2015: A year of solar power, battery technology advances.

2015: A year of solar power, battery technology advances.

By Bevan Jones, Technical Director at Soltra Energy

The past year witnessed a sharp uptick in interest in South Africa for rooftop solar photovoltaic (PV) power for a wide range of domestic, commercial and industrial applications. This was bolstered by an increasing determination on the part of consumers to reduce their reliance on Eskom.

Solar power – nature’s free alternative – is now seen as a cost-effective, ‘green’ solution, particularly when compared to noisy diesel- or petrol-powered generators.

Perhaps one of SA’s more memorable advances in the power provisioning field in 2015 was the development by Soltra Energy of a new installation paradigm for solar PV panels.

Soltra Energy is a leader in the field of solar PV power provisioning systems and infrastructures. Its innovative solution is set to provide businesses with more effective energy returns from rooftop solar PV solutions while boosting the often limited availability of Eskom power.

Conventional wisdom maintains solar PV panels should be orientated towards north in the southern hemisphere to allow for the most efficient power generation. The result, from a power production standpoint, is a ‘bell curve’ reflecting power increases throughout the day peaking at midday and gradually falling again to zero at sunset.

However, in a pioneering grid-linked hybrid solar PV application in Johannesburg, an east-west orientation was proposed by Soltra Energy, tested and found to be more advantageous in a business environment.

The motivation for the experiment was an Eskom electrical power supply unable to meet the business’ full demand. A complementary challenge was to reduce the aggregate electricity cost for the facility.

Soltra Energy initially evaluated power production from traditionally north-facing panels. Subsequently, various directions were tried culminating in a convention-breaking, east-west configuration which, in this application, provided significant cost advantages over a north facing system.

One of the keys to the success of the installation – and similar installations going forward - lies with its management. Sophisticated ‘smart’ power management solutions designed by Soltra Energy 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 possible battery storage for later or after-hours use as appropriate, and engage an optional generator to integrate seamlessly into the power supply grid should battery storage become depleted.

Another breakthrough in this field in 2015 was the launch of a locally-designed ‘power wall’ lithium-ion battery pack solution and making it available to the local market ahead of a similar unit produced by US manufacturer Tesla.

Like its American counterpart, the SA-manufactured Soltra Energy Wall is designed to store excess energy, whether it is derived from the Eskom grid, from solar panels or a combination of both as found in increasingly common hybrid systems.

The attractive, space-saving unit represents a leap forward in battery storage and is expected to boost the acceptance of rooftop solar PV-plus-battery solutions in 2016 and beyond, giving SA consumers greater control over their energy usage.

Efficient battery storage could quickly become one of the biggest game-changers in the South African energy landscape, which will continue to be characterised by a mismatch between demand and supply. It’s a technology whose time has finally arrived.

Find us:

www.soltra.co.za

The Tesla Powerwall: We couldn’t wait, so we designed our own.

The Tesla Powerwall: We couldn’t wait, so we designed our own.

By Jack Ward, CEO of Soltra Energy

From what we’ve seen in the media, the Tesla Powerwall lithium-ion battery pack is an attractive, wall-mounted, space-saving unit that represents a leap forward in battery storage technology.

For users opting for solar energy installations, either to complement or backup Eskom power – or move off the grid completely - the Powerwall concept will certainly boost the acceptance of rooftop solar PV-plus-battery solutions beyond all projections. It’s a technology whose time has finally arrived.

While the Tesla Powerwall has been eagerly anticipated by South Africans facing disruptive power outages and the real possibility of load-shedding in the near future, the first Tesla units for general distribution in SA are reportedly some months away.

Fortunately for local electricity consumers, there is no need to wait. The alternative to the Tesla Powerwall is already on the market. Thanks to local design innovation and manufacturing excellence, the Soltra Energy Wall is available for immediate delivery. There is no waiting for a supply channel to be formed, personnel to be hired or stock to arrive.

One of the most attractive features of the Soltra Energy Wall – which assuredly mirrors its opposition in terms of specification and presentation – is the price. As can be expected, SA’s falling rand against the US dollar has caused the retail prices of US-made goods to soar. According to reports, final pricing for the Tesla Powerwall will likely only become available closer to the battery’s local launch date.

