Running the World on Clean Energy, Literally


Last Christmas 🎄 I got my mom a FitBit and ever since that she been a lot more serious with working out, especially doing cardio (totally opposite from some people like myself). We have a treadmill in the basement, and she runs on that thing for almost 2 hours every day. Before Covid-19, she had a membership to the local fitness centre, and she would go to spin classes every day 🚴‍♀️.

With the FitBit, she started tracking all of her burned calories and it turned into a fun competition she would have with herself and her friends. Naturally at home, we’d talk about her fitness goals and she’d share how many calories ⚡she burned in a day (typically 1000+) from running on the treadmill, the elliptical and stationary biking.

After a while, I started to think to myself, that is a lot of energy being burned. My mom is definitely not the only person going to these cardio sessions, and there’s bound to be more fitness fanatics out there that burn ridiculous amounts of calories every day.

Is there any way we can somehow harness all of this energy? What if every single cardio equipment out there was fitted with equipment that let it store all of its harnessed energy to be re-purposed?

And this led me down a bit of a rabbit hole…

Initial Business Ideas:

I immediately thought to myself, what an amazing business idea, making people healthier while also benefitting the planet 🌎. This perfectly aligns with my interests in sustainable energy and healthcare! I categorized this potential business into 3 business models.

1. Starting my Own Gym:

This would be a gym strictly for cardio with bikes, ellipticals, rowing machines and treadmills that have the ability to store energy.

2. Manufacturing Cardio Equipment:

Create cardio machines with energy storing and transmitting capabilities and sell it to fitness centres. I was thinking fitness centres could justify the upfront costs for switching out their existing cardio machines to the ones I would create. Over time, they might recuperate their loses through energy savings as they could power the gym through their new equipment.

3. Retrofit Equipment

The final idea I thought about was creating a piece of equipment, a generator that can be retrofitted onto existing cardio equipment to allow it to start harnessing and storing the energy it generates. In this idea, not only would I target fitness centres, but also original equipment manufacturers (OEM).

Without putting much thought into it, I started by doing some research online to analyze companies offering existing services and products today.


The first company I came across was SportsArt. Turns out, they already have a catalogue of products that have the ability to harness energy and re-purpose it (stair-stepper, elliptical, treadmills, bikes) and as of 2019, they are already on the 3rd generation of their “Eco-Powr” product line. Some gyms have already fitted their cardio section with this equipment, and some have designed a creative incentive system for gym users: reducing member fees based on how much power the user generates.

The company claims that their treadmills can produce a MAXIMUM output of 200 watts per hours while the bikes and elliptical’s can get up to 250 watts. Moreover, SportsArt claims that the use of their equipment can save gym owners up to $900/year vs. ordinary equipment via energy savings. As I was reading, I thought to myself, this sounds amazing! The only problem was, I could never remember the last time I’ve ever seen one of these Eco-Powr cardio equipment at the gym. Why was this not super popular?

Estimates show that if a user was jogging at the maximum 200 watts per hour, it would only save them 2.4 US cents. And we’re talking about maximum output. Your everyday jogger is not going “Usain Bolt” on the treadmill to give you this maximum output. Moreover, each of SportsArt’s units cost around $10,000 USD and the electricity generated also can’t flow to the grid, it can only power devices in the room.

Efficiency Breakdown

There have been a few great websites that go in detail on the breakdown of how much money you would be saving and how environmentally friendly your efforts would be through working out. You can find them here and here. But to summarize my findings:

  • The average bike generator can produce about 100 watts per hour. Therefore every month you would only generate 3 kilo watts (kWh) if you’re biking for one hour every day (30 days). This is factoring in multiple things:

    • A lot of your energy is lost as heat/sweat

    • There are a lot of inefficiencies in capturing electricity. The friction generated between your wheel movement and the motor causes it to lose electricity. Furthermore, you’re also losing more energy when you transmit the electricity through various wires

If we consider the fact that the average household in B.C Hydro’s service area uses about 900+ kWh per month and about 30 kWh per day, we come to the conclusion that biking for an hour a day only generates about 0.33% of your DAILY household energy usage.

