Often theorized (but hardly evidenced), unlimited, clean and free energy in modern terms usually refers to the process of harvesting natural environmental conditions to produce power while having little impact on the actual environment from which those conditions are harvested.
Technologies like solar power, which according to futurist Ray Kurzweil has been doubling every two years for the past 30 years all the while costs have been dropping, represent a real strategy for unlimited clean energy. He believes that solar energy is only six “doublings” (or less than 14 years) away from meeting 100 percent of today’s energy needs. He further estimates that renewable sources will provide more energy than the world needs in less than 20 years and that even then, we will be using only one part in 10,000 of the sun’s light.
In places like Germany, Spain, Portugal, Australia, and the Southwest United States residential-scale solar production has already reached “grid parity” with average residential electricity prices. Simply put: it costs no more in the long run to install solar panels than to buy electricity from utility companies. This presents a scary thought for electricity producers.
That’s not all though. There are also technologies to harness the power of wind, biomass, thermal, tidal, and waste-breakdown energy and shows like Dirty Jobs has covered near-entirely self-sufficient farms that utilize a mixture of all of the above stated technologies in order to live free of the grid while producing very little waste. This is a veritable light at the end of the tunnel for environmentalists and scientists alike.
So back to the question: when will we have unlimited and free clean energy? The short answer, as always, is nobody knows for sure. Mr. Kurzweil offers a near-future outlook while many major media outlets appear to be spreading fear and doubt in order to discourage progress, an unstoppable train of innovation and promise that will happen whether or not we like it.