Home » Featured, Solar » What is Indirect Solar Power?


Everyone has heard of solar power, but not everyone is aware that there are in fact several distinct different types of solar power and these can be split into several categories. One important distinction to make however is indirect solar power, and here we will look at what precisely that means.

            Solar power of course is energy that comes from the sun. Generally we tend to think of this as meaning the use of solar panels in order to absorb energy (which themselves can be broken down in photovoltaic and solar thermal panels). However this energy is also used by the Earth in many other ways and this allows us to gather it after it has been absorbed or utilised in through other means – this is what is known as ‘indirect’ solar power.

            A very simple example of indirect solar power that’s easy to understand is geothermal energy. Geothermal energy is essentially energy that comes from deep within the Earth (thousands of metres down generally) in the form of heat. This heat can then be used to heat water which we can use in order to warm up our living spaces or to use for baths or swimming pools. The question is – where does this heat come from? And the answer is logically from the sun – which heats up the Earth over long periods of time so that deep below us where there is lots of insulation it remains constantly at a high temperature. This then is indirect solar power because the sun heated the ground and the ground then heated our properties.

            Meanwhile though other forms of energy are also indirect solar power in a way. Take wind energy for instance – this is gathered by utilising the kinetic energy in wind (wind is fast moving air particles) in order to turn rotors on wind turbines. This then powers generators which develop electricity via electromagnetic induction. However while this energy comes from the win, the wind itself is caused by the heating effect of the sun which heats up the ground and thus warms up the air close to it. This then causes that air to become hotter which then rises (because hot air exerts more pressure it is lighter than cold air – hence by hot air balloons work). In turn this then leaves air pockets which the cooler air on top all rushes into creating the effect of wind. Again then as the wind is caused by the sun, wind energy is really a form of indirect solar energy.

            But not all indirect solar energy is good – for instance the sun is also responsible for the fossil fuels that we burn. This is because the sun is what gives plants their energy – via photosynthesis – and then it is these plants that are broken down and become the fossil fuels we rely on over thousands of years. In a sense then, the vast majority of energy is really indirect solar energy (except with the exception of some tidal power which is caused by gravity) meaning that we would do well to simply cut the middle man and go directly to the source by using more direct means.

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