On the other hand, the SA-designed and manufactured Soltra Energy Wall – now available for country-wide installation - is cost effective and its price is easily justifiable for a wide range of applications. These range from domestic installations to the largest industrial sites where synchronised, multiple wall-mounted units and a unique, utility-scale, floor-standing version of the Soltra Energy Wall are ready for duty.

Most importantly, the Soltra Energy Wall is backed by a world-standard 10-year guarantee (subject to a 70% depth of discharge benchmark) and nationwide technical service by an existing, highly-trained and experienced customer support team.

While the Tesla Powerwall has been hailed as a game-changer, we can confirm that the locally-designed Soltra Energy Wall has already irreversibly altered the rules by which the power provisioning game is played in South Africa.

Find us:

www.soltra.co.za

  

Compare solar PV installers: Ask the right questions.

Compare solar PV installers: Ask the right questions.

By Jack Ward, CEO of Soltra Energy

 If you are considering a solar photovoltaic (PV) installation, you’ll probably be asking for quotes from a number of installers. Before you do, here are a few pointers to help you ask the right questions of the potential installers before comparing their costings and making a choice.

As you might expect, understanding the pricing structure of the installation as quoted will be a priority. An easy way to compare competing quotes is to ask the suppliers for their price per Watt (PPW). This is how professional contractors price out solar systems.

The PPW is the price for each Watt of solar energy you’ll be purchasing and it should be based on the completed system’s price, including VAT and other additional items. The ‘Watts’ element is calculated according to the installed DC Watts, which can be arrived at by adding the wattage of all solar panels to be fitted.

Don’t be confused by the fact that solar systems’ output is generally measured in kilowatts (kW) – simply multiply by 1000!

Some points to ponder:

• Make sure you compare ‘apples with apples’ by using the gross price of the installation including labour, materials, financial costs (if appropriate) and other overheads.

• Ensure that sure the specification meets your requirements. For example, do you need a domestic, grid-tied hybrid system without battery storage; or an off-grid system with batteries or something in-between. If you are running a business, you might opt for a solar/diesel hybrid system which should include a generator and an intelligent management system to automatically prioritise the power source as necessary.

• Are the Watts used in the calculation DC Watts? (Some quotes may detail AC Watts.)

• Bear in mind that some solar panels are better than others. Opt for Tier One, branded panels with warranty back-up but expect them to be more expensive than Tier Two panels or unbranded items from a fly-by-night supplier.

• The type of string or micro inverter selected can vary in price by as much as R4.00 per Watt.

Note that the biggest variance in price should be system size. However, as a system gets larger, not all costs increase proportionally.

Nevertheless, as a rule of thumb, your solar PV installation in South Africa should cost between R 20.00 per Watt for a grid-tied installation and R 40.00 per Watt for a hybrid alternative. Any price under or over this range should be closely examined for accuracy and supplier dependability.

Find us:

www.soltra.co.za

  

Your diesel generator running up unacceptable fuel bills during load shedding?

Your diesel generator running up unacceptable fuel bills during load shedding?

By Jack Ward, CEO of Soltra Energy

 We have the answer. Save fuel by creating a hybrid, grid-tied, diesel/solar photovoltaic (PV) installation. Such a system can save up to 30% of the fuel used in traditional diesel-only generation.

Soltra Energy is a leader in innovative hybrid technology that allows power generated by solar technology to work alongside power supplied by the grid and a diesel generator, allowing you to benefit from using less fuel while maintaining targeted power outputs.

In addition to slashing your fuel bills, the quick payback of the solar elements of a modern grid-tied, hybrid system can return their investment costs in three to five years.

Solar PV power is often the most economical alternative renewable energy source in South Africa where solar irradiation is both abundant and free. It is also one of the most desirable ways to boost efficiency, minimise energy waste and improve CO2 emissions at minimum cost.

The Solar PV elements of the system are modular and can be quickly installed anywhere and only minimal maintenance is required to keep them running.

An intelligent management system (controller) is a key component of a solar PV/diesel hybrid system. A software algorithm ensures the solar PV array operates at its maximum power output at all given solar radiation levels. Only when these drop below a specified point, or at night, are the grid and diesel generator brought in as necessary.

