OVER the weekend, President Ferdinand Marcos Jr. said that the country’s waste-to-energy (WTE) program should be up and running within 18 months in order to deal with the growing “sea of trash” drowning the Philippines. This was apparently after a visit by the chief executive to one of the city’s giant open sewers, which was spectacularly choked with floating garbage after heavy monsoon rains and flooding last week. The Department of Public Works and Highways (DPWH) and the Metro Manila Development Authority (MMDA) are in the process of cleaning up that mess; but of course, that simply means moving the problem somewhere else, adding several hundred metric tons to the country’s overstressed landfills.
Marcos, to his credit, did not lean into the “energy” part, but that didn’t stop the Department of Energy (DOE) from doing so, continuing a cynical campaign of utter gaslighting of the Philippine public that it has pursued for most of this year. Energy Secretary Sharon Garin announced that the Special Auction Round for WTE under the Green Energy Auction Program is back on, with the auction itself scheduled for mid-October. Winning bidders will be required to finish construction by the end of 2028, and begin delivering electricity to the grid by the end of 2029. The DOE initially set a target of 230 megawatts (MW) of WTE generating capacity, but after the Energy Regulatory Commission (ERC) set a slightly higher than expected green energy auction reserve (GEAR) price for WTE at just under P9.3 per kilowatt-hour (kWh), the DOE raised the capacity to be put up for bid to 400 MW.
As reported, the DOE estimates that Metro Manila generates about 9,000 metric tons municipal solid waste (MSW) daily, which the department says could potentially support up to 200 MW of WTE capacity. Back in May, I had run the calculations and determined that the entire daily MSW output of the Philippines would not produce anything close to that amount of electricity, but those figures were based on admittedly dated estimates. With the DOE providing a figure for Metro Manila’s MSW output — which presumably is the figure upon which its estimates of the potential generating capacity and thus the scale of the WTE auction are based — updating my original calculations based on that is in order. In addition, I have since gotten some technical specifications from real-world operations of a couple of WTE plants in the US, which also helps to hone the figures.
The good news in that is that I have learned modern WTE plants are considerably more efficient than I thought; the technology has improved a great deal in the past six years since I last did this sort of study. The bad news is that even with better equipment, the DOE’s WTE generating capacity aspirations remain out of reach.
Math time
Almost every WTE plant in operation in the US uses what is called a “mass burn” system, which incinerates everything but metal, glass and soil, stone and masonry found in MSW, or about 85 percent of the total MSW volume. Under the proposed new WTE law pending in Congress, the Philippines intends to segregate compostable and recyclable waste, which lowers the available volume for WTE down to about 30 percent of the total. However, since that law has not passed yet — although it seems likely to pass eventually — I’ll use the higher mass-burn figure. Eighty-five percent of 9,000 metric tons is 7,650 metric tons, so that is the potential amount of daily feedstock.
Depending on the calorific value of the MSW feedstock, a WTE plant burning at between 1,400 and 1,800 degrees Celsius — the high temperature is necessary to destroy toxins that would be emitted at lower temperatures — can produce between 400 and 700 kWh per metric ton of waste. The DOE has not provided an energy content estimate for Metro Manila’s MSW, so I’ll calculate a range. To produce 200 MW (200,000 kW) continuously, a WTE plant would require between 285 and 500 metric tons per hour. Thus, Metro Manila’s estimated volume of useable MSW would last between 15 and 26 hours.
That is close to what the DOE envisions in terms of capacity, but it is absolutely a best-case scenario. It assumes that the MSW stream does not decrease, that the restrictions of the impending WTE law are not implemented, and that the hypothetical WTE plant operates at 100-percent efficiency. None of those are conditions that can be counted on, so the output will be much less.
First, the capacity factor of WTE plants (i.e., how much electricity a power plant actually produces compared to the maximum amount it could produce if it ran at full power all the time) ranges from 80 to 85 percent, meaning that a 200-MW plant will only produce 160 to 170 MW. The way to compensate for that is to build an additional plant, or build one with a bigger nameplate capacity, but the MSW feedstock stream is already maxed out, so that’s not possible in this case.
Second, the scenario assumes that the MSW feedstock will be delivered continuously, 285 to 500 metric tons per hour, hour after hour, 24 hours a day, seven days a week. That seems unlikely, given the profound inefficiency of the metropolis’ current waste collection infrastructure. That means between 71 and 125 of the largest trash-hauling trucks that can navigate Metro Manila’s roads (they can carry about 4 metric tons at a time) arriving at the facility, every hour of every day. Again, not literally impossible, but so unlikely that it may as well be.
In the US, where there are 57 operating WTE facilities, WTE accounts for about 0.29 percent of the country’s total annual generating capacity. While Europe and Japan use WTE more extensively, with more than 500 plants in Europe and 415 in Japan, the technology still contributes less than one percent of total generating capacity (0.5 percent and 0.65 percent, respectively, to be specific). The US plants tend to be much larger, individually, but that is because the US is the most prodigious producer of MSW on the planet, so that is possible there.
As I pointed out in my May column, the US Energy Information Agency (EIA) classifies WTE as a “waste management technology” rather than a form of generation, and that is how the technology should be regarded here. It is feasible, but its potential output in terms of adding to the Philippines’ energy production is inconsequential, and will only decrease as time goes on. The DOE’s campaign to convince a skeptical public otherwise is foolish, and will only make the technology’s advocates look bad in the end.
ben.kritz@manilatimes.net
Bluesky: @benkritz.bsky.social
Website: www.badmannersgunclub.com
