石油および環境バイオテクノロジージャーナル

概要

The “Some Sense” of Biofuels

Madelyn R B Ball1, Ruth Chen2 and Yinjie J Tang2

Over the past years, the production of biofuels worldwide has increased significantly due to concerns over the limited quantity and high environmental impact of crude oil. 2011 saw a 2.5% increase in global primary energy consumption, yet renewables still only account for 2.1% of total energy consumption . Current biofuel production, primarily ethanol, has grown by the equivalent of more than 20 million tonnes of oil in the past decade, yet it makes up a very small fraction of the world energy sources. There is disagreement on whether biofuels are a worthy investment of research and production time and resources. Dr. Harmut Michel argues that it is nonsense to convert the solar energy into biofuel because of the poor energy capture by photosynthesis in plants, which gives as low as 0.2% energy efficiency. In contrast, current solar cells have efficiencies as high as 15%, which can effectively absorb solar energy and then be stored in battery systems. Furthermore, current biofuels depend mainly on crops, which may compete with food plants for agricultural land or result in removal of natural forests through conversion into oil palm plantations.