Cow Power

There are various new carbon offset projects being undertaken that focus on harnessing agriculturally produced methane through anaerobic digestion. Three of the most promising methods are covered lagoons, plug-flow, and complete-mix digester systems, according to the National Carbon Offset Coalition. Bacteria will produce methane from manure whether or not it occurs in an open field or in an anaerobic digester, but when it is in a digester, it can accomplish two important goals. First, it provides a source of renewable energy, which can be used to run turbines or generators for energy production, or it can be burned in boilers to produce heat. The second, and perhaps even more important goal, is that it keeps methane, an extremely powerful greenhouse gas, from entering the atmosphere.

Methane is produced from manure via a chain of reactions driven by bacteria, as is illustrated below by a simple flow chart from wikipedia. First, bacteria break down the large organic molecules in manure into sugars, fatty acids and amino acids through a process called hydrolysis. Methanogens (or, methane-producing bacteria) can eat these components, or they can be further broken down by acidogenic bacteria in the process of fermentation. The products of fermentation (carbonic acids and alcohols, hydrogen, carbon dioxide and ammonia) can then be broken down into hydrogen, carbon dioxide and acetic acid by acetogens. Finally, methanogens create methane, carbon dioxide and water out of the final remaining components.


(CLICK on the flow chart to make it BIGGER)

The Iowa Department of Natural Resources gives a good overview of the three main ways harnessing methane through anaerobic digestion. The first is the covered lagoon system, where waste manure from farm animals (cows, pigs, etc.) is stored in an above-ground lagoon, which is covered by impermeable tarps and sealed at the edges. A pipe runs under the cover to collect the biogas that is created through anaerobic digestion, and send it to generators or boilers.

The second method is the plug-flow digester system. Manure and water (to maintain the proper consistency) are added to a mixing tank, or plug, which is stored below-ground. The tank is sometimes heated (with energy produced by the tank itself!) in order to speed up production of biogas, which is then driven out, either via a pump or the pressure built up by gas production, into a pipeline to be sent to a generator or boiler.

The third way of harnessing methane from manure is called the complete-mix digester system. In the complete-mix system, manure is collected in an above-ground tank (or below-ground in colder regions). The manure is heated in this tank, to begin the anaerobic process, before being pumped into a reactor tank, where it is mechanically mixed to keep the solids separated from the liquids. As biogas accumulates, it is pumped away for use, and the left-over solids can be used as fertilizer.

The Iowa DNR estimates that manure-derived methane from Iowa, if harnessed, has the potential to fulfill all of the power needs for 325, 000 homes. For this to happen, however, the price of installing and managing anaerobic methane digesters will need to decrease. According to the DNR, installation of a new system costs between about $300,000 and $500,000, which is a substantial cost to farm-owners. Perhaps in the future, as prices fall and demand increases, this renewable energy source will become a reality for more farmers.

FTC and carbon offsets

Currently the carbon offset market functions on an entirely voluntary basis. Even so, it is growing at an incredible rate. According to the August, 2007 State of the Voluntary Carbon Market report by New Carbon Finance, a carbon market analyst and advisory firm, the number of organizations selling carbon credits into the marked has increased by 200% since 2002. In 2006, some 23.7 million tons of CO2 equivalent were traded in the voluntary markets. There are various ways to quantify carbon offsets, and there is also uncertainty about the efficacy of different methods. For this reason, and amid growing concerns that consumers are actually getting what they pay for and that offset projects aren't double-selling credits, the Federal Trade Commission has been looking into ways to regulate the market. The FTC held a conference in early January to discuss these issues, but so far, no new 'green guides' have come out.

In an effort to press the issue, the Attorney General's Offices from 10 states issued a request for the FTC to take the following steps in hopes of preventing fraud in the carbon market: 1) research on consumer perceptions of what carbon offsets are, 2) commission research into the efficacy of disclosure, or labeling (the AG's suggest putting a "carbon facts" box on marketing materials), 3) consumer education encouraging reduction of emissions, and guidelines for purchasing offsets, 4) require substantiation of projects, including evidence for permanence of projects, no double-selling of offsets, no selling offsets for projects that are undertaken for compliance with existing laws, evidence for no increase in emissions elsewhere as a result of project, and scientific evidence for the quantity of carbon offset (scientific evidence, as defined in the FTC's green guides). A statement and a copy of the letter can be found at the Vermont Attorney General's Office website.

