Carbon Management

What follows applies generally to most businesses or government organizations, and represents the core issues in pursuing goals of carbon reduction and containment in compliance with government mandates requiring so called carbon caps, that is, limits on emissions.

Definitions

The management of carbon emissions, more specifically carbon dioxide, lies at the heart of any organization's carbon policy.

Carbon dioxide is produced in any industrial process involving the burning of fossil fuel and also as a byproduct of many types of chemical manufacturing processes such as the production of ethanol or hydrogen gas. It is also produced in large volumes by most electrical power plants, and so any use of utility power by an organization is likely to produce emissions indirectly. In most cases meeting the transportation needs of an organization will also result in the release of CO2 into the atmosphere. And it goes without saying that using natural gas, coal, or bunker oil for heating produces CO2 as well. Thus any fuel production requiring combustion for the purpose of producing process heat is likely to produce CO2 as well. Moreover, some the production processes alternative fuels, notably ethanol, release carbon dioxide as an integral part of the core chemical conversion process.

These are the sources of emissions that are under the direct control of the organization, and they are what the carbon manager will focus upon in an effort to reduce or contain emissions. But arguably the carbon footprint, that is, the total impact of the organization on the global atmosphere, will go beyond those activities which it can directly control. For example, any manufactured goods used by the group have their own carbon footprints associated with them. The same would be true of most raw materials used in manufacturing processes.

Determining carbon footprint is the subject of the sections designated Monitoring and Measurement. There are many tools and formulas for determining carbon footprint, and they vary from industry to industry and from country to country. As with many aspects of the carbon economy today, there is insufficient standardization with regard to carbon footprint calculation.

Aspects of Carbon Management

Carbon management is basically about achieving and maintaining a predetermined carbon footprint—limiting one's emissions as it were.

Two means exist for accomplishing this goal: attacking the problem directly by reducing or capturing emissions, or by purchasing carbon offsets. The second approach is discussed in the section entitled Carbon Finance.

Reducing or capturing emissions comes under the designation of carbon mitigation. This is the direct approach, the one involving changes in one's business operations and/or the purchase specialized technology.

Emissions reductions may be achieved by increasing energy efficiency or by using sources of energy that produce less CO2 per Joules of energy generated. It's that simple. For instance, if one switches from low efficiency gasoline engines to higher efficiency diesel engines, one will reduce emissions by the first means. If one switches instead to natural gas engines, which, while not particularly efficient, produce much less CO2 per Joule of energy than do engines burning petroleum products, one will have achieved reductions by the second means.

There are of course many more ways to increase the energy efficiency of an operation than by adopting new modes of transport. A smart electrical management system for buildings can result in significant reductions in electrical consumption as can use of LED lighting in place of ordinary incandescent lights. Moreover, certain types of glazing may result in less energy consumed for climate control. We have devoted a special subsection to the general topic of energy efficient buildings.

Plant operations can also be made more efficient in many cases. Waste heat can be utilized to perform useful work, new designs of energy efficient boilers and combustors can be installed, and computerized process and flow control can also slash energy requirements. We've also devoted a subsection to this area.

Another means of achieving reductions is to buy or generate renewable energy including wind, solar, and biomass. The installation of solar panels is perhaps the most common way of reducing the consumption of electrical energy from high emissions sources, but there are several other technologies available as well. Again we've created a special subsection devoted to this topic.

Carbon Capture and Sequestration

Capturing emissions is the alternate tactic for directly reducing one's carbon footprint. This approach falls under the general designation of carbon capture and sequestration or CCS for short.

The term carbon capture and sequestration generally refers to the removal of CO2 from the exhaust stream of an electrical utility or industrial operation and the subsequent storage of the gas on a long term basis, or, alternately, the consumption of the gas in an industrial process such as the manufacture of synthetic liquid fuels.

Many authorities believe that carbon capture and sequestration is where the industry is going in the longer term. This belief is based on a number of assumptions.

The first of these is that fossil fuel will continue to play the dominant role in electrical generation far into the future and that the greenhouse gas problem is not going to be solved solely by promoting renewable energy. We happen to subscribe to this notion ourselves.

The second assumption is that the adverse political consequences of failing to curb fossil fuel emissions will become greater than those for implementing expensive retrofits at industrial sites and electrical generators, and for building a physical carbon network for dealing with impounded emissions.

The third assumption is that CCS is feasible.

We discuss CCS is great detail in subsequent pages. Here we provide only a bare outline of the issues and methods with major emphasis given to economic impact of this approach on individual businesses.

Capturing Carbon Dioxide

Most advocates of carbon capture believe that it will be initially applied to what are called large point source emitters. These are simply industrial installations that produce a lot of carbon dioxide on a yearly basis, and they include coal fired electrical power plants, petroleum refineries, steel mills, cement factories, ethanol distilleries, and various other types of heavy industry that consume a lot of fossil fuel or produce carbon dioxide as a byproduct of certain essential chemical processes. As in most other area of industrial engineering, economies of scale obtain in carbon capture and it makes sense to attack the big emitters first.

