The Potential of Energy Harvesting

Sensors Insights by Laurent Giai-Miniet

Energy is everywhere—it just needs to be harvested. Today, energy harvesting–enabled wireless systems are already well established in the commercial building automation sector. Technology providers now offer a wide range of energy-autonomous devices for connected buildings. Using motion, light, and temperature differences as energy sources, they can provide batteryless switches; intelligent window handles; temperature, moisture, light, and presence sensors; heating valves; and smart home systems. The technology, however, is still evolving. New applications of batteryless wireless communications will emerge that enhance the world in many ways, from structural health monitoring and water quality control to forest fire prevention, smart city management, and medical care.

Powering the Internet of Things
To put things into perspective, consider energy harvesting's role in the leading technology trends of the day. For example, everyone is talking about the Internet of Things, but how will these billions of connected devices be powered? The answer is: energy harvesting. Liberating sensors from the need for external power supplies, making them energy autonomous, sweeps aside once-insurmountable hurdles presented by cables and batteries and opens unlimited processing and monitoring applications.

The energy harvesting market is growing every year. Market forecasts predict this trend will continue, especially with the emergence of next-generation energy harvesting–enabled wireless systems.

Advances in Technology
The next generation of self-powered radio technology will be able to transmit data over distances as great as three miles—10 times greater than current technology—enabling outdoor applications with high-range requirements. These performance enhancements spring from improvements in energy converters that tap new energy sources and advance efficiency.

These advances include:

  • New types of mechanical energy harvesters that can extract energy from flowing gases and liquids, promising to extend smart meter functionality
  • Light harvesters combining smaller solar cells and enhanced energy storage that enable solar-powered devices to function in complete darkness for long periods of time, ranging from several months to as much as a year

Thermal energy harvesting also holds great promise, but the technology is still in the early stages of development. One option you may see in the future is the development of energy harvesting–enabled wireless systems that use temperature variations occurring between day and night to power outdoor applications.

New Applications
As energy-autonomous wireless systems advance in sophistication, a new range of applications will evolve. These will arise in a variety of industries and engineering disciplines. A few examples include:

Structural health monitoring. Large structures such as bridges, tunnels, dams, and drilling platforms have to resist extreme forces, such as weather, earthquakes, and traffic. Wireless sensors—powered by light, temperature differentials, and vibrations—can monitor critical parameters, identify nonconformance, and prevent structural failure. These sensors can also trigger alarms in the event of natural disasters such as avalanches and rockslides.

Environmental monitoring. Long-range, energy-autonomous wireless sensors can be distributed over large areas to monitor farm animals and crops to detect rapidly changing conditions. Such systems can prevent the spread of forest fires, optimize irrigation, and ensure the proper care of crops.

Resources monitoring. Because of their flexibility and autonomy, long-range, energy-autonomous wireless sensors are ideal for remote monitoring of environmental conditions and resources. For example, self-powered sensors can detect water, oil, and gas leaks.

Smart cities. By 2030, 60% of all people will live in a city. To provide adequate services, intelligent control of key infrastructures will be required. These will include automated control of traffic, lighting, energy, transportation systems, and waste disposal. This can only be realized with millions of energy-autonomous sensor nodes, collecting and delivering the necessary data to optimize operations.

Health care. Demographic changes and shrinking budgets are increasing pressure to reduce the cost of medical care. Remote patient monitoring offers one solution to these challenges. As a result, the market is already seeing the development of devices like bracelet prototypes that can monitor physiological conditions. These devices have the potential to operate for long periods of time unattended because they are powered by energy harvested from body heat. In fact, the energy converters promise to provide enough power to transmit wireless signals to gateways that pass the information back to medical centers via cell phones.

More to Come
These are just a few areas where energy harvesting is extending the functionality of wireless systems, opening new application opportunities, and laying the foundation for the Internet of Things. The role of energy harvesting in a broad cross-section of industries is still evolving, but one thing is clear: It is a key enabling technology in a number of emerging trends.

Laurent Giai-Miniet is the CEO of EnOcean GmbH. For more information on energy harvesting or EnOcean's products or services, please email [email protected].

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