Carbon offsetting is growing into a multi-million dollar market, and as such, it is in desperate need of regulation. As mentioned above, quantifying and verifying offsets is sticky business. For example, planting trees is a common carbon offset mechanism. Reforesting areas that were previously subjected to deforestation is one way to draw down atmospheric CO2 through photosynthesis by trees. The problem is that if that tree burns or dies and decomposes, the CO2 it once took out of the atmosphere is put back into the air. Another potentially negative implication of this practice is for biodiversity. Some tree plantations are being planned for areas that have never naturally had forests. Also, many plantations are only reforested with one type of tree for potential future use in logging or biodiesel production, and these monoculture tree farms can have serious impacts on biodiveristy.

Let's hope the FTC gets down to business and provides the carbon market with some rules and regulations as well as providing consumers with guidelines to navigate this complex arena.

Green Freedom

Here's a new idea (at least to me): why don't we sequester CO2 emissions right back into the form of gasoline and pump it into our cars and airplanes? This is the line of research being pursued right now at Los Alamos National Laboratory in New Mexico. Scientists there are pursuing the relatively simple concept that CO2 can be chemically absorbed from the air, using liquid potassium carbonate, for later conversion to synthetic gasoline. The chemical reaction involved is: (CO2 + CO3 +H2O -> 2HCO3), where CO3 comes from potassium carbonate (K2CO3).

While this technology has been explored in the past, the scientists at LANL claim that they have finally figured out a way to make CO2-scrubbing energy efficient enough to be carbon neutral and to produce competitive prices at the pump. The only glitch? The processing plants that would capture/convert CO2 to synthetic gasoline require a significant energy input. In order to maintain the carbon neutrality that makes this process so appealing, LANL scientists suggest nuclear energy. They tout nuclear as being the most cost effective at this point, although in the future, perhaps renewables (such as wind and solar) will be able to take up the slack. LANL has figured that with an initial investment of $5 billion in a nuclear plant, they can generate prices of between $3.40 and $4.60 at the pump.

This is certainly an interesting avenue for our country to be pursuing; leave it to Americans to find an economical and 'carbon neutral' way to keep plugging along at the status quo emissions-wise. I am somewhat skeptical, however, of the feasibility of this project. It seems unlikely that sucking air into towers attached to geographically dispersed production plants could actually have any effect on the overall concentration of CO2 in our atmosphere. Also, what about the other toxins spewed from the tailpipes of our cars and trucks? Perhaps this will be a viable solution for some technologies (jetliners, for example), but I think we're barking up the wrong tree as far as cars are concerned. Internal combustion engines are extremely inefficient machines, and I think that the most viable solution to this problem is to switch to fuel cell or battery-powered cars that we can plug into a grid powered with an integrated system of renewable energy sources. For airplanes this is not yet a reality; perhaps LANL's innovative ideas will effectively neutralize the carbon input/output of jetliners by powering them instead with synthetic gasoline.

Jeffery Martin, the principal investigator on the project will be presenting LANL's ideas tomorrow (February 20, 2008) at the Alternative Energy NOW conference in Florida. For more information, check out the official public release on Green Freedom from LANL. Also, running the search "Green Freedom" on the LANL site will yield access to some good pdf's detailing the science behind this technology.

the ecopsychologist

Another interesting character in the complicated realm of carbon emissions (and, more importantly, what to do with them) is that of the ecopsychologist. In a nutshell, the new and growing branch of ecopsychology deals with existential issues arising out of the human race's separation from nature. As humans' cultural evolution has outpaced that of the natural world, we tend to find ourselves (especially in America) substantially separated from the earth's complex network of ecosystem interactions. Humans suffer from this separation not only because of our loss of a connection with nature, but also because of the moral dilemmas which stem from the cause and effect relationship between our consumption and the destruction of natural resources and biodiversity.

So what sort of cure might be prescribed to a distraught earth inhabitant, reclining in despair on an ecopsychologist's couch? You guessed it-- the Rx of the 21st century is to start chipping away at the old carbon footprint. Of course, this is just one of the ways in which a person ailing from the ethical woes of an over-consumer or global-warming-catalyst can calm their karmic disquietudes, but it is one that is rising in popularity. Take the McLendon family, for example; two days ago this family was covered by the NY Times for their unique response to family therapy sessions. Instead of prozac or continued therapy, this family was advised to retrofit their house to be more green, and to take their kids outside more for play time and community service. The go-to source for those interested in this brave new foray into the ever more complicated American psyche is Ecopsychology.org. Here you can find literature, events, and lists of practitioners- there may be an eco-doc in your hometown, especially for those in (here's a shocker) California.

sequestration?

