In this interview, Rodrigo Barraza, academic and researcher at the Energy Transition Center (CENTRA) of the UAI School of Engineering and Sciences, and SERC Chile, addresses the crucial relationship between energy efficiency and competitiveness in copper mining, and explores how fluctuations in energy prices impact the sector, the specific challenges faced by mining energy management compared to other sectors, and the growing importance of renewable energies in the energy matrix. In addition, it offers insights on current and future strategies to optimize energy use, highlighting the role of emerging technologies such as Big Data and Artificial Intelligence.

How do fluctuations in energy prices impact mining competitiveness?

According to information available from Cochilco, energy costs represent about 18% of copper mining operational expenses, with electricity accounting for 12% and fuels for 6% of costs. The way to reduce these costs and make the mining activity more profitable is through access to better electricity and fuel supply contracts, replacement by cheaper and cleaner energy sources, and by increasing energy efficiency.

Compared to other sectors, what challenges does energy management face in mining?

Copper mining is a leading global industry, with state-of-the-art processes and technology. Unlike other industries, mining processes are continuously monitored in terms of both operational variables and energy use. The difficulty in energy management lies in the fact that, although a lot of information is recorded due to the volume of data, the management of this data is a challenge and optimization decisions must be made through automated processes due to the multiplicity of variables that affect the processes.

The variety of equipment and diverse suppliers also presents challenges, as it makes interoperability and standardization of information transfers to an expert system difficult. In addition, the useful life of process plants is long, so the implementation of monitoring and control technologies or their updating is also an issue to be solved in plants with more than 10 years of operation. In summary, the challenges for proper energy management go along the lines of implementing Big Data and Artificial Intelligence tools to automate analysis.

What are the main energy sources used in copper mining in Chile?

According to Cochilco reports, annual energy consumption (electricity + fuel) in copper mining is approximately 186,000 TJ, of which 53% corresponds to electricity and 47% to fuels. The largest fuel requirement is for CAEX trucks in open-pit mines and the largest electricity requirement is for milling processes.

Copper mining energy consumption has increased by approximately 2% per year, at least in the last 5 years, while fine copper production (in metric tons of copper not TMF) has remained the same or has marginally decreased. Therefore, the specific energy consumption of the sector, in TJ/TMF, has been increasing, which is explained to a greater extent by the lower mine grade.

What strategies are being implemented to optimize energy use in these operations?

The Energy Efficiency Law of 2021 and its respective regulation of 2022 establish that consumers with energy management capacity (companies with an annual consumption greater than 50 Tcal/year) must implement an Energy Management System SGE before August 2024. Most medium and large mining companies fall into this category. The implementation of the EMS in mining companies and its maintenance over time, requires these companies to monitor their consumption, create continuous action plans on energy efficiency and implement concrete measures to increase energy efficiency.

What is the role of renewable energies in the mining energy matrix?

Although renewable energies, and especially solar energy, have grown rapidly in recent years, this penetration is limited to the generation of electricity through photovoltaic plants. The electricity that reaches the mining sites comes from the national electricity system and 63% of the electricity generation of this system in 2023 was of renewable origin (28% hydraulic, 20% solar, 12% wind and 3% others). On the other hand, in terms of fuel replacement opportunities, it should be considered that 77% is vehicle consumption and mainly in CAEX trucks. The use of fuels for process heat is concentrated in smelting processes 9%, solvent extraction and electro-winning 5% and in services 4%. In these last two areas there are opportunities for the use of renewable energies for low and medium temperature heat supply. In this area, penetration has been timid and there are only two operational projects of a relevant magnitude, such as the Elvira Solar Plant that supplies heat to the electro-winning process of Minera Gaby and a similar initiative implemented by Minera Centinela, both projects have already exceeded a decade of operation. It is worth noting that a few months ago Gasco announced that it will build three solar thermal plants for Escondida and Spence to meet the heat requirements of the electro-winning processes at these sites.

What opportunities and challenges does the transition to a more sustainable copper mining industry present from an energy point of view in Chile?

The main benefits of adopting renewable energies are to develop a more sustainable copper mining industry, and also to reduce operational costs and thus be more competitive. In the use of electricity, probably the most efficient solution in a systemic way is to benefit from the fact that the energy matrix of the national electricity system is predominantly renewable and with the introduction of battery storage systems in the short and medium term will allow taking advantage of the excess electricity generation of photovoltaic fields in hours without sun, and thus increase the participation of renewable energy in the generation of electricity. In addition, in the future there are already plans and goals established at the country level so that at least there will be no contribution of coal generation by the year 2040, so the matrix will be even cleaner. In the short and medium term, the fuels used for medium and low temperature heat supply processes should be replaced by solar thermal projects, such as those of Gaby and Centinela, and now Escondida and Spence. There are no technical and economic barriers to their massification. In the future, the most relevant challenges are the replacement of fuel use in the fleet of trucks and machinery. Probably, the most adequate solution is the introduction of electromobility in low power, the use of green hydrogen in conjunction with fuel cells for medium power and the partial or total replacement of diesel by green hydrogen in high power vehicles.