TLDR: It's a great concept but it's about 100× more exhausting than you imagine.
I absolutely love stuff like this, and I also love cycling.
However, there is a big caveat here: I've been cycling for years and know my own power output:
Output -- Time Window -- Heart Rate
- 1400 W* | 60 seconds | 208 bpm
- 385 W | 20 minutes | 162 bpm
- 148 W | 6 hours | 110 bpm
*(yes, I know. My thighs are larger than some people's torsos and it scares me too)
That means that on average, around 13 and ½ hours of pedalling to charge this thing. (2 KWh is also worth $0.68¢ where I live at standard residential rates).
Humans are not great at converting their physical and thermal energy into kinetic or electrical (20-24% for most bodies).
Pedal power is amazing for things like charging phones or powering small devices and computers though, or for something completely meta: Charging up a eBike or electric scooter (120W), to then use without pedalling later.
Which then begs the question -- if our "human/person power output" is like 150 watts constant .. and the sun provides 1.4 kW/m² of energy -- why not just lay down a 150W photovoltaic solar panel ($89) in the sun and sip on some unsweetened iced tea instead?