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Primary metals

Petroleum and coal products 30%

Primary metals

Petroleum and coal products 30%

products 25%

Figure 4.9 Percentage of energy use in the manufacturing sector (Source: EIA, 1996).

Paper &

allied products 12%

products 25%

Figure 4.9 Percentage of energy use in the manufacturing sector (Source: EIA, 1996).

which cost some $3 million over the last two decades, transformed the world's window industry. New windows are three times as efficient as double-glazed windows. "Low-E" glass now accounts for 35% of all windows sold in the US. Cumulative energy savings from the diffusion of this technology to date have exceeded $2.1 billion in the US alone, and are projected to grow to $17 billion by 2015. However, this program also illustrates the long time period a new technology may have to wait for wide-spread adoption to occur, as 65% of all windows sold in the US today are still not as efficient as this proven technology.

The industrial sector is heterogeneous, as is shown in Figure 4.9, although the seven process industries targeted under the DOE Office of Industrial Technology's Industries of the Future program (aluminum, chemicals, forest products, glass, metal-casting, petroleum refining, and steel) are responsible for 80% of energy consumption in the US manufacturing sector.

One crosscut energy efficiency technology that has enjoyed both government support and successful industrial adoption is cogeneration utilizing gas or steam turbines as prime movers. In the UK, installed capacity of cogeneration has doubled in the last 10 years from an installed base of 1850 MWe to 3700

4.9.3 Industry

MWe, saving an estimated 20 million tonnes of CO2 each year (UK-DTI, 1998). This cost effective technology has benefited both from a consistent information program by the UK Government and the deregulation of the UK energy industry, with resultant opportunities for on-site energy generation.

4.9.4 Electricity generation

Many people are unaware that conventional electricity generation occurs only at an efficiency of 30-35%. This is based on conventional steam turbine plants and is largely due to the wastage of large amounts of heat that are inevitably produced during the combustion process. Commercially available combined cycle gas turbines (CCGT) generate electricity at 50% efficiency due to the use of waste heat from the gas turbine in a second-stage steam turbine. Even more impressive are prototype advanced turbines with a target electrical efficiency of up to 70% for a combined cycle (Energy Innovations, 1997). This public-private research effort is being coordinated by the US Department of Energy's Advanced Turbine Systems program. Advanced turbine systems enable higher operation temperatures (up to 2600°F) and thus improve thermal efficiency (from Carnot's law applied to thermodynamic machines). In practice, temperatures are limited by damage to the turbine blades, and this is being addressed by new materials research and new cost effective ways to cool the turbine blades. The private members of the consortium include six turbine manufacturers and 83 universities.

Advanced turbine systems (like conventional CCGTs before them) will have far reaching consequences for efficiency of electrical generation. As they are far smaller than centralized coal or nuclear plants, ATS plants can be built with short lead times, and at low enough costs to compete with the marginal operating costs of existing older plants, thus forcing the retirement of inefficient plant. As the electricity markets in developed countries become deregulated, and social pressure to prevent the construction of transmission lines develops further, the opportunities for highly efficient generation at the point of use grow. This offers the possibility of using the excess heat in a cogeneration scheme and a structural change to a decentralized paradigm of energy supply with great efficiency savings (Patterson, 1998).

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