Carbon Capture and Underground Storage - How might it impact the Everglades?
One of the major challenges to the continued health of the Florida Everglades, a freshwater “river of grass”, is sea level rise caused by global warming. As increased temperatures melt the Arctic and Antarctic icepacks, rising sea levels will push salt water north from Florida Bay into the freshwater system, killing the marshes inhabited by plants that can only thrive in a freshwater environment. Some of this can be mitigated by plans underway to increase the freshwater flow from north to south, such as new bridges on the Tamiami Trail to allow the flow of water now blocked by the roadway. Longer term, the preservation of the Everglades depends on efforts to stop, if not reverse, the continuing rise in temperatures.
There is no real scientific dispute today that increased emissions of carbon dioxide (CO2), caused by the burning of fossils fuels, are causing increased temperatures worldwide. Slowing the increase of CO2 in the earth’s atmosphere, if not a reduction from the current level, is required to at least stop the increased heating of the earth’s surface. One solution is to reduce the total demand for energy by society. This is already being achieved in developed countries, but the rest of the world wants air conditioning, especially in the tropics, and are probably not going to give it up once they are able to afford it. A family in Nigeria wants the same comfort during the summer that a family in Miami has come to expect. Given that world energy demand will continue to increase, the CO2 emitted to produce that energy must be reduced.
The realistic solutions to achieving this reduction are limited to a few choices. One is to replace electricity generated by burning hydrocarbons with wind and solar power. The increasing electrification of the automotive fleet only contributes to a reduction in CO2 emissions if the electricity that recharges the lithium batteries is derived from a power plant that does not emit CO2 into the atmosphere. Everyone is familiar with the concepts of wind and solar power, and the environment of south Florida is very conducive to continuing to expand it.
If you have lived near Crystal River further to the north, you are probably knowledgeable about nuclear power plants. Nuclear power is an efficient way to generate electricity and has zero emissions, but the risks have led to its expansion being largely rejected by society.
Some areas of the world have abundant geothermal energy, which results from heating of the earth’s crust by heat from the molten core of the earth. This is an advanced technology in places like Iceland where the local geology has brought heated fluids close to the surface but is not widely utilized in the US at this point.
Another alternative is to separate carbon dioxide from the emissions of a powerplant burning fossil fuel and injecting it underground. This alternative (also referred to as carbon sequestration) is less well known today and has not been widely implemented. Like wind, solar and nuclear, there are those who support it and those who are opposed. But regardless of one’s position, understanding is necessary to informed discussion and debate. It is a technology that is going to expand and become more visible in the near future.
The sketch above illustrates the concept. A powerplant (or a refinery, chemical plant, cement plant or other industrial facility) generates energy by burning natural gas, which generates CO2 and water. The chemical reaction that takes place is shown below:
CH4(Natural Gas) + O2(oxygen) >>> CO2(carbon dioxide) + H2O(water)
A scrubber at the top of the plant’s emissions stack separates the CO2 from the water (steam). The steam is harmless and escapes into the atmosphere. The CO2 is piped to a well drilled thousands of feet into the earth, into a porous rock. The CO2 is then injected down the well into the porous rock, where it will remain for hundreds of years (at least). The process allows the utilization of hydrocarbons as an energy source without the release of CO2 into the atmosphere. Essentially, the natural gas is produced from underground by wells, energy is extracted by burning it, and the resultant carbon dioxide is returned underground with no impact on global warming.
There are drawbacks and risks to this process. CO2 in high concentrations is a lethal gas, and underground storage must be done in a manner that assures it will remain in place. The mechanical integrity of the pipelines, pumps and wells must be sufficient to prevent any releases. The geology of the porous rocks that will contain the CO2 must be understood sufficiently so that injection on takes place where CO2 cannot leak upward to the surface. And a monitoring process must be put in place to ensure that once injected, any movement of the underground CO2 plume can be traced, and preventative measures put in place if required.
Opposition to the process falls into two areas. The first is concern that the process cannot be implemented satisfactorily, and the CO2 will be released to the atmosphere at some point, either short term or in the future. This should be an area of discussion, but the technology has been proven for years by underground storage of natural gas, and sufficient regulation and oversight should be capable of ensuring that it is done safely. The second concern is that the process is an excuse to continue burning hydrocarbons for power generation, and that solar and wind power should be immediately employed instead. The problem with this argument is that while solar and wind technologies and cost have shown impressive advances in the last ten years, they still only generate about twelve percent of total US energy consumption. (US Energy Information Agency). Without a drastic and unexpected change in energy consumption, oil and gas will be the primary energy source for years to come.
Carbon Capture and Underground Storage projects are being designed and implemented worldwide, and the beneficial impact is not related to the location of the project. Carbon dioxide circulates globally in the atmosphere, and a reduction in the amount released has a global effect regardless of where and how it is achieved. If this technology is successful in reducing the increase in the earth’s temperature and associated sea level rise, the Everglades will benefit.