Does solar work during load shedding?

As long as it is light, solar modules will be producing power. However, there is a misconception that a solar PV system will prevent load shedding – it’s actually a bit more complicated than this.

Firstly, there are different types of solar PV systems: grid-tied, off-grid (microgrids), and islandable on-grid microgrids. In South Africa, grid-tied solar PV systems are most commonly used, as these are the most affordable and have the best business case.

Unfortunately, grid-tied solar PV systems will generally be programmed to switch off during load shedding. Why is this? It comes down to international safety standards. Solar modules generate DC electricity, but this needs to be converted into AC to be used in buildings. As such, solar inverters are used to convert the electricity.

During a grid outage (such as Eskom’s load shedding), the solar inverters are designed to switch off. This serves as protection for grid personnel that might be working on transmission lines during outages. If buildings continue to generate power during a grid outage and potentially export power to the national grid, it could be fatal for maintenance personnel who are unaware that there is live electricity in the lines when the grid is off.

As such, grid-tied inverters cannot operate in off-grid conditions. However, it is possible to form one’s own “on-grid” microgrid, that essentially fools the inverters into thinking that they are grid-tied, but keeping them off-grid to maintain safety. This requires the use of a generator or battery and specialised control equipment. We have covered the article in depth, in our blog about options for C&I buildings during loadshedding.

How does solar power work?

Solar photovoltaic (PV) panels contain a semiconductor material (typically silicon-based) which converts sunlight into direct-current (DC) electricity. An on-site inverter converts the DC power to AC power, which can then be connected to a building’s power supply or directly to the electricity grid.

What makes SOLA different to the other solar companies out there?

At SOLA, we believe that Africa’s future relies on affordable, clean and accessible energy. Our highly-skilled team is committed to working for the greater good and we take pride in facilitating Africa’s prosperity through our clean and reliable energy systems. SOLA is able to handle projects of any size over 100 kW from feasibility, to design, through to procurement and construction. With over 12.5 MW of solar installed over the last four years and ISO 9001: 2015 quality assurance, we are able to provide a wealth of knowledge and experience to our clients. Contact us to be part of Africa’s growth story.  

Does solar make sense for my building?

​Perform a spot check to determine if your roof if free of shaded by trees, mountains or other buildings?  Is your roof is flat or mainly sloped in a northerly direction and has an uninterrupted northern exposure? If you have answered ‘yes’ to these questions your home, office or building may be ideal for solar PV.

What factors influence the economics of a solar system?

This is determined by a number of factors, including geographic location, specific energy consumption tariff, slope and shading of roof structure or piece of ground where solar panels will be mounted.

Is net metering allowed in South Africa?

A national legal framework for commercially viable net-metering schemes that would boost the residential and commercial PV roof segments is being developed. Certain municipalities are now allowing a limited amount of excess energy generated by solar systems to be off-set against energy usage, while others are now are allowing bi-directional metering: where consumption is billed at a pre-determined rate, and energy fed back into the grid is reimbursed to the consumer at a separate energy rate.

What incentives are available?

Currently, Eskom’s Standard Offer Program (SOP) subsidy is on hold, and is not available for solar projects. It is Eskom’s view that this program will be reintroduced to assist in incentivizing the installation of more renewable energy projects, which will assist with South Africa’s energy shortages. South African revenue Services (SARS) has introduced S12B accelerated wear & tear allowance, which allows businesses to write off any capital costs spent on renewable energy systems as a deduction against taxable income within the first 3 years of ownership of that asset.

Does my region get enough sun for solar power to make sense?

​South Africa has some of the world’s best solar resource. Certain parts of the country such as the drier interior experience better solar irradiation than others. However, solar energy can work just about anywhere, and even South Africa’s poorest solar resourced region experiences substantially higher solar irradiation than Germany, which as a country has the world’s most solar installed.

Will the panels work on our older roof structure? Can our roof take the additional load?

Solar Panels weigh around 12-14kg/m2 which is typically well within the capacity for roof loads. However, there are some roofs that may be unsuitable to handle additional loading. This is usually not related to age, but more to the design of the roof itself. Before proceeding with an installation, SOLA undertakes a structural assessment by a professional structural engineer to ensure that the potential installation would safely within the load-bearing capacity of the roof.

What does the Operations and Maintenance (O&M) service include?

The Operations and Maintenance service includes several activities to monitor solar system performance and detect errors early on, ensuring the overall efficiency of the system for its lifetime. These services generally include:

  • Monthly Reports showing PV performance, energy, demand and financial savings
  • On-site support and maintenance of solar systems, including fault fixing and routine cleaning
  • Comparison of PV performance with on-site irradiance
  • Access to an Online Portal to see live plant performance
  • Annual Report with financial and plant performance results
  • Continuous performance monitoring and alarm triggers indicating necessary remedial work
  • Access to highly experienced professionals for advice and queries on a range of topics related to Solar PV

Can solar and batteries help us to bring down our peak demand, even if our peak is early mornings?

Peak demand is a significant contributor to your electricity bill and if you are mostly a daytime energy user, then your demand is likely to happen during the day. During sunny months, the chances are good that with the implementation of solar PV, your peak load will be reduced significantly, because the injection of solar PV coincides with the peak use in the building during the day. A battery solution, which stores energy during non-peak times and discharges during peak usage hours, can further supplement this and increase demand savings, particularly with a demand peak in early morning or evening.

I use power at night, how will solar help me?

Despite using energy at night, a solar PV installation, coupled with batteries, could still be a fantastic solution. Nighttime energy users can make use of PV energy by storing the excess produced during the day in a Lithium Ion battery.  The battery will be charged  during the day by solar energy, and can then be discharged when the power is required during the evening hours when the energy is required.  The batteries can also be cycled for peak demand minimization which will make the business case even stronger.

What happens if my business shuts down after hours, but the solar system is still generating energy?

This depends on which grid your building or facility is connected to. Municipalities such as the City of Cape Town offer a reverse feed tariff, meaning that you can sell excess energy back to the grid and recoup costs. However, not all municipalities offer this facility. SOLA designs systems to maximise self-consumption and minimise reverse feed, because generally the feed-in tariff is lower than what you would pay for energy.