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.

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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]

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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.

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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.

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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.

   

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Air pollution: Is Jo’burg poised to become the next Lagos?

Air pollution: Is Jo’burg poised to become the next Lagos?

By Jack Ward, CEO of Soltra Energy

When the lights go out in Lagos, Nigeria – which happens on a regular basis – the generators fire up. Gradually, like fireflies emerging from a slumber on a hot summer’s night, the city lights flicker and re-ignite.

With increasingly frequent electricity outages – load-shedding – being a feature of life in Lagos (as it is in Johannesburg), diesel exhaust pollution is also getting worse. Fumes from generators and heavy commercial vehicles now combine to raise air pollution to levels that can lead to respiratory and cardiovascular diseases.

While pollution levels in Johannesburg, the industrial heart of South Africa, may not have reached crisis levels yet, there are those who believe a Lagos-like scenario is not too many years away, unless steps are taken to avoid it.

Eskom’s load shedding schedule remains as relentless as ever, with no end in sight to daily electricity outages. The answer, for many South African businesses and homes, has been the installation of a generator.

It’s a short term solution. The price of diesel is on the rise, meaning that the costs of keeping the lights on will rise over time – much as Eskom’s prices will inevitably continue to rise.

For those who believe in keeping the air breathable – and the evenings noise-free – the promotion of green solutions to address a potential pollution problem is a priority.

In this light, there a couple of solutions that are immediately available. Let’s take the uninterruptible power supply (UPS) system. Eminently more ‘green’ than the diesel generator, the price of a UPS is determined by its size and the number of batteries in its battery-pack. Both play vital roles in determining the total number of hours of back-up time available.

An installation’s requirements depend on a number of less-than-obvious factors, such as the maximum possible load required, the average likely load and the level of redundancy that may be needed to be on the safe side.

One of the advantages of a UPS system is its ‘power conditioning’ effect or the removal of so-called spikes and brown-outs from the power supply. This is vital for sensitive computer equipment. The down-side is it needs electricity to charge its batteries.

Significantly higher up the ladder in terms of its ‘green appeal’ is solar photovoltaic (PV) power. Not initially considered as a stand-by power supply solution, solarPV plus battery installations are now gaining momentum, helped by improving technology and falling hardware and battery prices. The Tesla Powerwall is a clear example of how storage technology is advancing and prices are falling.

Grid-tied, hybridised solarPV plus battery installations are targeted at domestic, commercial and industrial markets. Ideal for rooftop installations, they offers backup battery autonomy and are thus geared for load-shedding.

What will save Jo’burgers from Lagos-like pollution is their readiness to accept rooftop solar PV power solutions against the backdrop of concerns over power reliability, price hikes and the lack of leadership as Eskom lurches from one crisis to another.

When comparing the cost of setting up a solar plus battery solution to that of Eskom’s rising prices, parity has pretty much been reached. Should Eskom receive the 12.69% increase it has requested for the 2015/2016 billing period, solar will represent better value for money.

This calculation is supported by the Residents and Business Owners Association of the Johannesburg suburb of Parkhurst which has launched an ambitious plan to become a model of self-sufficiency and green living by persuading 2000 homeowners to install full solarPV plus battery systems over the next five years in a bid to cut ties with Eskom.

It is becoming clear that the current trend is away from generators, as users embrace nature’s free alternative.

   

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Solar PV plus battery solutions: Prices poised to plummet

Solar PV plus battery solutions: Prices poised to plummet

By Jack Ward, CEO of Soltra Energy

I’m on record as saying that the Tesla Powerwall, the revolutionary wall-mounted lithium-ion battery-pack, will gain general marketplace acceptance faster than predicted.

The latest news from Tesla certainly supports this. At launch earlier this year, the Powerwall was cheaper than most industry watchers were prepared for, mainly because Elon Musk, the South African-born founder of Tesla, was determined to demonstrate the broad global acceptance of his brainchild.

Now, the prices for all variants of the Tesla Powerwall are falling faster than expected even before the first Powerwall has been shipped! For example, the average Tesla Powerwall battery price on launch was around US$ 547/kWh. Now it’s around $350/kWh and set to breach the $300/kWh price point soon. What will it be when worldwide distribution begins in 2016?

According to industry watchers, Tesla’s batteries are already seven years ahead of the market when it comes to pricing, giving tens of millions more customers the opportunity to cost-effectively install solar PV plus battery systems in their homes.

Consequently, when the customer-friendly, aesthetic, well-designed Tesla Powerwall makes its appearance in SA it will have a ready market waiting. Expect stocks to evaporate faster than water in a parched desert. Globally, reserve orders are mounting - around $800-million worth as we speak.

Why are prices falling so fast? It’s due to the battery’s application in the automotive market. In the US, electric vehicles are big business. Already more than 3 million electric-drive vehicles are on the roads. Tesla, BMW and now Mercedes-Benz are vying for the lion’s share of this burgeoning market.

Bringing down the cost of an electric drivetrain is therefore an important step in increasing the adoption of zero-emission vehicles. Vehicles sales are thus at the centre of this development.

Here, in electricity-starved SA, electric vehicles may not be a priority, but preparing for disruptive load-shedding and soaring electricity prices is. With Testla lighting the path ahead, cheap battery storage is set to boost the acceptance of rooftop solarPV plus battery solutions beyond all projections. It’s a technology whose time has finally arrived.

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How susceptible are rooftop solar panels to devastating storm damage?

How susceptible are rooftop solar panels to devastating storm damage?

By Jack Ward, CEO of Soltra Energy

How do solar PV panels stand up to the extremes of rain, wind and hail? What about their resistance to the fury of the typical Highveld thunder storm? It’s a good question, considering the expected lifespan of a solar PV installation is 25 years or more. It’s bound to see a good many storms in its lifetime.

