GENERAL Q&A

What is a PV solar system?

A PV solar system, also known as a photovoltaic system, converts sunlight into electricity using solar panels made of semiconductor materials.

How do PV solar systems work?

PV solar systems work through the photovoltaic effect, where sunlight interacts with the semiconductor material in solar panels, generating an electric current. This direct current (DC) is then converted into usable alternating current (AC) electricity by an inverter for powering homes, businesses, or feeding into the grid.

What are the components of a PV solar system?

The main components of a PV solar system include solar panels (composed of PV cells), mounting structures, inverters (to convert DC to AC), wiring, and sometimes battery storage systems for energy storage.

Which battery should I use with my solar kit?
  • The battery storage options are mostly dependent on your budget.
  • We would advise for everyone to invest in lithium-ion batteries as they offer great warranties and also excellent performance. Unfortunately, lithium-ion batteries are expensive.
  • But there is not a one size fits all type of battery. Every system or solar setup requires a specific battery storage solution with specific battery types meeting your needs and your budget.
  • You can choose a battery depending on how much work you’re willing to do for battery maintenance versus the cost related for the battery you want to install.
What are the advantages of PV solar systems?

Some advantages of PV solar systems include renewable energy generation, reduced electricity bills, low maintenance requirements, long lifespan (typically 25 years or more), and environmental benefits such as reduced greenhouse gas emissions.

How long do PV solar systems last?

PV solar systems can last for 25 years or more with proper maintenance. Solar panels typically come with warranties ranging from 20 to 25 years, but they can continue to generate electricity beyond the warranty period.

What are the challenges of PV solar systems?

Challenges of PV solar systems include high upfront costs, intermittency (dependence on sunlight availability), energy storage limitations (for off-grid systems), land use requirements, and potential aesthetic concerns.

Can PV solar systems work during cloudy days?

PV solar systems can still generate electricity during cloudy days, although at reduced efficiency compared to sunny days. However, modern solar panels are designed to capture diffused sunlight, allowing for some electricity generation even under overcast conditions.

Are PV solar systems suitable for all locations?

PV solar systems are suitable for most locations with sufficient sunlight exposure. However, factors such as shading, orientation, tilt, and local regulations may affect the feasibility and efficiency of solar installations.

Are PV solar systems environmentally friendly?

Yes, PV solar systems are environmentally friendly as they produce electricity without emitting greenhouse gases or pollutants. They contribute to reducing reliance on fossil fuels and mitigating climate change.

TECHNICAL

What is Photovoltaic Technology?

‘Photovoltaic’ is a marriage of two words: ‘photo’, meaning light, and ‘voltaic’, meaning electricity. Photovoltaic (PV) panels form part of a complete solar system to generate energy from sunlight.

Photovoltaic technology is the term used to describe the hardware converting solar energy into usable power. At the heart of this technology is a semi-conductor material which can be adapted to release electrons. The most common semi-conductor material used in photovoltaic cells is silicon — an element most commonly found in sand. Silicon is the second most abundant material on Earth!

Solar panels are comprised of a series of cells. All these cells have two layers of semi-conductors: one positively charged and one negatively charged. When light shines on the semi-conductor, the electric field between these two layers causes electricity to flow, generating direct current.

The greater the intensity of the light, the greater the flow of electricity. A PV system does not need bright sunlight in order to operate. It can also generate electricity on cloudy days. Due to the reflection of sunlight, days with slight cloud can even result in higher energy yields than days with a completely cloudless sky.

With South Africa’s long sunny days, PV technology is the perfect way to generate power from such an available (and renewable) source.

What is kWh or kilowatt per hour or Utility Unit?

A kilowatt-hour (kWh) represents the amount of energy consumed or produced by a device with a power rating of one kilowatt (kW) operating for one hour. It’s a standard unit used by utility companies to measure electricity usage on consumer bills and is also used to quantify the output of electricity-generating systems like solar panels.

In easier terms:

a Utility Unit ( As indicated on Utility Bill ) is equal to 1kW or 1000W power of electricity used.
Example. a 100W Globe that burns for 12 hours will use 1.2kW or 1200W of power during the 12 hours.

If you power a 100watt light bulb for one hour, you are basically using 100watt hours.
If you power the 100watt light bulb for 10 hours, you’re at a 1000watts per hour or 1 kilowatt per hour. over the 10 hours.

