Sustainable Industry

Industries reduce CO2 emissions and costs through energy efficiency projects

Reduced energy consumption through the Alliance program is equivalent to that of a town with 60,000 inhabitants; this initiative also avoided the emission of 40 thousand tons of carbon dioxide

Replacing natural gas with charcoal for energy production, improving the insulation of furnaces, automating the temperature of machines, building a solar plant. These are some of the initiatives conducted by the industrial sector to foster energy efficiency. In addition to reducing production costs, these measures contribute to environmental conservation by reducing carbon dioxide emissions, the primary constituent of greenhouse gases.

Actions such as those implemented by the industrial sector will play a key role in reducing CO2 emissions. Estimates from the 2030 Ten-Year Energy Expansion Plan prepared by the Energy Research Enterprise (EPE) show that the gains in electrical efficiency will allow for a reduction of around 6% in the industrial sector’s total energy consumption by 2030.

When it comes to electricity consumption, a 3% drop in the same period is expected. This is equivalent to about 12 TWh, or the amount consumed by the mining and pelletizing (iron ore processing) industries in 2019.

These figures can be achieved through new, more modern and energy-efficient industrial plants (greenfield projects), energy use management actions, and upgrading of electrical installations, both through independent actions by industrial companies and sector-specific policies.

Solar energy to make shoes

In June 2018, Grendene inaugurated in Sobral (CE) a solar energy generation plant with an installed capacity of 1,137 MWh at peak. “It’s a pilot plant. We wanted to identify the generation potential and all the risks of expanding the operation. We had a lot of information about the market, but we didn’t know how it would work in practice”, says Carlos André Carvalho, manager for Sustainable Development at Grendene.

The feedback was positive and the intention is to build a unit at the plant in Crato, also in Ceará. “From an environmental perspective, it is a renewable energy, with no carbon emissions. From an economic viewpoint, it involves a low operating cost, provided that the project is well designed. It currently represents something between 2.5% and 3% of energy consumption in the Sobral plant, which is comprised of eight sites. The consumption is equivalent to that of a city with 100,000 inhabitants,” he explains.

Three thousand and five hundred panels have been installed, and they generate around 1,800 MW per year and account for 10% of the company’s carbon dioxide emissions reduction. Altogether, the changes to the plants prevented the emission of approximately 1,235 tons of CO2 per year.

In addition to the plant, energy efficiency actions focused on the use of thermal resources. The technical designs range from the furnace insulation component to the electronic temperature set. “This mechanism adjusts the temperature that is necessary for the product that is being produced. It’s an electronic thermostat set, which was virtually manual in the past,” says Carvalho.

In the case of plastisol furnaces (a mixture of the polymer known as PVC with plasticizers and other materials for the manufacture of shoes), thicker walls were put in place to enhance thermal insulation, in addition to changes in the door closing and opening systems and on the reading sensors so as not to burn sensitive parts.

In 2019-2020, 1,166 ovens were replaced, which led to a 43% reduction in energy consumption. The changes in the ovens have led to a 75% energy saving.

Today, the just-in-time demand of each factory is around 10 MW on average. The changes have reduced this volume by at least 1.6 MW in average, which provides for a 16% more efficient operation. In absolute numbers, 15,123.78 MWh are consumed per hour each year, equivalent to the consumption of 8,000 households.

Based on these and other changes implemented over the past five years, Grendene saved 13% of the energy consumed to make each pair of shoes. The company relies on 11 plants and has an installed capacity to produce 250 million pairs per year. The Sustainable Development manager believes that the change is acknowledged in the market. “We see that consumer profiles have changed. They will consider the purpose of the brand. We have our values ​​and they see the company’s purpose as having a lower impact on the environment and a better impact on people”, he says.

Savings of BRL 50 million per year

Located in the Metropolitan region of Vitória, state of Espírito Santo, ArcelorMittal Tubarão has a total area of ​​13.5 million square meters, and the plant occupies 7 million square meters. It is the third largest Brazilian producer of flat rolled steel plates; its production is geared for products such as vehicle wheels, pipes for oil and gas and parts for civil and naval construction.

