What Makes Grid Tie Limiters a Great Idea

Prepaid electricity meters are increasingly prevalent in South Africa, and today every new building is required to have an Eskom-approved prepaid meter. This system negates the need for Eskom to deploy more and more meter-readers around the country, and ensures that each household pays the exact price of the electricity consumed – no more, no less. However, these prepaid meters were not designed with solar energy use in mind – a decided inconvenience for anybody looking to go green.

A Pricey Problem

A conventional prepaid power meter cannot distinguish between power flowing from the grid and power coming from an alternative source. This means that if a homeowner installs a grid tied system, the meter will charge them for power in both directions. This is not a realistic or sustainable solution – in fact, it’s completely the opposite of what green energy should be. Luckily, the answer to this problem is a simple and affordable one, known as a grid tie limiter.

Simple as A, B, C

In the past, it was essential to have a “smart meter” (also known as a bi-directional meter) to ensure compatibility with a grid tied inverter. However, a grid tie limiter unit has the ability to: a) Prevent the export of power to the grid, b) Measure the power required by the load, and c) Electronically notify the GTI to restrict the power generated by the solar array so that it supplies equal power to that of the current AC load. This means that no excess power is generated; therefore no power can be exported. Now any South African on a prepaid electricity system can use a grid tied solar energy solution without the extra cost of installing a battery back-up system.


Grid tie limiters are suitable in buildings where power consumption is higher during the day and lower at night – for example, home offices and small commercial premises. Homes with relatively high daily usage can also benefit, for example the power generated by the system could be used to power the pool pump or irrigation systems. This solar energy solution has a lower impact on the environment, and on monthly finances, as it can make a significant difference to your electricity bill. Sustainable.co.za stocks state-of-the-art Microcare grid tie limiter units, as well as a range of grid tied solar power kits. Speak to us about designing a solar energy solution tailored to your requirements.