Spinach and renewable energy

We are using spinach in our cell biology laboratory to understand photosynthesis.

Solar energy is transformed into electricity and this energy (storage of electrons is an energy source; please, think about batteries) is used to convert CO2 to store the energy as organic material.

In our experiment we capture the electrons released with a chemical that is blue but colorless once it is reduced (when it captured the electrons). Consequently, the absorption change (if you see through a dark glass, compared to a non-colored glass, you will see less) is measured as a function of time.

(Purified Chloroplasts)

In the first experiment (dark circles), the purified Chloroplasts (our nuclear light reactor) are exposed every 30 seconds to light.

During the second experiment (white circles) while the experimental condition is the same the solution was stored in the dark. Obviously, without light exposure, the release of electrons is not working well.

In the third reaction we repeat the first reaction, but additionally a broadband pesticide is used. This pesticide captures the electrons and prevents the dark reaction (the conversion of electrons to organic material). If organic material cannot be produced the weed will not grow and eventually die.

What is the relation with renewable energy?

Let us remind us of the process.

Energy (Sun, Wind) is captured, but we need to store the energy (once is clouded or the wind is not blowing there would be no energy). In the cell we can capture the electrons. In the case of solar cells or wind-turbines, we can store the energy in batteries or convert the energy into chemicals (hydrogen).

If we want to capture CO2, we can use the stored energy to convert CO2 into gasoline.

This is very similar to the cell, which converts the energy into organic material.

Of course, every energy conversion is connected to a certain amount of loss of energy. Thus, maybe battery or hydrogen cars are more efficient. The energy efficiency of the last step is crucial because the further conversion of energy by utilizing CO2 could be too energy consuming. However, the CO2 capture in the last step might convert gasoline-powered cars to an environmental friendly alternative. Battery cars are still not environmental friendly (this will be another blog).

Anyhow, the ideas of all processes are not new; it is applied cell biology and an experiment with spinach will help you to understand this process.