Summary

Based on past experience, it is expected take a significant amount of time to deploy technology to counter anthropogenic emissions if the designs are a substantial departure from the current technology. Using established air pollution control technology as a benchmark for comparison, it has taken years to fully develop a much simpler SO2 technology mitigation with Flue Gas Desulfurization. Pilot studies underway today have a demonstration schedule on the order of 10 years before commercial availability [37]. Further, it has taken decades to build the supplemental nuclear infrastructure, one that is essentially described as "CO2 free."

Some have compared the task at hand to the Manhattan Project or the Apollo Project, but this may only be an appropriate comparison for the development phase of the technology itself. Deployment of this still-evolving technology might demand a comparison more like the construction of the United States interstate highway system. Construction of this project lasted from 1956 to 1991. Many of the technical innovations needed to build the system evolved from earlier designs, highways built in Pennsylvania in the 1940s and Connecticut in the 1930s. A cadre of young engineers and workers familiar with unique construction trades and equipment became widely available after the Second World War. In the end, the final cost of the system was nearly four times the original estimate, and it is in state of continuous repair. Where funding (or oversight) is limited, parts of the network are in various stages of decay and disrepair, occasionally making headline news when an entire segment, like a bridge, catastrophically fails.

Many of the newest technologies that are carbon-capture focused are only in very early stages of development. Advanced hydrogen storage, new catalysis methods, and solvents for carbon capture will require significant investments if they are to successfully reach commercialization on a broad scale. There is near unanimous expectation that such a wide reaching, yet fundamental change to our energy conversion infrastructure will require significant investment. Just upgrading and improving the United States power generation and T&D system could require over $1 trillion over the next 20 years [38]. Adding carbon controls adds an entirely new cost (and complexity) factor to the financial forecasts. To minimize the costs and the cost uncertainties, an intense, well-planned research program supplemented with full-scale demonstrations, is warranted. A cautionary note: It could take 10-15 years to move from developmental status to full commercial status, and many more years to convert (or rebuild) the entire network. Yet implementing some of the actions reviewed here (e.g., fuel switching, energy efficiency upgrades, plug in motor vehicles, renewables, nuclear power, etc.) has significant benefits to the economy as a whole, and they are technologies we are familiar with, a feature that makes them easier to utilize. Some power technologies that are essentially carbon-free (see Fig. 10.2) are available now. In a recent study on the challenges of reducing CO2 emission, EPRI estimated that the economic benefits could be as high as $1 trillion [39]. Some of the key technical challenges to be overcome are summarized in Table 10.3.

Since the radiative warming effect of CO2 impacts the global climate on the scale of a century (or longer), then it becomes more important to address the impact of what is released to the atmosphere today. Similar to a discounted cash flow, mitigating 50 tonnes of CO2 released to the atmosphere in 2010 could be equivalent to mitigating perhaps 100 tonnes of CO2 released in 2025. There is a sense of urgency, and a rewarding benefit, to early reductions. Yet we are limited in that there are no readily available technologies to inexpensively capture CO2 emissions from point or mobile sources. Globally, there are no functioning examples where a nation, region, or city has achieved a reduction in CO2 emissions by employing any technology that is specific for capture and sequestration. Certainly many nations are exploring control and mitigation measures at various levels. Some attempts to force the technology have focused on creating a market first, expecting that the instruments will evolve, with no appreciation that CO2 is radically different from any other gas. Despite our best efforts, even per capita emissions of CO2 are continuing to increase globally, making the challenge for a technical fix even more difficult.

As already noted, we have commercial products available today that could quickly achieve near term objectives of reducing CO2 emissions from major sources. This would be done by improving efficiencies at all levels, increased utilization of natural gas (or even conversion of low quality feedstocks to higher quality SNG),

Table 10.3 Summary of critical research and development requirements

Focus area

Challenge

Objective

Energy conversion and power transfer

Gas separation

Energy storage

Fossil power generation (steam turbines, gas turbines, fuel cells), nuclear power generation, propulsion (transport), electricity distribution.

Air separation plants (separation of oxygen from air), CO2 from product gases, and hydrogen from gasified fuels

Increase the energy density of rechargeable systems that can provide grid stability as well as adaptation to the transport sector

Improve overall system efficiency, alloys to reach 700°C+ on vapor power cycles. Enhanced design features to minimize the costs of super-alloys. Alloys resistant to fireside corrosion at ultra-supercritical temperatures. Safe operation of nuclear systems to allow higher operating steam temperatures for improved efficiency. Materials with reduced resistive losses (reduce losses to 5% of generation, maximum) Reduce water consumption for process cooling.

Reduce energy required to produce high purity oxygen (<150 kW h/tonne), separation of CO2 (<50 kW h/tonne), and concentrated H2 Improved solvents/membranes for gas separation. Enhanced solvent stability in the presence of oxygen; solvents not dependent upon steam or water consumption for regeneration. Low toxicity solvent/sorbents Demonstration of complex carbon capture systems in power generation applications. Increase energy density to reach a level of 10-25% of current hydrocarbon liquids.

end-use efficiency improvements (insulation, weatherization), and expanding renewables like wind. For the United States, the low-carbon energy situation has significantly improved with the exploitation of massive reserves of natural gas in tight gas formations. These gas reserves would support a significant expansion to the gas generation fleet in North America—both capacity (MWe) and energy (MWh). Technology improvements like enhanced energy storage would allow enhanced energy transfers between the power generation sector and other significant sources of CO2, such as transportation. Right now energy storage in hydrocarbons (10 kW h/l) is far greater than any battery alternative we have today.

Beyond that, we could develop more nuclear power, although there are severe limitations on how much nuclear power could actually be constructed in the interval desired. Longer term, beyond 10-20 years, we will need to be able to deploy the new concepts that will have to be developed in the interim. These might include new cycle designs, or advanced renewable technologies (e.g. novel coal-to-energy conversion systems, direct production of hydrogen from sunlight, etc.), or geothermal engineering on a global scale to meet the world's energy demands. It will take a very long time to change the system from its current status, to something radically different, while still providing significant benefit to the world's economies.

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