Global Climate Change - The Technology Challenge

This chapter aims to provide a succinct integration of the projected warming the earth is likely to experience in the decades ahead, the emission reductions that may be needed to constrain this warming, and the technologies needed to help achieve these emission reductions. Transparent modeling tools and the most recent literature are used, to quantify the challenge posed by climate change and potential technological remedies. The chapter examines forces driving CO₂ emissions, how different emission trajectories could affect warming this century, a sector-by-sector summary of mitigation options, and R&D priorities. It is concluded that it is too late too avoid substantial warming; the best result that appears achievable, would be to constrain warming to about 2°C (range of 1.3–2.7°C) above pre-industrial levels by 2100. In order to constrain warming to such a level, the current annual 3% CO₂ emission growth rate needs to transform rapidly to an annual decrease rate of from 2% to 3% for decades. Further, the current generation of energy generation and end use technologies are capable of achieving less than half of the emission reduction needed for such a major mitigation program. New technologies will have to be developed and deployed at a rapid rate, especially for the key power generation and transportation sectors. Current energy technology research, development, demonstration and deployment programs fall far short of what is required.

Coal is a key, growing component in power generation globally. It generates 50% of U.S. electricity, and criteria emissions from coal-based power generation are being reduced. However, CO₂ emissions management has become central to coal’s future. To meet growing electricity demand, coal use is expected to increase in the foreseeable future because it is cheap and abundant. For this to happen CO₂ capture and geologic sequestration (CCS) is a critical technology. With CCS, coal-based power generation can be made much cleaner. Commercial demonstration of existing technologies, including CCS, with the resultant improvements that will accrue, is key to advancing coal-based power generation and addressing important environmental issues.

Demand for liquid transportation fuels has been increasing by over 2%/year over the last two decades and is accelerating in the emerging economies which are moving to automobile ownership. Almost all liquid transportation fuels are derived from petroleum, which at the same time is coming under increasing demand pressure and price instability. A high degree of dependence on petroleum brings concerns about diversity and security as well as issues of decreasing CO₂ emissions associated with the transportation sector. This chapter examines the potential to use coal and biomass to replace petroleum-derived liquid fuels and thereby to address the concerns that are associated with near total dependence on petroleum-based liquid transportation fuels. The evaluation centers on the U.S. but is easily expandable to other developed countries and the developing world.

As this chapter will point out, nuclear energy is a low greenhouse gas emitter and is capable of providing large amounts of power using proven technology. In the immediate future, it can contribute to greenhouse gas reduction but only on a modest scale, replacing a portion of the electricity produced by coal fired power plants. While it has the potential to do more, there are significant resource issues that must be addressed if nuclear power is to play a larger role in replacing coal or natural gas as a source of electricity.

By 2050, the increased use of renewables such as hydropower, wind, solar, and biomass in power generation is projected to contribute between 9% and 16% of the CO₂ emission reductions. The share of renewables in the generation mix increases from 18% today, to as high as 34% by 2050. Hydropower is already widely deployed and is, in many areas, the cheapest source of power. There is considerable potential for expansion, particularly for small hydro plants. The costs of onshore and offshore wind have declined sharply in recent years through mass deployment, the use of larger blades, and more sophisticated controls. Costs depend on location. The best onshore sites, which can produce power for about USD 0.04 per kWh, are already competitive with other power sources. Offshore installations are more costly, especially in deep water, but are expected to be commercial after 2030. In situations where wind will have a very high share of generation, it will need to be complemented by sophisticated networks, back-up systems, or storage, to accommodate its intermittency. It is projected that power generation from wind turbines is set to increase rapidly. The combustion of biomass for power generation is a well-proven technology. It is commercially attractive where quality fuel is available and affordable. Co-firing a coal-fired power plant with a small portion of biomass requires no major plant modifications, can be highly economic and can also contribute to CO₂ emission reductions. The costs of high-temperature geothermal resources for power generation have dropped substantially since the 1970s. Geothermal’s potential is enormous, but it is a site-specific resource that can only be accessed in certain parts of the world for power generation. Lower-temperature geothermal resources for direct uses like district heating and ground-source heat pumps are more widespread. Solar photovoltaic (PV) technology is playing a rapidly growing role in niche applications. Costs have dropped with increased deployment and continuing R&D. Concentrating solar power (CSP) also has promising prospects. By 2050, however, solar’s (PV and CSP) share in global power generation is still projected to be below 2%.

