Electricity consumption and cost efficiency remain concerns for South African foundries, the South African Institute of Foundrymen (Saif) reports.
The industry body points out that cost efficiency is twofold, as it is affected by the furnace technology, which determines the amount of electricity required for operating the furnaces and the method of furnace operation that is employed.
“Foundries are currently melting and scheduling their operational programmes to ensure they keep costs as low as possible,” says Saif CEO John Davies.
He mentions that, while alternative power sources, such as solar and wind energy, are available for generating power, these options are not always viable.
For instance, in Gauteng, the use of wind energy is not viable, as there is insufficient wind to sustain the full 24-hour operation of foundries. This form of energy will have to be used in conjunction with other forms of energy, which could prove to be too costly.
Solar energy is also a challenge, as it also needs to be provided in conjunction with other energy forms to be viable, and this limits the production and functionality of the furnaces, says Davies.
He emphasises the need for foundries to gain a greater sense of the available and viable energy sources, such as offgases, that could be used as an energy source for internal consumption.
However, a lot of foundries are not inter- ested in pursuing those forms of energy, owing to economic uncertainties and the high capital cost of implementing those options.
“These alternative ways of generating power require high capital costs upfront and, once in operation, if they are no longer viable, the foundry cannot return the product. It becomes impractical for foundries to make such decisions,” says Davies.
Saif has, together with the National Foundry Technology Network (NFTN) and State-owned power utility Eskom, engaged in interventions, such as Eskom’s integrated demand management programme, to reduce electricity costs.
Davies notes, however, that the intervention programme has mostly been (widely) unsuccessful because 70% of the energy consumed in foundries is used in the melting plants. The high melting temperatures required for foundry raw materials result in a lot of energy being consumed, with electricity being the preferred choice of energy in South Africa for these operations.
“Eskom can assist in common issues faced in the industry but unfortunately, the utility does not have the expertise to solve problems pertaining to foundry melting plants. We have looked outside South Africa for assistance in that regard,” he adds.
The University of Johannesburg (UJ) is hosting a project, in conjunction with the German Foundry Institute and funded by both the NFTN and a German government agency, that involves foundry engineers from Germany, along with locally trained engineers, visiting foundries to assist in improving the efficiency of the plants and to consider ways of conserving energy.
Saif, its members, the NFTN, the Department of Trade Industry and the National Union of Metalworkers of South Africa, have also been involved in contributing to the setting of electricity prices by participating in meetings with the National Energy Regulator of South Africa and the South African Local Government Association to seek alternative solutions to the rapidly increasing cost of electricity in the foundry industry.
Types of Furnaces
A limited number of foundries have also resorted to using gas-fired furnaces, as opposed to electric furnaces.
Gas-fired furnaces are costly to operate in terms of high melting point materials.
However, the use of oxy-gas burners can be cost efficient if used during peak electricity usage times.
During peak times, electricity tariffs in the country are significantly higher than the normal tariffs. During this time, the electricity could be switched off and the gas burners turned on, and switched off again during off-peak times.
Unlike electricity prices, the cost of gas is constant, which allows a foundry to save costs without impacting on production, says Davies.
Davies notes that electric furnaces have evolved to operate on an 80%-plus efficiency in terms of converting electric energy to heat energy during operation.
“Coils and transformers are components in the furnace at which energy loss often occurs and, with new designs, more effi- cient coils and transformers are being used.
“With further developments, these medium-frequency induction furnaces might reach an efficiency rate of up to 84% or 85% in the next three to five years,” he says.
“Most of the furnaces currently used in South Africa (at this stage) are about 30 years old, making them less efficient.
“They are probably operating at about 70% to 75% efficiency – and even lower in some cases,” says Davies.
Saif has entered into a contract with NFTN to provide certain training initiatives in the foundries industry.
These training programmes are designed for people who are already working in the industry and provide them with a series of theoretical training that covers all aspects of metal casting.
At a technician level, the initiative offers workshops on aspects of foundry technology, with experts from South Africa and overseas presenting the material. The duration of the workshops varies between half a day and two days.
Saif has also initiated programmes for postgraduate students to study at the RWH Aachen University, in Germany, in the hope of developing the skills of technicians and engineers in more advanced metal casting methods that are required in the industry today.
The funding for this programme has been made available by the Department of Science and Technology.
“Four students from UJ are already in Germany and five students from the Cape Peninsula University of Technology will leave for Germany in September.
“Once they have qualified, we expect them to come back and apply their expertise in the academic field, the research and development institutions, or in the foundry industry itself,” Davies concludes.