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.

Find us:

www.soltra.co.za

  

Tesla Powerwall sparks scores of potential battery breakthrough announcements

Tesla Powerwall sparks scores of potential battery breakthrough announcements

By Jack Ward, CEO of Soltra Energy

Without doubt, the Tesla Powerwall represents a huge step forward in energy storage as it has lowered the price point of lithium-ion battery technology through mass production, based on the demand in the electric vehicle sector in which Tesla is a major player.

Now, this technology will be used to complement domestic and industrial solar photovoltaic (PV) systems and address time-of-day billing constraints, among many other applications.

The announcement that Tesla will be mass-producing lithium-ion batteries at its new Gigafactory fabrication and assembly plant has sparked numerous news stories highlighting other potential breakthrough technologies that may one day rival Tesla’s eagerly anticipated offering.

For example, researchers at an American university have unveiled a ‘solar air’ battery that integrates lithium-iodine and solar cell technologies. They say the concept may present guidelines that could be extended to other metal-redox battery systems which could herald a potential breakthrough for low-cost, grid-scale energy storage.

Scientists at the University of California have created a solar cell design that allows energy to be stored for fairly long periods. These cells, which mimic natural photosynthesis, are plastic and use polymers and nano-scale fullerenes (hollow carbon molecules) arranged in a manner that resemble ‘small bundles of uncooked spaghetti with precisely placed meatballs’ -according to a source close to the researchers.

A joint Swedish/American team has come up with ‘an elastic foam-like’ battery material that can withstand shock and stress. This nano-cellulose-based material is made from tree fibres and can pack a surface area equivalent to the size of a rugby field into a single cubic decimetre – the equivalent of one litre. Watch for this battery material to be incorporated into roofing, car bodies and even clothing.

Perhaps surprisingly, melanin, the human skin pigment or colouring is being tested for its potential in energy storage. Backed by a sizable grant from the US Department of Environmental Conservation, research is encouraging, hinting at the possibility of cheaper, safer batteries with lower environmental impact in the future.

Finally, a battery solution from left-field comes from Chinese and German scientists who have found that reed leaves might hold the key to the production of better silicon anodes (electrodes) for lithium-ion batteries. As a bonus, the reed leaves option is less complicated and expensive when compared to current anode production methods. 

Low-cost stationary storage represents the ‘holy grail’ for all renewable energy protagonists. As a result there is a significant focus on achieving this goal through diverse R&D projects. Watch this space, as the next game-changer could be announced soon.

Find us:

www.soltra.co.za