During the past year, it has become obvious that the energy harvesting (EH) market has not grown as anticipated. There are a variety of reasons for that situation, the primary one being a lack of cost-effective solutions. The incumbent solutions are simply much too expensive to enable mass adoption. That is set to change in a major way in 2014. Up to now, much of the EH market has been centered in Europe. Starting this year, that will also change and the market will move to become Asian and North American centric. The biggest factor in these impending developments has already occurred; it was the announcement of battery-free options for ZigBee Green at the very end of 2012.
The impact of the battery-free option for ZigBee Green has already begun appearing in the form of products designed to support the anticipated growth of the market for EH-powered devices. For example, Texas Instruments, Inc. (TI) introduced five new next-generation power management integrated circuits that efficiently acquire and manage microwatts (uW) to milliwatts (mW) of power harvested from light, heat or mechanical energy sources. The bq25570, bq25505, TPS62740, TPS62737 and TPS62736 claim the industry's lowest levels of active quiescent current and enable battery-free operation to wireless sensor networks, monitoring systems, wearable medical devices, mobile accessories and other applications with limited access to power.
And Fujitsu Semiconductor Limited announced the release of two new power management IC products developed to utilize energy harvesting, the MB39C811 dc-dc buck converter and the MB39C831 dc-dc boost converter. Sample shipments for the two new products are scheduled to start in June of this year. The MB39C811 buck converter features a quiescent current of just 1.5µA and achieves world-leading results in ultra-low power operation. Moreover, the MB39C811 represents the world’s first simultaneous use of energy generation from both light and vibration using only one power management IC device.
Green Power is an optional feature for the ZigBee PRO feature set that is part of the enhanced ZigBee 2012 specification recently ratified and released to Alliance members. It significantly expands the capabilities of ZigBee PRO, further strengthening its leadership position as the global standard for wireless sensor and control networks and the Internet of Things. With ZigBee PRO Green Power products, consumers and businesses can add ZigBee devices to many more areas including locations where power is unavailable, not allowed for safety reasons or for historical preservation purposes.
Product manufacturers can implement ZigBee into more products with confidence, knowing ZigBee is backed by a thriving, innovative and competitive ecosystem. It would not be surprising to see manufacturers currently using proprietary protocols to adopt (or adapt) ZigBee Green to their ecosystems of devices.
“The use of energy harvesting in commercial building automation, for example, can reduce operating costs while helping organizations to demonstrate ‘green’ credentials,” said Lisa Arrowsmith, manager of connectivity research for IHS. “Additionally, with over 35 million ZigBee-enabled ‘smart home’ and home automation devices that are not line-powered projected to be shipped by 2017, the ZigBee PRO Green Power feature also presents a compelling option in the residential space.”
An exception to the general "rule" that EH-powered systems are too expensive can be found in the U.S. at Virginia-based PulseSwitch Systems, LC. The company's Lightning Switch® uses NASA-developed Thunder® piezoelectric technology to self-power a radio frequency transmitter, sending a unique ID-encoded signal to a Lightning® receiver. It provides portable, remote control of electrical loads at distances of up to 100 feet, or at unlimited range with optional repeaters. These systems have been installed in over 12,000 buildings.
Thunder, which is the highly-rugged and low-cost piezoelectric element that generates electric power, is a breakthrough technology from NASA space research and it is sold separately as a component for integration into OEM systems, in addition to being used in the Lightning Switch. In 2007, Lightning Switch was named one of NASA’s top 20 spinoff technologies of the past five years. Lightning Switch is a winner of the International NOVA Award for innovation in construction technology, and the international SPIE Smart Structures Product Implementation Award. Lightning Switch is also featured in the Department of Housing and Urban Developments PATH Concept Homes. The piezo elements in the Lightning Switch are manufactured and sold under license from NASA.
"Lightning Switch was the first commercial application of this class of flextensional actuators and generators," commented PulseSwitch CEO Brad Face. "Lightning Switch systems have been installed in more than 12,000 buildings and we've never had a single failure of the piezo element. In the last couple of years, despite the economic downturn, the OEM interest in using these piezo devices has increased dramatically and the big reason is price. Our customers tell us Thunder and Lightning save them 50% to 85%. New products using these devices should start appearing on the market in the near future."
Also within the past 12 months, MicroGen Systems, Inc. announced that vibration energy harvesting BOLT Power Cells enabled a live wireless sensor network (WSN) using Linear Technology Corp.'s Dust Networks LTC5800-IPM SmartMesh IP mote-on-chip at the Sensors Expo and Conference exhibition in Rosemont, IL on June 5-6, 2013. The Linear mote was powered by MicroGen's piezoelectric Micro Electro Mechanical Systems (piezo-MEMS) vibrational energy harvester or micro-power generator (MPG) technology.
The Linear WSN consisted of four motes, and their WSN software for efficient power managed communication was used. The self-powered motes were enabled by electronic shakers set at typical industrial vibrations levels of 120 Hz and acceleration G-level 0.2 g (g = 9.8 m/s). MicroGen placed vibration powered motes at the Linear booth and at the X-FAB MEMS Foundry booth. These motes were on the order of 20-30 meters away from MicroGen's booth. This was the first fully MEMS energy harvesting powered WSN completed by a commercial company.
On a relatively large-scale, Redpine Signals, Inc. recently announced the industry’s first multi-functional device with Wi-Fi, BT and BT-LE connectivity and incorporating photovoltaic energy harvesting. The device includes a sensor and an e-paper display that maintains display content at microwatts of power consumption. The device uses Redpine’s RS9113 M2MCombo SoC device to provide connectivity through Wi-Fi, BT and BLE wireless interfaces for sensor data transfer and display updates through the Internet of Things (IoT).
To summarize, as reported a year ago in PowerPulse, “the announcement last month (December, 2012) by the ZigBee Alliance of “Green Power” as an optional feature for ZigBee PRO is one of the most-striking indications that battery-less, wireless systems are poised for a surge in growth.” Until the ZigBee announcement, the options for deploying energy harvesting (EH) powered controls and sensors were limited, and so was the market potential of those devices. Prior to the ZigBee announcement, there were fewer than 50 companies seriously involved in the market for EH-powered devices. As a result of the news from ZigBee, today there are hundreds of companies involved in this area.
The changing and expanding standards landscape is only one of the significant developments that will drive EH products into the mainstream in 2013. A convergence of technologies will also be a major driver in the growth of this market. The power consumption needs of control and sensor systems is falling with each successive generation of semiconductor devices and the energy-delivery capabilities of energy harvesting systems is rising with successive generations. At the same time, the cost of wired systems continues to rise as basic materials such as copper wiring and installation costs (labor) continue to rise. Copper is being replaced with silicon. As a result, the energy harvesting market is well positioned for accelerated growth starting in 2013 and continuing over the next several years. This year will see accelerated growth as the EH market awakes and moves out of Europe into the broader global market.