Renewable Energy

Developing a hybrid energy model

For all those nations with abundant coal reserves, fossil fuels will remain a key source of electricity. In parallel, though, is the inevitable shift to renewable alternatives that help to reduce our reliance on fossil fuels, says Thinus van As, function manager: Power and Energy, SMEC South Africa.

By Alastair Currie

The transition to alternative energy has been on the cards for decades, and it starts with implementable solutions that lower the lethal carbon dioxide emissions that threaten earth’s longer-term sustainability. In the immediate future, examples include the UK’s plan to end the sale of new petrol- and diesel-driven vehicles by 2030.

“It’s a parallel transition to a greener future that holds exciting possibilities for how the power mix will unfold,” says Van As. “At SMEC, we’re working with private and public sector stakeholders to develop practical models, for either end users or independent power producers (IPPs).”

South Africa’s Renewable Energy Independent Power Producers Procurement Programme (REIPPPP) first launched in 2011 (Window 1). Local and international teams responded with enthusiasm, executing landmark wind, concentrated solar power, and solar photovoltaic (PV) power projects, many of which, at the time, were the largest globally. Examples include the 75 MW Kathu Solar Park in the Northern Cape, and the 138.6 MW Cookhouse Wind Farm in the Eastern Cape. Through successive REIPPPP stages, South Africa has now moved to the preparation stages for Window 5. Interested bidders can submit bids ahead of the 16 August 2021 deadline set by the Department of Mineral Resources and Energy (DMRE). Allied to this is the DMRE’s Risk Mitigation Independent Power Producer Procurement Programme (RMIPPPP), where the list of preferred bidders was announced in March 2021. The objective of the RMIPPPP is to add 2 000 MW to the national grid by June 2022, taking some of the pressure off Eskom as it restructures and repositions itself.

Thinus van As, function manager: Power and

Energy, SMEC

South Africa

A mindset shift

“There’s been a definite shift in mindset when it comes to renewables since 2011. Then, for example, remote mines that operated off the grid automatically factored in diesel generation

Droogfontein 2 solar PV array

power as an inevitable running cost,” Van As explains.

“Now that renewable alternatives are far more mature, however, we are receiving growing enquiries about how mines can greater leverage this, from power security, carbon tax requirement and cost-saving perspectives. The same interest equally applies to general industry,” he continues.

“Our services at SMEC include power feasibility studies for clients that help them optimise potential cost savings using renewable energy. Renewable energy is also clearly in increasing demand as a power security backup measure, given the instability of present Eskom supply,” he adds.

SMEC’s involvement on REIPPPP projects to date includes the following: - Kathu Solar PV - Herbert Solar PV - Greefspan Solar PV - Jeffrey’s Bay Wind - Loeriesfontein Wind - Noupoort Wind - Droogfontein 2 PV - De Wildt PV - Zeerust PV - Perdekraal Wind - Kangnas Wind.

Battery projects

The rapid pace of battery technology research and development is making longer-term energy storage and utilisation increasingly viable. Electric car batteries are a case in point.

“Another evolution in thinking is the way large-scale embedded battery energy storage systems sync with the grid to ensure power stability during peak and offpeak periods,” says Van As. “That includes active power support, frequency response support, and voltage support.”

City of Cape Town

The City of Cape Town stands out as one of the early adopters of renewable energy and has earmarked various sites to build PV plants. Typical sizes envisaged range from 5 MW to 10 MW.

“To put that in perspective, the city currently uses around 1.7 GW of peak power. But it’s a step in the right direction, especially in working through and refining current and future IPP regulatory frameworks. Smart metering technology must come into play here in maintaining an equitable tariff model,” Van As continues. For municipalities, there are two main implementation options available. The first is to go the build, own and operate route, selling renewable energy into the grid at an agreed-upon tariff, plus some wheeling charges. The second option is to lease or sell land to an IPP and then buy power from them.

Rooftop solar

Within the energy mix, the lowhanging fruit are the small-scale embedded generators – essentially the growing population of rooftop solar installations across residential, commercial and industrial buildings in South Africa.

“It’s definitely realistic for gigawatts of power to be generated in this way,” he explains. “However, managing and controlling the buying and selling of surplus power via a network of this nature is a complex challenge that still needs to be thought through.

“What is clear is that there will be an evolving model. Here, energy efficiency will be common cause in lowering the carbon footprint via a stepped approach. The rest will be driven by economics,” Van As concludes.