When I was an undergrad, I remember going to the gym with my housemate and the two of us trying to work out just how much electricity you might be able to generate from all the stairmasters, rowing machines, bikes etc. I hear you now, ‘silly engineers…’, but this recent Wall Street Journal article shows that a gym in Hong Kong is taking the idea to heart. Unfortunately the article says that 13 machines give only 300 watts total, though the rowers figure you might be able to average around 200 W on an erg, which is a bit better.
So should you be trying to jury-rig your home gym to generate electricity? Probably not. Let’s compare it to a micro-wind turbine for example. A recent BBC report (Home turbines ‘lack power’) quoted the owner of a turbine (in the city) as saying it gave him 7 kWh in 3 months. So in workout equivalent, we’re talking about 35 hours of vigorous rowing or about 3 hours per week. Of course, that electricity will be pretty low quality so you’ll need some (expensive) electronics to condition and convert it into something usable, say at 80% efficiency. Overall then, you’re looking at half-an-hour of hard rowing every day of the week to give you about £2.40 of electricity each year.
Cheaper than a gym membership I suppose…
