With the rising costs of electricity, many people have invested in solar energy equipment. To better understand the impact these systems are having on your energy needs, it is helpful to refer to a typical daily solar generation curve vs load curve diagram. The diagram below represents a typical installation for a commercial or light industrial facility.

The red line represents the generation of electricity from the solar panels which generate power from sunrise till sunset with peak generation achieved in the middle of the day. This curve is different every day, depending on the time of year and cloud cover. During the summer months, the days are longer, there is less cloud cover and the sun has more intensity, so the curve is wider and taller. During the winter months, the days are shorter, there’s more cloud cover and the sun has less intensity, making the curve narrower and shorter.

The blue line represents the load of your facility. This is also unique to your site and also varies depending on the time of year. Some facilities increase their load demand before sunrise, needed to power up machinery, turn on air conditioning / heating systems, computers, etc. Other facilities continue with a high load demand after sunset as they may be closing late in the day, running double shifts, etc. During the early hours when the facility is closed, a base load is required to power refrigeration, lighting, data, security systems, etc.

The electricity that is produced surplus to requirements is represented by the orange area on the graph. This energy is exported back to the grid. The electricity that you need to meet the load at times when your solar panels are not generating electricity is represented by the blue area on the graph. This has to be purchased.

The payment that you receive for your exported electricity is called the Solar Feed-in Tariff (FiT). A few years ago, the Fits offered around Australia were reasonably generous, making an investment in solar energy equipment worthwhile.

However, in recent times the Solar Feed-in Tariffs have been significantly reduced. For example, the PFiT scheme in Victoria ended in 2024 and the minimum feed-in tariff was set at 3.3 cents per kilowatt-hour (kWh). Simultaneously, the average cost of electricity per kilowatt-hour (kWh) in Australia typically falls between 25 and 45 cents, but this can vary significantly depending on your location and electricity provider.

This represents a dramatic rise in electricity costs for solar users which defeats the purpose of investing in solar in the first place! When you consider the cost of cleaning your solar panels and maintenance, there are hardly any gains achieved at all.

Challenges with solar panels alone

1. Mismatch Between Energy Production and Consumption

Solar panels may generate more electricity than you need during peak daylight hours (especially in summer) or too little when your energy demands are higher (eg. in winter or at night). This can lead to inefficiency, such as excess energy being wasted or insufficient energy to meet your load, forcing you to rely on grid power.

2. Intermittency and Reliability

Solar panels generate electricity only when there is sunlight. This means that energy production is intermittent and can fluctuate depending on factors like time of day, weather, and seasons. Your load may require a continuous and reliable supply of power, which solar panels alone cannot always guarantee, especially during cloudy days or at night when there is no sunlight.

3. Grid Dependency

If your solar system is grid-tied, you will still be dependent on the grid for backup power during times of low solar generation. In areas with unreliable or costly grid electricity, this dependency can be frustrating or financially burdensome, especially when power outages occur.

This is not ideal. If a battery storage system could be added to your system, that would be very helpful and to facilitate this, you need to replace your string inverter with a hybrid inverter. The Sinexcel ISUNA system goes beyond just a hybrid inverter and has capabilities that were considered impossible only a few years ago. Exciting times!