methods of harnessing solar energy

Indirect Methods of Harnessing Solar Energy

Energy from Sun is available on earth in various forms.
some forms can be direct where we have developed technologies to harness the direct forms such as photon energy and thermal/radiation energy.
but Energy exists in various forms and changes from one form to another.
Let us know about There are two ways for the utilization of solar energy.

  • Direct Methods
    • Thermal
    • Photovoltaic
  • Indirect Methods
    • Wind
    • Biomass
    • Wave Energy
    • Ocean Thermal
    • Marine Currents
indirect methods of harnessing solar energy
flow chart depicting solar energy types

In this article, we will be discussing all the indirect methods of harnessing Solar Energy .

1. Wind

The wind originates due to uneven heating of the earth’s surface by the sun. The heat due to the sun generates atmospheric pressure. This atmospheric pressure results in the blowing of wind by the process of diffusion. The area near the equator gets warmer than the area near the poles. The hot air rises and the pressure of the area near the equator becomes low as compared to the pressure at the poles. Now, due to this pressure difference, cold winds blow from poles towards the equator. Simultaneously, the hot air which rose up due to warming migrates towards the poles and gets cooled up there. This cycle continues.

how is wind created ? it is via solar energy

2. Biomass

Biomass is the organic material which is produced by plants and animals. But how is it related to the sun? Let’s find out. The plants which produce this biomass use solar energy to synthesize their own food with the help of photosynthesis and the animals feed on plants to live. In this situation too, the solar energy is indirect, but the primary source of energy. The steam produced by burning of biomass can be used to rotate the turbine and generate electricity.

Bio mass energy is indirectly related to solar energy.

3. Wave Energy

Wave energy is produced by the movement of waves of the ocean. Waves are created when wind moves over the surface of ocean. Wind in turn is a produced due to heating of the sun. These waves can travel several kilometers with almost no loss of energy. The kinetic energy of these waves can be converted to electricity with the help of Wave Energy Converter (WEC). This WEC drives a generator which produces electricity.

Wave energy electricity generation schematic

A simple example of how energy is created by the motion of waves is shown below.

4. Ocean Thermal Energy

When the sun rays fall on the surface of water, the surface absorbs the rays and becomes warm while the water at deeper level remains cold. This creates a temperature difference between the upper surface of water and the water at deeper level. This temperature difference can be utilized to generate electricity. A plant is set up between these two layers of water with a working fluid which has a low boiling point like ammonia. When the working fluid reaches the surface of the region it gets vaporized. This vaporized fluid is used to drive the turbine of the generator. The vaporized fluid is then condensed with the help of condenser which uses the cold water from the deeper section of the ocean.

Ocean Thermal energy from solar energy

5. Marine Currents

Marine Currents are of two types: surface driven and deep ocean currents.

The surface currents are caused when wind moves the upper layer of water in the direction of its propagation. The upper layer then pulls the layer of water beneath it and that layer further pulls the layer under it. This is the principle of viscosity. This phenomena gradually diminishes as we go down deep inside water. These movements of layer of water are called currents and the kinetic energy of these currents can be used to produce electricity.

marine currents caused by solar energy radiation

The deep ocean driven currents are caused due difference in the density of upper and lower layers of water. Water density depends on  the temperature, salinity (saltiness), and depth of the water. The colder and saltier the ocean water, the denser it becomes.

Now some people might think that what is the difference between Wave energy and Marine Currents?

In wave energy, the molecules of water just oscillate about their mean position up and down which produces a transverse wave. But, in Marine currents, the molecules of water travel from one place to another.

These Topics of Indirect methods of Harnessing Solar Energy as often not talked about from a business point of view , as the economics of making these technologies viable and profitable is lagging in terms of scales of operations required.
These technologies offer an insight to what forms of Solar energy are available to us on Earth, and how the energy from Photons and heat is changed into different forms of energy. ALL POSSIBLE from a DWARF STAR called The SUN.

We wanted you to know about these sources/ indirect forms of solar energy aswell.