A hairdryer is running at 1000watts, if you power it for one hour, that will consume 1 kilowatt per hour or (kWh). All electrical appliances have different electricity ratings and how many watts they will consume every hour. Wattage multiply the amount of hours will give you the kWh per hour.

What are the different types of PV solar systems?
OFF-GRID

Operating totally off the grid requires a large capacity battery array capable of powering the property during periods of low irradiance in winter and an inverter capable of supplying the maximum load ever required at one time. This requires a significant investment in PV modules, inverters and especially batteries which cannot normally be justified if there is a good quality grid connection available at the property. An off-grid system is well suited to rural areas with little or no grid connection but is unlikely to be a viable solution in a well-connected urban area. Should however fixed connection charges for electricity become more common and higher then disconnecting from the grid may become a more viable option in the future.

GRID-TIED

A pure grid-tied system with no storage or load management for a user with fixed rate power charges is a viable option for South Africa but the system will need to be significantly under sized to minimise the wasted energy generation as typically no surplus power can be exported. Essentially the PV system has to be sized to generate only sufficient power for the base load during the day, i.e. the fridge, freezer, pool pump and other permanently on devices. The low investment cost of a small PV system with a high self-consumption rate should make them quite attractive especially for households with family at home during the day.

GRID-BACKUP

If frequent load shedding continues each winter then there will be continued demand for grid-backup systems that can operate with no grid for prolonged periods of time. Adding a battery inverter or a hybrid inverter along with a battery makes it possible to combine the energy from the PV system with that from the stored battery to power at least the essential loads in the property. The size of the battery required depends on the rating of the essential loads to be driven from it at times of no solar power being available. Load shedding typically occurs during the evening peak in winter from 5:00PM – 10:00PM so there will normally be little or no solar power available to supplement the battery. Shown below is a typical system layout for a grid-backup system using a Solar PV inverter and a Battery Inverter which gives maximum flexibility in the system design and can be retrofitted to an existing Solar PV system:  An alternative solution for new installations is to use a combined PV and battery inverter, commonly referred to as a hybrid inverter. This is a multi-function device that includes all the functions required to configure a grid-backup solution:

What factors affect the performance of PV solar systems?

Performance of PV solar systems is influenced by factors such as sunlight availability, system orientation and tilt, shading, temperature, system size and efficiency, and proper maintenance.

What is net metering, and how does it work with PV solar systems?

Net metering is a billing mechanism that allows owners of solar energy systems or other renewable energy generators to receive credit for the electricity they generate and export to the grid. It essentially enables consumers to “bank” excess electricity produced by their renewable energy systems and use it to offset their future electricity consumption.

Here’s how net metering typically works:

  1. Installation of Renewable Energy System: A homeowner, business, or institution installs a renewable energy system, such as solar panels, wind turbines, or hydroelectric generators, on their property to generate electricity.
  2. Generation of Electricity: The renewable energy system generates electricity, which can be used on-site to power appliances, lighting, equipment, and other electrical loads.
  3. Exporting Excess Electricity: If the renewable energy system generates more electricity than is needed at any given time, the excess electricity is exported to the utility grid.
  4. Metering: A bidirectional meter, also known as a net meter, is installed to measure both the electricity imported from the grid and the electricity exported to the grid. This meter records the net amount of electricity consumed or produced over a specific billing period.
  5. Credit for Excess Generation: The utility company credits the consumer for the excess electricity exported to the grid. This credit is typically applied at the same rate as the retail electricity price or at a predetermined rate specified by regulations or utility policies.
  6. Offsetting Electricity Bills: The credits accumulated through net metering are used to offset the consumer’s electricity bills in subsequent billing periods. If the consumer’s electricity consumption exceeds their generation during a billing period, they will use their credits to offset the cost of electricity from the grid.

Net metering allows consumers to benefit financially from their investment in renewable energy systems by reducing their electricity bills and providing a mechanism for compensating them for the electricity they contribute to the grid. It promotes the adoption of renewable energy technologies and helps to integrate distributed generation into the electricity grid.

What is the Best Battery Solution ( Battery Guide )

The choice of a battery is one of the most critical decisions that needs to be made when designing a grid-backup or enhanced self-consumption solar PV system. The two main types of battery commonly chosen for solar PV systems are Lead Acid and Lithium Ion with various different specific types and products from many different manufacturers available on the market. The table below gives a summary comparison of the key attributes of these two different battery technologies.

