Solar irradience on the surface of Earth is about 1200 W/m^2 Total energy consumption in 2008 was 143,851 TWh Take panels that have 20% efficiency, and assume

Solar irradience on the surface of Earth is about 1200 W/m^2 Total energy consumption in 2008 was 143,851 TWh Take panels that have 20% efficiency, and assume they can absorb for 6 hours a day, for 70% of the year (255 days). You can generate 368 kW/year. To generate the total 143851 TWh, you'd need about 3.91e11 m^2 of area. That sounds a lot, but it's only a square of land 625 km per side, or about 90% of the area of California. Note that this is of course a very hand-wavey order of magnitude estimate. The problem isn't the abundence of energy sources, it's the collection, retainment, transmission and generation reliability of it (those factors overlap - generation reliability can be offset by better transmission and vice versa). We don't really have to go looking far for energy sources, we just really struggle to harness them with current technology.