What’s the most abundant source of clean energy available to us? We see it rise in the East every morning and watch it set in the West every night.

In theory, solar energy could more than meet the energy demands of the entire global population. In reality, though, many hurdles stand in the way of that goal, in particular cost (political will is another issue). Another obstacle is that sunlight is unevenly distributed across the planet … and is available for only half the day at most, meaning we’ll need more technological advances for storing solar energy for access at night.

Consider these facts about solar energy today:

• On average, our planet receives about 340 watts of solar energy per square metre, though just under half of that is available at the surface. The rest is reflected back into space by clouds or absorbed by gases and particles in the atmosphere.
• Solar energy is the largest energy resource available to us; one hour’s worth exceeds what all 6.8 billion of us consume in a year. (If you want to extend solar’s punch even further, consider that many of our other key energy resources — from oil and coal to wind — also come to us courtesy of the sun, which helps drive atmospheric mixing and enabled the growth of ancient life that eventually became fossil fuels.)
• Solar-generated electricity capacity has been, on average, doubling every two years since 1998, according to BP’s Statistical Review of World Energy 2009. As of 2008, the total global solar energy capacity had reached 13.4 gigawatts. Most of that growth — more than 75 per cent — came from expansion in just two countries, Spain and Germany.
• The world’s largest photovoltaic installation is currently Spain’s Olmedilla Photovoltaic Park, which went online in 2008 and has a peak generating capacity of 60 megawatts. The biggest solar thermal energy facility is NextEra Energy Resources’ SEGS complex in California’s Mojave Desert, with a maximum generating capacity of 354 megawatts.
• The Desertec project, an initiative announced last year, could conceivably generate up to 470 gigawatts of electricity by 2050, according to research by the German Aerospace Centre. The project entails installing a massive solar thermal array in the North African desert to provide up to half the energy needs for North Africa, the Middle East and Europe combined.
• At today’s level of global energy consumption — 18,000 terawatt-hours per year — we would need to cover just 3/1000th of Earth’s desert regions, about 90,000 square kilometres, to meet demand.

• What parts of the world get the most sunlight?
• What we know about solar energy
• Where to see the highest solar panels in the world
• 8 minutes and 19 seconds that could change the world
• Solar energy goes through the roof in Germany
• Water + solar = savings for cash-strapped California utilities
• Remembering Brian Robertson of Amonix
• In job growth, US solar industry outdoes the average big time
• Solar and oil: New energy helps extract old in California
• Oregon eyes energy, economy boost with US’s largest solar highway