Changing directions: Solar panel optimisation – a South African first?

Changing directions: Solar panel optimisation – a South African first?

By Jack Ward, CEO of Soltra Energy

It’s a question I’m often asked: In what direction should solar photovoltaic (PV) panels be sited for optimum energy production?

Conventional wisdom says the panels should be orientated towards north in the southern hemisphere to gain maximum benefit. More specifically, solar panels should be pitched between 25 and 35 degrees (approximately equal to the site’s latitude) to allow for the most efficient power generation.

The result, from a power production standpoint is a true ‘bell curve’ reflecting power increases throughout the day peaking at midday and gradually falling again to zero at sunset.

But what if we said it was best to point the panels eastwards? Or westwards? Surely the loss of energy recovery as the sun reaches its zenith would be detrimental to overall energy production?

The answer is that it would, if other sources of energy – grid power, battery stored energy and generator power – were not factored into the equation.

The fact is, solar power is seen today as one of the offsets for load shedding, the scourge that will be with South Africans for many years to come. As such it needs to be fully integrated into every user’s power provisioning strategy.

One of the objectives of such a strategy should be to maximise off-grid energy resources at peak offtake times.

In most business and domestic applications, the bell curve is more square and flatter with morning and late afternoon demand equalling the midday demand – where conventional north/south PV production is greatest.

So aiming the solar panels eastwards and westwards – on a flat-roofed building or east/west facing roofs – will significantly smooth the supply of power during the day and prevent spikes of power at midday. Importantly, this will reduce the overall amount of electricity needed from the national grid during an average working day.

At Soltra Energy we have confirmed that an east-west orientation of solar panels is more effective at capturing solar energy early in the morning and late in the afternoon. We’ve confirmed that east-west panel orientation helps flatten the bell-curve and optimise solar power generation to suit a demand generated by business.

The results of Soltra Energy’s research will hopefully motivate energy users to integrate, fine-tune and manage their use of solar, grid and backup power.

The key to the success of such an installation lies with its management. Thankfully, sophisticated ‘smart’ power management solutions can now be installed and tailored to users’ needs.

These systems will, for example, complement grid power with solar power when necessary (at peak times), divert excess solar power to battery storage for later or after-hours use as appropriate, and fire up a petrol or diesel generator to integrate seamlessly into the power supply grid should battery storage become depleted.

With the trend towards computer-controlled smart devices gaining momentum, one of their most practical applications will be in the power management arena. At Soltra Energy we have designed a range of micro smart-grid solutions that measure the generated solar power on a minute-by-minute basis, compare it to current grid power availability and assess current load states.

Thus, should load changes occur or a sudden collapse in solar power feed-in happen as clouds cover the sun, or the grid supply is cut, sufficient spinning reserve is always available from battery banks or generators. The priority is always solar PV, followed by grid power, then stored energy and finally generator power.