Hermann Diels popularized the term pre-socratic in Die Fragmente der Vorsokratiker (The Fragments of the Pre-Socratics) in 1903. However, the term pre-Sokratic was in use as early as George Grote's Plato and the Other Companions of Sokrates in 1865.
The cost of a solar panel today is around $3 per watt, and the extra cost of installation brings costs up to $5- $6 per watt. Note: Installation costs for PV systems include both labor and the electronics needed to tie the solar array into your existing electrical system.
Solar power is a clean, renewable energy source, yet it makes up less than 1 percent of the power used in the United States [source: USA Today]. Part of the reason more people aren't using solar energy to power their homes is the cost. Solar panels can cost $30,000 or more to install, an investment that can take 10 to 15 years to recoup [sources: Live Science, CNET News, Walsh].