Experiments are under way to harvest free energy through motion and the environment, which could lead to devices such as mobile phones that can be recharged without electricity. One Laptop Per Child has experimented with charging XO laptops through solar power, foot pedal and pull-string. Nokia last week released a kit that draws energy from cycling to recharge phones.

Orange said it would demonstrate boots that recharge mobile phones through energy derived while walking. While Orange's contraption is experimental, Tremont Electric is already selling a device that captures energy from running or walking to recharge mobile devices.

Gumboots that charge mobile phones

Orange this week announced Wellington rain boots that can generate energy through walking to recharge mobile devices such as cell phones and MP3 players. Called "Orange Power Wellies," the boots use modified soles that generate energy with each step, which is then channeled to recharge mobile devices.

Orange Power WelliesA sole includes thermoelectric modules sandwiched between two thin ceramic wafers. Stepping creates heat on the top ceramic wafer and coolness from the ground is applied to the lower wafer, which generates electricity. The hotter a foot gets, the more energy it produces. Around 12 hours of walking charges a mobile phone for one hour of use.

Orange announced the electric boots in time for the Glastonbury Festival in the UK, where they will be on display between June 23 and 27. The festival is a vehicle for Orange to announce renewable energy prototypes, last year the company pitched the Glastonbury Solar Concept Tent, which included photovoltaic threads for solar energy to recharge devices.

The Wellies were developed with GotWind, a company that experiments with renewable technology resources. Orange and GotWind two years ago at Glastonbury demonstrated a "Dance Charger," a small generator mounted in an armband that created kinetic energy through dancing.

Kinetic energy goes commercial

Speaking of kinetic energy, Tremont Electric is selling a portable device that can recharge smartphones through everyday activities like running or walking. The NPower PEG (personal energy generator) is small enough to be carried or placed in a backpack, according to company executives. It includes a recyclable lithium-polymer battery that stores energy and attaches to portable devices through a USB port. Tremont sells the charger for $149.99. It works with Apple's iPhone, Research In Motion's BlackBerry and HTC smartphones.