Futurist Ray Kurzweil notes that solar power has been doubling every two years for the past 30 years — as costs have been dropping. He says solar energy is only six doublings — or less than 14 years — away from meeting 100 percent of today’s energy needs. Energy usage will keep increasing, so this is a moving target. But, by Kurzweil’s estimates, inexpensive renewable sources will provide more energy than the world needs in less than 20 years. Even then, we will be using only one part in 10,000 of the sunlight that falls on the Earth.

If you were to build a city from scratch, using current technology, what would it cost to live there? I think it would be nearly free if you did it right.

We decided to combine our energy innovation study’s best-case scenario results with Hansen’s climate model to see whether a 55 percent emission cut by 2050 would bring the world back below that 350-ppm threshold. Our calculations revealed otherwise. Even if every renewable energy technology advanced as quickly as imagined and they were all applied globally, atmospheric CO2 levels wouldn’t just remain above 350 ppm; they would continue to rise exponentially due to continued fossil fuel use. So our best-case scenario, which was based on our most optimistic forecasts for renewable energy, would still result in severe climate change, with all its dire consequences: shifting climatic zones, freshwater shortages, eroding coasts, and ocean acidification, among others. Our reckoning showed that reversing the trend would require both radical technological advances in cheap zero-carbon energy, as well as a method of extracting CO2 from the atmosphere and sequestering the carbon.

Science journalist Ranga Yogeshwar has gained extensive access to Japan's battered Fukushima power plant. He speaks to DW about exploring radiation-contaminated zones, and how the cleanup has progressed so far.

Think for a second how much energy is literally washed down the drain when you take a shower. Not the water itself — just the energy that’s lost when you heat up said water, pump it through a series of pipes to your showerhead, and then let all that warm goodness run straight down your body and into a hole in the floor. By some estimates, 80 to 90 percent of the energy it takes to heat that water ends up going straight to the sewer. Considering the fact that the energy required to heat water is one of the biggest energy expenditures at home (right behind heating/cooling/ventilation), that’s a monumental waste of juice. But not to worry; there’s a new device on the market that could help to recapture some of that wasted energy.

It’s called EcoDrain, and while it’s definitely not a new concept, it’s a fresh new take on an old idea, and finally makes waste heat recovery a viable possibility for regular homeowners.

There are many designs for efficient stoves, and gasification is only one way to boost the efficiency of a cooking fire. The wood gas stove in this article is an elegantly simple gasifier design called a TLUD stove (for top-lit updraft), also known as an inverted downdraft stove. If you don’t care how it looks, you can build it with a can opener, a punch, and a big rock. This design, which I’ve adapted from one I first saw on Instructables, is built around a 1-quart paint can. It easily boils enough water for a small pot of tea or a bowl of noodles, using nothing more than a fist-sized charge of scrap wood.

TEPCO has become a symbol of everything that is wrong with the nation of Japan: cronyism, collusion, gentrification, corruption, weak regulation, and entropy. Despite being in the spotlight for the worst nuclear disaster since Chernobyl, TEPCO continues to engage in questionable labor practices, and has escaped bankruptcy in closed-door meetings with politicians, and through denying culpability has shifted part of the reparations burden onto taxpayers – deeds which testify to the extent to which TEPCO still has plenty of political power, if not as much nuclear power.

Using nuclear power in place of fossil-fuel energy sources, such as coal, has prevented some 1.8 million air pollution-related deaths globally and could save millions of more lives in coming decades, concludes a study. The researchers also find that nuclear energy prevents emissions of huge quantities of greenhouse gases. These estimates help make the case that policymakers should continue to rely on and expand nuclear power in place of fossil fuels to mitigate climate change, the authors say (Environ. Sci. Technol., DOI: 10.1021/es3051197).

Hypothetically, switching off the lights for an hour would cut CO2 emissions from power plants around the world. But, even if everyone in the entire world cut all residential lighting, and this translated entirely into CO2 reduction, it would be the equivalent of China pausing its CO2 emissions for less than four minutes. In fact, Earth Hour will cause emissions to increase.

Japan may face a total nuclear shutdown in the summer for the second time since the March 2011 Fukushima disaster as the country's two operating reactors close for maintenance and tough new safety checks keep the rest of the fleet offline.

That could force Japan to import even more fossil fuels for power generation, adding to an onerous energy bill that helped push the country into a record trade deficit in 2012.