Table 1 Distribution and significance of nano-mechanical energy harvesting systems over various renewable energy sources of MEH and categorization concerning output power

Road profile

✓ 

[43]

Piezoelectric EH structure

2–4 mm, 5–10 Hz

3 mW

–

 × 

[44]

Chessboard sliding plate on the road

–

66 W

62.4%

× 

[45]

Piezoelectric MEH using road bump

10–30 km/h, 38–53 kg

4.1 W

13%

 × 

[46]

High-efficiency MEH paver

80 kg

12 W

50%

✓ 

[47]

MEH from multi-directional vibration

5 km/h

1.4 mW

–

Railway track vibrations

 × 

[48]

Electromagnetic energy convertor

1–2 Hz, 6 mm

6.5 V

56%

✓ 

[49]

Thermoelectric EH using railway track

–

317 mW

60%

✓ 

[50, 51]

Smart railway monitoring system

10–30 Hz

548 mW

–

 × 

[52]

Vibration EH using multi-frequencies

5.6 Hz

1.5 W

–

 × 

[53]

The electromagnetic based EH from the railroad

-

10–100 W

74%

Shock absorber vibrations

 × 

[54]

MEH from hydraulic shock absorber

5–25 mm, 1–5 Hz

397 W

50%

 × 

[55]

Electromagnetic shock absorber EH for railway cars

2–4 mm, 2–4 Hz

1.2 W

68%

 × 

[56, 57]

Regenerative mechanism for shock absorber

5–10 mm, 1–3 Hz

0.5 W

84%

✓ 

[58]

Self-powered sensor nodes for freight rail transport

80 km/h

263 mW

65%

 × 

[59]

Energy regenerative shock absorber based MEH

2.5–7.5 mm, 1–2.5 Hz,

4.3 W

55%

Ocean wave

 × 

[60]

Ocean-wave based energy harvesting mechanism

Wave height of 0.2 m

63 W

–

 × 

[61]

The floating WEC

0.8 m, 0.76 Hz

–

39%

 × 

[62]

WEC with power take-off mechanism

8 mm, 3 Hz

–

67%

✓ 

[63]

Oscillating buoy as WEC

15 mm, 1.2 Hz

3 V

57%

 × 

[54]

Hydraulic energy regeneration from shock absorbers

72 km/h

397 W

50%

Wind energy

✓ 

[64]

Piezoelectric EH from wind energy

6.5 m/s

25 mW

–

✓ 

[65]

Wind EH using fibre composites

7.5 m/s

0.53 mW

–

✓ 

[66]

High-performance piezoelectric EH for wind energy

2.1 m/s

1.2 mW

–

✓ 

[67]

A rotational piezoelectric wind energy harvester

14 m/s

160 V, 2566 μW

–

✓ 

[68]

Vibro-impact dielectric wind EH

4 m/s

0.72 mW

–

Bio-mechanical energy

✓ 

[69]

Scavenging energy from human motion

5 Hz

9 mW

8%

✓ 

[70]

Electromagnetic EH from human movements

9 km/h

85 mW

92%

✓ 

[71]

MEH for ultra-low frequency vibrations

4 Hz

5.3 mW

–

× 

[72]

A human motion-based vibration energy harvester

4.8 km/h

5.1 W

–

✓ 

[73]

Biomechanical energy harvesting pavement

30 Hz

300 mW

–