Climate Change 2001: Working Group III: Mitigation

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3.5.3 New Technological and Other Options for CO₂ and Energy

3.5.3.1 Energy Efficiency Improvement

Energy efficiency improvement can be considered as the major option for emission reduction by the manufacturing industry. A wide range of technologies is available to improve energy efficiency in this industry. An overview is given in Table 3.19. Note that the total technical potential consists of a larger set of options and differs from country to country (see Section 3.5.5). Especially options for light industry are not worked out in detail. An important reason is that these sectors are very diverse, and so are the emission reduction options. Nevertheless, there are in relative terms probably more substantial savings possible than in heavy industry (see, e.g., De Beer et al., 1996). Examples of technologies for the light industries are efficient lighting, more efficient motors and drive systems, process controls, and energy saving in space heating.

An extended study towards the potential of energy efficiency improvement was undertaken by the World Energy Council (WEC, 1995a). Based on a sector-by-sector analysis (supported by a number of country case studies) a set of scenarios is developed. In a baseline scenario industrial energy consumption grows from 136EJ in 1990 to 205EJ in 2020. In a state-of-the-art scenario the assumption is that replacement of equipment takes place with the current (1995 in this case) most efficient technologies available; in that case industrial primary energy requirement is limited to 173EJ in 2020. Finally, the ecologically driven/advanced technology scenario assumes an international commitment to energy efficiency, as well as rapid technological progress and widespread application of policies and programmes to speed up the adoption of energy efficient technologies in all major regions of the world. In that case energy consumption may stabilize at 1990 levels. The difference between baseline and ecologically driven/advanced technology is approx. 70EJ, which is roughly equivalent to 1100 MtC. Of this reduction approx. 30% could be realized in OECD countries; approx. 20% in economies-in-transition, and approximately 50% in developing countries. The high share for developing countries can be explained by the high production growth assumed for these countries and the currently somewhat higher specific energy use in these countries.

Apart from these existing technologies, a range of new technologies is under development. Important examples are found in the iron and steel industry. Smelt reduction processes can replace pelletizing and sinter plants, coke ovens, and blast furnaces, and lead to substantial savings. Near net shape casting techniques for steel avoids much of the energy required for rolling (De Beer et al., 1998). Other examples are black liquor gasification in the pulp industry, improved water removal processes for paper making, e.g., impulse drying and air impingement drying, and the use of membrane reactors in the chemical industry. A further overview is given in Blok et al. (1995). Although some of these options already can play a role in the year 2010 (see Table 3.19), their full implementation may take some decades. De Beer (1998) carried out an in-depth analysis for three sectors (paper, steel and ammonia). He concludes that new industrial processes hold the promise to reduce the current gap between industrial best practice and theoretical minimum required energy use by 50%.

