No, You Cannot ‘Power Your Home’ by One Hour of Cycling Daily

In the past days different versions of an article had popped up in my social media streams again and again – claiming that you could power your home for 24 hours by cycling for one hour.

Regular readers know that I craft my statements carefully in articles about energy, nearly as in the old times when submitting a scientific paper to a journal, with lots of phrases like Tentatively, we assume…

But in this case, I cannot say it more politely or less distinctly:

No, you cannot power your home by one hour of cycling unless the only electrical appliance in your home is the equivalent of one energy-efficient small computer. I am excluding heating and cooling anyway.

Yes, I know the original article targeted people without access to the power grid. But this information seems to have been lost in uncritical reshares with catchy headlines. Having seen lots of people – whose ‘Western’ homes will never be powered by a treadmill – discussing and cheering this idea, I want to contribute some numbers [*].

This is all the not-exactly-rocket-science math you need, so authors not adding conclusive numbers to their claims have no excuses:

Energy in kWh = Power in Watts times hours divided by 1000

Then you need to be capable to read off your yearly kWh from your utility bill, divide by 365, and/or spot the power in Watts indicated on appliances or to be googled easily.

A professional athlete can cycle at several 100 Watts for some minutes (only) and he just beats a toaster (which needs a power of 500-1000W):

So an average person cannot cycle at more than 100-200W for one hour, delivering 0,2kWh during that hour at best.

With that energy you can power a 20W notebook or light bulb for 10 hours, and nothing more.

Anything with rotating parts like water well pumps, washing machines, or appliances for cutting or mixing need much more power than that, usually a few 100W. Cycling for one hour can drive one device like that for less than half an hour.

An electric stove or a water heater needs about 2kW peak power, at half of the maximum such appliances would consume 1kWh in one hour. An energy-efficient small fridge needs 0,5kWh per day, a large one up to 4kWh.

A TV set could need 150W[**], so you might just be able to power it while watching. I don’t say that this is a bad idea – but it is just very different from ‘powering your home’.

I’ll not link those click-bait articles but an excellent website instead (for the US): Here you can estimate your daily consumption, by picking all your appliances from a list, and learn about the power each one needs. At least it should give you some feeling for the numbers, to be compared with the utility bill, and to identify the most important suckers for energy.

http://energy.gov/energysaver/estimating-appliance-and-home-electronic-energy-use

I have scrutinized our base load consumption in this article: In summer (without space heating) our house needs about 10kWh of electrical energy per day, including 1-2 kWh for heating of hot water by the heat pump. The base load – what the house needs when we are away – is about 4kWh per day.

There are numerous articles with energy statistics for different countries, I pick one at random, stating – in line with many others – that a German household needs about 10kWh per day and one in the US about 30kWh. But even for Nigeria the average value per home is about 1,5kWh, several times the output of one hour of cycling.

________________________

[*] I’ve added this paragraph on Feb. 8 for clarification as the point came up in some discussions on my post.

[**] Depends on size, see for example this list for TVs common in Germany. I was rather thinking of a bigger one, in line with the typical values given also by the US Department of Energy (300W for a plasma TV!).

14 thoughts on “No, You Cannot ‘Power Your Home’ by One Hour of Cycling Daily

  1. Oh my; I’ve seen these absurd articles! I put it right up there with mounting PV panels on an electric car. Orders of magnitude. I will say, as was eluded to above, that there are some reasonable uses for human bicycle power in the low energy world, and have been for a very long time. However, generating electricity has been a very small part of it. Mechanical operations like pumping, grinding, mixing, cutting, and even compressing refrigerant :), are all used more extensively and successfully.

    Here is an article to some neat examples. If you weren’t familiar with the site, I think you’ll really enjoy it, Elke.

    http://www.lowtechmagazine.com/2011/05/pedal-powered-farms-and-factories.html

    • It’s a nice article, thanks – and they provide reasonable numbers, like a human can cycle at 150W for 2 hours. The absence of cooling winds (in contrast to a real bike) and thus the risk of overheating the body is a very interesting aspect.
      Talking about the human body, it also reminds of a main disadvantage of anything human-powered: you need to be healthy and strong enough to drive that machine. I would assume that in rural villages in developing countries most people do not have the first world problem of ‘having to work out’ in addition to their daily toils so the combination of workout and power generation is not a plus. This ‘combination’ was also one of the arguments in some of the click-bait articles that made it unclear who the real target group should be and mislead people who work out daily in their Western homes.

