TechTheDay

Often, when it comes to discussing solutions to the problem of climate change, the first thing that comes to most people’s minds is the shift to renewable energy along with the use of efficient technologies. Since it’s widely known how fossil fuels greatly contribute to global warming crisis, what most people think as the viable solution is the development and wider use of renewable energy. This infers the gradual abandonment of the use of fossil fuels.

However, it appears that climate change solution advocates are missing out on something equally beneficial. Not much attention is being given to carbon capture technology. It is regarded as an underfunded technology – which should not be the case, especially with a recent report from the Intergovernmental Panel on Climate Change (IPCC) stating that carbon capture technology at power plants could have a great impact on the economics of solving the climate change problem. As reported at the MIT Technology Review, the cost of limiting climate change could have a twofold increase sans the use of carbon capture technology.

The IPCC report found that if solar and wind power don’t meet the targets, their effect on limiting global warming would only be around a 6% increase in total costs. This is a surprisingly small amount considering that renewable energy is widely known to be a major solution to climate change. On the other hand, if carbon capture and storage (CCS) technology isn’t deployed, the study found that the costs would double. The reasons for such unexpected cost differences are as follows:

• There are other alternatives to solar and wind power that are not that contributory to climate change. One good example is nuclear energy.
• There are no immediate replacements for carbon capture and storage technology.

So how does carbon capture and storage technology work? Why should it be given more attention? The following discussions will attempt to offer answers:

Carbon Capture

There are three types of carbon capture methods in current use. These are post-combustion capture, pre-combustion capture, and oxy-fuel combustion. Post-combustion capture is typically used in fossil fuel burning power plants. With it, carbon dioxide is captured from the flue gases or the emissions that come out of flues. Pre-combustion carbon capture is mostly used in facilities for producing fertilizers, chemicals, and gaseous fuels. This method calls for the partial oxidation of fossil fuels in a gassifier or other similar systems to produce syngas that is shifted into capturable carbon dioxide and hydrogen. Oxy-fuel combustion, on the other hand, is based on the burning of fuel in oxygen instead of typical air. This results in a flue gas the contains carbon dioxide and water vapor. Water vapor is separated through condensation and the carbon dioxide stream is sequestered and stored.

Carbon Storage

Storage can be done through a number of methods. These are mainly through geological and mineral storage. In geological or geo-sequestration storage, carbon dioxide is injected into underground formations such as oil and gas fields, coal seams deemed unmineable, saline formations, and saline-filled basalt formations. Carbon dioxide injection is believed to help hasten oil recovery in oil fields with declining reserves. Mineral storage involves the exothermic reaction of carbon dioxide with available metal oxides to produce stable carbonates. This is basically an emulation of the naturally occurring process responsible for the production of surface limestone.

Ocean storage was once believed to be another way of doing carbon sequestration but it has since been outlawed after it was found that it aggravates ocean acidification.

Energy Requirements and Costs

The cost of carbon capture and storage is not cheap. Its energy requirement alone is something that will immediately discourage plant owners or operators. In one report, it was found that the process can take up around a quarter of a power plant’s output capacity.

Carbon capture and storage is generally done at the source, at the factory or production plant that uses fossil fuels for example. Unfortunately, there are no commercial scale projects that make use of carbon capture technology yet. The exact costs involved are uncertainly but they are certainly on the expensive side. A 2009 estimate of the US Department of Energy estimates the cost to be around $60 per ton, which can translate to an electricity price increase of around $0.06 per kWh that in turn can double the price of electricity.

There is a need to undertake more research and development efforts on improving carbon capture technology to make it less expensive and more efficient. It is doubtlessly one of the vital solutions in addressing climate change but at its current state, it is not a very viable option. It is comparable to geoengineering as a climate change solution at its present state. Hence, more funding for carbon capture and storage research is needed.