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Interesting article, although it doesn't break down where the savings come from. It appears that most of the savings come from the compaction and communication

by travisp 14y ago

Interesting article, although it doesn't break down where the savings come from. It appears that most of the savings come from the compaction and communication about the cans being full. Given that solar is still often of questionable cost-efficiency (especially, I would imagine, on sidewalks in Philadelphia), I would think that not much of it comes from the solar aspect (unless the cost of hooking up the cans to power or changing a battery is high). The article doesn't really make it clear.

smspence 14y ago
The article makes it pretty clear. Third paragraph: "...communications systems for real-time reporting on a bin’s capacity. By allowing municipalities to service the BigBellys only when they are full, they are saving hundreds of thousands of gallons of fuel annually across all BigBelly units." Fourth paragraph: "...information gained from each compactor allows waste managers to optimize collection schedules and routes. Before BigBelly, trash collectors had to clear out each can three times a day. Now they do so three times a week."
- greenyoda 14y ago
  The hourly cost of labor for a couple of unionized employees (the minimum would probably be a driver and a loader) is probably greater than the hourly cost of the fuel that's used, especially if they're running overtime. Factoring in employee costs like health insurance, pensions and vacation time, I'd guess at least $100 per hour for a two-man crew. You can get many gallons of diesel for that amount, especially if you purchase in bulk for a fleet of city vehicles. Also, the number of garbage trucks that the city would need to own would go down, as would the number of employees needed to maintain them. I think the article emphasized the fuel savings because they didn't want to explicitly call attention to the fairly obvious conclusion that this efficiency improvement, if successful, would cause lots of city employees to lose their jobs.
  - sfall 14y ago
    they said they didn't get rid of personnel just now use them for the recycling program
sophacles 14y ago
I would speculate that the solar power isn't the big cost savings here, in terms of operating costs. However, in terms of installation costs, it is probably a win - getting power to these would add a significant up-front cost, because a large chunk of sidewalk would need to be torn up to get power to the device.
- smspence 14y ago
  In this situation, why would solar power alone account for ANY cost savings? They just replaced traditional garbage cans (that require no electricity/power at all) with compactors that run on solar power and send out an electronic message when they are full. It's not like the previous garbage cans ran off of electricity from the local power grid, or required gasoline or something to run, and now the new solar-powered units yield a cost savings because they are off-grid. They were just regular old trash cans that sat there and did nothing but hold trash, no electricity required.
  - schiffern 14y ago
    The savings were because of new capabilities, not new efficiencies. Adding power (which they happened to use solar power) gave them new capabilities (compaction, signalling), which saved them almost a million bucks. Solar was still the enabling technology. Marginal energy cost comparison with grid electricity is irrelevant, since the cost structure is dominated by fixed costs. Can you imagine installing, reading, and maintaining an electric meter and utility interconnect for every single trash can?
  - deleted 14y ago
    [deleted]
  - sophacles 14y ago
    Wow, OK simple math lesson for you: I can reduce my per year cost by $X, but I need to spend $Y to install some technology to enable the savings. If $Y < $X * N (where N is the number of years that tech will last), then you are saving money. Now lets say the cost of putting in those trash cans is $Y1 with a wired connection. $Y1 includes tearing up the street to run power cables. That makes $Y1 not meet the inequality. No savings happen. But with solar powered trash cans, which cost $Y2 to install, and $Y2 meets the inequality, then the solar power is enabling the savings. That is the difference. In another post you already mention that you understand why the savings occur - fewer trips because of logistical planning from communications, plus fewer trips because compaction allows more trash per bin. This makes me wonder if you are just being disingenuous with your second paragraph. Or maybe you just don't understand that less time and fuel means less money spent. The fact that you and the GP are fixating on solar being off-grid to provide savings doesn't even make sense as the article doesn't claim that to be the case.

by travisp 14y ago

smspence 14y ago

The article makes it pretty clear. Third paragraph: "...communications systems for real-time reporting on a bin’s capacity. By allowing municipalities to service the BigBellys only when they are full, they are saving hundreds of thousands of gallons of fuel annually across all BigBelly units." Fourth paragraph: "...information gained from each compactor allows waste managers to optimize collection schedules and routes. Before BigBelly, trash collectors had to clear out each can three times a day. Now they do so three times a week."

greenyoda 14y ago
The hourly cost of labor for a couple of unionized employees (the minimum would probably be a driver and a loader) is probably greater than the hourly cost of the fuel that's used, especially if they're running overtime. Factoring in employee costs like health insurance, pensions and vacation time, I'd guess at least $100 per hour for a two-man crew. You can get many gallons of diesel for that amount, especially if you purchase in bulk for a fleet of city vehicles. Also, the number of garbage trucks that the city would need to own would go down, as would the number of employees needed to maintain them. I think the article emphasized the fuel savings because they didn't want to explicitly call attention to the fairly obvious conclusion that this efficiency improvement, if successful, would cause lots of city employees to lose their jobs.
- sfall 14y ago
  they said they didn't get rid of personnel just now use them for the recycling program

sophacles 14y ago

I would speculate that the solar power isn't the big cost savings here, in terms of operating costs. However, in terms of installation costs, it is probably a win - getting power to these would add a significant up-front cost, because a large chunk of sidewalk would need to be torn up to get power to the device.

smspence 14y ago
In this situation, why would solar power alone account for ANY cost savings? They just replaced traditional garbage cans (that require no electricity/power at all) with compactors that run on solar power and send out an electronic message when they are full. It's not like the previous garbage cans ran off of electricity from the local power grid, or required gasoline or something to run, and now the new solar-powered units yield a cost savings because they are off-grid. They were just regular old trash cans that sat there and did nothing but hold trash, no electricity required.
- schiffern 14y ago
  The savings were because of new capabilities, not new efficiencies. Adding power (which they happened to use solar power) gave them new capabilities (compaction, signalling), which saved them almost a million bucks. Solar was still the enabling technology. Marginal energy cost comparison with grid electricity is irrelevant, since the cost structure is dominated by fixed costs. Can you imagine installing, reading, and maintaining an electric meter and utility interconnect for every single trash can?
- deleted 14y ago
  [deleted]
- sophacles 14y ago
  Wow, OK simple math lesson for you: I can reduce my per year cost by $X, but I need to spend $Y to install some technology to enable the savings. If $Y < $X * N (where N is the number of years that tech will last), then you are saving money. Now lets say the cost of putting in those trash cans is $Y1 with a wired connection. $Y1 includes tearing up the street to run power cables. That makes $Y1 not meet the inequality. No savings happen. But with solar powered trash cans, which cost $Y2 to install, and $Y2 meets the inequality, then the solar power is enabling the savings. That is the difference. In another post you already mention that you understand why the savings occur - fewer trips because of logistical planning from communications, plus fewer trips because compaction allows more trash per bin. This makes me wonder if you are just being disingenuous with your second paragraph. Or maybe you just don't understand that less time and fuel means less money spent. The fact that you and the GP are fixating on solar being off-grid to provide savings doesn't even make sense as the article doesn't claim that to be the case.