Solar energy just means energy (light or heat) that comes from the sun. Solar energy has existed for five billion years, since the sun was born. humans have been using solar energy for thousands of years. The Greeks were the first to use solar architecture, over 2,000 years ago. They built their houses such the way the sun's rays entered during the winter, but weren't able to enter during the summer so they weren’t too cold or too hot. Entire cities were built this way! (They were way ahead of us.) The Romans got the idea to put glass on windows, which allowed the sun's light to pass through but trapped its heat. They even built glass greenhouses so they could have fruit and vegetables during all winter.

There are many different ways to use solar energy First, we can use it to heat, the water in our houses, the food in a solar cooker, and so on. This is called solar thermal energy. (Thermal means heat, so solar thermal energy just means heat energy from the sun.) The second basic way it’s using solar energy to turn light from the sun directly into electricity, for that you have to use solar panels.

To harvest the solar energy, the most common way is to use solar panels. solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, solar hot water, solar cooking, and high temperature process heat for industrial purposes. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy.

Even though humans have been using the sun's energy for thousands of years, solar electric technology is still very new and sometimes it's very hard to switch to a new system when you have another system working already.
Whereas Solar energy technology is also getting better every year, a lot of people might not realize that it's become as effective and usefull as it has maybe because of Making electricity with solar energy is still more expensive than