is using 100 of those 100 watt light bulbs worth of energy.

This energy use comprises everything in the country that requires energy: homes, transportation, industry and government to name a few. One-fourth of that total is for personal stuff: cars, homes, televisions, mobile devices. If we were to one day become solely reliant on renewable energy, we would need to cut down consumption by half in every category, Chung said.

“The world’s energy problem that we face is global, but the solution is local,” he said.

America’s energy consumption

For the last 50 years, America’s energy consumption per capita has taken the honors for the highest in the world. For the last three years, consumption in the U.S. has flattened because of the economic crisis, but still, compared with Europe and developed countries in Asia, America is the top energy user.

China uses more energy than the U.S. but not nearly as much per person. The price of energy in the U.S. tends to still be cheap, and that pushes up consumption, said David Dunand, professor of materials science and engineering at Northwestern University.

“The important thing to remember is that we are an oil producing country here,” Dunand said. “It just happens that we use it all and then some more.”

The three main sources of energy in the United States include coal, mainly for electricity; oil, for transportation; and natural gas, for electricity, heating and industry. These three sources make up 85 percent of all energy, and the rest comes from nuclear, hydro, wind and other renewables – all used mainly for electricity, Dunand said.

“So when you pay at the end of the month, you are accessing – whether or not you want it – the regular mix that is constantly changing,” Dunand said.

In fact, when we plug into the power grid for electricity, we are all getting a mix of anything that is centralized: wind energy, nuclear energy, coal. Solar energy, which tends to be decentralized, sold in modular systems, provides an option for consumers to increase their usage of renewable energy. People can choose to add solar panels to their homes to generate a higher percentage of their own energy, Dunand said.

The trend in the last couple years has been to use less coal and more natural gas and wind energy – both cleaner and cheaper options. But how do we know which options are best?

The answer is life-cycle analysis.

“One should look – and it’s called life-cycle analysis – over the whole life-cycle from the production [of the energy source] to the disposal and recycling, at what the full life-cycle burdens are in terms of carbon, but also in terms of emissions,” Dunand said.

Life-cycle analyses, or assessments, for energy technologies look not only at emissions from generating electricity, but also energy use in gathering the resources, transportation and building power plants. The assessments also evaluate emissions from those activities, said Margaret Mann, a researcher with the Life Cycle Assessment Harmonization Project, which was led by the National Renewable Energy Laboratory.

This means consumers need to be aware of every aspect of how the energy they use is produced. The Harmonization project shows that our top sources of energy – coal, oil and natural gas – are also the top producers of greenhouse gas emissions. Renewable energy sources such as wind and solar and nuclear energy produce significantly less emissions on average.

Mann said these assessments help us recognize that emissions aren’t just coming out of the stacks at power plants but from the entire process of extracting fuels and brining them to the plant.

“The goal is to take a much more comprehensive view at what causes emissions,” Mann said.

Researchers with the Harmonization project looked at more than 2,000 life-cycle assessments for electricity-generating energy technologies and worked to show these assessments in a consistent light. They looked at averages and identified outliers, and ultimately they were able to derive greater certainty about the greenhouse gas emissions of the different technologies, said Mann.

“Our goal was to do credible and objective work so decision-makers have greater confidence in what they are looking at,” Mann said.

This means that, ideally, decision-makers such as politicians and utilities will better be able to assess the types of electricity-generating energy technologies that they are looking at.

The future of transportation

Life-cycle analysis can come in handy when assessing the differences between fueling a typical combustion-engine vehicle and an electric vehicle. Because someone with a plug-in vehicle is plugging into the grid, the differences depend on how the local electricity is produce, Dunand said. This brings us back to the unique local mix of energy.

“We want zero emissions from well to wheel,” said Michael Farkas, CEO of CarCharging Group.

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