State-owned power utility Eskom intends to start construction of a 100 MW central-receiver system concentrating solar power demonstration plant, near Upington, in the Northern Cape, in 2013. The proposed project is currently the largest of its kind in the world.
“The 4 km2 plant, comprising between 4 000 and 5 000 heliostat mirrors, will involve the use of thermal storage to ensure a readily avail- able power supply to offset morning and evening peak capacity demands,” explains Eskom divisional executive for corporate services Dr Steve Lennon.
The plant is scheduled to be fully operational by 2015; however, Lennon would like to see this deadline moved forward.
Eskom has secured the environmental approvals as well as land and water for the project and is currently in the process of appointing an owner’s engineer, the repre- sentative of the commissioning company.
The initial indication of the project’s cost is between R6-billion and R7-billion; however, as this is a demonstration project, there is a lot of uncertainty surrounding the costs. The true cost of the project will only be known once the commercial bids have been finalised, says Lennon.
Eskom also intends to develop a full-scale 1 GW solar plant, near Upington, in parallel with the development of the demonstration plant.
The aim of the commercial plant is to produce electricity at a cost competitive with that of wind power generation, which is currently priced at about R1,20/kWh.
“This is incredibly ambitious as solar is priced at about R3/kWh. However, as the technology evolves, this cost should reduce signifi- cantly to become competitive with coal and nuclear power generation,” says Lennon.
The 1 GW commercial plant may potentially form part of the Department of Energy’s proposed 5 GW solar park, which has an estimated cost of more than R20-billion. This project is in partnership with the Clinton Climate Initiative, an organisation headed by former US President Bill Clinton, and is currently under- going a feasibility study.
“The Northern Cape has more than enough solar energy potential to support a project of this size, as it is one of the best solar resources in the world. However, issues that need to be considered are the availability of water, which solar plants require for cooling and washing, and transmission interconnection capacity. The implementation of a 5 GW project, in the central region of South Africa, will require significant transmission investment,” says Lennon.
He also notes that, should Eskom fund 1 GW of the proposed 5 GW project, the remaining 4 GW presents a significant opportunity for independent power producers (IPPs).
Wind Power Generation
Eskom’s 100 MW Sere wind farm on the west coast, near Koekenaap, is in the procurement phase and is on track to meet its 2013 deadline, says Lennon, who adds that Eskom may be able to bring the completion date of the project forward by a year.
This project currently has an approved project cost of R3,4-billion, which is subject to change.
Simultaneously, the utility is conducting a feasibility study for a 500 MW wind farm, earmarked for the Southern or Western Cape.
Lennon says it is difficult to determine South Africa’s potential wind energy capacity, as that depends on the number of commercially viable wind farms in operation, while wind turbine technology is constantly improving to operate more efficiently at low and high wind speeds.
Eskom’s renewables business unit, which was set up to increase the utility’s renewables footprint and reduce its carbon dioxide (CO2) emissions, came into operation on April 1.
Since 2007, the utility has aimed to reduce its relative CO2 emissions for every unit of electricity produced up to 2025, there- after concentrating on its absolute emissions. Currently, Eskom produces 0,98 kg of CO2/kWh.
To reduce the carbon emissions emitted by its coal-fired power stations, the utility is concentrating on improving the efficiency levels at which the stations burn coal.
Further, the utility is investigating biomass cofiring to reduce its carbon emissions by 10% at each of its coal-fired power stations. This involves blending biomass with coal, and a feasibility study is at an advanced stage.
Eskom is also investigating solar augmentation, which involves preheating water for boiler use, using solar concentrators, as well as the use of photovoltaic (PV) solar modules to offset the power requirements of each unit at its coal-fired power stations by 20 MW.
To further reduce its carbon emissions, the utility also intends to increase the number of renewables projects in its portfolio and execute nuclear build projects, which are dependant on government’s directive under the second Integrated Resources Plan.
Over the past five years, the utility has also been investigating marine current energy extraction, particularly from the Agulhas current, which is the western boundary current of the south-west Indian Ocean and flows along the East Coast of Africa.
“The concept involves the instal- lation of turbines on the seabed to harness the energy produced by the current. This technology has been piloted by other countries and is currently being evaluated by Eskom,” explains Lennon.
He says South Africa has limi- ted hydro potential, with most of the country’s hydro potential exploited by a 360 MW hydroelectric power station at the Gariep dam. Eskom is considering smaller projects; however, these projects may be better suited to IPPs, notes Lennon.
This year, the utility also intends to implement a solar project in the parking lot of its Megawatt Park head office, which involves the use of PV panels as carport roofing.
The project will be used to offset the electricity demand at Megawatt Park and will incorporate an electric vehicle (EV) charging station. Eskom has received interest from various EV manufacturers and is willing to work with them to develop EV charging standards. The utility also expects a proposal from vehicle manufacturer Nissan soon.
“Eskom will encourage the use of EVs and is exploring the use of EVs in its vehicle fleet. The implementation of this will depend on the pace of commercial roll-out of EVs in South Africa,” says Lennon.
Before the implementation of the renewables business unit, renewables projects were being run by Eskom’s research and development and generation divisions.
Currently, the operating costs of the renewables business unit is pegged at between R50-million and R100-million a year. The capital costs of renewables projects will be determined by whether Eskom provides full funding or funds the projects through partnerships.
Eskom started investigating large-scale renewables projects in about 2000 and by 2002 was operating a 3,6 MW Klipheuwel wind demonstration farm, worth R20-million, and a R5-million solar unit at development finance institution Development Bank of Southern Africa, while also developing large-scale PV solar projects.
“Since 2007, we have prob- ably spent between R100-million and R200-million on renew- ables projects, with the majority of these funds allocated to project development involving wind and solar power generation,” says Lennon.
However, in 2007, funding constraints put the development of renewables projects identified by Eskom on hold. Funding for these projects was included in the utility’s application for its $3,7-billion loan from the World Bank, which was secured in April 2010.