To continue our brief overview of what carbon offsetting and carbon sequestration are, let's focus on the latter. New technology and ideas focused on carbon sequestration are aimed, in a general sense, at pulling CO2 out of our atmosphere. Whether by enhancing natural sinks, or by creating new sinks, the idea is to draw down this greenhouse gas or trap it at its source, and then sequester it, or isolate it from the atmosphere.

The website of the Department of Defense's Office of Science provides an overview of the technologies that currently exist or are being developed to sequester carbon. One idea, already being tried at one coal-fired power plant in West Virginia, is to trap carbon before it is emitted into the atmosphere and to store it underground, typically in empty oil reservoirs. A New York Times article about this plant describes the process: as CO2 passes through the flue, chilled ammonia traps it and compresses it into liquid form so that it can be injected some 9,000 feet below the surface of the earth.

The second major realm of sequestration technologies is enhancement of natural sinks on land. The projects focus mainly (as I understand them) on enhancing photosynthesis and carbon fixation, conversion of carbon into organic matter, reducing re-emission of CO2 through respiration, and increasing primary productivity in degraded lands and deserts. Examples include forest harvesting and pasture management (storage of CO2 in the soils of pasture lands).

A third focus area is on carbon sequestration in the ocean, as earth's oceans naturally represent about half of the world's atmospheric CO2 sink. Current proposed projects include fertilizing the ocean with limiting nutrients to enhance primary productivity and direct injection of CO2 into the deep ocean (1000m+). Great uncertainty surrounds both of these methods both in terms of effectiveness and environmental implications.

A final idea proposed on the DOE website is that of sequencing the genomes of microbes that generate or ingest carbon compounds. The DOE suggests that with greater understanding of the genetic pathways which allow organisms to manipulate carbon, we may some day be able to develop a microbial carbon sink, possibly one that converts methane to hydrogen.

So.... what's an offset?

To get this blog started, I thought it would be best to begin by reviewing what carbon offsetting and carbon sequestration are... we'll start with carbon offsets: how does it work? why is it important? who are the key players?

First, Why? The purpose of this blog is not to delve into explanations or philosophical discussions of what global warming is and why it is bad for our planet. Suffice it to say that human activities have increased the amount of CO2 in the atmosphere from preindustrial levels of 280 ppmv to around 380 ppmv today. Geologically speaking, this rate of change in atmospheric CO2 is unprecedented. Furthermore, the Earth has not seen such high levels of atmospheric CO2 for roughly 40 million years. Carbon offsetting is a way for people to reduce their individual CO2 emissions in an attempt to slow anthropogenic global warming. In the words of carbonfund.org, the idea is to reduce what emissions you can, and offset the rest.

Second, How? What does carbon offsetting actually mean? A key idea in considering one's impact on the planet is that of the carbon footprint, or how much CO2 is emitted as a result of one's actions. For instance, driving my subaru outback 2,000 miles emits about .74 tons of CO2. This is just one of the many components of my carbon footprint; others include how I heat my home and how often I fly. Once you've calculated your carbon footprint, you can turn to a company like carbonfund.org to buy carbon offsets. When you pay for carbon offsets, you are paying for the equivalent of your energy use (using the currency of CO2 emissions) in alternative energy, energy efficiency, or carbon sequestration (for example, through reforestation). According to carbonfund.org, it would cost about $4 to offset that 2,000 mile road trip in the subie.

So, who are the main players in this seemingly simple equation of buying and selling carbon offsets? First, there are those who purchase offsets: businesses, individuals, event coordinators, organizations... the list goes on. Second, there are those who sell offsets: including groups like carbonfund.org, LiveNeutral, Terrapass, and NativeEnergy. Some groups are non profit, others are for profit. Third in the equation are those who are actually producing and developing projects to generate alternative energy, improve energy efficiency or sequester carbon. These groups can range from owners of wind farms to producers of new technology for fuel efficiency. Yet another key group are those who certify the producers of marketable offsets; they are poised to act as watch-dogs to ensure that buyers don't get 'greenwashed'. There is also a host of mediators and third parties involved in the trading of carbon credits and offsets. The final player, and one that is poised to become more involved in the near future, is the Federal Trade Commision. The F.T.C. is in charge of guidelines for environmental advertising, and there haven't been changes made to these rules since 1998. Given the myriad of new activity on this front since then, it is long past time for the F.T.C. to step in and insert a legal backbone into the carbon trading market.