Table 2 Features and characterization of some previously developed nano-systems to harvest renewable energy from natural resources (wind, ocean and solar resources)

Electromagnetic generators (EMG)

Portable wind energy harvester based on S-rotor and H-rotor

5–12 m/s

108 mW, 23.2%

(\(\uparrow\)) powers the monitoring sensors in railway tunnels

(\(\uparrow\)) uses hybrid S-rotor and H-rotor

Double-Skin Façade system for harvesting wind energy

3–8 m/s

1110 W/m²

(\(\uparrow\)) low turbulence and uniform flow due to cavity

(↑) provides a wide range of angles for incident wind

Galloping, vortex shedding, flutter, and aerodynamic instability

2–6 m/s

1 W

(↑) based on wake galloping

(↑) a simpler mechanism for structural health monitoring system

(↑) powers wireless sensors

Piezoelectric nanogenerators (PENG)

The flutter of a flexible piezoelectric membrane

9 m/s

5 mW/cm³

(↑) simple inverted flag orientation

(↑) Self-aligning capability

(↑) can operate in low-speed regimes

Vortex-induced vibration-based piezoelectric EH

1–1.4 m/s

0.6 mW

(↑) facilitates Y-shaped attachments on bluff body

(↑) provides an enhanced energy harvesting efficiency

MEH is composed of permanent magnets, rotor, piezoelectric stack, and flexure mechanism

100 rpm

0.2 mW

(↑) simple and compact design

(↑) optimal performance with a larger power output

Pyroelectric (PEG)/ Thermoelectric generators (TEG)

Flexible vortex generator or turbulator

1–25 m/s

3 \(\mu\) W/cm²

(↑) Flexible structure with un-interrupted energy output

(↓) possesses low pyroelectric coefficient

Harvesting solar and wind energies using thermal

oscillations through sustainable PEG

2.5–5.3 m/s

421 \(\mu\) W/cm³

(↑) provides high power density

(↓) power density depends on the intensity of the solar irradiations and wind speed

Triboelectric nanogenerators (TENG)

A rotary TENG based on mechanical deformation of multiple plates

15 m/s

39 W/m²

(↑) facilitates the application of polymer nanowires

(↑) can be used as a self-powered wind speed sensor

TENG-based windmill composed of nanopillar-array architectured layers

14–15 m/s

568 V, 26 μA

(↑) simple and cheap fabrication

(↑) high output and optimal performance

(↑) high stability

Pendulum-based TENG using a pendulum structure with high energy conversion efficiency

2 m/s, 2 Hz

56 V

(↑) superior durability

(↑) ultrahigh sensitivity

(↑) long-time operation

(↑) energy harvesting from wave and wind