The objective of this chapter is to review this history, focusing initially on the historical growth patterns and the resulting environmental consequences; then on the current control efforts around the world; and finally on the emerging efforts to transform vehicles and fuels to accommodate increased vehicle use while minimizing impacts on the environment. Progress in mitigating emissions of criteria air pollutants has been impressive, especially in the developed world. The situation with regard to climate change is particularly challenging. Transportation is already a large contributor to the problem and is a rapidly growing sector. Modest programs to reduce fuel consumption or greenhouse gas emissions from light duty vehicles are being phased in and California and the EU have initiated efforts to reduce the carbon content of vehicle fuels. But much more will need to be done with a likely shift to battery electric vehicles fueled by green electrons or fuel cell vehicles fueled by renewable hydrogen in future decades. As efforts to reduce CO₂ by 70 or 80% by 2050 receive high priority, aggressive short-term actions to reduce short-lived greenhouse pollutants hold promise. The US, Europe and Japan are phasing in high efficiency PM filters which will also reduce black carbon emissions dramatically.

Addressing building energy use is the critical first step in any strategic plan for mitigating climate change. Buildings have a direct impact on estimated global climate change due to their large carbon footprint. Energy use in the building sector is the largest man-made contributor to climate change, and coincidentally a key sector to start mitigating climate change. To avoid revisiting problems such as sick building syndrome arising from aggressive building weatherization programs in the 1970s, it is critical that policy makers, regulators, and strategic planners remember that the primary function of buildings is not saving energy. The bottom line of why we build buildings is for safety and comfort in our homes, to enhance productivity in the workplace, and to ensure an optimal learning environment in our schools. The fundamental services of improving human health, comfort, productivity, and performance should not be compromised as we strive to minimize energy use in buildings. A one-dimensional focus on energy could result in unsustainable policies and practices. Much is understood about technologies, materials, and design techniques that can reduce energy use in buildings. However, much attention must be paid to recognizing how these approaches can enhance or damage human health and productivity as well as the environment. The focus of this chapter is not existing energy sectors and conservation technologies that have been extensively understood and considered in the literature, but on underutilized mitigation techniques that both increase the sustainability of our buildings while maintaining a focus on human health and the environment. A key intersection between climate change, buildings, and human health is building materials and products, and an effective testing and information transfer program is urgently needed so that building stakeholders have the information and tools they need to make good decisions during the design, construction, operation, and renovation phases of buildings.

Carbon dioxide (CO₂) accounts for more than 90% of worldwide CO₂-eq greenhouse gas (GHG) emissions from industrial sectors other than power generation. Amongst these sectors, the cement industry is one of the larger industrial sources of CO₂emissions. In 2005, this industry accounted for about 6% of the global anthropogenic CO₂emissions. Further, global production of cement has been growing steadily, with the main growth being in Asia. Considering these trends, the worldwide cement industry is a key industrial sector relative to CO₂emissions.

In this chapter, ISIS was used to conduct an example analysis of the U.S. cement sector to gain some insights relative to two broad questions: (1) what range of CO₂reductions may be practicable in the near-term, and (2) for that range, what may be the market characteristics for the U.S. cement industry. These questions are relevant because in the absence of carbon capture and sequestration (CCS) technology, the path forward for reducing CO₂emissions in the near-term (e.g., decade ending 2020) will need to depend on the currently available energy efficiency measures and raw material and product substitution approaches.

With the concentrations of atmospheric greenhouse gases (GHGs) rising to levels unprecedented in the current glacial epoch, the earth’s climate system appears to be rapidly shifting into a warmer regime. Many in the international science and policy communities fear that the fundamental changes in human behavior, and in the global economy, that will be required to meaningfully reduce GHG emissions in the very near term are unattainable. In the 1970s, discussion of “geoengineering,” a radical strategy for arresting climate change by intentional, direct manipulation of the Earth’s energy balance began to appear in the climate science literature. With growing international concern about the pace of climate change, the scientific and public discourse on the feasibility of geoengineering has recently grown more sophisticated and more energetic. A wide array of potential geoengineering projects have been proposed, ranging from orbiting space mirrors to reduce solar flux to the construction of large networks of processors that directly remove carbon dioxide from the atmosphere. Simple estimates of costs exist, and some discussion of both the potentially negative and “co-beneficial” consequences of these projects can be found in the scientific literature.

