These slides use concepts from my (Jeff Funk) course entitled analyzing hi-tech opportunities to show how energy harvesters are becoming more economically feasible for the Internet of Things (IoT). Small amounts of energy can be harvested from vibrations, temperature differences, and radio frequencies using various types of electronic devices such as piezoelectric, MEMS, thermo-electric power generators, and other devices. As improvements in them occur and as the energy requirements of accelerometers, pressure sensors, gas detectors, bio-sensors, and readout circuits fall from microwatts to hundreds of nano-watts, energy harvesters become cheaper and better than are batteries. Improvements in energy harvesting are occurring in the form of higher power per area or higher power per temperature difference and improvements of about five times are expected to occur in the next 5 to 10 years. The market for energy harvesters is expected to reach $2.5 Billion by 2024. In addition to their impact on buildings and the other usual applications for IoT, they will also impact on agriculture, aircraft, and medical implants.

1. ENERGY HARVESTERS
POWERING THE IOT
MT5009 Analyzing High-Tech
Opportunities
National University of Singapore
Rhee Min Woo A0132465J
Douglas Gong A0034283L
Karen Tan A0132409M
Thomas Chan A0133076L
Wang Niyou A0039878H
Tan Geok Bin A0110245Y

2. • Introduction to IoT And Sensor
• Energy Harvesters (EH)
• Important Dimensions Of Performance &
Cost For EH
• EH Technology Drivers, Challenges &
Roadmap
• EH Applications For Entrepreneurial
Opportunities
• Conclusion
AGENDA

3. IoT - A SMART WORLD of Sensors

4. EH DEVICES SUSTAINING POWER IN TEMPERATURE SENSORS, AIR QUALITY SENSORS, USED IN HEATING,
VENTILATION, AND AIR CONDITIONING (HVAC) ,LIGHTING APPLICATIONS, HEALTHCARE
SMART WIRELESS SOLUTIONS
Source: https://www.enocean-alliance.org
SMART OFFICE SMART HOSPITAL
SMART HOME SMART FACTORY
others…retail buildings, schools, streets, amusement parks, malls, sports complex, hotels, airports,
transportations etc

5. TRILLION SENSORS in IoT

6. SHRINKING SENSORS COST WITH REDUCED SENSOR SIZE
>~ $300
<<$1
2010 2015 2020

7. • Introduction to IoT And Sensor
• Energy Harvesters (EH)
• Important Dimensions Of Performance & Cost For EH
• EH Technology Drivers, Challenges & Roadmap
• EH Applications For Entrepreneurial Opportunities
• Conclusion
AGENDA

8. WHAT IS ENERGY HARVESTING?
Energy harvesting is the process of capturing
ambient energy and storing as electricity.
4 main ambient energy sources present in our
environment:
• Mechanical energy (vibrations, deformations)
• Thermal energy (temperature gradients or
variations),
• RF energy (radio transmissions)
• Solar energy (sun)
It is FREE energy.

9. AUTONOMOUS WIRELESS SENSOR NETWORKS & NEEDS
Energy
Harvesting

10. BATTERY OPERATED WSN VS ENERGY HARVESTED NODE
Source: http://www1.i2r.a-star.edu.sg/~hptan/publications/icc2010_wsnheap.pdf
1 year
infinite
time

11. MEGA-SCALE MESO-SCALE MICRO-SCALE
• Large scale energy production
• Harvested power density in the
range of MW/cm3
• Large scale power devices
• Power density in the range
of W/cm3
• MEMS-NEMS Scale, for Ultra low
power electronics such as WSN
• in IOT
• Power density range of μW/cm3
ENERGY HARVESTING TAXONOMY
NOW NOW MINIATURIZATION in the IOT Era
Vibrations EH mounted on industrial
motor

12. POWER CONSUMPTION FOR VARIOUS
APPLICATIONS
Zigbee

13. HOW MUCH MICRO-SCALE EH POWER CAN
BE TAPPED ?
Source: Holst Centre

14. MEMS VIBRATION ENERGY HARVESTING
Power ~ 100uW /cm2
Source: Development of piezoelectric microcantilever flow sensor with wind-driven energy
harvesting capability
Huicong Liu, Songsong Zhang, Ramprakash Kathiresan, Takeshi Kobayashi, and Chengkuo Lee
PIEZOELECTRIC
10 × 8 × 0.45mm3
3D VIBRATION-DRIVEN ELECTROMAGNETIC
MEMS ROTARY COMB ELECTROSTATIC

15. THERMOELECTRIC ENERGY HARVESTING
CMOS MEMS-Based Thermoelectric Energy Harvester ~14uW/cm2 @ 5K
Source: Jin Xie, Chengkuo Lee, Ming-Fang Wang, and Hanhua Fang, Seal and encapsulate cavities for CMOS MEMS thermoelectric power
generators, J. Vacuum Sci. & Technol. B, vol. 29, no. 2, pp. 021401, Mar 2011

