Corne Groenewald, Installations Manager at Probenergy, says an energy audit is the essential foundation of a successful solar installation. “If you’re investing in a system, take the guesswork and assumptions out of it. Having accurate data informs the size and scope of an optimal solar energy system, so you don’t end up having to spend more at a later stage. Detailed energy audits also assist in optimising energy efficiency and strategising energy usage.” 

Residential installations

According to Groenewald, a simple checklist doesn’t cut it when it comes to an accurate view of energy usage. “When it comes to energy consumption, it is not solely about the amount of energy used, but also about the patterns of usage. I’ve seen multiple identical residential units have completely different energy consumption and peaks, depending on how they use power and their energy efficiency variables.”

The energy audit provides insights that help Probenergy’s engineers tailor systems to meet specific client objectives, says Groenewald. “A client may want solar energy with a 4-hour back-up. Through logging, we can see overall consumption as well as peaks. These peaks determine the size of the inverter. The back-up duration required determines the size of the battery.”

For residential customers, Probenergy uses the Emporia online logger for a full week. The logger connects to the customer’s WiFi to provide real-time energy usage data. This tool, capable of logging both single and three-phase houses, helps identify energy consumption patterns and peak usage times. 

By breaking down the distribution board using up to 16 Current Transformers (CTs), the team can pinpoint which appliances or areas of usage are energy hogs, allowing for a tailored solar solution. The DB board can then be split into essentials and non-essentials. Bi-directional inverters, now required in the Western Cape, can feed energy back to the non-essentials or to the grid once essentials are covered. However, this requires the grid to be available, and doesn’t happen when operating on battery power. “While there are certain products that can shave the battery to push power to non-essentials, this depletes the battery very quickly,” Groenewald explains. 

“The energy audit gives clients clear visibility into their energy data, allowing for better planning and usage,” says Groenewald. “For example, with a hybrid solar setup including an inverter and a battery, one can optimise energy consumption by allowing the battery to fully recharge during early solar hours (7 am to 11 am) and strategically scheduling heavy appliance usage after 11 am, maximising efficiency and reducing reliance on the grid during peak demand. “

Commercial installations

In the commercial realm, the approach differs with the use of Tinytag loggers. These devices are deployed to gather comprehensive data across large facilities, often requiring multiple loggers to capture the full energy profile. This rigorous data collection enables a detailed technical analysis, informing the engineering team with proper data to design for the full scope of the facility. Once the audit is complete, the data is meticulously analysed, culminating in a report that highlights inefficiencies and offers a proposal for a solar installation.

It is important to advise on energy efficiency upfront, indicating necessary changes like transitioning to LED lighting or optimising HVAC schedules, says Groenewald. “If changes are going to have a major impact on energy efficiency, we advise clients on this investment before we do the logging. For example, LED lights are 75% more efficient that traditional fluorescent lighting, so changing these throughout a factory can have a significant effect on energy consumption.” 

Groenewald notes that industrial and commercial spaces frequently use substantial generators as part of primarily grid-tied systems. “Businesses want solar power to cut costs or to mitigate the limitations imposed by local councils,” Groenewald explains. “The common council constraint of a 1,000 kWh limit can lead to financial penalties for businesses that exceed this threshold, making it critical to optimise power systems.” 

In this scenario, batteries can serve not only as a backup, but as a means to significantly reduce energy expenses. By integrating solar power with efficient energy management, these businesses can navigate regulatory challenges while achieving substantial savings. Overall, energy audits ensure that commercial solar installations are both cost-effective and efficient, supporting long-term sustainability and financial goals.

The increasing complexity and customisation of solar solutions makes energy audits invaluable. By accurately sizing the solar system based on detailed energy data, clients can avoid the pitfalls of under- or over-investing in solar infrastructure, and get the best return on investment.