Power from Plants

At the moment the amount of electricity generated in this way remains tiny, but the potential is huge

Throughout history many cultures have worshiped the Sun for its life-giving powers.  In reality it is not the Sun itself, but rather the plants that have learned to harvest that all powerful sunshine, to whom we should bow on bended knees.

Think about it. Everything you have ever eaten, or will ever eat, can ultimately be traced back to an organism carrying out photosynthesis.  The word itself, “Photosynthesis” says it all: “To create from light.”  And the precious oxygen we breathe is one of the waste products of that creation.

The oldest known fossils are those of cyanobacteria, microscopic organisms that 3.5 billion years ago evolved the ability to turn water, carbon dioxide and sunlight into sugar, that magic molecule that fuels all cellular life.  Through a fateful encounter with a different and more complex cell, cyanobacteria eventually gave rise to the ancestor of those organisms today known as plants.  Today those remnant cyanobacteria are known as chloroplasts.

Most people know that plants take in water and CO2 and produce carbohydrates and gaseous oxygen.  But what is often misunderstood is the source of those oxygen molecules.  They come from the splitting of water, not the CO2.

The first step in photosynthesis uses the energy of sunlight to break a water molecule into its basic parts; an atom of oxygen and two atoms of hydrogen.  Known as “photosystem II” (named that way because it was discovered after the second step in the process, photosystem I) the hydrogen protons are stripped away from a water molecule and two atoms of oxygen are joined together released as a waste product.

As positively charged protons accumulate on one side of a membrane a sort of chemical battery is created, the power of which is then used to generate the energy-rich molecule ATP which in turn is used to fix CO2 into the sugars that feed almost all life on the planet.

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