Welcome to the Glass Age

113 flame temperatures typically equating to higher NO x emissions. Oxy-gas furnaces may therefore be more attractive when hydrogen is affordable. Electric melting The first continuous regenerative glass melting furnace was invented by Charles William Siemens of Westminster England between 1872 and 1880 and modern regenerative furnaces have changed little since. Many do not realize though that continuous all electric melting (AEM) is almost as old as gas-fired regenerative melting. The first electric furnace was built in 1905 following French Sauvageon’s design and was for window production. The specific energy consumption was even then only 0.73 kWh/kg. Many designs have been implemented since but recently electric melting has fallen in popularity due to its high cost compared to widely available fossil fuels. Global warming and pressure on carbon footprints, has rekindled interest in full or partial (hybrid) electric melting. Alternative energy sources for electricity have helped to lower costs and production is essentially CO 2 free; for example in Germany, 40% of electricity is generated using renewable resources such as wind, solar, hydro, and bio. The question for the future is not if more electricity will be used for glass melting but what will be the balance between fully electric and hybrid furnaces (substituting bio fuel for fossil fuel). Glass is important in generating green renewable energy, or “green electricity”. Most wind turbine blades are composed of reinforced glass fiber. And most solar panels use large quantities of flat glass. In the future photovoltaics will probably be widely integrated into windows. These applications mean that glass is not only a consumer of renewable energy but also has an important role in generating it. Figure 7.4. An 80 TPD cold top rectangular all electric melter using top, side and bottom molybdenum electrodes. Source: Courtesy of IWG Wagenbauer and Glass Service.