Attribute Lead Acid Lithium Ion
Total Storage Capacity An individual lead-acid battery will typically have a gross storage capacity of 100Ah – 200Ah @ 12V or 1.2kWh – 2.4kWh. They may be connected in series for a higher voltage and/or in parallel for greater capacity at the same voltage. A typical lead-acid pack suitable for a residential grid-backup solution will be in the range of 8kWh – 25kWh depending on the length of time required to operate off-grid and the total power of the loads to be supported. Lithium Ion battery packs typically are supplied as self-contained units with a built-in battery management system (BMS). Gross capacities vary from about 2kWh up to 8 – 10kWh depending on the model and manufacturer. Some models may be connected in parallel, others may be extended with expansion packs and all need to be fully supported by the software in the battery charger/inverter chosen.
Daily Usable Capacity There is a close relationship between the amount of the total battery capacity that is used each day and the life of the battery as expressed by the number of cycles and typically it is recommended to only discharge a lead-acid battery down to about 50% of the total capacity of a lead-acid battery, this if referred to as a 50% Depth of Discharge (DOD). This makes the storage capacity available for daily use only 50% of the gross storage capacity. Most lithium-ion batteries can be used daily down to about 90% of their gross storage capacity with little or no impact on their lifetime in terms of number of cycles. This makes the storage capacity available for daily 90% of the gross storage capacity.
Full Cycle Efficiency Lead-acid batteries tend to get less efficient the nearer to full capacity they reach which either results in a low full cycle efficiency of less than 80% if they are re-charged near to their full capacity or designing the system to only use about 80% of their full capacity in order to maximise their efficiency. Most lithium-ion batteries have a full cycle efficiency around 95% even for a cycle from their full depth of discharge up to full capacity making them ideally suitable for daily use applications like solar PV systems which need to use most or all of their retained energy in the evening/night and charge up again fully during the day.
Lifetime (Cycles) The number of cycles that a lead-acid battery can be used for is directly related to the amount of energy charged and discharged in each cycle. With a system configured to utilise 50% of the gross storage capacity of a daily basis a typical lead-acid battery will have a lifetime of 2,000 – 2,500 cycles. Allowing for some degredation over the life of the battery a useful lifespan of about 5 years in a well designed system may be expected. A good quality lithium-ion battery may have a lifetime of 5,000 – 7,000 cycles which is considerably more than 10 years of normal usage. The built-in battery management system will ensure that the battery condition is always maintained in optimum condition and a full 10 year life may be expected.
Cost The initial investment cost of a lead-acid battery will be relatively cheap when expressed as Rand per kWh of gross capacity but all comparisons should always be done a Rand per kWh of usable capacity which makes a lead-acid battery twice as expensive as it may initially appear. The initial investment cost of a lithium-ion battery may be 2.5 – 3 times more expensive per kWh of gross capacity compared to a similar sized lead-acid battery but when comparing the Rand per kWh of usable capacity the difference will be typically about 1.5 times as expensive. The lithium-ion battery will however last twice as long as the lead-acid so over a 10 year period the lithium-ion will almost always be a cheaper option with no need to renew the battery after 5 years.
Weight A lead-acid battery may weigh between 70kg and 80kg per kWh of usable capacity so a typically 5kWh – 6kWh domestic battery pack may weight in excess of 350kg which may cause difficulty in locating a large battery pack in a residential property as a strong floor will be required. A good quality lithium-ion battery pack will typically weigh between 10kg and 15kg per kWh of usable capacity so considerably less than a equivilant lead-acid pack but a typically residential battery pack will still weigh 75kg – 100kg requiring some consideration as to where to place it.
Charge / Discharge Power Most lead-acid batteries can be charged and discharged relatively rapidly and when connected in parallel the total charge/discharge rate is in effect increased. In a typical solar PV system a lead-acid battery pack may be charged and discharged in 2 – 3 hours with a peak discharge rate much higher for short period of times. Most lithium-ion batteries have a relatively restricted charge/dischage rate often needing 3 – 4 hours to charge and a maximum discharge rate of between 1kW and 2kW for a typical residential system. A system utilsing lithium-ion batteries therefore needs to be designed to take care to only connect essential loads to the circuit that will be powered from the battery pack.
Operating Temperature Lead-acid batteries are significantly impacted by the ambient temperature and an increase from 20c to 30c can result in a 25% reduction in the lifetime as defined by the number of cycles and a 50% reduction in the lifetime as defined in years. Lithium Ion is less impacted by moderate temperature changes and ambient temperatures in the range of 15 – 30 degrees centigrade will not significant impact the lifetime nor performance of the battery.