16. PHOTOVOLTAIC ENERGY HARVESTING
Solar Power Energy Harvester In MEMS Wireless Intra-ocular
Pressure Sensor ~ 10mW/cm2

17. RF ENERGY HARVESTERS
RF Energy Harvesting Converts Radio Waves Into DC Power ~ 0.1uW/cm2

18. ENERGY HARVESTERS TECHNOLOGIES
Thermal 100uW/cm2 ; Vibration 300uW/cm2; PV 15mW/cm2 ; RF 10uW/cm2

19. Reduce the power consumption per transducer below 100 nW, while meeting resolution,
bandwidth and measurement range constraints
SENSORS ROADMAP – POWER REDUCTION IN IoT
CURRENT SOA EH TECHNOLOGIES (10uW to 15mW) MEETING DEMAND OF IoT
SENSORS

20. Scaling in Piezoelectric Vibrational EH
Reference : APEC2011 MicroGen
PRICE REDUCTION WITH REDUCED EH SIZES
Miniaturization driven by MEMs technology reduces cost
$300~900 à less than $50 (2014). In IoT, < $1 integrated micro-EH

21. • Introduction to IoT And Sensor
• Energy Harvesters (EH)
• Important Dimensions Of
Performance & Cost For EH
• EH Technology Drivers, Challenges & Roadmap
• EH Applications For Entrepreneurial Opportunities
• Conclusion
AGENDA

22. IMPORTANT DIMENSIONS OF PERFORMANCE
& COST FOR ENERGY HARVESTERS
Performance
- Effective Energy Source (Motion/Light/Temperature)
- Power output (μW, mW, Voltage x current)
- Conversion efficiency (%)
- Life time-reliability (hr/month/year)
Cost
- MEMS / Wafer scale 6,8,12,18 (inch)
- MEMS / Device Miniaturization
- Device Packaging &Test ($)
- Process Platform, yields (%)

23. IMPORTANT DIMENSIONS OF PERFORMANCE
& COST for Energy Harvesters
– Energy Sources
Reference : APEC2012
Reference : ECTC2014

24. IMPORTANT DIMENSIONS OF PERFORMANCE
for Energy Harvesters
– Power Generation vs Vibration G in VEH
– Power Generation vs Device Size in VEH
Reference : APEC2011 MicroGen
P ∞ A
– Power Generation increased by size (A) and intensity of external
energy source (G)

25. IMPORTANT DIMENSIONS OF PERFORMANCE
FOR ENERGY HARVESTERS
– Power Generation vs Temperature difference/ Size in TEG
Reference :
P ∞ ΔT
P ∞ A
Larger
– Power Generation Temperature difference (ΔT) and
device size (A)

26. IMPORTANT DIMENSIONS OF PERFORMANCE
for Energy Harvesters
– Performance (ZT / Power density) of Thermoelectric materials for TEG
Reference : Northwestern University Reference : Nextreme
– TEG materials for Higher ZT is continuously developed
– TEG with thin film technology showed significantly improved power density
Seebeck coefficient S,
thermal conductivity λ, and
electrical conductivity σ,
and temperature T.

27. IMPORTANT DIMENSIONS OF PERFORMANCE
for Energy Harvesters
– Power Generation vs Operational Life Expectancy
– Battery continuously decrease the power density as years goes by (5yrs max)
– EH shows stable power supply over the years, normal target is > 20yrs

28. • Introduction to IoT And Sensor
• Energy Harvesters (EH)
• Important Dimensions Of Performance & Cost For
EH
• EH Technology Drivers,
Challenges & Roadmap
• EH Applications For Entrepreneurial Opportunities
• Conclusion
AGENDA

29. • Proliferation of autonomous sensing and communication systems
• Advanced infrastructure, materials and design tools
(micromachining, functional thin films, wafer stacking)
• Techniques for integration with ultra-low power electronic circuits
and sensors
• Better understanding of energy efficiency limits
• Availability of hybrid harvesters
• Going beyond CMOS disruptive energy efficient technologies
and devices towards Nanotechnology (nanowire electronics,
NW, NCTs, carbon and graphene ,spine electronics, memristive
devices, photonics, synthetic photovoltaic cells etc)
TECHNLOGY DRIVERS & CHALLENGES FOR
ENERGY HARVESTERS

