Innovations in energy harvesting are set to increase the sustainability of sport and recreation. Through these devices, users will be able to create electricity while they exercise.
Tough environmental challenges are forcing people to address the sustainability of their homes and businesses; the time has now come to address the sustainability of recreation and sport. The enjoyment and well-being sport brings come at a cost in terms of negative environmental impacts. Greenhouse gas emissions (GHG), irresponsible economic and energy practices, and intensive production of sports equipment all affect the environment.
The European Commission ‘White Paper on Sport’ insists on environmentally sound management which address GHG emissions and energy efficiency. While this requires a global reappraisal, it offers an excellent opportunity for innovation and job creation.
One development helping to make sport more sustainable is energy harvesting. A range of different technologies offer consumers the chance to make their sporting activities more sustainable by positively contributing to energy production. Energy-harvesting technologies harness the motion of the body during physical activity to generate electrical power. This may be achieved using piezoelectric devices to produce power upon application of mechanical strain or motion-harnessing technologies, which make use of oscillations created by the body to generate electricity.
Electrical energy generated from natural motion, such as walking, has long been thought a viable power source. Researchers at the US Space and Naval Warfare Systems Centre patented a technology that uses energy-harvesting devices in a shoe. This innovative technology could allow joggers, hikers and service personnel to recharge batteries or power small electrical devices continuously while walking or running.
Energy-harvesting devices built into the shoe sole use electrostrictive polymers. When deformed, the energy created by the movements of the wearer can create electrical energy. The shoe developers believe this technology can convert the energy produced by a person weighing 50 kilos into 5 W of electrical power, generating 5 J/s. This energy can be used to power health-monitoring equipment, personal global positioning system (GPS) devices or other small electronic equipment.
Canadian developer Bionic Power produced an innovative device known as the Bionic Energy Harvester. This was designed for people such as hikers who need access to off-grid power. The product is an unobtrusive wearable device that resembles a knee brace.
Just as a hybrid vehicle recovers power from the energy of braking, the Bionic Energy Harvester takes advantage of the negative or energy-absorbing work naturally performed by leg muscles during walking. Rather than creating resistance that demands additional effort, the device actually helps muscles do their locomotive work by engaging only during the ‘braking’ phase of the leg's swing when muscles are acting to decelerate the limb.
Without adding any noticeable effort to the wearer, a pair of the harvesters working together will passively extract up to 10 W of power. The manufacturers believe two minutes of walking will generate about one-and-a-half hour’s talk time on a mobile phone. As with the power-generating shoes, the Bionic energy harvester could also be used to charge batteries for radios, GPS or other electronic devices.
Energy harvesting of physical activity need not rely solely on adapted clothing or wearable devices. One innovative gym in the USA is recycling the energy generated by members as they work-out to create electricity. The Green Microgym in Portland, Oregon has installed specially adapted exercise bikes, cross trainers and treadmills fitted with energy-harvesting technology that create usable electricity.
“The big challenge has been finding the right equipment and adapting the technology,” says gym owner Adam Boesel. “Almost all the exercise equipment has a spinning wheel, and if you can spin a wheel, you can make electricity.”
Green Microgym teamed-up with Texas-based Henry Works to install a device it has developed called the Human Dynamo. This connects several exercise bikes with a battery that stores the energy generated as people pedal. Electrical appliances in the gym can then be plugged straight into the battery pack.
“A lot of gyms have a large spinning group exercise with 30 to 50 people exercising at the same time – and that is a perfect environment to use a machine like this,” says Max Taggett, inventor of the Human Dynamo. “Everyone is working extra hard and you have a lot of people doing it at the same time, and with a machine like the Dynamo, if you figure 100 W per machine and you have 40 machines that’s 4 kW.”
At present, the energy-harvesting devices in the Green Microgym only power the electrical appliances in the building, and do not contribute to the grid. However, developers at Henry Works are working on a new device, known as the FireWheel, which feeds the power generated by the exercise machines directly into the grid. This device will be tested at the Green Microgym.
Despite the obviously potential in using energy-harvesting technologies in the gym or offering it to off-grid joggers and hikers, such technology is not limited to these environments. Indeed, it can even be adapted in the most social of settings.
The WATT Sustainable Dance Club – the world’s first sustainable night club – opened in Rotterdam, the Netherlands in September 2008, and is set to make substantial savings on energy and water consumption. The centrepiece is its Sustainable Dance Floor. The concept for this unique feature was devised by the Sustainable Dance Club itself – which is an initiative of sustainability innovator Enviu and Dutch architect Döll.
The dance floor consists of a 30-m2 movable surface that converts the kinetic energy from dancers into electricity, which is then used to light the floor. The floor is made-up of 0.42 m2 tiles that move slightly vertically – no more than 1 cm – when a person dances on the surface. This movement is registered by advanced mechatronics and converted into electricity by an electric motor. Each person is able to produce 5 to 20 W of power, depending on their weight and the intensity of their dancing.
Innovative technologies, such as energy-harvesting devices, could represent stepping stones to the kind of sound environmental management outlined in the European Commission White Paper on Sport. As consumers become ever more conscious of the environmental impact of their actions, the need for viable energy-efficient and sustainable solutions becomes greater. By enabling people to create electricity as they exercise, these innovations provide users with the opportunity to harness their physical efforts for the good of the environment.
European Commission White Paper on Sport [COM(2007) 391 final]:
http://ec.europa.eu/sport/white-paper/doc/wp_on_sport_en.pdf [85 KB]
‘Motion-generated electrical energy’ US Space and Naval Warfare Systems Centre:
http://enterprise.spawar.navy.mil/cmt_uploads/29/Motion%20Generated%20Electrical%20Energy%20TIP%20Pacific.pdf [55 KB]
The Green Microgym:
The Human Dynamo:
Sustainable Dance Club: