ミチェル博士の論点は、「光合成」を新エネルギーの根底とするには、光合成のエネルギー産生の効率が悪すぎるというもので、いままで私達が考えていた「光合成ほどエネルギー産生効率のいいものはない」という常識を、少なくとも教授にとっては覆すものでした。
特に、蒸気機関車のエネルギー効率が１％以下との比較で、光合成の効率の高さがいろいろなところで記述されていたことを記憶していたからです。それから、確かに時代は大きく変わったことは間違いありません。
とくに、光合成をベースにした新エネルギーは、コストが高く付きすぎるという論点でもありました。
このあたりは、しっかり調べて見る必要があるようです。
＜参考＞ノーベル化学賞受賞者Dr. Hartmut Michel (Max Plank Institute for Biophysics)のキーノート講演「The Nonsense of Biofuels」（バイオ燃料のナンセンス）の要旨
「Wednesday, January 15, 7:00 – 9:00 p.m. KAUSTAuditorium building 20
[Nobel laureate, Hartmut Michel, Director of Max Plank Institute for Biophysics]
Biofuels are obtained from biomass, and are derived from the photosynthetic activity of recent years. Fossil fuels are, however, the result of photosynthesis millions of years ago. The lecture will focus on the efficiencies of the individual steps in photosynthesis and discuss potential ways to improve their yield.
The overall efficiency of photosynthesis is very low: less than 1% of the energy in sunlight is stored in the form of biomass, and there is not much hope for substantial improvement. Biogas and biodiesel per area unit and year contain about 0.4 % of the energy of sunlight, which the unit area has received in the same period.
In addition, at least 50% of the energy of biogas or of biodiesel had to be invested from conventional (fossil) energy sources to produce the biogas or biodiesel. Therefore, production and usage of biogas or biodiesel is not CO2 neutral.
By comparison, usage of photovoltaic cells is more efficient by a factor of 50 to 100 with respect to energy conversion, and electric engines are fourfold as efficient as combustion engines. In comparison, driving a car using electric batteries loaded by photovoltaic cells and electric engines requires only 0.2% of the land that would be required when driving a car with a combustion engine using biodiesel.」
Growing energy plants and biofuel production is therefore a very inefficient use of land. The usage of biofuels made of palm oil or soybeans from tropical countries will enhance deforestation, lead to a loss of the tropical rain forest and increase climate changes. In addition, we will lose biodiversity and many biological compounds that might help fight human diseases. Most importantly, we need the land to feed an increasing world population.]