 

The choice of battery type is not a simple decision with many different factors to take into account but we would always recommend that a comparison is made using the above considerations and looking at the total cost over the life of the system and not simply choosing the lowest initial cost option which in many cases may be more expensive over the life of the system. Equally critical is the size of the battery with one too small providing insufficient benefit and one too large being a significant additional unrequired expense. Detailed below are some of the factors that need to be considered when determining the size of battery required:

 

Attribute Comments
Essential Load Energy Usage

For a grid-backup solution the most important thing to consider is the loads that need to be supported when the grid has failed. It is not generally practical to consider powering all the loads in the property, e.g. an electric oven, geyser and pool pump will all consume considerable amounts of electricity and would require a very large battery to run even for a short time. A good way to consider this is to generate a list of essential energy loads to be backed up and the amount of time they’re needed in a typical day. An essential load is basically something energy must always be available for. This could be something normal like a freezer or burglar alarm, or something site specific like a fish tank. If no power was available, would it lead to loss of (fishy) life or just defrosted ice cream? In the UK, power cuts are relatively rare but for more remote locations or other countries it is definitely worth considering. A lot of loads won’t require their maximum power all the time, so you can add a factor to take that into account. Once that’s done, you’ll have an accurate baseline of energy consumption and be able to consider the appropriate battery capacity.

 

Load Power (W) Time Factor Daily (Wh)
Lights 200 5 1 1000
Fridge 150 24 0.3 1080
Freezer 150 24 0.2 720
WiFi Router 10 24 1 240
Phones 50 1 1 100
Fish Tank 30 24 1 720
TV 170 4 1 680
Other 100 24 1 2400
Total 7690
Battery Operating Time The next critical decision is to decide the number of hours that the system needs to power the essential loads for. Typically a planned grid outage due to load shedding will last for 4 – 6 hours whereas a failure due to a grid fault will typically last for between 1 and 24 hours. The decision on how many hours to allow for is largely driven by the budget available as the cost of the battery pack will be directly related to its size and its size will be directly related to the number of hours chosen. Usually a system will be sized to support the essential loads for between 12 – 24 hours.
Space Available Especially when choosing a lead-acid battery the space available to hold the installed battery and the strength of the floor may be a consideration that imposes a limit on the maximum size of the battery that can be installed. With a Li-Ion battery this is unlikely to be a major concern as a Li-Ion battery will be much smaller and lighter than a similar usable capacity of lead-acid battery.
Charging Time and Rate The battery will be charged from the surplus energy available from the PV system, this is the difference between the energy generated by the solar PV system and that used by the loads during the daylight hours. It is therefore important to ensure that the battery can be fully recharged during a typical day of sunlight, especially in the winter months. A battery pack which is too large relative to the PV system will not get fully recharged and therefore not be fully available to provide power in the event of a grid failure.
Maximum Depth of Discharge Each battery pack will have a recommended maximum depth of discharge, e.g. lead-acid might be 50% and Lithium Ion might be 90%. Having determined the total energy required to be generated from the battery pack with the equation : ‘essential loads energy in 24 hours divided by 24 multiplied by the required battery operating time’ then the gross battery capacity needs to be determined by dividing by the recommended DOD. e.g. 7690W / 24 * 12 hours / 90% DOD = 4272kWh.

Our Services

What Solar package is right for me?

We offer backup battery kits, off-grid solar kits, grid-tied solar kits, and hybrid solar kits.

It all depends on what you require. If you need to be independent of the utility grid or, save money by feeding into the grid and lastly, having the best of both worlds. Unfortunately, in South Africa, grid-tied systems for feeding electricity into the grid, are not available in every region across the country.

Do you offer solar installations?

We can provide you with solar installations in all areas of Gauteng. We make use of solar installer contractors who conducts all our residential solar installations for us.

Are installations included in the prices?

