Energy from solar panels

Is solar energy truly free? What are the pros and cons of renewable power sources? What do we prefer not to mention ...

Basic units: volt, amper, watt

Before talking about solar energy, we have to define some electrical units tightly connected with the subject. 

  • A volt is a unit of voltage. The battery in a cellular phone has a nominal voltage of 3.7V. Starting battery in a passenger car has a nominal voltage of 12V. 
  • An ampere (A) is the unit of electrical current
  • When describing the power of an electric item, in most cases we use Watt. One Watt means 1 Volt multiplied by 1 Ampher. More volts and amperes in the circuit the more power (more Watts).

Power of items around us

Cordless kettle consumes a power of 2000 VA or 2000 W. An electric heater can have a power of 1000 - 3000 W. The engine of an average passenger car has a power of 100-200 Power Horses, that is around 150-300 kW.

The power that human can generate

When going by bike an average man can generate one-tenth of the power needed by the electric kettle. A professional cyclist can generate up to 400 Watts for an hour or two. Best cyclists can produce over 1000 Watts but only for a short time. That means that we would need at least two professional cyclists to boil the water in an electric kettle. And after that, they would be completely exhausted.

Demand for energy

The modern world needs lots of energy. Highly developed societies, like North America, consume a lot of power. The majority of that energy is produced by burning fossil fuels. This causes the greenhouse effect and is responsible for a significant part of air pollution. 

People want cheap or even free energy. Some people want to be independent of the public power grid. More and more people are motivated by environmental reasons - they want to reduce their carbon footprint. As a result, alternative energy sources are gaining popularity all over the World. 

The efficiency of solar panels

The solar panel's efficiency increases each year and the cost per kVA, gained from solar cells, falls. This means that solar energy becomes cheaper each year. The Sun is pretty old but still in good condition and scientists say that it is going to operate for a long time. We can treat the sun as an infinite source of free energy.

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