The road to net-zero

Shree Cement, one of India's top three cement producers with a production capacity of 35Mta, has announced its commitment to set a science-based target to cut its greenhouse gas (GHG) emissions and help tackle climate change. The company follows two other leading Indian cement producers, Dalmia Cement and Ambuja Cement in setting science-based targets and provides "a powerful signal of change", according to global non-profit coalition We Mean Business. However, is reaching net-zero emissions from the global cement industry possible?

The Energy Transitions Commission (ETC) certainly thinks so. In its recently-published "Mission Possible" report, it showcases a range of strategies to reduce emissions from the cement and construction industries, including demand management, energy efficiency and decarbonisation technologies.

While limiting demand for cement may understandably not be the favoured option of the cement industry, cement companies can take measures to considerably reduce their GHG emissions. Key actions, highlighted by the report, centre on improving energy efficiency, changing the fuel used to produce the heat in pyroprocessing and applying decarbonisation technologies.

Improving energy efficiency

The report identifies 20 technologies (including retrofits), which when applied together, have the potential to deliver a 10 per cent reduction in energy consumption in the typical cement production process – most with a two-year pay-back period. These technologies include the use of multi-channel burners and precalciners as well as the reduction of the clinker-to-cement ratio. While these can all contribute to reducing GHG, other strategies will also need to be employed to achieve net-zero emissions.

Fuel changes and decarbonisation technologies

The heat required to produce clinker accounts for around 35 per cent of cement plant emissions. In the short term, cement plants can and have successfully reduced their GHG emissions by switching from coal to gas. However, in the longer-term a more significant shift will be needed. Increasing the use of waste or biomass as a fuel, replacing fossil fuels with hydrogen and switching to electricity as the heat source are all viable strategies, according to the report.

But these measures all come at a cost in terms of investment. While increasing the use of alternative fuels from waste and biomass only requires a modest retrofit to existing kilns, replacing fossil fuels with hydrogen requires a more "committed approach" of redesigning the cement kiln.

Switching to electricity as a heat source also begs the question by which means this electricity is generated – in coal- or gas-fired power stations or through the use of solar or wind power? The report foresees the operation within 15 years of electricity systems based on renewable energy sources that are able to generate 85-90 per cent of power required. However, a rapid pace of renewables deployment in the cement industry, and elsewhere in the global electricity generation infrastructure, would be key.

Furthermore, cement companies will also need to balance electricity tariffs with the cost of carbon credits, adding an extra layer of complexity to the net-zero emissions debate.

Concerted effort

It is clear that while reducing GHG emissions is possible, the reality of achieving net-zero emissions in the cement industry will require a concerted approach by the players in the industry and investment both in terms of time and cost by the sector and wider society.

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