Back in October 2007, in our post “Ze-Gen’s Waste to Energy” we reported on a Massachusetts-based company, Ze-Gen, who appeared to be “possibly the furthest along in the race to develop technology to turn waste into fuel – eliminating the need for landfills in the bargain.” That was then. There are other contenders in this race…
|Plasco’s Ottawa Waste-to-Energy Plant.
(Photo: Plasco Energy Group
Just one day after we posted this report, Plasco Energy Group, based in Ottawa, Canada, announced in a press release “Plasco Energy delivers power to Ottawa grid,” that they have completed a waste-to-energy plant and are beginning the commissioning process.
Plasco’s technology, as described in the “how it works” page on their website, begins with municipal solid waste (presumably pre-shredded) being fed into a primary chamber, where most of the waste is converted into gas.
The gas is then further cleaned in a secondary chamber and is then used to power internal combustion engines which turn a generator. The residual solid waste is transferred to a different chamber where it is melted and converted into ingots. Here is what Plasco claims their plant can do with one ton of municipal solid waste:
One Ton of Municipal Solid Waste Equals:
1.4 megawatt-hours of electricity
300 liters of potable quality water
7-15 kilograms of metal
5-10 kilograms of commercial salt
150 kilograms of construction aggregate
5 kilograms of agricultural fertilizer
It will be interesting to see how soon Plasco completes the commissioning process for this first plant and brings the facility into its full rated capacity of 85 tons (metric) of municipal solid waste per day. Given that on December 3rd, 2007, Plasco Energy Group closed an equity financing of C$54 million led by First Reserve Corporation of Greenwich, Connecticut, there is reason to believe they are breaking in their new plant according to plan.
There are interesting contrasts between the Plasco claims and those from Ze-Gen. Most significantly, Plasco has apparently solved the challenge of processing municipal solid waste, a feedstock that is more problematic to convert (mostly due to higher and less predictable water content) than construction debris. The energy recovery per ton (normalized to short tons) differs greatly when comparing municipal solid waste (1.4 megawatt-hours per ton according to Plasco) and construction debris (4.2 megawatt-hours per ton according to Ze-Gen. Presumably the composition of typical construction debris – 90% scrap lumber – accounts for the energy density claimed for construction debris being literally triple that of municipal solid waste.
Finally, should an energy density of 1.4 megawatt-hours per ton in the case of municipal solid waste be applied when calculating the energy production potential of the 100 million tons of construction debris and 220 million tons of municipal solid waste produced in the USA each year, then the percentage of total energy production in the USA that could be offset by converting 100% of these waste streams into energy (as we calculated in our report on Ze-Gen) is not 4.0%, but 2.5%. Still a worthy proposition.