How much is a usefull amount of electricity?

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I got to thinking yesterday about green power and recalled the dynamo that powered the little headlamp on my old pushbike.
I also got to thinking about the obesity epidemic and people who go to a gym or ride an excercise bike at home.

I got to thinking that if everyone who rode an excercise bike was at the same time generating electricity it might help save some coal, oil and greenhouse gasses.

I got to thinking that we need to get to a stage in our society where we accept every opportunity to generate electricity for either storage (battery) or transfer to grid.

How much electricity can you generate on an excercise bike and can that smalll an amount be reasonably stored or sent to the grid?

Aside from riding an excercise bike can you see any other areas where human movement could generate electricity?

Imagine if the all step machines and excercise bikes at all the gyms in the first world were each connected to a dynamo and then to the grid or a battery storage system.

Imagine if the teaming millions of poor people in India, the favellas of brazil and shanty towns of South Africa were all given excercise bikes with a little dynamo that could be connected to the grid. Would the manufacturing costs and carbon used in manufacture and transport outweigh the benefits in the short or long term?

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@dadpad,

can I hook one to my car?

I have trouble handling all the exercise I get now...

2 Replies

@dadpad,

Just a one significant digit estimate, but if you burn 600 kcal/hr on an exercise bike, the conversion is 1 KCal/hr = 1.163 watt, so you could generate around 700 watts max while riding. Assume a decent efficiency for conversion and it's probably around 500 watts.

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@dadpad,

Quote:

Pedal Powered Generator - Electricity From Exercise

"Power From The People!"

Welcome!

Curious about Human Power? Need some exercise? Looking to lose weight? Need inspiration? Researching technical information? Expensive gasoline making you nuts? You have come to the right place.

Every morning, I pedal to generate electricity. The Pedal Generator I ride charges batteries, that run an inverter, that produces 110v AC, that powers LED lights, the monitor on my computer, my cell phones, and charges my Roomba as well as many other small battery-powered things. It is the most inspiring workout you can imagine.

...

http://www.los-gatos.ca.us/davidbu/pedgen_pppm.html

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@Rockhead,

Quote:

can I hook one to my car?

theres no such thing as a free lunch
I'm guessing that the amount of electricity generated would increase the amount of fuel burnt. you use a certain amount of fuel moving the vehical from start to your destination any added drag in the form of a dynamo or generator would increase fuel consumption.

Imagine the decrease in fuel consumption if you could remove the alternator drive belt.
But heres a thing.... do you actually use all the electricity your vehical can generate with its current alternator?

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Quote:

Piezoelectric flooring is a technology with a wide range of applications that is slowly being adopted in the race to develop alternative energy sources. After all, human power is readily available in pretty much any area with heavy foot traffic, such as a dancefloor, or a tourist attractions. Naturally, we were excited to hear that JR East will be installing these systems in the floor of one of busiest subway stations on the planet.

JR East has been trialing these systems for the past year. They have recently improved and expanded the system by changing the floor covering from rubber to stone tiles, and have improved the layout of the mechanisms to improve energy generation. The total amount of floor-space will add up to around 25 square meters, and they expect to obtain over 1,400kw per day " more than enough to power their systems.

http://www.inhabitat.com/2008/12/11/tokyo-subway-stations-get-piezoelectric-floors/

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@dadpad,

A really strong cyclist can maintain around 400 watts for an hour. I don't know what they spend on groceries. I have fun with the idea the output could be used to charge the battery on an electric bike.

Didn't you go to photovoltaic awhile back, dadpad? How is it working out. Are you having to store in batteries and run it through an inverter to get it into household circuits? I'm also wondering about the control circuitry involved.

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@roger,

We did indeed go to PV. I'm very happy with the result. we can generate around 6KW over a summers day, average over a year would be around 4 Kw per day. Today (early autumn 3.00pm) so far just over 3 kw.
Its made a huge difference to our power bill.

Quote:

Are you having to store in batteries

No batteries. The system is grid connected via an inverter. Essentially electricity not being used by the household goes back into the grid. We had the option of installing a dual meter which measures electricity going into the grid as well as measuring houshold use but chose not to due to the cost of the new meter. Measuring electricity going back to the grid would have netted us a rebate of 60 cents per Kw hr on our electriity account
Our existing meter actually runs backward during peak production hours provided no appliances are running (fridge, wash machine, electric kettle) which effectivly nets us around 21 cents per Kw hr for anything going back to the grid without incuring the cost of a new meter. New meter would be about $400.

Based on sending a total of around 1 kw average per day to the grid pay back time for the meter would be 6 - 8 years.
I'm still not sure i made the right decision there.

Sometime in the next 2 years we'll put in a solar hot water service.

2 Replies

@dadpad,

Oh, I love it. You essentially get to use the grid for excess generation. I was seriously concerned about power losses into and out of an array of batteries, and further loses when you had to use an inverter for any kind of appliances.

