Solar energy goes back as far as some of the first people on the planet. When ancient ruins are discovered today, its often seen that they were built to take full advantage of the sunlight at various times of the day and/or at various times of the year. Instinctively, these people realized that they needed the sun for their food and for warmth when the weather got cold. They built their homes and common areas to protect themselves and to harness as much warmth and value from the sun as they could. It didnt seem to take them long to figure that out, and its still being done in areas of the world where there isnt access to electricity.
Many people in impoverished countries or very remote areas still live with no electricity or running water. They use the power of the sun for warmth just like people did hundreds and thousands of years ago.
More recently, solar energy is being harnessed in better ways, through the use of technology. Solar panels, actually called photovoltaic cells, are designed to collect the energy from the sun and store it, allowing the homeowner to use it as needed to power the home. Most people dont get all of their power that way, but it does help them lower their electric bills.
Some people are also able to go off grid, and live in some ways like the people of old – relying on the sun for warmth and daily life needs. While initial cost may prohibit this for many people, the costs are coming down.