Table 3.19: Overview of important examples of industrial energy efficiency improvement technologies and indications of associated emission reduction potentials and costs. For an explanation see the legend below. Note that the scale is not linear. Cost may differ from region to region. This overview is not meant to be comprehensive, but a representation of the most important options. Sources: Kashiwagi et al. (1996), De Beer et al. (1994), ETSU (1994), WEC (1995a), IEA Greenhouse Gas R&D Programme (2000a), Martin et al. (2000).
Sector	Technology	Potential in 2010	Emission reduction costs		Remarks
All industry	Implementation of process control and energy management systems		-		Estimate: 5% saving on primary energy demand worldwide
	Electronic adjustable speed drives		++		In industrial countries ~30% of industrial electricity demand is for electric drive systems
	High-efficiency electric motors		+	*
	Optimized design of electric drive systems, including low-resistance piping and ducting		+++		Not known for developing countries.
	Process integration, e.g., by applying pinch technology		+		Savings vary per plant from 0%-40% of fuel demand; costs depend on required retrofit activity.
	Cogeneration of heat and power		-
Food, beverages and tobacco	Application of efficient evaporation processes (dairy, sugar)		+
	Membrane separation		++
Textiles	Improved drying systems (e.g., heat recovery)		++
Pulp and paper	Application of continuous digesters (pulping)		+		Applicable to chemical pulping only; energy generally supplied as biofuels
	Heat recovery in thermal mechanical pulping		+++		Energy generally supplied as biofuels
	Incineration of residues (bark, black liquor) for power generation		+
	Pressing to higher consistency, e.g., by extended nip press (paper making)		-		Not applicable to all paper grades
	Improved drying, e.g., impulse drying or condensing belt drying		-		Pre-industrial stage; results in a smaller paper machine (all paper grades)
	Reduced air requirements, e.g., by humidity control in paper machine drying hoods		+
	Gas turbine cogeneration (paper making)		-
Refineries	Reflux overhead vapour recompression (distillation)		+
	Staged crude preheat (distillation)		+
	Application of mechanical vacuum pumps (distillation and cracking)		+
	Gas turbine crude preheating (distillation)		-		Applicable to 30% of the heat demand of refineries
	Replacement of fluid coking by gasification (cracking)		+
	Power recovery (e.g., at hydrocracker)		-
	Improved catalysts (catalytic reforming)		+
Fertilizers	Autothermal reforming		-	*
	Efficient CO2 separation (e.g., by using membranes)		+	*	Saving depends strongly on opportunities for process integration of old and new techniques.
	Low pressure ammonia synthesis		+	*	Site-specific: an optimum has to be found between synthesis pressure, gas volumes to be handled, and reaction speed
Petrochemicals	Mechanical vapour recompression (e.g., for propane/propene splitting)		+
	Gas turbine cogeneration		-		Not yet demonstrated for furnace heating
	De-bottlenecking		-		Estimate: 5% saving on fuel demand
	Improved reactors design, e.g., by applying ceramics or membranes		+		Not yet commercial
	Low pressure synthesis for methanol		+	*	Site-specific: an optimum has to be found between synthesis pressure, gas volumes to be handled, and reaction speed
Other chemicals	Replacement of mercury and diaphragm processes by membrane electrolysis (chlorine)		+	*	In some countries, e.g., Japan, membrane electrolysis is already the prevailing technology
	Gas turbine cogeneration		-
Iron and steel	Pulverized coal injection up to 40% in the blast furnace (primary steel)		-		Maximum injection rate is still topic of research
	Heat recovery from sinter plants and coke ovens (primary steel)		+
	Recovery of process gas from coke ovens, blast furnaces and basic oxygen furnaces (primary steel)		-
	Power recovery from blast furnace off-gases (primary steel)		+
	Replacement of open-hearth furnaces by basic oxygen furnaces (primary steel)		-	*	Mainly former Soviet Union and China
	Application of continuous casting and thin slab casting		-	*	Replacement of ingot casting
	Efficient production of low-temperature heat (heat recovery from high-temperature processes and cogeneration)		++		Heat recovery from high temperature processes is technically difficult
	Scrap preheating in electric arc furnaces (secondary steel)		+
	Oxygen and fuel injection in electric arc furnaces (secondary steel)		-
	Efficient ladle preheating
	Second-generation smelt reduction processes (primary steel)		-		First commercial units expected after 2005
	Near-net-shape casting techniques		-		Not yet commercial
Aluminium	Retrofit existing Hall-Héroult process (e.g., alumina point-feeding, computer control)		-/+
	Conversion to state-of-the-art PFBF technology		+
	Wettable cathode		+++		Not yet commercial
	Fluidized bed kilns in Bayer process Cogeneration integrated in Bayer process		++
Cement and other non-metallic minerals	Replacement of wet process kilns		-/+	*
	Application of multi-stage preheaters and pre-calciners		+		No savings expected in retrofit situations
	Utilization of clinker production waste heat or cogeneration for drying raw materials		-
	Application of high-efficiency classifiers and grinding techniques		+
	Application of regenerative furnaces and improving efficiency of existing furnaces (glass)		+		Costs of replacing recuperative furnaces by regenerative furnaces are high (++)
	Tunnel and roller kilns for bricks and ceramic products		-	*
Metal processing and other light industry	Efficient design of buildings, air conditioning and air treatment systems, and heat supply systems		-	*
	Replacement of electric melters by gas-fired melters (foundries)		-	*
	Recuperative burners (foundries)		-	*
Cross-sectoral	Heat cascading with other industrial sectors		+
	Waste heat utilization for non-industrial sectors		+
Legend Potential: = 0-10MtC; = 10-30MtC; = 30-100MtC; > 100MtC. Annualized costs at discount rate of 10%: - = benefits are larger than the costs; + = US$0-US$100/tC ; ++ = US$100-US$300/tC; +++ > US$300/tC An asterisk (*) indicates that cost data are only valid in case of regular replacement or expansion.