Renewables absolutely have the capability to meet out energy needs. Solar alone has reached to point where a sub-$10k installation can power a reasonably efficient house, even in the Northern US; in places that get enough wind (a lot more places than you might expect), a single small turbine can power a house, or a modest sized tower can power an entire neighborhood.
No, renewables can't meet the demand today, and possibly never will. You have made the classic mistake of assuming your experience is typical of everything everywhere. A typical solar installation is capable only of meeting a normal households power needs part of the time. Even with neighborhood wind turbines, you will not cover 100% of the power needs. Now consider that household power only accounts for 21% of the U.S. energy consumption. The overwhelming majority comes from industrial and commercial power use which has a much higher land density, and simply cannot be covered in any meaningful way with solar or wind power. Now you're back to needing industrial scale power generation which requires massive amounts of land for the scale required by industry and you're back to needing big again. If you covered the entire island of Manhattan (every square inch of exposed surface) with solar panels, you would only add up to about 1/4 of the total power demand. Sure you have lots of open space in Arizona, but you have to get the power from Arizona to Manhattan and its just not that simple. Also, how much deforestation are you willing to undertake to supply the energy needs of industrialized nations?
You are a very large part of the problem. Your arguments are bunk and fail to stand up to the realities of the world, and yet on the surface sound plausible enough to convince at least three moderators to mod you up on Slashdot (which I like to think has a smarter than average population). You and your ilk will have us so paralyzed following dead end projects that we'll all end up cooked thoroughly from global warming before any one of you will even be willing to concede that you're not half as smart as you think you are.
A group of very intelligent individuals from some of the most highly recognized institutions of the world tells you that renewables cannot be made sufficient to stop global warming, and you are going to tell the rest of us that they are wrong because of your own anecdotal experience? I think its high time we started calling your type out for the BS you're spewing.