The critical, missing piece in the discussion of geoengineering as a strategy for managing climate is an integrated evaluation of the downstream costs-versus-benefits inter-comparing all available climate management options, including geoengineering. Our examination of the literature revealed a number of substantial gaps in the knowledge base required for such an evaluation. Therefore, to ensure that the decision framework arising from this analysis is well founded, a focused program of scientific research to fill those gaps is also essential. As with any sound engineering plan, international decisions on how to address human-induced climate warming must be founded on a thoughtful and well-informed analysis of all of the available options.

In this chapter we explore the challenges in developing and deploying technology for mitigation of CO₂ emissions associated with power generation. Past successes with controlling other pollutants (notably SO₂) provide insight as to the difficulty of extrapolating those successes to applications for carbon capture and control. Technology innovations that have yet to reach commercial fruition are noted, but for the near term we can make effective use of commercial processes readily available and achieve significant reductions in carbon emissions. These reductions can be obtained by fuel switching, efficiency upgrades introduced fleetwide, and expanded use of lower CO₂ emitting technologies, all of which should be done in parallel with a robust R&D program to develop new technologies for extraction of CO₂ from exhaust gases or strategies for fuel decarbonization.

China, India, and Mexico are among the top developing country emitters of CO₂. The electric power sectors in China and India is dominated by coal-fired power plants, whereas fuel oil and natural gas are the key fossil fuels in Mexico. Spurred by economic development and population growth, demand for electricity in these countries is expected to continue to rise. Meeting this increased demand will have a significant impact on emissions of greenhouse gases (GHG). While available portfolio of generation and mitigation technologies may not suffice to arrest the growth of emissions, it can help reduce the rate of emissions growth. To achieve significant reductions, multiple approaches are required, such as reducing demand by adopting end-use efficiency improvement measures, accelerating the deployment of renewable and nuclear power, and adopting cleaner more efficient generation technologies. Retrofitting the existing fleet to meet strengthened environmental standards, and accelerated fleet-turnover, coupled with adoption of state-of-the-art high efficiency generation technologies, such as supercritical and ultra-supercritical boilers and advanced combined-cycle gas turbines, should play an important role in meeting the increasing demand with the least amount of GHG emissions. In parallel, significant R&D efforts will have to be undertaken to adapt off-the-shelf generation technologies to suit local needs. In the medium to long term, developed countries will need to provide financial and technical support for these countries and partner with them to develop, design, demonstrate, and deploy technologies for capturing and sequestering carbon dioxide.

The Fourth Assessment Report released by the Intergovernmental Panel on Climate Change (IPCC) in 2007 was unequivocal in its message that warming of the global climate system is now occurring, and found, with “very high confidence” that it was “very likely” that the observed warming was due to anthropogenic emissions of greenhouse gases (GHGs). To address the problem, the IPCC developed an outline of approaches to reduce GHG emissions to desired levels. The expected changes in technologies and practices needed to mitigate emissions of GHGs will lead to changes in the impacts to the environment associated with energy production and use. Some of these changes will be beneficial, but others will not. This chapter identifies some of the potential environmental impacts (other than the intended mitigation of climate change) of implementing GHG mitigation strategies, but will not attempt to quantify those impacts or their costs. Included are discussions of the impacts of implementing energy efficiency and conservation measures, fuel switching in the power generation sector, nuclear and renewable energy, carbon capture and storage, use of biofuels and natural gas for transportation fuels, and hydrogen and electricity for transportation energy. Environmental impacts addressed include changes in air emissions of nitrogen oxides, sulfur dioxide, and particulate matter; impacts to water quality and quantity; increased mining of coal to meet the power demands of carbon capture systems and of metals to meet demands for vehicle batteries; and impacts to ecosystems associated with biofuel production and siting of other renewable energy systems.