Over 86,000 terawatts of solar energy reach the Earth’s surface each year- enough to satisfy current global energy demand 1000 times over. In 2008, solar electric power amounted to a mere 0.2% of global energy produced but it is at a tipping point with a growth rate of 40% per year. Exponential growth, enormous solar resources and the global economy's unquenchable demand for electricity increasingly position photovoltaic power as vital to 21st century technology.