For South Africa’s high-energy sectors, such as manufacturing, food processing, commercial estates, industrial operations and hospitality, energy is more than just a line item. It is a growing risk.

Many of these businesses operate when electricity is at its most expensive: early evenings, weekends and seasonal high-demand windows. Even with solar solutions in place, Time-of-Use (ToU) tariffs often penalise businesses that use the right amount of electricity — at the wrong time.

But advanced engineering of solar and battery solutions can help forward-thinking businesses to flip the model. They are not reducing how much energy they use, they are managing when they pay for it — and turning tariff complexity into a long-term cost advantage.

ToU tariffs: The hidden drain on profitability

In a typical ToU structure, peak tariffs can be two to three times higher than off-peak rates. For high-load operations, this means the same process can cost dramatically more depending on the time of day or season. And when production schedules or operational uptime cannot be moved to off-peak times, most businesses are stuck paying the premium — month after month.

This is where energy arbitrage becomes a powerful lever.

Shift & Save: What is energy arbitrage?

Shift & Save is energy solutions provider RenEnergy’s intelligent energy management strategy to shift cheaper energy to times when electricity is expensive, helping its clients to save on energy costs. It is not about using less power – it is about using it smarter. 

Also called “time-of-use energy arbitrage” in the industry, it is the practice of storing energy when it is priced lower — from solar photovoltaic (PV) and/or off-peak grid supply — and using that stored energy when electricity prices are higher. This is not about backup, it is about smart timing and financial precision.

Shift & Save works especially well for businesses that:

• Are on ToU or seasonal tariffs
• Operate during expensive, high-demand periods
• Already have, or are considering, solar PV systems
• Want a smarter return on their energy investment.

Shift & Save may sound simple, but the impact can be substantial.

A modelled example: Nearly R3-million saved through smart load shifting

RenEnergy recently conducted an in-depth energy audit and modelling exercise for a high-end hospitality client. The goal: identify how much money could be saved by shifting from reactive energy use to proactive energy management.

The proposed solution was 1 MWp rooftop solar PV, a 2.4 MWh battery energy storage system to shift energy usage across tariff periods, and a custom control strategy for peak-time dispatch and load smoothing. 

According to the client’s data, without PV nor storage, their total yearly electricity spend was R6 255 227, where the major cost drivers were peak and standard-time tariffs. Detailed modelling specific to the site’s solar potential and ToU structure reveals a new yearly energy cost of R3 318 008 — a yearly saving of R2 937 218 (47%). 

The table shows how energy consumed on peak and standard tariffs have been shifted, with off-peak energy increasing slightly. The solution does not reduce operational energy needs. It reduces the cost of meeting those needs — with a payback timeline driven by arbitrage savings, not backup protection. 

Shift & Save is a financial conversation

The real win here is not only energy efficiency — it is cost predictability. For CFOs and business owners, Shift & Save means:

• Smoother, more predictable energy bills
• Maximised returns on solar investments
• Reduced exposure to future Eskom tariff hikes
• Clear sustainability benefits for investors and customers

RenEnergy Africa MD Claude Peters frames it this way:

“Shift & Save is a financial strategy. Our work pays off not only when the grid fails, but when tariffs increase. With Shift & Save, clients don’t have to change when they operate. They only change what they pay.”

This distinction is critical. Shift & Save does not depend on grid failures. It thrives on smart timing, structured storage and performance-focused design. 

A common concern among businesses is the perceived high cost of batteries. While this was once a valid barrier, the economics have shifted significantly. Battery prices have steadily declined in recent years, driven by global innovation and scale in energy storage manufacturing. At the same time, Eskom tariffs have continued to rise — widening the gap between off-peak and peak rates.

What this means in practice is that Shift & Save does not just save money, it shortens payback periods. In some of RenEnergy’s recent modelling exercises, Shift & Save 

enables clients to recover the cost of batteries in far less time than anticipated. In some cases, the energy cost reduction brings the entire solar-plus-storage solution into positive cash flow within four to six years.

The engineered advantage

Often, solar and energy storage is treated as a backup feature — a knee-jerk response to loadshedding. But RenEnergy approaches it differently. Every solution is engineered around how and when energy is consumed, with a strategy that begins well before any hardware is selected.

The team starts by analysing the client’s tariff structure, modelling their consumption patterns, and forecasting savings based on optimised battery discharge. Hardware specification only follows once the business case is clear — because with RenEnergy, it is not about batteries or panels. It is about performance.

This performance is sustained over time through dedicated asset management, including continuous monitoring, diagnostics and optimisation to ensure your solution operates at peak potential throughout its lifespan. Behind every project is the financial strength of RenEnergy and its parent company Aggreko, giving clients confidence that their partner is stable, well-capitalised and built to last.

With over a decade of experience in both South Africa and even longer in the UK, RenEnergy combines technical credibility with institutional longevity — and can resolve underperforming existing solutions installed by less experienced providers. What sets RenEnergy apart is not just what it builds, but how it builds partnerships: grounded in measurable outcomes, aligned to your strategic goals and committed to long-term success.

What is your savings potential?

If your business operates on a ToU tariff, and especially if you already have or are planning solar, you may be sitting on an untapped savings opportunity.

“When you match solar and storage with smart timing, you don’t just power your business, you protect your margins,” says Peters.

To Shift & Save: email consultants@renenergy.co.za to book a diagnostic session with our team. We will help you see your energy spend as an asset waiting to be optimised.

Want to future-proof your energy strategy? 

Email:  consultants@renenergy.co.za

www.renenergy.co.za