The industrial sector is responsible for about 25% of global CO2 emissions – or about 9.3 billion metric tonnes per year and growing.
In a new study published in the journal Joule, the researchers went through a range of different industrial sectors looking at the available options for decarbonization, their emissions reduction potential, and their technology readiness level
– a measure of how close a given technology is to being ready for widespread mass adoption.
Most iron and steel production processes involve fossil-fueled blast furnaces and blast oxygen furnaces to achieve high temperatures, as well as coke as a reductant, resulting in about two tons of C02 emissions for every ton of steel produced.
Even if a steelmaker wants to keep its existing furnace assets, the study finds that CCS can sequester 86% of steelmaking emissions, at the cost of 17% higher energy consumption.
There are some high emissions processes, such as ammonia synthesis, for which there are proven green alternatives.
Using CCS alone, some 90% of current emissions can be sequestered – albeit requiring somewhere around 25% more energy.
In steam reforming, for the production of methanol and hydrogen, electrolyzers are well established and can totally eliminate carbon emissions – at the cost of a massive amount of electricity, representing a 743% jump in energy consumption over current methods.
Here, CCS will be less effective, capturing only 52-88% of emissions from existing production processes and requiring around a 10% increase in energy consumption.
Most of the carbon emissions from cement and lime are “Process emissions” that appear unavoidable if we’re to continue using these compounds.
Most of the emissions in aluminum production at the moment – about two thirds – come from the regular, dirty electricity used to power the electrolysis process, so that’s an easy win; use green energy.
Some of the remaining emissions are process-based; these can be addressed with a 20% energy consumption penalty by using inert anodes instead of carbon ones in the electrolyzers.
The remaining 13-16% of emissions can be eliminated by moving to electric or hydrogen-fueled boilers and calciners in the alumina refining process, although these still need considerable development.
By far the cleanest and easiest current way to produce aluminum is to recycle it through a well-established secondary production path, which the researchers estimate cuts emissions by about 95%. Pulp and paper.
There aren’t any process emissions to deal with in pulp and paper; decarbonizing the combined heat and power systems and boilers is where it’s at here, as well as a number of efficiency measures to bring total power consumption down.
As you might imagine, furnace heat is the biggest source of emissions when it comes to glassmaking.
Simply switching to an electric or biofuel furnace drops around 80% of total emissions – and in the case of electric, you’re actually reducing energy consumption by 15-25% compared with traditional methods.
Beyond that, using additional cullet and calcined input materials offer a potential extra 5% emissions reduction potential without adding significantly to materials or energy costs.
While this, like chemical production, is a pretty diverse segment, most of the emissions involved are from the use of steam in heating and drying processes, and from the direct burning of fossil fuels for CHP. There are a variety of electric, biofuel, hydrogen, microwave, ultrasonic, concentrated solar, geothermal and UV processes ready to go.
By now, the picture’s fairly clear; the lion’s share of industrial emissions come from heat and power use – the vast majority of which can be electrified or converted to clean fuels – and from process emissions, the vast majority of which can be captured and stored.
There are still some technological gaps to absolute zero carbon emissions, particularly in areas like ceramic requiring extremely high heat – but an 85% reduction in industrial emissions is achievable using machines and techniques that are already available.
For starters, you can electrify things all you like, but until you decarbonize the power grid, you’re just pushing emissions upstream.