Living with Solar –Part 1

AWPower Bulletin: October 2016

Living with a solar PV (photovoltaic) system is very different from conventional electricity sourced from the grid. It has a magic that rubs off, making you aware and appreciative of its renewable nature, with the result that solar users become smart energy users. It has immense benefits in terms of cost reduction, as shown in the graph below, but it can also provide energy security.

This is the first article in a series that will keep you updated on best practices for energy efficiency. We start by sharing actual cost reductions achieved at AWPower’s experimental site in Cape Town.


AWPower’s experimental solar PV installation is being used as a testing ground by our engineers together with main suppliers to ensure that we deliver high quality energy solutions for residential, commercial & industrial applications. The different phases in development of this experimental installation, in order to reduce the actual monthly expenses, are summarized below:

Phase 1 (Jan 2015)

Installed a pre-paid meter & replaced all light bulbs with LEDs. This exercise illustrated the importance of implementing energy efficiency measures as a priority.

Phase 2 (Mar 2015)

Installed solar PV system for essential loads, 280Wp PV, 1kW inverter & 1 x 12V 230Ah calcium alloy battery. Our first experience with solar worked well to counter load-shedding for essential loads such as TV, PC & some LED desk lamps.

Phase 3 (Oct 2015)

Upgraded to 4kW Hybrid inverter with 2.25kWp PV (9 x 250Wp PV modules), 4 x 12v 230Ah calcium alloy batteries. The economical Axpert Hybrid inverter worked well but could not cope with the geyser. The batteries could not support the household throughout the night. The inverter eventually burnt out.

Phase 4 (Jan 2016)

Upgraded to 6kW MLT Oasis Off-Grid inverter 2.25Wp PV, 8 x 6v 225Ah lead-acid batteries, supporting full load including geyser. The difference in performance between the heavy duty MLT Oasis inverter and the lower cost Axpert was very obvious. The system struggled a bit during winter with only 9 x 250Wp PV modules.

Phase 5 (Aug 2016)

Upgraded the solar PV system to 3kWp PV (12 x 250Wp) which had a major impact on performance and cost reduction. We are now paying only R300 p/m for pre-paid electricity, whereas we would have paid approximately R1,700 had we continued with our original setup.

Phase 6 (Oct 2016)

We increased the solar PV system to 3.75kWp PV (15 x 250Wp) of which 6 of the PV modules are Building Integrated PV (BIPV pictured below).


Upcoming in the next edition of Living with Solar:

integratred-pv Building Integrated PV (BIPV)

This opens up the use of PV by replacing roof structures with integrated PV for both new and old roofs. High performance and good looking. We share our experiences with you in Living with Solar – Part 2.

Future topics in Living with Solar:

measures Energy efficiency measures

Converting existing light bulbs to LED should be one of the first steps towards increasing energy efficiency for any building. AWPower engineers are achieving pay-back of less than a year in most cases.

sizing Choosing & Sizing your Solar PV System

We will provide an overview of the basic configurations for residential, commercial & industrial applications and how to select an appropriate system, sizing it for maximum benefit and future expansion.

inverters Solar Inverters

Grid-Tied solar inverters (no batteries) allows for very attractive savings for day-time commercial & industrial energy users. Average pay-back periods are between 4 to 5 years, and the savings could equal the monthly instalment if the right finance package is selected.

batt-inverters Battery Inverters

This is the brain of the Solar PV system and where local backup and support becomes crucial. We share with you the benefits of buying from a local manufacturer.

pv-modues Solar PV modules

The PV module is the engine room of the solar energy solution and recent reductions in prices allows for very attractive pricing on PV systems. We will discuss the choices of PV modules and mounting structures.

batteries Solar Batteries

The battery bank is probably taking the bulk of the strain during a typical 24-hour solar cycle. We share with you our experience with the various types of lead-acid batteries and how lithium-ion is reducing the pay-back period for a solar PV system.

circuits Smart circuits

We share with you the benefits that can be derived from intelligent circuits that AWPower engineers have designed, including essential & non-essential loads/circuits and how it maximises the utilization of renewable energy.

geyser Geyser management

We believe traditional solar geysers will be replaced by integrated systems where the conventional geyser is retro-fitted with a hi-performance element and managed with an intelligent timer system, better insulation etc.

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