How to limit your reliance on Eskom

How to limit your reliance on Eskom

By Jack Ward, MD of Powermode

If you’ve thought about living off the grid, not having to deal with Eskom’s ‘load shedding’ schedule that seems more onerous by the day, then perhaps it’s time for you to begin limiting your reliance on our power provider, gradually closing in on your goal.

What’s involved in generating your own power? There are a number of levels of separation from Eskom that can be achieved, all contributing to generating the energy you’ll eventually need to live or work comfortably off the grid.

Solar power is the most likely solution that springs to mind. The sun-powered option, which includes roof-top solar photovoltaic (PV) panels and an inverter, is able to provide significant amounts of ‘free’ electric power when the sun shines. In addition to the energy cost-savings, the big benefit of a solar PV solution is the lack of moving parts, resulting in little maintenance.

In South Africa, solar power has proved to be a viable and reliable energy source, thanks to the country’s sunny climate in which solar irradiation is abundant.

However, if you intend to rely heavily on solar generated power in a 24-hour business or domestic environment, a battery pack to store energy for the hours of darkness will be required.

The downside, at least for now, is the cost of the deep-cycle battery packs - which will need replacement around every five years - and their limitations in terms of storage capacity, restricting their application to emergency power. It's easy to see why solar remains a part of the answer, and not the complete solution.

The next level of separation from Eskom could centre on the introduction of a diesel or petrol-powered generator to complement your solar PV installation.

Incorporating solar PV power and generated electricity in modern grid-tied hybrid systems is increasingly popular in the commercial sector for their reliability and cost effectiveness. In many countries, solar PV/wind hybrid solutions are gaining currency, as are solar PV/ fuel cell alternatives.

Let’s focus on solar PV/generator hybrid systems. They work in fully automatic mode by prioritising solar power. A software algorithm ensures the solar PV array operates at its maximum power output at all given solar radiation levels. Only when these drop below a specified point (such as on a cloudy day or at night when backup battery power is depleted) is the generator brought into the picture (in an off-grid solution).

To realise optimum benefits from solar PV/generator hybrid systems, the sizing of the various components making up the installation will need to be done on a case-by-case basis.

A key consideration is whether an off-grid system or a grid-tied system is required as every application will be different depending on specific load profiles, solar irradiation, back-up battery capacity and generator setup. Cost is a key consideration as an off-grid system will need to be substantially more robust than a grid-tied system.

An intelligent management system is a key component of a solar PV/ hybrid system. This software-based solution provides the interface between the generator, solar PV system, battery pack and the load, managing seamless, demand-based energy feed-in from the most appropriate source. 

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www.powermode.co.za