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Vaporizing Garbage to Create Electricity

CaroKann writes "Geoplasma is planning to build a power plant in St. Lucie County, Florida that will generate electricity by vaporizing landfill trash and sewage treatment plant sludge with plasma arcs. It will be the first plant of its kind in the USA and the largest in the world. The power plant is expected to destroy 3000 tons of garbage, generating about 120 megawatts of electricity per day. The plant will also supply steam to a nearby Tropicana juice plant. The landfill is expected to be depleted in about 18 years. In addition, up to 600 tons of melted, hardened sludge will be produced each day and will be sold for road construction."

20 of 492 comments (clear)

  1. Megawatts per day by Anonymous Coward · · Score: 5, Informative

    "The power plant is expected to destroy 3000 tons of garbage, generating about 120 megawatts of electricity per day."

    Watt is a measure of energy per second. That is, power. Saying 120 megawatts of electricity per day is nonsense. I think they meant to just say 120 megawatts.

    Doesn't slashdot have editors for this kind of stuff?

  2. Re:Whence this vapor? by Junior+J.+Junior+III · · Score: 5, Insightful

    The summary also mentions processing 3000 tons of garbage a day, and yielding 600 tons of sludge. Unless they're converting mass directly into energy, a la nuclear fission, I'd say there's about 2400 tons of apparent gas that needs to be accounted for still.

    --
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  3. Could happen in the Toronto area soon as well by ergo98 · · Score: 5, Informative

    Here in the Halton region, which is comprised of some suburbs just West of the Toronto metro, there has been some talk of building one of these plants (although they've tossed around the number $700 million). This is an effort to deal with the reality of garbage, not to mention that reality that Toronto has been giving the entire country a continual black-eye by shipping waste to Michigan (if I were a Michiganer, I'd be pissed to be another regions dumping ground. Even as an Ontarian, the endless row of trash hauling trucks, each leaving a wake of loose garbage, is untenable).

    But despite the reality that no one wants to build dumps, and Toronto has been spending millions shipping it to an entirely different country, there are still the head-in-the-sand dreamers who would rather the issue just disappears. A prominent Toronto city bureaucrat, for instance, has poo-poohed the idea, decrying the vile idea of "burning" waste. They'd rather drive it 500 miles in transport trucks to dump it somewhere else.

  4. How many AOL CD's? by phatvw · · Score: 5, Funny

    Let me try to brush up on my yank-math...

    3000 tons = 6,000,000 pounds
    120,megawatts = 120,000,000 watts
    A CDROM weighs 1/2 oz.

    So you'd need approx 96 AOL CDs per hour to run a 60W lightbulb. I think I have just enough of those to get me through the end of the year...

    1. Re:How many AOL CD's? by iamhassi · · Score: 5, Insightful

      "So you'd need approx 96 AOL CDs per hour to run a 60W lightbulb. "

      Wait... let me get this straight, someone explain this to me.

      I pay money for them to pick up my trash right?

      They take my trash, zap it into electricity.

      I have to pay for electricity.

      So, I'm basically paying to have my trash back? WTF? Why can't I just install a trash plasma zapper under the sink and skip the expensive middle-man? My trash + electricity a month is $200+, I'd love to keep the money in my pocket.

      "Hunny, the A/C's not working!"
      "Just throw some more AOL CDs at it!"


      This is better than solar power if it works! Now bring on those electric cars :)

      --
      my karma will be here long after I'm gone
    2. Re:How many AOL CD's? by GungaDan · · Score: 5, Funny

      "Using 'plasma arcs' to 'vaporize' garbage sounds vaguely dangerous."

      It's perfectly safe, provided you never cross the streams.

      --
      Eloi are stupid, throw morlocks at them!
    3. Re:How many AOL CD's? by Nutcase · · Score: 5, Funny

      It would be bad.

  5. Attempted before...unsuccessfully by PreacherTom · · Score: 5, Informative

    This has been attempted before. I used to work in the waste industry, and one of my clients had a plan to develop this kind of technology. The problem was that, despite predictions, the waste simply did not burn hot enough. If they've managed to overcome this obstacle, this is going to be huge. The cost-effectiveness still concerns me, but government subsidies can take care of that.

  6. The people of St. Lucie County won't go for it by BeeBeard · · Score: 5, Insightful

    This will never get built. Let me explain: People near the Treasure Coast are retirees. And I don't mean in the "Oh, it's Florida...of COURSE there are retired people there" sense. I mean that many of its communities were planned and built specifically for bluehairs. Port St. Lucie, for example, is just such a community.

