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Wind and solar the cheapest way to power South Africa

Wind, solar can supply bulk of South Africa’s power at least cost, CSIR model shows, Creamer Engineering News  22nd August 2016 BY: TERENCE CREAMER , There has been much discussion in recent months about the work done by the Council for Scientific and Industrial Research Energy Centre into the role that renewable energy could play in South Africa’s future electricity mix. In an extensive interview with Engineering News Online, Dr Tobias Bischof-Niemz outlines the key findings of the research and unpacks the possible implications. The article follows:

The dramatic fall in the cost of supplying power from wind and solar photovoltaic (PV) plants has moved the global electricity supply industry beyond a critical “tipping point”, which leading energy scientist Dr Tobias Bischof-Niemz says is irreversibly altering the operating model, with significant implications for sun-drenched and wind-rich South Africa.

Instead of renewable energy playing only a modest and supportive role in the future supply mix, research conducted by the Council for Scientific and Industrial Research (CSIR) Energy Centre shows that, having the bulk of the country’s generation arising from wind and solar is not only technically feasibly, but also the lowest-cost option.

“The notion of baseload is changing,” Bischof-Niemz tells Engineering News Online. Over a relatively short period, renewables have become cost competitive with alternative new-build options in South Africa, dramatically altering the investment case.

Until the large-scale global adoption of wind and solar PV, a phenomenon that has only really taken hold over the last ten years, generation technologies were not dispatched by nature. The objective was, thus, to use the assets as often as possible in order to reduce unit costs. Under such conditions, it made sense to first build baseload, such as coal and nuclear plants, and use these as much as possible, before deploying the more expensive mid-merit plants and the peakers, which acted as the ultimate safety net.

With the large-scale adoption of renewables (in 2015 a record 120 GW of wind and solar PV were added globally, more than any other technologies combined), the model is being turned on its head, particularly as costs have fallen, making them competitive when compared with alternative new-build options in many countries, including South Africa.

CSIR Energy Centre research goes so far as to suggest that it now makes sense, for cost reasons, to favour renewables generation over traditional baseload sources, and to supply any “residual” demand using “flexible” technologies able to respond to the demand profile created when the sun sets and/or the wind stops blowing.

This has been stress tested using a simulated time-synchronous model, integrating wind and solar data from the Wind Atlas South Africa and the Solar Radiation Data respectively. The outcome is reflective of South Africa’s impressive wind and solar resource base, with a capacity factor of 35% found to be achievable anywhere in the country – far superior to the 25% actually achieved in Spain and the 20% in Germany.

“On almost 70% of suitable land area in South Africa a 35% capacity factor or higher can be achieved,” Bischof-Niemz says, noting that a key finding is that South Africa’s wind resource is far better than first assumed.

“The wind resource in South Africa is actually on par with solar, with more than 80% of the country’s land mass having enough wind potential to achieve a 30% capacity factor or more. In addition, on a portfolio level, 15-minute gradients are very low, which makes the integration of wind power into the electricity system easier compared to countries with smaller interconnected areas. On average, wind power in South Africa is available around the clock, but with higher output in the evenings and at night.”

TECHNICAL & FINANCIAL FEASIBILITY

The unit’s research has gone further, though, testing the technical feasibility of supplying a theoretical baseload of 8 GW resulting in a yearly electricity demand of 70 TWh using a mix of solar PV (6 GW) and wind (16 GW), backed up by 8 GW of flexible power, which could be natural gas, biogas, coal, pumped hydro, hydro, concentrated solar power, or demand-side interventions. In such a mix, 83% of the total electricity demand is supplied by solar PV and wind, and the flexible power generators make up the 17% residual demand. The carbon dioxide emissions of this mix per kilowatt hour are only 10% of what a coal-fired power station would emit.

The economic feasibility, meanwhile, has been tested using the 69c/kWh achieved for wind in the fourth bid window of the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP) and the 87c/kWh achieved for solar. The flexible solutions to fill the gaps are assumed, “pessimistically”, to carry a cost of 200c/kWh.

Bischof-Niemz notes that 200c/kWh for flexible generation is a “worst-case” assumption, as is the assumption that any excess energy produced when solar PV and wind supply more than the assumed load is simply discarded and, thus, has no economic value.

The outcome shows that it is technically feasible for such a 30 GW mix to supply the 8 GW baseload in as reliable a manner as conventional baseload generators, while the economic analysis suggests that such a mix will deliver electricity at a blended cost of 100c/kWh. “Does it make sense to supply 8 GW baseload with an installed capacity of 30 GW? Yes, because it’s about energy, not capacity,” Bischof-Niemz avers………http://m.engineeringnews.co.za/article/wind-solar-can-supply-bulk-of-south-africas-power-at-least-cost-csir-model-shows-2016-08-22#.V8UXNQMApLs.twitter

August 31, 2016 - Posted by Christina Macpherson | renewable, South Africa