The continued use of fossil fuel including oil, gas, and coal to meet our energy requirements is expensive, ever-depleting, and labor extensive with damaging effect on the environment and ecosystem we depend on for our very existence.
It is the main factor, if not the only, that causes air pollution, the greenhouse effect, rising sea levels, climatic changes – global warming in general – a growing concern for environmentalists and scientists the world over.
Although humans have been harnessing the Sun’s energy or solar energy since time immemorial, it is now, in this century, and to some extent the latter part of last century, that a range of technologies for harnessing this freely renewable source of power have been developed and is ever evolving.
The Earth intercepts about 173,000 terawatts of solar power which is easily 10,000 times more energy than what the entire population of the planet consumes.
So, is there a chance that some day we could be totally reliant on solar energy? In order to address that question we first need to examine how solar panels convert solar energy into electrical energy.
Solar panels are made up of small units called solar cells. The most common solar cells are made from silicon, a semiconductor that is one of the most plentiful elements on our planet.
In a solar cell, crystalline silicon is sandwiched between conductive layers. Each silicon Adam is connected to its neighbors by four strong bonds which keep the electrons in place so no current can flow.
A silicon solar cell typically involves two different layers of silicon, the “N” type silicon and the “P” type silicon. While the “N” type silicon has extra electrons the “P” type has extra spaces for electrons called holes.
Where the two types of silicon meet they form a “PN” junction. Electrons move across the “PN” junction leaving one side positively charged while creating the negative charge on the other.
One can visualize light as the flow of minute particles called photons emanating from the Sun. A photon striking the silicon cell with enough energy can dislodge an electron from its bond leaving a hole.
This enables the negatively charged electron and location of the positively charged hole to move around freely.
However, they can only move one way because of the electric field at the “PN” junction. Hence, the electron moves to the “N” side and the hole to the “P” side.
Thin metal fingers at the top of the cell collect the moving electrons and it is from here that the electrons flow through an external circuit to complete some electrical work like powering a light bulb, for example, before coming back through the conductive aluminum sheet on the back of the solar cell to where it started from.
The output capacity of each silicon cell is merely half a volt; however, you can string them together to get more power. While 12 photovoltaic cells are sufficient to charge a mobile phone, many would be required to power an entire house, for instance.
What is remarkable about solar cells is that they can last for decades as the only moving parts in the cell are the electrons which, in any case, go back to where they start from. There is nothing in a solar cell that goes through any wear and tear.
So, why have we not yet become 100 percent reliant on solar power? It must be mentioned that there are many political factors in play. Also, vested interests and non-renewable energy businesses are continuously lobbying to maintain status quo. They make every attempt to ensure that their applecart is not upset.
However, for the time being, let’s concentrate on the physical and logistical hurdles in the way of total reliability on solar energy. For one, solar energy is unevenly distributed across the planet with some parts being sunnier than others. Also, it is not very consistent in that less solar energy is available at night or under overcast conditions.
Therefore, to achieve complete reliance, effective and efficient storage of energy has to be ensured in order to get solar power from sunny areas to the not-so-sunny ones.
Another challenge is the efficiency of a cell itself as sometimes sunlight is reflected instead of absorbed. Also, a dislodged electron may well fall back into the hole before going through the circuit resulting in the loss of that photon’s energy.
The most efficient solar cell can only convert about 46% of available sunlight to electricity while most commercial systems are only 15-20 percent efficient.
However, in spite of the limitations and drawbacks, the existing solar technology in the world today is good enough to meet the power demands of the entire planet.
To achieve complete reliance on this renewable source, proper funding for developing the necessary infrastructure and a lot of space would be required. It is estimated that it would take hundreds of thousands of square miles which may seem to be a lot of space but don’t forget that the Sahara desert alone is more than 3 million square miles of open space with more than enough sunlight.
As time progresses solar cells keep getting better, cheaper and are competing with electricity from the grid. Furthermore, innovations like floating solar farms may change the entire field of play thereby solving space problems on land, if any.
It is estimated that in developing countries over a billion people don’t have access to a reliable electric grid. Now, most of these countries receive ample sunlight making solar energy a much cheaper and safer option in these places than the available non-renewable alternatives like kerosene.
Here are some important points to note in regards to solar power and its benefits. It might encourage you to make the switch from conventional to renewable energy sooner rather than later.
Fixed or eliminated utility costs
Immunity from fluctuating energy economy
Predictable energy spending for decades
INCREASED PROPERTY VALUE
Tax credits available
Up to 30% increase in property value
Higher resale value
No Carbon Emissions
Positive environmental impact
Limitless Energy Supply
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