Fortunately, the answer is certain panels – from reputable manufacturers - stand up very well to the rigours of harsh weather. The key is to select panel arrays capable of withstanding Mother Nature’s rage and ferocity at its worst.

Panels featuring tempered glass, for example, are particularly strong and long-lasting while amorphous panels, combining flexible plastic material, are highly resistant to hail damage and any harm that may occur (unlikely) will not substantially affect the array’s performance.

The strength of solar PV panels is measured and rated in a number of ways. The first rating is for static loading – usually applicable to snow loading - which shouldn’t interest us here in sunny South Africa.

What should interest us is the rating for wind loading. Wind is a much more dynamic force and can fluctuate in intensity rather rapidly. This is referred to as mechanical load.

Solar PV installation by Soltra Energy

While static and mechanical loading are tested in different ways, the combined force a panel can withstand is measured in Pascals (Pa). The normal test threshold is 2400 Pa, but it’s best to choose a panel capable of passing a mechanical load test of 5400 Pa – particularly if it’s going to be part of an array sited in extremely windy areas, such those found along the eastern Cape coastline.

By far the most impressive test of a solar PV panel is for its hailstone resistance. The Class 4 hailstone test (devised by the Renewable Energy Test Centre in California) subjects solar PV panels to multiple impacts from 50mm diameter hailstones – bigger than golf balls – frozen at minus 17degrees, at terminal velocities of 76 metres per second or a staggering 400-plus km/h. Panels that pass this test represent the very best available.

So, if you are in the market for a rooftop solar PV installation, take out good insurance in the form of a quality solar panel array from a reputable supplier and breathe easy for 25 years or more.

  

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Power storage for all with Tesla’s new Powerwall

Power storage for all with Tesla’s new Powerwall

By Jack Ward, CEO of Soltra Energy

One of the most exciting announcements in the renewable energy arena has come from Elon Musk, CEO and chief product architect of Tesla Motors, and chairman of SolarCity. 

His Tesla Powerwall battery system represents a game-changer in this industry sector. It is a development stemming from Tesla’s pioneering work in bringing affordable lithium-ion (Li-ion) batteries to market for the company’s successful electric vehicles - the Tesla Model X and Model S.

The Tesla Gigafactory - currently being built in Nevada in the US - will mass- produce these batteries, bringing a-step change in terms of reducing Li-ion battery costs to market.

How will this be achieved? Tesla will use its considerable automotive experience to package Li-ion batteries into attractive, space-saving wall-mounted units. The Powerwall’s design will allow batteries to be mass produced and installed safely in homes and businesses - by the tens of thousands.

Powerwall is a boon for the solar photovoltaic (PV) industry because it brings to market an electrical storage unit that’s three to four times cheaper than conventional lead acid-based batteries.

Technically, lead-acid batteries have not really improved since their introduction some 150 years ago.  Now, thanks to Tesla, every solar PV installation - grid-tied or not – should be configured around electrical storage with a view to significantly improving the availability of supply and the overall return on investment (ROI) of the solution.

Unlike lead-acid batteries that degrade drastically if discharged by more that 30-40%, depth of discharge (DoD) is no longer an issue with the Tesla Powerwall. 

Li-ion holds great promise, as the battery can be fully discharged in every cycle. What’s more, the Tesla Powerwall will last as long as 20 years and comes standard with a 10-year guarantee.

Good news is that in South Africa there is currently no import duty on Li-ion batteries (unlike automotive lead-acid batteries) bringing solar PV systems ever closer to economic viability and parity in terms of costs with increasingly expensive Eskom power.

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Electricity consumers search for new solutions

Electricity consumers search for new solutions

By Bevan Jones, Soltra Energy MD

In the face of Eskom’s supply uncertainty and price hikes, consumers are on the lookout for new, innovative alternatives. This was evident at the recent Power & Electricity World Africa 2015 show in Johannesburg where Soltra Energy took the opportunity to launch its new high capacity Soltra GTB 10 000.

This is a 10 kVA capacity, utility grid-connected, hybrid solar photovoltaic (PV) power system suitable for small-to-medium-size enterprise and domestic markets. Ideal for roof-top installation, it offers a greater degree of backup battery autonomy and is thus geared for load-shedding.

Our belief, that the Soltra GTB 10 000 is a good fit for consumers’ current mind-set, was borne out at the show by the many interested visitors who took time to call at our stand.

They confirmed what we already believed: There is burgeoning interest in rooftop solar PV power solutions for domestic, commercial and industrial applications. It is gaining momentum on an almost daily basis as our parastatal power provider lurches from one crisis to another.

Without doubt, consumers from all sectors of the economy are keen to reduce their reliance on Eskom. Concern over power reliability, price hikes and the lack of leadership at the highest levels was reaffirmed by almost all our visitors.

It became crystal clear that the current trend is away from generators – which are often seen as too noisy for domestic use. Solar power - nature’s free alternative - is gaining ground as it is becoming an attractive, cost-effective solution, particularly when Eskom’s new pricing structures are taken into account..

In this light, our new Soltra GTB 10 000 functions as a back-up rather than a complementary power source in the event of a power outage. This sets it apart from conventional solar PV power systems.

For the technically minded, the 10 kVA capacity unit is a hybrid solar PV power system that can be operated in three modes: linked to the electricity grid (grid-tied); as grid-tied unit with battery backup (in a hybrid configuration); or as a stand-alone hybrid unit. In line with uninterruptible power supply (UPS) and other conventional solutions, switchover time from mains to batteries is a rapid 15 milliseconds. 

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