Finding alternative energy sources is a global problem. Companies and individuals work to make energy cheap and available for everyone. Some projects are large-scale and some are tiny, but there's a place for all kinds of experiments when you talk about life-changing innovations.

A week ago a new crowd-funding campaign started on Indiegogo - VAGA HandEnergy. It is named after its developer Michael Vaga - a 17-year-old student from Belarus. This pocket energy generator is not his first idea - but the first one to become a real device. The current prototype is based on a rotor gyroscope and weights about 400 gr - a little heavier then a regular gyroscope exerciser.

But Michel plans to make it smaller and put all electronics into a short wrist strap. Now the device generates a little less energy then gadgets can get from a socket - you'll need to spin it for about 25-30 minutes to charge a cellphone for 10%. HandEnergy can also accumulate some charge but Michael says it is small comparing to the phone's battery. The team is working to reach 2000-3000 milliapmere of accumulated charge.

Of course, this is an emergency solution first of all. But for Michael it is just the first step towards changing the global energy system. And looks like he is one of those smart, pushing and - that's important! - realistic people who really can make a change.

And using human body as an energy source is not a utopia.

Researchers at the University of California, San Diego have designed a sensor in the form of a temporary tattoo that can make electricity out of sweat. Or, to be more specific, out of lactate produced by the body during physical exertion. In testing, the maximum amount of energy produced by a not-so-fit person was only about four microwatts, or less than half the energy needed to run a watch.

But what if we use bigger "tattoos"?

For instance, LED lights in the corridor at the busiest Terminal 3 of Heathrow Airport are powered by 51 Pavegen tiles which harvest energy from footsteps. The charge may be stored in batteries or used immediately. Though Pavegen is headquartered in London, its flooring technology is used not only in the UK.

The same tiles are used outside a busy train station in Saint Omer (France), in Melbourne's Federation Square (Australia), the world's first people-powered football pitch in Rio de Janeiro (Brasil).

And there are so many crowded places where such tiles could perfectly work - busy streets of New York and Tokyo or any playground and amusement park.