Under my concept, the system would only be practical for something on the order of charging something like an electric car.

Thanks.

0 Replies

@JTT,

JTT wrote:

Quote:
Piezoelectric flooring is a technology with a wide range of applications that is slowly being adopted in the race to develop alternative energy sources. After all, human power is readily available in pretty much any area with heavy foot traffic, such as a dancefloor, or a tourist attractions. Naturally, we were excited to hear that JR East will be installing these systems in the floor of one of busiest subway stations on the planet.

JR East has been trialing these systems for the past year. They have recently improved and expanded the system by changing the floor covering from rubber to stone tiles, and have improved the layout of the mechanisms to improve energy generation. The total amount of floor-space will add up to around 25 square meters, and they expect to obtain over 1,400kw per day " more than enough to power their systems.

http://www.inhabitat.com/2008/12/11/tokyo-subway-stations-get-piezoelectric-floors/

Thats a fantastic idea and just what i had in mind.
I was thinking on a much smaller scale though. like a shoe based system where a lI batterty is inserted into you show heel and the peizo charges your battery say over a day or a week.
The point being that it doesnt matter how long it takes to charge the battery as long as it does, that saves some baseload power being produced.

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@Rockhead,

Ive read a little about peizo electricity generation.
A company in israel is installing peizo generators into road surfaces and generating electricity from vehical movement over roads. Essentially the energy wasted on compression of the road surface is harvested and used to power street lights in the vicinity.

My immediate thought was perhaps the technology could be incorporated into tyres and harvested to charge an electric vehical thus extending the vehicals range.
There would be a whole range of cost benefit problems to be sorted out like tyres only last for 12 months so the peizo incorporated in tyres would be thrown away is that environmentally and cost efficient.

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anything further to add?

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Thanks for this thread. I would love to do solar electric at my house.

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@dadpad,

Quote:

a rebate of 60 cents per Kw hr on our electriity account
Our existing meter actually runs backward during peak production hours provided no appliances are running (fridge, wash machine, electric kettle) which effectivly nets us around 21 cents per Kw hr for anything going back to the grid ...

Are you sure those prices are right, Dadpad? Is that what Aussies pay for electricity?

1 Reply

@JTT,

I've just checked my account.

TRU energy
Go for More - peak charges rate band 1 = 18.38 cents per kWh
off peak (electric hot water only) 11.00 pm - 7.00 am 10.37 cents per kWh
GST (tax) adds 10%.
Discount 6% if paid by due date
Avg daily use 6.93 Kw.
same time last year 14.73 kWh (no solar)
Period of use 26 Oct 29 Jan (part spring part summer)

Feed in tarrif .60 Cents per kWh (Paid as a rebate on electricity account)
http://www.energymatters.com.au/government-rebates/feedintariff.php

Most aussies would pay within a few cents of that. Businesses have a diferent tarrif around the 25 cent mark I think. (could be wrong there)

1 Reply

@dadpad,

Will the utility pay $0.60 for every KW fed into the grid? Why so much? It sounds like there's money to be made there at that rate. Is there much wind where you're located? Does Au have wind farms?

1 Reply

@JTT,

Quote:

Will the utility pay $0.60 for every KW fed into the grid?

Unsure. As it is a rebate i can only see the rebate being applicable against my quarterly account.
Any amount after that i suspect would need to be contracted and would be subject to wholesale rates.

Not enough wind here to be commercially viable i suspect. I do know of one domestic turbine operating.

There are wind farms in Australia.

Quote:

At the close of 2008, there were 50 wind farms in Australia, with a total of 756 operating wind turbines. The total operating wind generating capacity at the end of 2008 was 1,300 megawatts (MW) providing 1.3% of Australia's national electricity demand.
http://en.wikipedia.org/wiki/Wind_power_in_Australia

0 Replies

Odd Spot
April 5, 2010
Inmates in an Arizona county jail have to pedal on exercise bikes to watch television. The bikes generate 12 volts, enough electricity to power a 48-centimetre TV. One hour of pedalling equals one hour of television watching.
http://www.theage.com.au/world/oddspot/odd-spot-20100405-rlut.html

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@dadpad,

dadpad wrote:

Imagine if the teaming millions of poor people in India, the favellas of brazil and shanty towns of South Africa were all given excercise bikes with a little dynamo that could be connected to the grid.

I would tell them to immediately sell it. Exercise is not one of their typical problems so it'd just be unpaid labor for them.

But you are touching on the "smart grid" concept that I wholly support.

1 Reply

@Robert Gentel,

Quote:

I would tell them to immediately sell it (the ecercise bike?). Exercise is not one of their typical problems so it'd just be unpaid labor for them.

Selling the electricity produced by the excercise bike was the general idea.

Perhaps a work for the dole project in first world countries. Of course the civil libertarians would be up in arms about forced labour and all.

0 Replies

How much is a usefull amount of electricity?

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