    Now as impossible as it may seem, octogenarians are not really up on the newest technological advances. The moment you say the words "landfill trash" to these people, the NIMBY (not in my backyard) impulse will dominate, and granny and gramps will be making phone calls, changing zoning rules, voting down money, and generally just making Geoplasma's job as difficult as possible. They're retired. If you thought they didn't have the time or inclination to do these kinds of things, then you're mistaken.

    I know it makes no logical sense to want to make use of modern garbage disposal technology, and yet not want it anywhere within a million miles of you, but trust me, that is the mentality. The article characterizes this as a county-wide effort. I bet not. I bet the people who are slated to have this trash burning marvel right next to them will soon be mad as hell in 3...2...1...

  7. Downsides by Tablizer · · Score: 5, Funny

    "Okay, who is the shit-head who threw away a barrel of sodium!"

  8. Energy / time^2? by Will_Malverson · · Score: 5, Informative
    From the summary:

    ...generating about 120 megawatts of electricity per day


    120 megawatts per day? So, after about 8 days, it'll be generating a gigawatt? In a year, will it be producing 43.8 gigawatts?

    Probably not.

    My first guess was that it's probably generating 120 megawatt-hours per day, or what those of us who know physics would call "5 megawatts".

    They say that they'll use about 1/3 of the generated energy, and plan to sell the remainder back to the grid. Electricity is usually worth something like $20-$50 / MWh. If they're selling 3.3MW into the grid, they might be able to get $1600 - $4000 / day from this thing.

    However, they also say that they can recoup their $425M investment in 20 years. Assuming a 4% interest rate (municipal borrowing is cheap!), they'd need to pay back a little over $2.5 million per month, or about $85,000 per day.

    If the power plant is actually generating 120 megawatts, then they're looking at (80*24) megawatt-hours per day, or $38,400 - $96,000. They're also selling steam and sludge, and I don't know what the current market value of those is. Yes, I know that you pay $60 - $100 / megawatt-hour for your home electric service, but electricity on the bulk market (especially at night) is a lot cheaper.

    1. Re:Energy / time^2? by CaffeineJedi · · Score: 5, Funny
      My first guess was that it's probably generating 120 megawatt-hours per day, or what those of us who know physics would call "5 megawatts".

      Um... no. I think they actually meant 120 megawatts. Because you see:
      120 megawatts * 24 hours = 2880 megawatt-hours.
      If the price of a megawatt-hour is about $35 dollars (we'll just use the median value of your estimate), then they are making $100 800 a day .
      Multiply that by 365, and you get: $36 792 000 dollars a year.
      Which means... that if they sell back 2/3 of the energy over the course of 20 years, they will make: $490 560 000 dollars (gross, in today's dollars)

      Just FYI, some of us also "know physics" and can actually use Google calculator to make an estimate ;)
  9. Re:Whence this vapor? by interiot · · Score: 5, Informative

    "Plasma arc" = incinerator. No fancy chemical or nuclear processes happen, they still dump out a huge amount of CO2, just like normal incinerators. Sure, they scrub the exhaust for really harmful chemicals and particles, but they still release a lot of CO2.

  10. Re:It's a waste of valuable garbage by gameforge · · Score: 5, Insightful

    I don't know anything about waste management, but if people care about recycling plastics, shouldn't they be doing that before they throw it in the trash? I think once it's in the landfill, it's "gone"; that means even if we wanted to, there's no way to harvest it out of a landfill that's remotely profitable. I mean, how much would they have to pay you to start digging through landfills for eight hours a day? And that's just the cost of mining the plastic out of the landfill.

    People need to worry about recycling these materials (plastic, aluminum, paper, etc.) before they toss them into the trash. Many people (myself included) have signed up for seperate services for recycling stuff like this, and put out a recycling bin once a week with the trash.

  11. Re:Whence this vapor? by Skye16 · · Score: 5, Insightful

    As would the oil/coal/natural gas power plant that was burning afore mentioned fossil fuels, as well.

    If we require a amount of energy and produce x amount of CO2 and y amount of trash, but have a way to reduce y without drastically increasing x, then I don't see why this is such a bad thing. If the exhaust is scrubbed, and the CO2 is nearly the same, then we've taken one little step toward a cleaner world.

    Ideally, there may come a time when our cars don't produce CO2, industry produces minimal amounts, and our power plants are primarily green as well. In that case, dumping *some* CO2 into the atmosphere while reducing the amount of landfill we need for garbage is one hell of a bargain.

