How far can industrial energy users go towards decarbonising their manufacturing processes? Those industries able to use by-products of their own manufacturing processes as fuel for their operations have a distinct advantage and can go further than most.
Oil refineries are the classic example, where ‘waste’ gases from crude-refining operations are often used in on-site cogeneration systems to fuel refining operations. However, refineries are hardly the best decarbonisation example as the products they manufacture – mainly fuels for vehicles, ships and aircraft – tend to be very carbon-intensive. Nevertheless, full marks for operating a waste-as-fuel principle.
A couple of recent announcements suggest that the refinery cogeneration sector is alive and well. Mexico’s state-owned oil company Pemex has established a subsidiary, PMX Cogeneracion, through which to invest $3 billion in refinery CHP schemes as part of a strategy to cut carbon emissions. Meanwhile, BP plans to build a cogeneration plant fuelled with waste ‘dry gas’ to provide the entire heat and power requirements of an oil terminal and processing plant in Scotland, UK.
In a variation of the principle, Capstone has won a contract to supply five of its microturbine units with total generating capacity of 4.6 MW to burn otherwise wasted – flared – gas at an energy project in the US. Capstone says that hard times in the oil and gas industry are forcing companies to look hard for ways to reduce operating costs at existing assets.
But it’s not only oil and gas players that have ‘waste’ fuels lying around. A Finnish company is currently planning to build a 27 MWe, 90 MWth CHP scheme at a paper mill in Turkey – to be fuelled with waste paper produced at the site. Indeed large quantities of combustible paper off-cuts make paper mills another classic home for cogeneration schemes around the world. Wastewater treatment plants are the next best example – biogases produced during waste treatment make a fine fuel for CHP engine-generators.
But might carbon neutrality be possible at an industrial site? Cosmetics giant L’Oreal says yes – the company has been improving the energy efficiency of its Yichang factory in China for some years and has now connected it to the nearby giant Three Gorges Dam hydropower scheme. Power from this and on-site PV panels supply all of the plant’s electricity needs. Planned conversion of gas-fuelled boilers to electric operation will complete the project.