In order to make America more sustainable, we need to take a realistic look at how we use oil and what the alternatives are, according to Gary Dirks, director of LightWorks at Arizona State University and a renewable energy expert.
Dirks said cars, trucks and buses make up 29 percent of U.S. energy use.

"In addition to a long-term transportation energy plan that does not include fossil fuels, we need a nearer term solution that can take us from the traditional internal combustion vehicles to tomorrow's advanced fleet," said Dirks. "That future should include the sun.

"There are techniques and nascent technologies in the works that will take carbon dioxide, water and sunlight and combine them in such a way to generate fuels for our cars, but today they are too expensive," Dirks said. "More research and development is needed to make these fuels a reality. That is why the U.S. Department of Energy (DOE) is sponsoring an energy innovation Hub to make 'drop in' fuels from sunlight."

According to Dirks, these fuels don't require the production of any fossil fuel and are created from renewable components. The process is similar to photosynthesis, by which concentrated solar energy is used in conjunction with carbon dioxide and water to create hydrocarbons. In addition to creating combustible fuels like methanol and ethanol, additional processing can yield more traditional fuels like gasoline, diesel and jet fuel.

"The fuels that result from these processes will look, feel and perform just like what we pump into our cars today," he said. "They will use existing refineries to prepare fuel blends and existing gas stations to deliver the fuel to today's cars."

The new fuels will be carbon neutral, he said, and will not require drilling or off-shore production.

The DOE Hub, along with several other initiatives, specifically looks at processes for making solar liquid fuels and bringing them to market in a developmentally rapid, 15-year time span.

"Even with subsidies, the cost difference could be dramatic," Dirks said. "Five dollars for a gallon of solar liquid fuel is a realistic short term target, but it could be more. So, we need to ask ourselves, do we want to continue with what is convenient and economical today or do we want to focus our efforts on what is the logical next step in our long-term energy future?"