30. MEMS TO NEMS TECHNOLOGY ROADMAP
THERMOELECTRIC EH POWER DENSITY 0.5mW/K2
to 4.5mW/K2

31. UNDERSTANDING EFFICIENCY LIMIT FOR
THERMOELECTRIC ENERGY HARVESTERS
CARNOT EFFICIENCY FOR DIFFERENT THERMO MATERIALS

32. TOWARDS NANOTECHNOLOGY ROADMAP
PHOTOVOLTAIC ENERGY HARVESTER
EFFICIENCY (@40% in 2023 > SQ LIMIT 33.7%)

33. PHOTOVOLTAIC MATERIALS FOR OPV DEVELOPMENT

34. PHOTOVOLTAIC EH EFFICIENCY
LIMITED BY SHOCKLEY QUEISSER (SQ 33.7%)
30%
15%
2013 2018 2023
33.7%
SQ Limit
CIGS
20%
CdTe
16%
amo
Si
13%
Polymer 8%
DSSC(solid)
7%
DSSC(liquid)
13%
STATE OF ART
PV EH
Efficiency
Single
crystal
Si solar
cell -
costly
KEY RESEARCHER
Challenge to
Exceed the SQ
Limit at lower cost
in IoT.

35. MEMS TO NEMS TECHNOLOGY ROADMAP
VIBRATION ENERGY HARVESTERS
Power density 1.5mw/cm2 to 10mw/cm2

36. HYBRID VIBRATION ENERGY HARVESTORS PROTOTYPE
Development of combo Piezoelectric & EM EH prototype @ NUS MEMS energy
harvester dept - Increase power density from 0.1mw/cm2 to 5mw/cm2

37. • Introduction to IoT And Sensor
• Energy Harvesters (EH)
• Important Dimensions Of Performance & Cost For
EH
• EH Technology Drivers, Challenges & Roadmap
• EH Applications For
Entrepreneurial Opportunities
• Conclusion
AGENDA

38. GLOBAL MARKET FROM 2014-2024
Economically feasible
technologies:
Thermoelectric and
Piezo EH
Early adopters stage:
Entrepreneurial opportunities
starts now. Get ready for
launch by 2017!

39. WHY THE THERMOELECTRIC AND
PIEZOELECTRIC EH SEGMENTS?
› Thermoelectric have no moving parts
› Piezoelectric promises high efficiency (up to
90% with further research)
› More affordable
› Superlative energy density

40. CHALLENGES
1) Energy capacity: still limited to some low-powered
devices
2) Cost: an energy harvesting device is and will remain
for a while considerably more expensive than batteries
or the main grid (batteries are typically US$0.30 to US
$1)
3) Size: must be small to enable mobility <1cm3; and
lightweight.
4) Integration: between different involved parts. Using
energy harvesting would require changes in the supply
chain.

41. ENERGY HARVESTERS MARKET POTENTIAL

42. WIRELESS SENSING FOR AGRICULTURAL MONITORING
Precision Agriculture Monitor System (PAMS) is an intelligent system which
can monitor the agricultural environments of crops and provides service
to farmers. PAMS is based on the wireless sensor network (WSN)
technique. EH powered sensors.

43. WIRELESS SENSING FOR HUMS FOR AIRCRAFTS
Positions of sensors required to monitor the health and usage of the
Cougar’s Sikorsky S-92. EH powered sensors.

44. THERMOELECTRIC EH: IN CHIPS
Micropelt Thermogenerators
http://www.micropelt.com/thermogenerator.php

45. ENERGY HARVESTERS IN WEARABLES
Thermoelectric watch Perpetual Energy Source
Sola
r
cell
EH

46. PIEZOELECTRIC EH: CONSUMER APPLICATIONS
Piezo Vibration Sensor
Figure shows an energy harvesting
device attached to a pig’s heart.
Battery-less pacemaker may
eliminate the main shortcoming:
wearing out of batteries.

48. SUMMARY ON MARKET FEASIBILITY STUDIES
1) EH Technology: Thermoelectric & Piezoelectric are the
2 more ready EH technologies for commercialization.
2) Market Readiness: dependent on specific application.
Can be implemented for wireless sensors applications
in the Consumer Electronics sector.
3) Market Potential: Studies predicts a $2 billion potential
by 2024 for just the thermo and piezo-electric EH
market.
4) Sectors with Opportunities: Mainly in wireless sensors,
wireless switches, sensors for rotating machines, in
HUMS for aircrafts and human healthcare monitoring.

49. • Introduction to IoT And Sensor
• Energy Harvesters (EH)
• Important Dimensions Of Performance & Cost For
EH
• EH Technology Drivers, Challenges & Roadmap
• EH Applications For Entrepreneurial Opportunities
• Conclusion
AGENDA

50. CONCLUSION
In a SMART WORLD, autonomous smart devices
and sensors requires:
• Off-grid power
• Power source that lasts the lifetime of the
device
• Miniaturized and Cheap
Micro-Energy Harvesters satisfy these needs with
effective and efficient power management
solutions through scaling and materials
development towards Nanotechnology.