Three means exist for capturing CO2 from a point source emitter, pre-combustion capture, post-combustion capture, and oxy-fuel combustion.

In the first instance, one processes the fossil fuel to remove the carbon content before burning it. Fossil fuels are hydrocarbons, so if you remove the carbon you're essentially burning hydrogen and producing only water vapor and nitrous oxides at output, and the latter can be fairly easily removed from the exhaust by established means. Unfortunately, the economics of pre-combustion carbon removal are not very good at present, and if this technique were used in existing coal fired power plants or in industrial combustors, much new plant equipment would have to be required. Even in the case of new plants the capital costs are much higher than for established designs, and, absent subsidies or tough regulations phasing out old combustor technology, pre-combustion designs simply won't be adopted—at least not with current economics.

Post-combustion capture takes place in the exhaust stream and so leaves most of the existing plant intact. This is the area where most of the research is taking place, and many companies have claimed recent breakthroughs. But the fact is that established methods, which all fall under the nomenclature of amine capture, are very costly to implement and very energy inefficient. Until the newer methods are proven in the field and in the marketplace, post-combustion capture will not be widely adopted.

Oxy-fuel combustion refers to a family of combustion techniques where a mixture of oxygen and carbon dioxide rather than ordinary atmospheric air is used to support combustion. The technology is promising and can be applied to legacy plants in some cases, but is still largely experimental at this time. A primary problem with the technique today is the high cost of extracting pure oxygen from the atmosphere, but much research is underway to bring such costs down.

There is also a certain amount of research underway for capturing carbon dioxide from small scale emitters including automobiles. We believe that real progress in this area is a long way off, however.

Carbon Sequestration

Carbon sequestration refers to the storage of carbon subsequent to capture. Several techniques exist for doing so including storage in the depths of the ocean, geological storage in rock formations, storage in the soil, and storage in chemical compounds. In most types of sequestration the carbon will be stored in the form of carbon dioxide gas.

Separate subsections are devoted to each technique.

Currently, geological storage is the only technique in actual use, and a mere handful of projects have been undertaken. Many uncertainties remain as to the long term stability of CO2 reservoirs and to the cost effectiveness of this approach. Suitable geological formations do not occur everywhere, and many large point source emitters are located hundreds or even thousands of miles away from prime locales.

Distribution and Storage

If carbon sequestration becomes commonplace, extensive pipelines will have to be constructed to transport the gas from the places where it is emitted to the locations where it is to be sequestered. CO2 pipelines do in fact exist today, but they are almost exclusively devoted to distributing the gas for industrial uses, primarily enhanced oil recovery. A network that could effectively manage most of the output of large point source emitters in the United States would be roughly the same extent as today's natural gas pipelines.

Industrial Uses for Carbon and Carbon Dioxide

Carbon dioxide is used primarily for the enhanced recovery of fossil fuels including both petroleum and natural gas. It is also used in the beverage industry for carbonation, and as a refrigerant, and as cleaning agent. Elemental carbon as opposed to CO2 has a multitude of industrial uses including metal smelting, heating, and the manufacture of various chemicals and materials. It also finds use in agriculture.

Carbon dioxide is used in oil and gas wells to boost declining production, and this takes place on a fairly large scale and constitutes an immense potential market for emitters. The gas is injected into a well whose pressure has dropped, and by doing so one can force up a large part of the remaining hydrocarbon resource. As petroleum and natural gas supplies are depleted, the demand for CO2 for such purposes will grow. Conceivably, emissions sold to oil and gas companies could become a new profit center for a number of heavy industries in the U.S. and abroad.

Most CO2 used in enhanced recovery today is extracted from natural reservoirs, but, particularly in Canada and the U.S., we're beginning to see pipelines constructed specifically to utilize waste CO2 from power plants that would otherwise be vented into the atmosphere. We see this as an area that may expand greatly in the years to come.

An intriguing variant of enhanced recovery is the use of CO2 for extracting coal bed methane which is natural gas found in coal seams where it constitutes a safety hazard. Coal bed methane is a superabundant resource, but is rather hard to extract by conventional means. When CO2 is injected into a coal seam, the molecules bond permanently with the coal while expelling the methane, solving two problems simultaneously.

A particularly intriguing industrial use of CO2 which is just now emerging is the production of liquid fuels from the gas. By using CO2 as a liquid fuel feedstock one has the potential to close the carbon cycle and to make motor fuel entirely carbon neutral.

A couple of approaches exist at present. The CO2 may be used to nourish algae which would then produce lipid oils that could be subsequently converted into biodiesel and then further converted into petroleum analogs. CO2 can also be split into carbon monoxide and oxygen, and the carbon monoxide can be combined with hydrogen to produce petroleum like synfuels.

Both approaches are experimental at present but both appear promising.