Industry And Climate Change

According to the IPCC, the industrial sector produces slightly over 30% of global emissions. While the sector is a necessary part of economic development, it is a big climate polluter.

The five biggest industrial emitters of greenhouse gases are chemicals, steel, cement, shipping and aviation.

In this article, we are going to focus on three sectors: cement, steel and chemicals.

A manufacturing plant

 

  The cement and concrete industry make up about 8% of global emissions of carbon dioxide, the principal gas causing climate change. In terms of ranking, when viewed as a country, it would be number three globally after China and the USA. The cement and concrete industry add up to 15% of all emissions from the industrial sector.

Cement is mixed with other substances i.e. water, sand and gravel to make concrete which is the main construction material used globally. It closely follows water as the most used substance worldwide. About 12 billion tons of concrete and 1.6 billion tons of cement are used annually. Cement is made from calcium carbonate, normally known as limestone, a sedimentary rock common in many areas throughout the planet.

The CO2 emissions from the cement industry arise from three main sources. Half of it is from the reduction and burning of limestone (calcination) to produce cement. Limestone (CaCO3) is roasted at very high temperatures to reduce it to calcium oxide (CaO), a process which releases waste carbon dioxide. When further burnt in a kiln, the result is a hard substance called Portland clinker, which is the main ingredient of cement.

The fuel used in this process is coal, itself a fossil fuel, and it releases carbon dioxide, about 40% of the total. The last 10% is from extraction, mining and transport, all of which release greenhouse gases as well.

Cement emissions are likely to rise from now to 2050 and to the end of the century. This results from demand spurred on by rapid urbanization especially in China and India. The EU rounds up the top 3 producers of cement and concrete. In the coming years however, demand is set to shift to Sub Saharan Africa, Asia and Latin America as countries there build infrastructure and modernize rapidly.

Although demand has increased thrice in the last three decades, yet emissions have fallen by 18% because of more energy efficient kilns that ensure there is no waste heat.

Because of the nature of making cement, there is little that can be done about the chemical process itself.

The main methods for reducing carbon emissions from cement are lowering the levels of clinker used in cement. This naturally decreases emissions from roasting limestone. Alternatively, cement can be blended with other substances. Portland clinker can be substituted with waste from burning coal or blast furnace slag from the refining of steel.

Fly ash, volcanic ash, ash from rice husks and silica fumes can be used in place of cement as binding substances.

However, the large scale industrial use of these substitutes presents a problem because the main source, coal plants, are increasingly being decommissioned and shut down.

Carbon capture and storage can be used to capture carbon dioxide in the calcination process. Innovatively, the carbon captured can be driven through concrete and used to cure the mixture instead of water. This carbon cured concrete is stronger, locking in carbon emissions to re-form limestone again.

Other fuels instead of coal can be used. They include natural gas and biomass which is not as high in carbon.

Alternatively, concrete can be crushed and reused once again, though new clinker will be needed.

The cement industry is not regulated in terms of climate, however, there is a cement sustainability initiative made up of industry players, which aims to cut emissions from cement by 20-25% by 2030, which is in line with the 2 degree temperature goal of the Paris Agreement.

Steel is another ubiquitous product. It is found virtually everywhere: buildings, roofs, wires, bridges, cars etc. Steel is made from reducing iron ore. Iron ore means the oxides of iron. Iron is the fourth most widely available and naturally occurring mineral element in the planet. It is quick to react and so combines with other elements to form iron compounds or ores. Of the iron ore that is extracted from the ground, over 97% is used to manufacture steel, and steel itself constitutes slightly more than 94% of all metals made.

China is the biggest producer of steel, followed by EU, Japan, USA and India. About half of all steel produced is used in the construction industry. The iron and steel industry produces 7-9 percent of global greenhouse gas emissions. China, Australia and Brazil are the biggest sources of iron ore.

Basically, the iron ore is burnt in a blast furnace where the carbon is removed to make pig iron. This pig iron is further smelted and reduced to form cast iron.  This is when different substances are added in different proportions to produce steel for different purposes. The process is carried out in a blast furnace. The steel making process produces 1.83 tons of carbon dioxide per 1 ton of crude steel.

The emissions result from the use of limestone in the smelting process and the use of coal in the form of coke as fuel.

There are four main varieties of steel. Carbon steels are almost pure steel and contain very little of other elements. They are 90% of all steel. Alloyed steel is steel mixed with other components such as manganese etc. The other two are stainless steel which is a mix of iron and chromium and duplex steel.

To cut emissions, instead of making new steel, scrap is often melted to make “new” steel. However, in today’s world, almost all steel in existence is already recycled. It is also recommended to use natural gas as a fuel in place of coal. This saves 1 ton of carbon emissions per ton of steel. Again, one can use hydrogen, especially if it is from renewable electricity.

For the steel industry to become low carbon, more government regulation is needed, green policies and supporting framework, financial incentives and even the use of a carbon tax to encourage less emissions.

The chemicals industry is the largest consumer of oil and gas and has the lion’s share in comparison to the other two. This industry uses above 10% of all fossil fuels available and emits 3.3 gigatons of carbon dioxide yearly. However, its carbon emissions are lower than cement and steel because of the way fossil fuels are used. Half of all fossil fuel used in the sector is used as raw materials or feedstock from which other chemicals are further minted or refined. The entire chemical industry is carbon based: so many of the chemicals used in today’s world have carbon as a major ingredient and are derived from fossil fuels.

These artificial chemicals are varied and include fertilizers and other farm chemicals, makeup and personal care products, medicines, cooking ware, vehicle coatings and of course one of the worst, plastics.

This type of use does not generate direct emissions, but does so at a later stage in the future, when the products are discarded as waste.

The other half of fossil fuels is used to produce energy in factories and plants for the manufacture of chemicals.

In fact, because the world in general is pivoting to renewable energy, the fossil fuel industry is turning its focus to the chemical industry as the main consumer of its products namely, coal, gas and oil.

The mitigation measures in this industry include maximum utilization of energy to reduce energy waste in factories. That simply means energy efficiency in the plants. Renewables could be used as a source of energy but this will require massive investments in green energy because the manufacturing process is energy heavy.

Plastics, which are direct derivatives of fossil fuels, are some of the most widely consumed chemical products in the world, and so the plastics industry is huge on fossil fuels. This can be solved by the use of bio plastics, which are made from organic sources, such as sugarcane, maize and hyacinth.

But this needs to be closely monitored so as not to initiate deforestation, another environmental problem.

Another way is to convert agricultural waste or discarded plastic back to feedstock i.e. use it in the place of raw fossil fuels in the manufacturing process.

There are innovative companies that transform waste carbon dioxide into methanol for fuel or as a raw material.

Additionally, waste gases from the cement and steel industries could be used a raw materials for the chemical industry in place of fossil fuels.

Still, multipurpose units can be constructed to combine steel, cement and chemical manufacturing dependent and reliant on each other.

For all this to happen, government support in form of financial incentives and regulatory framework is needed. Carbon capture and storage is also part of the solution for this sector.

The world in general needs to cut back on the use of unnecessary chemicals as this triggers over-supply and more emissions.

The Industrial Revolution is responsible for the climate change we experience today, but time is now ripe to transform it to low carbon.