Energy Efficient Processing
The aim here is to reduce energy consumption in all core processes involved in product manufacture and supply. At the HighEFF centre, SINTEF is working with partners from the oil and gas, energy, aluminium/metallurgical and foodstuffs sectors, all of which are reliant on energy-intensive processes. By studying these processes and developing more efficient technologies and systems, our partners will be able to generate “more product per unit energy cost”. In other words, more wealth generation for every kilowatt hour consumed.
In any industrial enterprise, a reduction in the consumption of energy driving its primary processes corresponds to reduced consumption of electricity and other primary energy sources such as oil and gas. It is important to note here that it is the specific consumption of energy that we are seeking to reduce, i.e. a reduction in the kilowatt hours used in the production of a specific product, such as a kilogram of aluminium. In other words, higher levels of production for a given unit of energy input.
One of the overall goals of the HighEFF centre is to promote technology development that can contribute with between 20 and 30 per cent reductions in specific energy consumption, and a 10 per cent reduction in greenhouse gas emissions. However, future energy efficiency potential within the different sectors varies to a great extent.
In some industries, work at the HighEFF centre has already led to the development of new concepts that meet these targets, and these technologies are now being implemented. One example is in the dairy sector4, where the targets were achieved by means of the implementation of innovative refrigeration and heat pump technologies, combined with greater integration internally within the process.
In other industries and sectors, implementation can be much more challenging. Many industries have been working actively for many years to reduce their specific energy consumption, often because energy expenditure has been a leading component of their production costs. For this reason, the achievement of further reductions using current technologies is very challenging. An example is found in the manufacture of aluminium using electrolysis. In this case, specific energy consumption has been reduced by almost 40% during the last 50 years5. Further opportunities to reduce consumption linked to core processes using current technologies do exist, but their implementation is somewhat demanding. The greatest potential most probably lies in the supply of waste heat, either to external consumers or for power generation, which in turn will contribute towards a reduction in net electricity consumption. Alternatively, it may be possible to identify entirely new processes and technologies, although no clear opportunities have been recognised to date. Aluminium production by electrolysis also generates greenhouse gas emissions. Of these, PFCs (perfluorinated compounds) and CO2 are the most important. Globally, PFC emissions have been reduced by about 80 per cent during the last 30 years.6. In Norway, where electricity generated from renewable hydropower, CO2 is released into the electrolysis bath. This is heavily diluted in a mixture with air, making the gas difficult to capture without major investment costs. If emissions are to be reduced, new anode materials or new process concepts appear to provide the most realistic options. It should be added here that aluminium production in Norway generates very low volumes of CO2 emissions compared with manufacture in countries that use electricity derived from the combustion of coal or other fossil fuels.