The gas is generated by the chemistry of the stuff that was put there. Moving the stuff there takes a lot of energy, but everything sitting there mainly just needs a pump and treatment system.
This is besides the point because environmentalists (who were carped at above) tend to seek to reduce the amount of trash that needs to be shipped off to somewhere.
reducing trash is useful. Recycling of trash is sometimes worse than throwing it in a landfill. There are many different plastics and many different grades of used paper so there is no one size fits all. People often want to think I recycle so I'm good - but effort is needed to reduce packaging and things that break early.
I think their point was the delivery of that garbage over time is subject to entropy, and from first principles probably took more energy consumption than a sustained 84MW over the time period the landfill is a viable source for energy.
I know nothing about landfill engineering here, to be frank, simply being a grease for good online gearing.
A single truck requires more energy to operate in a year than 70k homes do!? I find this extremely difficult to believe.
As far as I can tell, the EIA [1] suggests the average home uses 10,791 kWh a year. A gallon of gasoline contains ~33.7 kWh of energy per the EPA/Wikipedia [2].
This would mean that a single truck would be burning 70,000 * 10,791 / 33.7 = 22,414,540 gallons of gasoline a year or 61,409 gallons a day. Seems like wild bullshit to me.
you should note that a gas engine does not convert all that 33kWh of energy into mechanical energy. a gasoline engine has about a 25% conversion into mechanical energy. https://www.fueleconomy.gov/feg/atv.shtml . diesel might be a bit better than a car but it's city driving by nature.
just heat alone is the largest waste product in a car or truck
A tank of gas is still a tank of gas, regardless of what it gets used for.
Energy in = energy out + waste + energy stored
The truck is barely storing anything on average, so what you've described is energy out and waste, but the calculations to compare the truck to the landfill was done on Energy in - the amount of gas that it needs to be filled with.
For the same total job, you could raise or lower how quickly the truck goes through a tank of gas, but that variance has already been averaged out
According to [1] an electric garbage truck traveling 15,000 miles a year uses about 38,960 kWh. An 84 MW power plant produces 84,000 kWh every hour, or enough to power more than two trucks for an entire year. Even if we assume that the diesel equivalent uses a hundred times as much it's still a tiny fraction of what the plant in TFA produces.
Couple issues with that comparison: 15k seemed low given I drive ~10k a year and I don't work a job that uses my car, so I checked refuse trucks drive on average more like 25k miles per year and there are many servicing a single dump. Also most garbage trucks are still diesel so you've got to 5-10x that power usage number and there's all the vehicles used to compact and move the trash once it reaches the landfill which are also (currently) pretty exclusively diesel powered (think bulldozers and soil compactors with some excavators thrown in).
A 500 hp semi truck engine running at peak power is like 350 kw, so 84 megawatts (84,000 kw) is more than 200 of those engines at full throttle at all times.
This is my argument against recycling. It is not sustainable to recover a tiny amount of energy when balanced with the extra diesel-guzzling truck traversing the neighborhood. All so we can think we're "making a difference" by keeping plastic bottles out of a landfill.
> It is not sustainable to recover a tiny amount of energy when balanced with the extra diesel-guzzling truck traversing the neighborhood.
It’s a good thing we have electric motors, then. An additional benefit is that they are much less likely to wake you up when they get your bins at 5am.
Exactly. Recycling shouldn't be implemented if it uses dirty energy. There should be accounting and accountability. Don't pretend an operation is green unless it really is.
I think people generally want to do what they feel is right. The problem lies in 1) the use of propaganda to force blanket solutions to what they pose as the problem and 2) not using evidence-based scientific methods.
for 1) various groups show heart-breaking images of wildlife suffering due to pollution, then work to mobilize the outrage into their solution. for 2), recycling programs should have had metrics, such as lbs of plastic "saved" from the landfill, energy saved from collecting cans, but also the counterpoints such as "tons of CO2 emitted by recycling trucks", and "dollars removed from poor people when local cash-for-cans businesses are shuttered". If the data show they emit more CO2 equivalent than they save, then they should concede that the program has failed. If the program needs a jump-start before it is "ecologically profitable", they should say so and agree to cancel the program if their goals aren't met by X date.
It all sounds and reads like a fairytale but none of this is sustainable.