While I am mildly embarrassed to be a regular user of K-Cups, I am not embarrassed about the fact that our company, like many, pays extra to ensure our K-Cups aren’t thrown in the trash. Rather we collect them in a special bin and they are shipped to the Lafarge Cement Plant in Kamloops where they are used as an alternative fuel source. For those of you unfamiliar with cement plants, they are ubiquitous, energy-hungry and a tremendous source of greenhouse gas emissions. They are ubiquitous because everywhere you go in our modern society we have a need for cement since it is the primary ingredient in concrete and each plant is limited in the volume it can produce. The production of cement is a very energy-intensive activity as the lime kiln needs to be heated up to 1400 oC and held there for a long period of time since the calcium carbonate (read limestone rock) needs to reach a temperature over 900 oC in order for the chemical reaction necessary to produce quicklime to occur. What most people don’t realize, though, is how this energy-intensity reflects in carbon dioxide emissions. As an Earth Institute report (ref) details:
Producing a ton of cement requires 4.7 million BTU of energy, equivalent to about 400 pounds of coal, and generates nearly a ton of CO2. Given its high emissions and critical importance to society, cement is an obvious place to look to reduce greenhouse gas emissions
The cement industry has managed to keep its head down in the climate change debate but as noted in the Earth Institute report, as an industry it represents 5% of global carbon dioxide emissions and has been growing at a rate of 2.5% annually. That is not to say the industry is not trying, indeed they are (ref). The issue they face is that about half of the carbon dioxide emissions associated with the cement industry are based on the chemical processes involved (calcium carbonate is converted to qiuicklime with the release of a carbon dioxide molecule); these chemical-based emissions cannot be eliminated. Instead the industry has to concentrate on the other half of their emissions, the greatest part being associated with the fuel being burned to generate the heat. So one of the big goals of the cement industry is to move away from combustion fuels like coal or natural gas towards renewable fuels like wood waste or...you guessed it K-Pods. Ironically enough K-Pods make up a very reasonable source of combustible material for a cement kiln. They are made of hydrocarbons (which burn) and the excess coffee grounds don’t really hurt as they actually serve as useful biomass. So here we have an industry that is producing a waste stream (K-Cups) that would otherwise clog up our waste chains and fill up our landfills and we have a second industry looking for an alternative fuel source. What we have is a good, but imperfect, solution to an otherwise intractable environmental problem. You see, K-Cups aren’t going anywhere until public perception makes it impossible for environmentally aware companies and individuals to use them; and even then they will not disappear completely as they are (as described by the creator) like a cigarette for coffee. Moreover, our society cannot operate without cement. As described in the Earth Institute report concrete is the second most consumed substance on earth after water.
One of the big fears expressed with burning plastics in cement kilns involve the off-gases from the combustion. What most people don’t recognize is that the heat and retention time needed to heat solid rock to over 900 oC is also ideal for breaking down fuel sources to their base components with few or no nasty by-products. You see the reason most engines give off nasty gases is that they do not get hot enough, long enough to get complete combustion of the fuel. Instead, in most auto or diesel engine, they get partial combustion and all sorts of interesting and distressing combustion byproducts are produced. In a cement kiln the combustion is contained to prevent loss of heat. This results in as close to an ideal combustion chamber as we will see in modern industry. These near-ideal combustion chambers were actually tested for use in eliminating PCBs and other hazardous wastes in the 1980’s and 1990’s and were determined to combust the compounds with essentially 100% efficiency (ref). The main reason the plants were not turned into giant hazardous waste disposal facilities had to do with optics and politics rather than the actual chemistry involved in the processes.
Ironically, using renewable energy sources like PCBs, K-Cups and used tires in the combustion process can actually reduce the negative emissions from the kilns. One of the historic issues with these kilns has been the release of gaseous mercury from the combustion. As many of you know, amongst their many downsides, all coals contain some mercury, with concentrations in US coals ranging from 0.08 μg g for coal in the San Juan and Uinta regions to 0.22 μg g−for the Gulf Coast lignites (ref). Mercury, unlike the coal, does not burn, so by replacing coal with renewables we actually see a reduction of mercury emissions from the cement kilns (ref).
The inspiration for today’s post was a news story I watched last night on my local television station (ref). It was all about the effort by Lafarge Canada to use K-Cups in their Kamloops cement plant. As I write above, while not the perfect answer it is the best, imperfect solution to an otherwise intractable environmental problem. At the end of the story the reporter interviewed a local environmental leader who tried to throw cold water on the project. He said (pardon my poor transcription):
In this case when you talking about, you know, burning plastic instead of coal it is perhaps a tiny little step in the right direction but it comes with a lot of consequences....It is not the kind of stuff you want in the atmosphere
It was clear from this answer that the environmental leader had no idea how a cement kiln works and rather than saying “I don’t know enough about this to comment, let me look into it and get back to you” he spouted off a negative answer. This hubris amongst the leaders of the environmental movement is one of the things that really turns me against the movement. One of the most important things I was taught in graduate school was the ability to admit “I don’t know” rather than trying to bluff my way through problems. Once you learn to say “I don’t know” you can learn much more quickly and oddly enough, it adds tremendously to your personal credibility. People will feel comfortable coming to you when they know that you will not set them on the wrong course rather than admit to not being fully informed. The funny thing is that given the size and complexity of the environmental field, much of the time any one individual will not have the skills needed to accomplish a task. In our office we have civil, chemical and mechanical engineers, we have a chemist, a couple biologists, a toxicologist, a couple geographers, a couple geologists and a hydrogeological specialist. Even with all this in-house expertise we are willing to bring in outside help when the need arises. This is because we have all learned the importance of recognizing our own limitations and the perils of hubris. To maintain this culture we all have been told again-and-again stories of failures based on hubris until they were drilled into our heads. We are told stories of other companies drilling without proper daylighting and hitting tanks or utility lines, stories of consultants who tried to do it all and failed in one spectacular fashion or another because someone was not willing to admit when they needed help. We emphasize this to remind ourselves that no one is all-knowing or competent in all things. The problem with the environmental movement of today is that instead of recognizing their limitations these folks wander around in a Dunning-Kruger haze and instead of making us trust them we become less and less trusting in their knowledge or expertise. When a Council of Canadians handout tells me that benzene is a polycyclic aromatic hydrocarbon (ref) I start to wonder what else they may be saying that is completely wrong. When an environmental group trumpets a “cancer cluster” that is ultimately proved to be no such thing I know not to trust them the next time. When an environmental leader goes on television and dumps on a win-win attempt to reduce waste going into our landfills while reducing greenhouse gas and mercury emissions from a necessary industry then I begin to wonder how anyone can trust these people on other big issues.
In high-school, like many of my peers, I read Shakespeare’s Macbeth and learned early on that hubris is a great failing. In university, and my current occupation, I have been taught that hubris can be controlled by the simple action of admitting that I don’t know everything and recognizing that sometimes I need technical help. Until the leaders of the environmental movement learn this truth they will continue to trip over their own feet, delaying good projects because those projects may not be perfect and slowing environmental improvements because they are unwilling to admit that they aren’t all-knowing.
Excellent post. I wonder if the cement plants can't be modified to use enriched air and capture the CO2ReplyDelete
There are efforts to move towards carbon capture technologies but these are still in their infancy.ReplyDelete
Keurig is great for my every morning, very convenient and I can preserve used coffee.ReplyDelete
Thank you so much.