  12. In Mickey Mouse Land by rahvin112 · · Score: 5, Insightful

    I'm guessing the most optimistic person in the world wrote that. First they aren't generating much power, the waste steam is a huge maintenance hassle as steam pipes either need to be made of stainless steel or something else that isn't going to rust. Second, after building it they are going to discover that they need to spend millions every year on scrubbers just to keep themselves below the EPA limits on the pollution, heavy metals and other nasty stuff from getting into the air. After doing that they will find out that their garbage fees go up astronomically as a result of the number of shutdowns due to violating said EPA standards because half the residents are throwing away toxic materials in the trash (you can ask people not to throw mercury, batteries and toxic chemicals away but they will still do it) and as a result of the damage said materials do to the scrubbers, incinerator and geration systems. And finally they will be paying to dispose of the hazerdous sludge that contains the remainder of the heavy metals and other toxic chemicals (take two household chemicals toss in a plasma arc and what will you get? millions of cominations of nasty nasty substances that can't be predicted or accounted for) that weren't belched out of the smoke stack. And if they think for a minute any roadway designer or contractor is going to use that stuff without being mandated by law they need to lay off the crack.

    The fact is that you don't build roads with materials that have unknown and extremely variable properties. 50 years ago they might have used the sludge in road construction (because they didn't know better) but not now, the chemical properties could be destructive/corrosive to the roadway, cause hazardous contamination in runoff and dust, and it could range from hard durable rock like material to a bad bit of clay. We don't build roads out of trash, unless someone is paying for you to take that trash, and it's a guaranteed uniform and chemically neutral substance, like glass. But this is what happens when you let the marketing department write your article.

    Our county made the mistake of building an incinerator 20 years ago, it was the worst mistake they ever made and became the biggest money suction device that has kept the county broke for the length of the factility. I bet the total cost over 20 years not including interest was double the estimated price and it would have been cheaper to ship the garbage to China at the prices being paid per ton to incinerate the garbage.

  13. Napkin numbers by gregor-e · · Score: 5, Informative
    It takes 9000 tons of coal per day to run a 1000 MWe generation plant. Geoplasma says they plan to consume 3000 tons of garbage per day to generate 120 MW. That'd give garbage about 1/3rd the energy density of coal using this process, which doesn't seem preposterous. They say the plasma will consume 1/3rd of the electricity, yielding 90 MW of marketable electricity. Florida commercial average is 5.86 cents/kWh, so 90 MW ought to go for about $126 thousand per day.

    Their other products are chump change:

    Quarried rock goes for about $3.75/ton. Of the 9000 tons of garbage they burn, they end up with 600 tons of slag, worth about $2000/day.

    Steam is worth about $10/1000 lb. The 80000 lbs of steam they'll sell to Tropicana is worth about $800/day.

    They don't mention it, but they are probably able to collect tipping fees from the sewage folks and, once this landfill is gone, dumping fees for future garbage.

    Still, the bottom line is electricity. If their efficiencies are off or if the market for electricity gets cheap, they may have a hard time amortizing $425 million in debt, even at favorable bond rates. $425 Million at 4.5% over 30 years would require about $2 million/month to service. Their $126K/day income gives them a gross of $3.8 million/month. Enough to service the debt and have about $1.8 million/month for salaries and other recurring costs. It might fly. But if they rack up significant maintenance costs that amount to a significant fraction of their total $425 million plant cost over the 30-year lifetime, it probably won't.

  14. Re:Indeed by c6gunner · · Score: 5, Insightful

    You'd be surprised. These plants exist in other parts of the world already, so it's a proven process. Toronto's been debating building one for a while (mainly for the garbage-disposal value since we now ship our trash to Michigan) but every time the environuts hear the word "incinerator", they get their collective panties in a collective bunch. Doesn't matter that the technology is proven, clean, and a damn sight better than wasting thousands of dollars and burning fossil fuels to ship our garbage to another country. Environutism has never been about being rational.

  15. Re:Mr. Fusion! by nuttzy · · Score: 5, Funny
    The landfill is expected to be depleted in about 18 years.
    Once again, using up all of natural resources!
  16. Byproducts by Xybot · · Score: 5, Interesting

    Sounds like a great idea but I'm still a bit skeptical about the composition of the byproducts. Contaminants like mercury don't simply go away, I assume they will be bound into the sludge portion of the byproduct, which is likely to be quite high given the fact that they are re-processing sewage.

    What about the Dioxins from vapourised plastics, A plasma arc produces an incredible heat but Dioxins are also very resistant to being broken down in this way.

    Sulphur? How is this kept out of the exhaust gases?

    --
    God was my co-pilot, but then we crashed and I was forced to eat him.