growth rate) that Turner mentioned earlier. Scientists can create new technologies to improve the energy payback, according to Nocera. Turner agreed, and said that scientists need to find less energy-intensive ways to make energy conversion systems, while also maintaining the growth rate. The quicker that more efficient, less expensive materials and systems are identified, the easier society can move to a sustainable energy system.
Frankie Wood-Black of ConocoPhillips mentioned that there can be unintended consequences of new energy systems and that scientists will need to consider these potential unintended consequences when new technologies are being developed. She used hydrogen and electric cars as an example. Since those vehicles are much quieter than vehicles with traditional combustion engines, pedestrians do not hear them and are at risk of being involved in an accident.
Charles Casey of the University of Wisconsin brought up concerns about hydrogen as an energy carrier because of infrastructure challenges. He suggested that hydrogen be converted into hydrocarbons since the infrastructure is already available for hydrocarbons. Turner responded by stating that the infrastructure really does not exist for synthesis of these proposed hydrocarbons. Carbon dioxide would have to be taken out of the air and added to hydrogen in order to generate a fuel, which is a huge challenge in the United States, said Turner. He argued that a hydrogen infrastructure does indeed exist since 9 million tons of hydrogen is produced every year in the United States. The hydrogen infrastructure is just not in a form that is recognized.