In May 2018, planning for the Alliance program at the company began. The initiative was launched in 2015 and relies on a partnership between the National Confederation of Industry (CNI), the Association of Large Industrial Consumers of Energy and Free Consumers (Abrace) and the Government’s National Electric Energy Conservation Program (Procel) with the Federal University of Campina Grande (UFCG).

This is intended to reduce energy and water consumption in large industrial companies by making adjustments in production processes, identifying opportunities for treating and reusing waste and wastewater, and for reducing greenhouse gas emissions.

In the case of ArcelorMittal, a technical team from the program and from the steel plant in Tubarão jointly outlined six production processes in the steel supply chain, in addition to water and effluent treatment systems and production systems and supply of utilities for the plant that could be improved from an energy usage point of view.

In field work, the team identified 32 opportunities and 21 of these are now complete. 88,300 MWh/year were saved, in addition to avoiding the emission of approximately 5.78,000 tons of CO2 per year along the supply chain.

As far as cost reductions were concerned, expectations were to reduce costs by at least BRL 35 million, and actual cost reductions reached BRL 50 million in 2020. This is because a project intended to improve the gas cleaning system in a coke plant (where coal is transformed into coke for steel production) made it possible to increase the share of high sulfur coal in the mixture.

The Alliance program provided specialized workforce with expertise in process efficiency analysis. The team carried out a complete modeling and simulation of the processes with the help of software programs, which allowed for theoretical changes in the processes before their actual implementation.

Clean energy in steel production

With a focus on the production of seamless steel tubes for the oil and gas sector, the Jeceaba plant, state of Minas Gerais, was the stage for the implementation of the Alliance Program within Vallourec, a company in the steel sector. Natural gas continued to be replaced by charcoal, which is a renewable alternative with zero CO2 emissions. The changes also helped reduce costs by more than BRL 4 million per year.

Improvements were made in several areas, from iron ore processing, a stage where the material is separated after extraction, to steelmaking, a stage where the iron is transformed into types of steel, in addition to other processes, such as lamination and heat treatment.

A great example of the benefits from the new processes was observed in pelletizing, one of the main iron ore beneficiation processes. The reduction in natural gas and its replacement by charcoal was supported by computer models and simulations, which made it possible to validate and prioritize scenarios that led to successful industrial tests.

The use of chemicals for water treatment was also reduced, and the operating parameters of engines were revised and temperatures were checked in the rolling and tempering furnaces of the tubes for the effectiveness of the work methods adopted by the company. In addition to the advice provided by CNI, the program supported a technical partnership between Vallourec and the Federal University of Campina Grande.

Alliance Program

Under the Alliance Program, the CNI provides a work methodology, a team of specialized consultants, software and laboratories, training and monitoring by the industry team. In return, the company agrees to implement the approved actions and maintain the program for 24 months.

Phase one of the Alliance Program was implemented from 2017 to 2020 in 12 industrial plants in sectors such as steel, metallurgy and mining, cement, paper and cellulose; and chemicals. The changes have yielded energy savings of over 175 GWh per year, enough to power a town with 60,000 inhabitants for an entire year. The companies also approved more actions to be implemented, which could reduce the plants’ consumption by 611 GWh/year. The reduction in GHG emissions was 40,075.03 tons of CO2.

In addition to the benefits for the environment, the initiatives resulted in a reduction of BRL 122 million per year in the corporate operating costs, with an average payback of less than one month. Investments of BRL 5.75 million were made by the participating industrial companies, and 45% of the budget required for consulting services for the identification and implementation of actions was funded through an agreement between the CNI and Eletrobras, through the Resource Application Program (PAR Procel – 2017).

In the case of metallurgy, steel and mining, actions included increasing steam generation in boilers and leveraging the blast furnace. In the chemical, petrochemical, automotive, and paper and cellulose sectors, steps included ammonia consumption reduction and use fluid dynamic modeling for recovery boilers.

For the development of these solutions, the network of SENAI Institutes of Innovation is a partner in the search for energy efficiency. For example, at the SENAI Institute of Innovation in Metalmechanics, located in São Leopoldo (RS), researchers have developed a sensor system for tracking failures in production processes.

New technologies and process digitalization make it easier to use energy more sensibly in industrial settings. For instance, this is the case of machines that control their electronic systems based on the information they receive. With the help of data, equipment or tools, they can learn – in what is known as Machine Learning – how to turn off subsystems and parts that are not being used