Ladies and gentlemen, biking for an hour is not easy, let alone trying to do that every single day. As we can see, the electricity output is quite minimal. To show just how minimal this output actually is, let’s consider some situations such as your weekly spin class and the Tour de France to see how much electricity we can generate for the efforts we put in.

Spin Class

This amazing article entertains the idea of equipping an entire spin class and even the Tour de France with electricity generating bikes.

Imagine a full spin class with 50 bikes running at an average wattage output of 100 watts/hour for a 60-minute session. Our output would be 5 kWh per session. That equates to supplying 16% of energy that ONE household would use for ONE day. If you wanted to power one home for an entire day, you’d need about 6 of these classes per day.

Now that’s a lot of biking.

Tour de France

In 2018, there were 145 cyclists with an average tour completion time of 85.5 hours.

Based on our previous estimates of 100 watts per hour:

145 cyclists X 85.5 hours X 0.1 kWh = 1,239.75 kWh of bicycle energy

After converting that over to an average daily household usage, we conclude that the Tour de France could only power about 45 homes for one day. And we’re talking about the most elite bikers in the world.

Simply put, most of the research I did around generating green electricity pointed me to a few main conclusions:

1.     You can’t generate a significant amount of electricity for your input efforts

2.     It won’t save you much money

3.     Generator inefficiencies is a barrier and there’s no efficient way to get the electricity connected to the grid.

4.     If you really consider the energy used to produce your calories (i.e. the food you eat), technically it’s not even green energy anymore. You are just an inefficient converter.

These inefficiencies with generating electricity and storage are seen even more with existing generators that can be retrofitted. Not too mention I know absolutely nothing about electrical engineering and I totally lack the technical expertise to start a project on this.

A Brighter Future?

A difficult problem has never stopped humans from entertaining the thought of new technologies and the same can be said for our ambition to capture our energy from motion.

Right now, there are already gyms that are looking to self-power themselves via their cardio equipment. For example, the Green Micro gym has been able to generate nearly 40% of its own electricity from solar panels and exercise machines (curious to learn about the split here). There are currently converters for cardio equipment in about 80 locations across North America. Some equipment manufacturers have even tried adding in “hand-pedals” onto bikes in an effort to generate even more wattage output.

Some architects even designed a floating river gym as part of an eco-friendly fitness design contest to travel in a 15-minute circuit around the Hudson and East Rivers in New York. Not only would the River Gym offer a spectacular view for those looking to get a workout in, but it would also have capacity to carry additional passengers and commuters. Of course, the River Gym was designed to be equipped with exercise equipment that can harness energy and store it in on-board batteries to power the pod.

Perhaps a combination of technologies that can harness the energy from “sweat power” would enable us to do so in an efficient manner. This has been considered quite literally as a group of scientists from UC San Diego have designed a small skin patch that can transform lactate (one of the chemicals released in sweat) into electrical energy. So far, they’ve only been able to generate 4 microwatts which is less than half of what it takes to power a digital watch. The article was released in 2014 with research stating they were focusing on scaling the amount of energy they might be able to get out of sweat and storing it efficiently in batteries. Interesting applications of their skin patch could also be used in the emerging wearable devices field, as tracking lactate excretion can be a solid indication of endurance levels and overall fitness.


As of now, it just doesn’t make economic sense for fitness centres to splurge on eco-friendly cardio equipment. It’s too expensive and the electricity generated isn’t enough. The River Gym pod sounds like a fascinating idea, but it doesn’t look too feasible. The original design was created back in 2009, there have been no developments since. This is the same situation with the skin patch, ever since 2014, there hasn’t been any new updates on the technology. There’s likely much more money being poured into areas like hydro, wind and solar energy technology that can yield better returns, but we can’t say for sure the human race has given up on this idea.

What if we could design cardio equipment that was cheap, could efficiently harness significant energy from human motion, store it and transmit it to the grid?

Wouldn’t that be exciting 😃?


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