"The good news is that we have plenty of energy from the sun. Every day, the sun sends to the earth's surface about 173,000 terawatts of energy, or more than 10,000 times more that is used by human society. So, we have a lot of what we like to call 'upside potential' for capturing sunlight energy."
Up to now, harnessing the energy of the sun has proven to be technically and socially challenging. In particular, approaches to make biofuels from crops such as corn have been met with skepticism in recent days.
"When people think of capturing sunlight energy in biomass, they focus on plants, which are familiar. However, plants are quite inefficient at capturing sunlight energy and turning it into biomass that can be used a fuel," Rittmann explains. As a result, plants could provide only a tiny fraction of our society's energy needs. "Obviously, we need the plants for producing food and sustaining natural ecosystems. Plants simply fail the scalability, environmental, and food tests."
In contrast, microoganisms, the smallest forms of life on Earth, can meet the scalability and environmental tests. Rittmann sees a vast untapped potential of using microbes in service to society to meet our energy challenges.
"Photosynthetic bacteria can capture sunlight energy at rates 100 times or more greater than plants, and they do not compete for arable land," Rittmann said. This high rate of energy capture means that renewable biofuels can be generated in quantities that rival our current use of fossil fuels.
In addition, non-photosynthetic microorganisms are capable of converting the energy value of all kinds of biomass, including wastes, into readily useful energy forms, such as methane, hydrogen, and electricity.
"Microorganisms can provide just the services our society needs to move from fossil fuels to renewable
|Contact: Joe Caspermeyer|
Arizona State University