      I’ve linked an article below in the comments, about one of the many solar startups in Africa I’ve read about recently. One modern panel has about 0,160-0,180W peak power, so the energy harvested in a day will beat the treadmill for sure – especially in countries near the equator – on most days. On a rainy day, the output of a single panel might be less than the output of cycling: For example, we harvest only 1kWh with a 5kW generator on a rainy and cloudy day (on a perfect day: More than 30kWh). So a 180W panel would yield only 0,036kWh. Correcting for the latitude the yield may be ~0,05kWh-0,07kWh, one fourth of cycling. So you’d need 2-3 panels to beat the cycler every day. On the hand, this problem will be mitigated by using a battery which was also part of the proposal for the ‘treadmill generator’.
      The lowtechmagazine.com article only mentions the comparison with fossil fuels (stating we should not compare with that, but with our or animals’ limited power we had before), not with solar energy, which seems a bit unfair given all the new solar initiatives for developing countries. But the article is from 2011, and so much progress has been made in recent years. I am pretty sure that batteries for such small daily consumptions will be or are already affordable for people who need it. A human being’s peak power is modest, a few 100W, so also the required inverter’s output power (to beat a human cycler) should not be an issue (as it is when you want to power really any device in a modern household any time and also from the battery).

      I’d rather compare the whole setup to what ‘energy pioneers’ did in offgrid homes in the mountains here in Austria – long before solar was fashionable: Mounting a few panels (less efficient ones than today), using a cheap car battery or equivalent for storing the energy, driving a few DC-powered devices with a simple DC inverter.

    • Thanks, Dave 🙂 I don’t want to be ‘too negative’ on this blog but in this case I felt it was my duty to say something. I read so many questions like ‘Can this work?’ ‘Is this true?’ – from people who live in countries where energy needs are 100 times what a treadmill can create. And every mainstream ‘green blog’ or newspaper just copied the claim uncritically, without adding a simple reality check.

  2. So I watched that video…

    30 years ago (I barely dare to type that), I visited India, the north to be precise. There in Srinagar, the winters are bad. People have no heating other than small wood stoves for which they haven’t got a lot of wood. They use it to keep the windowpaneless houses they live in above freezing point during the day. At night they use blankets to survive.

    My then girlfriend-now-wife and myself couldn’t hack it in moved out of the houseboat into a “hotel” WITH electrical heating. Alas, the grid was too weak to provide power and by 19:00 the grid voltage would drop from 220V to (an estimated) 100V. Not enough for electrical heaters and so the heaters would switch off and the grid came back to power a few light bulbs.

    In that world, and that world only, pedaling for one hour will give you a precious 0.1 kWH to power your iPad and a couple of LED lamps.

    The genius behind the cycle generator has basically invented the wheel. I hate to think how much it will cost to produce those contraptions and the economics fail completely. I suspect that the energy that goes into producing the steel and aluminium, the manufacturing and transport cost would easily provide electricity for more than an iPad and a few LEDs for a lifetime… Not to mention that a few voltavoltaic panels would do the trick for a lot less.

    Still, the guy is a local folk hero and will probably score some time at TED.

    In the meantime, the real heroes are people that divide their heating bill by x (where x > 3) by building a home heat pump.

    You know Elkement, if a few people like you and me would put their minds to it, we could probably find a smarter way to provide 0.1 kWH to those 3 billion energy deprived.

    • Thanks a lot – I could not agree more. When I started nitpicking on friends’ timelines I have also pointed out that the only target group that might make sense are people without any access to the power grid. But then, I’d like to see an economic comparison with small solar panels and small wind turbines. There are so many solar energy initiatives in Africa that are going to provide affordable power. I have also read this heartening and impressive book a few years ago about the African boy who ‘harnessed the wind’ and built his family a windmill.

      Maybe if those articles would clearly have been targeted to developed countries I might not have bothered to write that rant. But it was those click-bait headlines on mainstream ‘Western’ media that freaked me out. I also know from personal experience how highly misleadimg claims like that put very distorted views about energy use into home owners’ heads – about whatnot can be powered and heated by which kind of technology. I am also more than baffled that nobody does the simple math.

      • Simple maths & economics don’t get clicks. If anything this hoax type story is a good reminder that a) a lot of people need a little bit of energy and b) we haven’t tried very giving it to them. When you compare the kWH needs of your average western household vs the energy poor who would be happy with a few LEDs and a phone charger, the discrepancy is measured in 100’000 range.
        One-laptop-per-child got a lot of press and had some success. How about donating solar panels? To get the equivalent of 1 hour cycling (0.1kWH), you’d need $30 worth of solar panel, including a battery. You can probably get that for 3 times less.
        My electricity supplier could send 12 panels to these people and I wouldn’t notice the difference. Now THAT would be innovative.

        • This is one of the African solar energy startups that came to my mind: http://reneweconomy.com.au/2016/the-off-grid-solar-company-connecting-12000-homes-a-month-19292
          “The principal behind Off Grid Electric is to create the world’s first massively scalable off-grid electric company. …
          They can choose a single panel to power a few lights, or have the whole solar and storage kit that can power whatever it is that they want or need.
          The success behind Off Grid Electric is that it operates as a service model that removes risk for customers. It uses financing measures – effectively a solar lease – to offer the latest in solar technology for less than or equal to a customer’s average energy spend on kerosene and diesel.”

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