"I hope he paid taxes." Snarky Californian take.
Inventor harvests methane gas from ditches and ponds to power his moped
111–120 of 181 posts
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#112Given that this involves disturbing the bottom of the pond, and that burning methane still produces CO2, this may actually be less environmentally friendly than just using gas.
Methane is estimated to be an order of magnitude or two more powerful than CO2. https://unece.org/challenge
That's if you release the methane, not if you burn it; assuming you burn all of it, the resulting CO2 is the bigger concern.
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#113There aren't a lot of places that use anaerobic digesters (fermenting waste to methane) to treat wastewater. Anheuser-Busch does it at their breweries because their wastewater is particularly rich. If more municipalities built those at their wastewater treatment plants, then it would be a sizeable amount of carbon-neutral fuel. There are already 1200 municipal wastewater treatment plants in the US that do this accord…
The energy generated from biogas recovery at Melbourne's two main sewerage plants (~100 GWh) isn't even enough to make them net generators [1]. The main environmental benefit isn't actually from the carbon footprint of biogas, it's the reduced methane and NOx emissions from capturing the gas. [1] https://www.melbournewater.com.au/water-data-and-education/e...
Ya, but I would guess the story is a bit more complicated. Consider (off the top of my head):
I imagine there's a real concentration problem there. Sewage is incredibly diluted if you think about it (divide your estimate of how much organic waste you generate by the amount of water used in your water bill).
If, instead, houses had grey water systems (i.e. the sink in you bathroom is used to fill up your toilet tank), or if black waters had a separate sewer (sure, not feasible in suburbia), the energy budget would change considerably.
Either way, the affluent is full if nutrients even if we can't recover the energy. Nutrients our soil is rapidly being depleted of (thanks to our modern use of sewers!)
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#114I'm not sure disrupting the ecosystem at the bottom of the pond is an ecologically sound move. Biodiversity is important! Obviously I understand this is a proof of concept and not the solution to fossil fuels.
Agreed this was one of the first things I thought outside the balance of energy required for the whole thing doesn't make much sense.
What are we supposed to take away from this project other than its kind of neat and that methane occurs natural in the environment? We are not about to mining ponds for methane - we already have plenty of it accessible at LFG, waste water treatment facilities, methane from O&G operations.
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#115If you want to do this seriously, you could probably do quite well by creating biogas from kitchen scraps: https://www.motherearthnews.com/renewable-energy/other-renew...
I’m curious what moped km per day one could generate with human waste, food and yard scraps.
Here's my rough estimation:
Anaerobic digestion of food and green waste yields ~0.22 toe/tonne of biogas, and manure yields up to 0.04 toe/tonne [1]. (toe = tonnes of oil equivalent)
Australia wastes 300 kg/year/capita of food [2] (across the entire supply chain, from farm through fork)
Americans generate 90 kg/year/capita of yard waste [3]
That's 1.07 kg/day, for 0.24 kg of oil equiv.
The average adult produces ~0.4 kg/day of manure [4], for 0.02 kg of oil equiv.
All up that's 0.26 kgoe/day, or 0.3 L [5] of petrol.
The most efficient scooter I could find (Honda Activa-i) does around 70 km/L (165 mpg)
So optimistically, you could generate 21 moped kilometers per day of biogas. In more normal units, that 3 kW/h or 11 MJ.
[1] https://www.iea.org/reports/outlook-for-biogas-and-biomethan...
[2] https://www.environment.gov.au/protection/waste/food-waste
[3] https://www.waste360.com/mag/waste_yard_waste_4
[4] https://www.emedicinehealth.com/ask_how_much_does_poop_weigh...
[5] 1 kgoe = 1.16 L of petrol
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#116Earlier quoted context omitted.
A thousand-mile journey begins with the first step. Even a little helps.
With the obesity epidemic it is probably better to tell people they can just compost their food if there is too much and they can't eat it. And then cook a little less next time. I keep 100% of foodstuff out of my trash, and an added benefit is that you never get stinky trash that needs to be taken out. I take my trash out every 2 weeks and it never smells at all.
I seperate my compostables as well. I don't even use a trash bag in my bin anymore. My trash bin fill up so slowly that I go months without taking it to the street.
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#117> Eight hours of hoeing in a ditch supplies him with enough fuel to ride his vehicle for 20 km Hmm, this is an art project but you can cycle 20km fairly leisurely in an hour. 8 hours of toiling in the ditches probably might be better used growing vegetables so your food isn’t being driven in?
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Re: Inventor harvests methane gas from ditches and ponds to power his moped
#118> Eight hours of hoeing in a ditch supplies him with enough fuel to ride his vehicle for 20 km Hmm, this is an art project but you can cycle 20km fairly leisurely in an hour. 8 hours of toiling in the ditches probably might be better used growing vegetables so your food isn’t being driven in?
I know HN comments have a knack for trying to min/max and optimize something posted, but honestly that's not the point here. He's proving that it's possible to harvest methane from ponds, enough to power a moped. OF COURSE there's more efficient ways to get around, this isn't an attack on anyone's intellect or common sense and there's no need to react to getting nerdsniped by going "well ackchyually" and reinventing…
People have built solar bikes, as in regular ebikes with 2-300w panels attached that power the motor. That's more impressive if you ask me.
Other than that, lots of people (myself included) have run old, indirect injection diesels on used veg oil. That was years ago when it was financially very advantageous.
If you ask me, these are more impressive/interesting technical feats, but with real world applicability and usefulness.
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#119Searching for the terms "secu" and "safe" doesn't yield any results. I know this is more of an art project, but in a photo he's driving through a city. What are the security implications of this? Also searching for "poly" doesn't yield any results, so I'm left to hope that the is using polycarbonate to provide some kind of safety shielding in case things go south. Also not on http://uitsloot.nl/sloot-motor/
I don't understand what the security implications might be? It's just the normal gas that's available from mains gas everywhere, in a low-pressure tank. Probably no more dangerous than existing CNG/LPG vehicles.
Much less dangerous as the pressure is very low and the quantity of gas very small.
Re: Inventor harvests methane gas from ditches and ponds to power his moped
#120Earlier quoted context omitted.
I know HN comments have a knack for trying to min/max and optimize something posted, but honestly that's not the point here. He's proving that it's possible to harvest methane from ponds, enough to power a moped. OF COURSE there's more efficient ways to get around, this isn't an attack on anyone's intellect or common sense and there's no need to react to getting nerdsniped by going "well ackchyually" and reinventing…
People have built solar bikes, as in regular ebikes with 2-300w panels attached that power the motor. That's more impressive if you ask me. Other than that, lots of people (myself included) have run old, indirect injection diesels on used veg oil. That was years ago when it was financially very advantageous. If you ask me, these are more impressive/interesting technical feats, but with real world applicability and us…
That's what popped into my mind: the old waste fryer diesel fuel. A nice "gee whiz" science reporting that the MSM eats up, but not scalable in any way for any significant application.