This software-based solution provides the interface between the grid, the generator, solar PV system and the load, managing demand-based PV feed-in.

For example, when the grid fails and the generator is required to run, the solar installation synchronises with the generator. The solar fuel saver/ controller protects the generator and ensures that the electrical system is stable. The controller regulates output from the solar installation and ensures that the generator is always running above its minimum threshold.

Importantly, if the system is used in a commercial/industrial setting where the premises are occupied only during the working week, the generator can be disabled at night and on week-ends to further save fuel.

[ENDS]

Find us:

www.soltra.co.za

  

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

  

Best advice for solar PV installations

Best advice for solar PV installations

By Jack Ward, CEO of Soltra Energy

Rooftop solar photovoltaic (PV) solar systems are mushrooming around the world. In South Africa they have gained significant ground as users look to supplement Eskom power, combat load shedding or move off the grid altogether.

Over the past year, system components have grown more mature, capable and reliable. At the same time solar PV systems have become more price competitive and viable, particularly when seen in the light of spiralling electricity rates.

While small-scale solar systems are increasingly sold in hardware stores and builders’ supply depots, users should resist the temptation to effect a DIY installation. Here are just some of the reasons why:

Although most roofs can support the added weight of a solar energy system, some can’t. It takes a professional – preferably a structural engineer - to check the condition of the rafters and assess the capability of the roof to safely support the added dead load of the solar array, the mounting rack and the temporary live load imposed by the installation crew. (Unsurprisingly, the latter calculation is often omitted by DIY’ers.)

While the type of solar panels (be wary of thin film modules which have a lower yield) and the number to be installed will need to be professionally selected and calculated, it’s important to choose a manufacturer that will back its products with an optimum performance guarantee of 80% over a 25 year period and offer panels with an expected lifetime of over 30 years.

Note that the orientation (north–facing) and angle of inclination of the solar array are both critical for optimum performance. So is the spacing between solar arrays to allow channels for electrical cabling. Ideally, the array should be located near the main electrical service board if a grid-tied system is being installed.

Grid-tied PV systems should be interconnected by a licensed electrician while solar hot water systems (often employed in tandem with a solar PV system) should be installed by a licensed plumber.

Choosing a solar PV inverter also requires expert intervention. The inverter converts solar energy to electricity and will also have to be expertly sized and selected. Many inverters are energy wasters. Choose one that isn’t.

In most grid-tied installations, the building’s electrical demand may be determined and used to specify the inverter needed for the solar PV system. In other cases, however, the estimated peak array output is used as the basis for specifying the inverter.

In a remote or stand-alone solar PV system installation, the average daily electric load of the building needs to be calculated first. The building’s electric demand should include the Watt demand of all AC loads running at the same time, plus the wattage from the surge of starting motors, and all DC loads operating simultaneously. This demand should be further increased by a factor of 1.2 to 1.4 in order to account for inverter losses.

In both grid-tied and remote site situations, the initial estimate of the inverter’s capacity may be impacted by future plans, such as increasing the size of the PV array. This needs to be accommodated at the planning stage by a professional PV system engineer.

Eskom produces electricity that is a true sine wave. A modified sine wave inverter produces a slightly squared off electrical waveform, but some computers, power tools, refrigerators and most other powered equipment can use this generated electricity.

On the other hand, pure sine wave inverters produce a true sine wave that is the same as Eskom’s which is needed by high-end audio and other specialised equipment that are electrically sensitive, such as life support systems.

Importantly, in grid-tied installations the inverter must be able to be shut down rapidly in situations where utility power goes down. This is called anti-islanding and is a safety function for any Eskom personnel and electricians who may be working on the lines in the area.

An off-grid system will require storage batteries (the number and capacity are critical) and – usually – a backup diesel or petrol generator to take up the slack on cloudy days.

There are any number of economic studies that reveal how this calculations should be made and more about the long-term value of installing a solar PV system. But in the main, these studies are only as good as the input data. Make sure you are professionally advised when working with the numbers.

   

Find us:

www.soltra.co.za