MTN implements concentrated solar power cooling plant
Submitted by: Jonathan Ramayia, Tuesday, August 26, 2014
Multinational telecommunications Giant, MTN recently unveiled a concentrated solar power (CSP) cooling plant at its headquarters in Roodepoort. The system, which sits on the roof of the MTN Innovation Centre’s data centre was commissioned and installed at a cost of just over R5 million and serves to cool IT equipment housed in the building below.
According to the Project Manager, Willem Weber, the installation is in line with MTN’s strategy to reduce their cost of operation in the face of more competitive pricing in the cellular market. “We don’t have the luxury of increasing our pricing, and at the same time, one of our major inputs, electricity is always going up. The only way to counteract this is to cut on operating expenditure, one of which is to pay less for energy,” explained Weber.
Concentrated Solar Power
The CSP system consists of 242 solar mirrors positioned at different angles to maximise exposure to the sun. The mirrors are mounted on moving trackers that use GPS to track the sun and concentrate the reflection from the mirrors on the central absorber tube. The reflection heats the water in the central tube to 180 degrees Celsius. The heated, high pressure water then powers an absorption chiller that produces chilled water that is eventually circulated into the data centre, cooling the IT equipment. Absorption chillers work by using heat to drive the refrigeration cycle. The absorption chillers utilised in the plant use a lithium bromide water solution as the refrigerant. This means that the system has no global warming or ozone depleting potential.
MTN opted for CSP technology instead of a solar photovoltaic system in order to achieve higher efficiencies, notes Weber, “we looked at efficiencies – with solar PV the efficiencies at best, are only about 16% and after energy passes through an invertor the efficiencies are further reduced. It didn’t make financial sense to run an air-conditioning system using solar PV,” he added.
The system takes the weather into account, when it’s the sunniest there is the greatest need for cooling of the equipment, conversely when there is no sun, the IT equipment needs less cooling. Weber, notes, however that the system does not totally replace the need for conventional air-conditioning as more and more IT equipment is always being added.
Conceptualised two years ago the system was designed by REACH Renewable and implemented jointly with Industrial Solar and AOS Consulting at a total cost of R5 million. According to MTN, the savings in electricity expenditure amounted to R1million per annum resulting in a five year payback period.
MTN has also tried to get a tax concession through the SARS Section 12B allowance where machinery that is used for renewable energy electricity generation is non-taxable. Given the ground breaking nature of the technology SARS has not yet granted the request “because technically no electricity is being generated, “ said Weber, “we’re still in discussion with them and hopefully it will be granted,” he added.
The CSP project forms part of the dena Solar Roofs Programme, by the German Energy Agency which aims to introduce and develop German solar technology in foreign markets. Weber explained that through the programme, renewable energy companies in Germany can go to the German government to receive subsidies or funding for implementing projects in developing countries so long as they have a willing and reliable partner in the donor country.
Weber notes that although the technology is mainly German, the much of the assembly took place in South Africa, which he says could be the start of the development of the manufacturing industry for CSP here in SA.
The project comes off the back of MTN’s 2MW trigeneration plant implemented in 2010 which uses methane gas to power the data centre and a test switch centre at the Roodepoort head office. Eventually, Weber hopes that the entire head office would be energy independent with plans afoot to eventually make use of gas to generate up to 7MW of electricity. .
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