Energy harvesting is the process of collecting low-level ambient energy and converting it into electrical energy to be used as a power source for miniaturized autonomous devices. Examples of this can be seen in structural health monitoring, smart packaging solutions, communication systems, transportation, air and aerospace vehicles, structural biology, robotics, microelectromechanical systems (MEMS) devices, sensor networks, wearable electronics, agriculture, forest fire detection, or various Internet of Things (IoT) components
The large growth of internet of things (IoT) and sensor networks is predicted in the future. Cisco predicts, by 2020 the world will have trillions of sensor units distributed on the earth. For trillions of batteries that are vastly distributed and each having a limited life time, monitoring, replacing, recycling and exchanging batteries would be a huge and even an impossible task. Batteries have several disadvantages in: the need to either replace or recharge them periodically from fixed power sources, and their relatively large size and weight. Many batteries are rated for a typically 3- to 10-year lifetime; but in most practical applications they last for significantly less, often months rather than years.
Therefore researchers are therefore looking for alternative models to power the future IOT sensors. One of them is to integrate an energy harvester together with a battery to form a self-powered system. Human energy harvesting is a term used to describe systems that utilize the human body as a primary generator. Biomechanical energy harvesting from human motion, such as walking step; ankle, knee, hip, shoulder, and elbow joint motion; and center of mass vertical motion, are potential anchors for electrical power generators. However, human energy harvesters are not capable of generating sufficient energy to perform mechanical work, but could still power low-energy electronics.
Militaries are also exploring Energy harvesting technologies to tackle the issues with solar power like in extreme cold when the batteries fail to hold a charge, and in heavy shade the panels don’t operate. Researchers at the Natick Soldier Research, Development and Engineering Center are working to develop wearable energy-harvesting technology solutions including wearable solar panels as well as backpack and knee kinetic, energy-harvesting devices to reduce weight and the quantity of batteries soldiers required to power their devices.
The possibility and the effectiveness of extracting energy from human activities has been under study for years. As a matter of fact, continuous and uninterrupted power can potentially be available: from typing (~mW), motion of upper limbs (~10 mW), air exhalation while breathing (~100 mW), and walking (1 W). Reimer and Shapiro theoretically proved that up to 4 W could be generated with a 4-mm compression of a shoe sole that is easily achieved at natural pace, that is, two steps per second (or 1 Hz per insert) by a person of 80 kg. The maximum energy that can be generated, assuming that 50–80% of the energy during walk is stored as elastic energy in the shoe would be 2 W.
The increase in minitarization and energy efficiency of electronic components are also aiding in employment of energy harvesting solutions. “Technology advances have enabled modification of the size and shape of the electronic components to the microscale, with commensurate scaling down of their power requirements to milliwatts and microwatt range. Consequently, many complex electronic systems and devices such as wearable medical and autonomous devices consume power in the range less than 200 μW, and wireless sensor networks in the range μW to 100 mW are operated on battery power,” write Vikrant Bhatnagar, and Philip Owende.
“We’re on the path toward wearable devices powered by human motion,” said Nelson Sepulveda, associate professor of electrical and computer engineering and lead investigator of the project, in a press release. “What I foresee, relatively soon, is the capability of not having to charge your cell phone for an entire week, for example, because that energy will be produced by your movement.”
Nanotechnology research, development and application are relevant and potentially beneficial to almost every facet of our lives, including health, energy, infrastructure, information technology, transportation, food safety, environmental science, as well as defence. Nanotechnologies can greatly aid in meeting the future demand for energy harvesting. Some nanotechnologies can operate without a traditional electricity source and can draw the energy they require from the environment in which they operate.
Global warming and the resultant energy crisis has motivated scientists to search for renewable and green energy resources in order to ensure sustainable development of our human civilization. Nanotechnologies will significantly assist in meeting the future demand for energy harvesting. The goal of energy-harvesting technologies is to develop nanogenerators which operate over a broad range of conditions for extended time periods with high reliability. The discovery of nanogenerators is one of the top ten world discoveries in science, according to academics from the Chinese Academy of Science. Their discovery could have equal importance as the invention of mobile phones in 10 to 30 years, according to the New Scientist. Nanogenerators are in the top six future and emerging technologies selected by European Commission for support in the next 10 years.
IDST Monthly Access Membership Required
You must be a IDST Monthly Access member to access this content.