The main feature of global demand for energy is a shift to maximising efficiency through delivering energy at the lowest cost per kilowatt per hour, says independent process industry consultant Santosh Gunpath.

He tells Engineering News that this was evident from his interactions with industry players and academics from Europe, the US and Australia at the Investing in African Mining Indaba earlier this year.

Preceding this shift was the common concern around electricity generated from fossil fuels, with significant research and development (R&D) into alternative energy sources, such as biofuels and biomass, as well as renewables such as solar, wind and water.

Rather than focusing on sourcing energy, as it is abundant, and can be harnessed in most of its available forms using modern technology, “we need to focus on harnessing and channelling energy to be cost effective to meet the needs of the population at large”, Gunpath says.

He adds that energy is an integral input in every process, from the basic human function of breathing, to extracting and beneficiating ore in mining.

Gunpath indicates that the majority, if not all, of the advances in technology related to alternative or supplemental energy production have not gained traction on a large scale, owing to the increased capital expenditure (capex) and operating expenditure (opex) of companies or the disruption this would cause existing processes required to bring these on line.

Alternative Strategies

Gunpath highlights an emerging alternative strategy being considered, particularly in the US, where the grid is supplemented by the back-end processes that produce electricity that feeds into the grid, rather than supplementing the grid with alternative energy.

He indicates that this keeps existing grids – owned by utilities such as State-owned power utility Eskom – and associated infrastructure intact, or ensures that there is minimal impact on it, which potentially reduces the rand per kilowatt per hour (R/kWh) at which energy is delivered.

“Using solar or hydroelectric energy to supplement the coal-fired power stations, which reduces the demand for coal, is a prime example of this.”

However, Gunpath avers that, in his experience of dealing with original-equipment manufacturers and engineering, procurement and construction management, there has been negligible change and innovation for power-hungry process equipment.

He elaborates by pointing to vibrating equipment to justify the claim. By nature, such equipment needs to be heavy and robust to cope with the forces it experiences; thus, much of the R&D has been directed to the lightweight areas, for example, screen panels, he explains.

“It can be argued that this is what influences process performance, but there is a point of diminishing returns where the scale of investment in innovation is not justified by the performance improvement, which is the case currently.”

This is applicable to not only large complex units, such as vibrating equipment, but also pumps, which are one of the most basic pieces of process equipment. Pumps can provide much scope for improvement, for example by making use of more efficient pumps and pumped processes to transport slurries around the circuit, Gunpath explains.

He enthuses that more efficient pumps will significantly reduce energy use, which is exemplified when gland water leads to process dilution and requires further downstream processes to correct the slurry density. “Rather than attempting to reduce the electric demand of the motor required to drive the pump, the same results can be attained with smaller motors. As such, in terms of energy efficiency, the focus will be on what supports the pumping process, rather than on the pump itself.”

Gunpath indicates that it would be advisable for piping engineers to consider overlooked aspects of plant design, such as friction factors of the specified piping and routing of pipes, to reduce the size of the pump required. While this may lead to a higher capex at the design phase, it will reduce the opex because of reduced electricity demand.

A potential solution for energy efficiency is further found in developments in the material science and engineering sectors that feed into the manufacturing, production and beneficiation industries, he postulates. Such developments can investigate replacing traditional heavy steel with lightweight materials, such as aluminium or a lightweight alloy, but that have the stress properties of steel, or similar properties, tailored to the application.

Benefits would include development of a new industry sector of material science – leading to further job creation, collaboration of tertiary institutions with industry, and making industry a lower user of energy – and reduced demand on the national energy grid, he explains.

Further, Gunpath says the automotive industry has become particularly reliant on aluminium, which is evident in the latest engines from Jaguar and the Alfa Gulia, both of which constitute mainstream brands. While he concedes that aluminium is an energy-intensive metal, owing to the Bayer Process – the principal industrial means of refining bauxite to produce alumina – this is in the process of being addressed. Aluminium is also highly recyclable, another favourable feature.

Moreover, if the location is conducive to renewable-energy sources, advantage can be taken of renewable energy to power the production process, with some existing processes currently using up to 70% of hydroelectric power to supplement the electricity generated from coal.

“The solution is to move from the fixation on renewable energy and innovation in this sector, to integrating existing renewable- energy technology to feed into electricity from fossil fuel production, rather than replacing it. This will break the cycle of ‘analysis-paralysis’ that currently grips the industry,” he concludes.