Gerdau Ouro Branco digitalizes energy and resources management

The effective management of energy and resources has become a critical source of competitiveness and sustainability for industrial operations, particularly for the steel segment. Given the complexity and interdependence of its processes, which is often the case of integrated plants, the adoption of digital solutions that enable managing energy performance, improving efficiency continuously, forecasting energy demand, and managing contracts, budgets, and costs becomes an imperative.

The Ouro Branco Plant is one of Gerdau’s major capacity units with a wide diversity of production processes, comprised of hundreds of machines which, in turn, use dozens of types of energy sources and utilities.

For the purposes of digital transformation, the Ouro Branco Plant has various sources of data that must be accessed frequently to provide the information required for the goals of managing energy and utilities. In accordance with the nomenclature stipulated by the ISA-95 standard, the Ouro Branco Plant has, merely at Level 2, three different Plant Information Management systems, provided by three different suppliers. Even though all three offer the OPC (Open Platform Communications) interoperability standard, none of them completely covers the plant’s production processes. Furthermore, a set of connected systems developed locally supplements the sources of information with specific functions and data. An integrated view of all the users would only be possible using an application that could ensure connectivity with all of the available sources of data.

The priority of implementing the Energy Management System (EMS) would focus on:

• centralizing the collection and storage of data on energy use and conversion and utilities, as well as relevant production data, including quantities, routes and other data typically found in production orders, recording them in digital versions of the physical and variable measuring devices found in the plant and in the Plant Information Management Systems;
• determine and log energy yield indicators, be they absolute (e.g. kWh, Nm3 or specific (e.g. kWh/t, Nm3/t), including the possibility of stratifying the use of energy and utilities according to pertinent variable in each production process;
• provide balance sheets, warnings, reports and various analytic views to make continuous improvement of energy efficiency and yield possible.

The first phase of implementation required 12 months of design work. The Vetta company (formerly Viridis Soluções en Energia S.A.) was contracted for the supply, implementation and configuration of the system. The numbers below give an idea of the scale and complexity of implementation of the EMS at the Ouro Branco Plant:

• 2,700 variables, representing direct measurements of power, current, flow rates and status, as well as mathematical relationships between those variables (formulas or virtual measuring devices);
• 380 machines and production lines;
• 72 energy and utilities inputs, including primary sources, fuels, industrial gases and air at various pressures, water in various states and by-products.

Deployment of the energy and utilities digital management system at the Ouro Branco Plant made it possible to achieve major quantitative results:

• Operational continuity: The establishment of routines for the continuous monitoring of the levels of cryogenics prevented supply shortage incidents and the consequential interruption of production. Such incidents may have a substantial financial effect of approximately R$ 1.5 million.
• Efficient use of resources: The configuration of automatic warnings and automatic notifications, and the implementation of corrective actions helped stabilize the distribution of argon throughout the plant, thus avoiding the need for vaporization and losses of around R$ 300,000 per incident.
• Reduction of losses: The monitoring of energy yield indicators, such as nitrogen consumption in Blast Furnace 2’s crushed coal injection facility avoided financial effects of around R$ 11 million per day.

In addition, implementation of the system and the resulting adoption of it as a support tool for the effective management of energy and utilities led to significant improvements in terms of agility, transparency and operational safety:

• Connectivity: Integration of multiple sources of data, promoting greater robustness (e.g., by eliminating electronic spreadsheets), agility, transparency and democratization of the information on energy and utilities, with the consequent engagement of various operational teams and areas. In particular, to establish connectivity with all of the Ouro Branco Plant’s PLCs, for both reading and writing variables, the EMS acts as a gateway between various applications, also making it possible to produce important information on the gas operator’s control screens, thus providing his decisions with great agility and assertiveness.
• Quality of the data: Real-time analysis of the quality of the data acquired from the various sources found at the Ouro Branco Plant, with automatic correction of problems typically found in industrial environments: missing data, values outside upper and lower limits, frozen values, abrupt variations, among others – by means of heuristics – interpolation, the use of alternative measuring devices – previously configured in the system.
• Support for exceptional situations: Provision of information on energy and utilities usage in real time, which facilitates operational continuity, especially in exceptional situations, e.g., in the distribution of industrial gases when the steelworks or coke plants gas meters are not available.
• Balancing energy usage and production: Precise monitoring of the process of co-generating energy from industrial gases and from natural gas, making it possible to optimize costs and to better take advantage of the resources of the energy matrix.

Digital systems for the management of energy and utilities have great potential to improve not only the maturity, but also the results achieved by more robust and frequent management practices. Such practices involve the collection and processing of energy usage data, the determination and analysis of yield indicators, and the identification and implementation of opportunities for continuous improvement in energy efficiency, planning and governance.

The implementation of an energy management system at Gerdau’s Ouro Branco Plant provided a series of quantitative and qualitative benefits, made viable by the integration of various sources of data and by consistent actions on the part of the Energy and Utilities staff, who combined their technical knowledge with the analytic capacity and agility provided by the system. Such results are consistent with the recommendations of ISO standard 50001, since they implement controls and procedures intended for the routine management of energy yield and its continuous improvement in a sustainable manner.