All our products are sold without installation, except if it states otherwise on the product. We supply installers and the public with affordable solar components. But, we can assist with installations if required by our recommended solar installer contractors where required.

Finances

How much money can I save with a PV solar system?

The amount of money you can save with a PV solar system depends on factors such as your electricity usage, local electricity rates, the size and efficiency of your system, available incentives, and financing options. On average, homeowners can save thousands of dollars over the lifetime of their solar system.

Do PV solar systems eliminate my electricity bill?

PV solar systems can significantly reduce or eliminate your electricity bill, especially if your system is appropriately sized to meet your energy needs and if net metering is available in your area. However, factors like system size, sunlight availability, and energy usage patterns will influence the extent to which your bill is reduced.

How long does it take to recoup the investment in a PV solar system?

The payback period for a PV solar system varies depending on factors such as system cost, energy savings, incentives, and financing terms. In many cases, homeowners can recoup their investment within 5 to 10 years, with continued savings over the system’s 25-year lifespan.

Are there any upfront costs associated with installing a PV solar system?

Yes, there are upfront costs associated with installing a PV solar system, including the cost of solar panels, inverters, mounting hardware, installation labor, permits, and any additional components such as battery storage. However, there are various financing options available, including solar loans, leases, and power purchase agreements (PPAs), which can help spread out the upfront costs.

Are there any ongoing maintenance costs for PV solar systems?

PV solar systems generally have low ongoing maintenance costs. Routine maintenance may include occasional cleaning of solar panels to remove dirt and debris, as well as inspections to ensure proper functioning of components. Most reputable installers offer warranties and service plans to cover maintenance and repairs.

Can I make money with a PV solar system?

In addition to saving money on electricity bills, homeowners with PV solar systems may have opportunities to earn money through programs such as net metering, where excess electricity generated by the system can be sold back to the grid for credits or payments. Additionally, some regions offer incentives or feed-in tariffs for solar energy generation.

Will installing a PV solar system increase my home's value?

Research has shown that installing a PV solar system can increase a home’s value. Homebuyers are often willing to pay a premium for homes with solar panels due to the long-term energy savings and environmental benefits they offer. However, the exact increase in home value may vary depending on factors such as local market conditions and the size and efficiency of the solar system.

Are there any tax incentives or rebates available for installing a PV solar system?

As of the last update in January 2022, South Africa had various tax incentives and financial mechanisms in place to promote the adoption of renewable energy, including photovoltaic (PV) solar systems. Here are some of the key incentives related to PV solar installations in South Africa:

 

  1. Income Tax Allowance for Renewable Energy Projects: South Africa offers tax incentives for businesses investing in renewable energy projects, including PV solar installations. These incentives may include deductions or allowances for capital expenditure incurred on renewable energy infrastructure.
  2. Accelerated Depreciation: Businesses investing in PV solar systems may be eligible for accelerated depreciation allowances, allowing them to depreciate the cost of the solar assets more rapidly for tax purposes.
  3. Section 12B Tax Allowance: Section 12B of the South African Income Tax Act provides for an additional tax deduction for energy efficiency savings achieved through renewable energy projects, including PV solar installations.
  4. Renewable Energy Tax Credits: Some municipalities or provincial governments in South Africa may offer tax credits or rebates for businesses or individuals installing PV solar systems. These credits can offset a portion of the upfront costs of the installation.
  5. Value-Added Tax (VAT) Exemption: In South Africa, certain renewable energy technologies, including solar PV panels, inverters, and batteries, may be exempt from VAT. This exemption can help reduce the overall cost of installing a PV solar system.
  6. Carbon Tax Offset: South Africa has implemented a carbon tax, which aims to incentivize businesses to reduce their greenhouse gas emissions. Investing in PV solar systems can help businesses reduce their carbon footprint and potentially offset carbon tax liabilities.
  7. Feed-In Tariffs (FiTs) and Net Metering: While not directly related to tax incentives, feed-in tariffs (FiTs) and net metering policies allow PV system owners to sell excess electricity generated by their systems back to the grid or receive credits for it. This can provide financial benefits by reducing electricity bills or generating additional income.
How can I estimate the potential savings from a PV solar system for my home?

You can estimate the potential savings from a PV solar system by analyzing your current electricity usage, understanding local electricity rates, considering available incentives, and consulting with solar installers for quotes and savings projections based on your specific circumstances.

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