The amount of energy used in the extraction process is relatively low compared to the high about of energy necessary for the production and refinement process. Bauxite extraction uses less than 1.5 kg of fuel oil and less than 5 kWh of electricity per tonne, this energy is mainly associated with diesel in haul trucks. There are two forms of aluminum production that require greatly different energy consumptions, aluminum production from raw materials and production from recycled materials. The refinement process, a chemical process, for raw materials is very energy intensive in the forms of heat, steam, natural gas, coal, and oil. The Bayer process energy input is dependent on the quality of the raw material, the higher the temperature digestion the higher the energy/ fuel input. With just investments in cost effective technology and equipment upgrades, the energy efficiency of the Bayer process can be improved by 10% in 5 years with no change to input material. Energy consumption and greenhouse gas emission is also associated with fuel combustion in the production and transportation process of aluminum, so with improved energy efficiency and fuel switching these two problems can be mitigated. The production of recycled materials is much less energy intensive, only needing to clean and separate aluminum scrap from other materials and then melting down for production, this process only requires 5% of the energy of production from raw materials. The most commonly recycled products are beverage cans, aluminum automotive parts, and building materials.
The main hub for aluminum production is from Asia, more specifically China, so there is a large amount of energy consumption due to extraction being focused in China. Subsequently, a large amount of the energy consumed with regards to aluminum is in China. Since the raw materials are being extracted in China and the majority of the bauxite is being produced into aluminum there or transported to other areas. With such a large automotive industry in China, the demand for aluminum is there, with the lighter and more durable frame that aluminum provides. Since the cars produced are used around the world, such as US and Europe, after the energy cost of production from raw materials, most energy intensive, the energy cost to transport finished goods around the world adds to the cost. The energy needed and used in Asia and China from the extraction, production, transportation, and use of aluminum is very large. The disposal aspect is the smallest because of the 100% recyclability of aluminum, so the energy used for the production of recycled materials is much less, 5% of the production from raw materials is a commonly used figure. So the energy cost for disposal/recycle for aluminum is much lower than all other aspects (extraction, production, transportation, and use) due to its recyclability and amount of recycle plants.
The transportation energy associated with the production of aluminum is a significant proportion of the total energy associated with the manufacturing of the final product. In comparison to the extraction and chemical production process, the energy associated with the transportation is significantly less, about 2% of total energy associated with aluminum production in US. The energy cost varies greatly based on a number of factors, such as location of extraction site compared to production plant compared to final destination, multiple modes of transportation used (conveyors, trucks, trains, ocean freight, air freight), etc. For the secondary production using recycled material the energy cost is more complicated to estimate and accounts for about 6-8% of total energy associated with aluminum production in US. The complicated estimates of energy cost for secondary production result from these varying factors, individual consumer drop-off, curbside collection, transfer station collection, and actual transportation to secondary processor. The differences in each case make the energy cost estimate difficult, some aluminum products are put in the recycle on the curb which eliminates consumer drop off. But some larger scale projects, such as construction jobs, can make hundreds of trips per project to the recycle center which increases the consumer drop off significantly. And the variation in frequency of curbside collection and distance from collection center and secondary processor are vastly different throughout the country. While to total energy cost associated with transportation of aluminum is very large, when compared to the extraction and production process the energy costs are not comparable. This gives a glimpse into how much energy the production and transportation of aluminum is on a global scale.
The energy lifecycle for aluminum is heavy intensity in the early stages, and then the energy use tapers off as the product begins to be recycled. With the 100% recyclability of aluminum, the life cycle is somewhat never ending since the aluminum product can be recycled continuously and is rarely disposed of. The far and away, largest demand phase is the production phase, and more specifically primary production using the Bayer process to chemically turn bauxite, the raw material, into aluminum, the finished product. The energy associated with the production of raw materials is much larger than the rest of the phases, extraction is significantly lower than the refinement process, transportation is only 2-8% of total energy use, and disposal/recycle is 5% of the energy as compared to production of raw material. But with the continued life cycle and recycling, the energy for production is not as great as some other products since so much material is able to be reused.
The main environmental issue is with the primary production of aluminum from the raw material bauxite. Since the process is so energy intensive and the main source of energy is electricity, courtesy of coal, the greenhouse gases emitted as a result of the power use is high. While aluminum itself is not harmful to the environment, the chemical process of breaking it down to create the final product uses an excessive amount of electricity. The harm of greenhouse gases causes global warming which melts ice caps and leads to rise in sea level, which impacts artic animal habitat and coastal infrastructure around the world. Future plans to improve energy demand is more renewable energy sources, such as solar, wind, ocean, etc. The revolution of the energy industry from fossil fuel dependent to renewable energy is the current plan, hoping to lead to more energy efficiency and mitigation of climate change. With less greenhouse gas pollution, the temperature increase can be slowed and hopefully reduced to bring balance back to the environment and save animals in these environments, including humans.