Dejargoning solar: from A to Z

Simplifying common terms you will find in the solar industry.

What is Solar Energy?

Solar energy is the radiation from the sun that can produce heat, cause chemical reactions or generate electricity. The sun is Earth's greatest resource; it is in abundance and clean, and harnessing it is key to fighting climate change and creating a sustainable future.

For millennia, humans have harnessed the sun's chemical and heat reactions for domestic and industrial applications; now, the excitement is around using the sun for electricity generation. Solar electricity generation technology has made significant advancements in the last few decades, making it a viable alternative for domestic and industrial applications.

Where do I even start when looking for a Solar Energy solution for my business?

Due to inflationary pressures and the international supply market, energy prices are rising and you don't want them to affect your business. A solar solution can help you lock in energy prices for decades and reduce the cost centre in the long run. You know that South Africa has lots of sun and you wish to switch to renewable energy. That's smart, but where do you start?

Start by understanding the terminologies. Every industry has its language, and the energy sector is no different. Understanding the terminology will help you discern what you need and how it can fit into your operations.

  • AC - Known as Alternating Current which is an electric current that periodically reverses direction and changes its magnitude continuously with time.

  • Alternative energy - Alternative energy is a catch-all term for new kinds of energy, namely renewables and nuclear energy. It became popular when the world was still heavily reliant on coal, petroleum, and diesel, so any form of energy other than those is usually known as an alternative.

  • Azimuth - The orientation / angel of the solar panels to the sun.

  • Base load - The minimum level of power used on an electrical grid over a period of time.

  • Cash purchase (all-cash purchase) - is when a user purchases the entire solar energy system in a single immediate payment. It's an option for those with the funds available and who want to lock in their energy costs in advance.

  • Consumption- is the amount of electricity you use over time; measured in kilowatt-hours (kWh).

  • DC - Known as Direct Current which is an electric charge that flows in one direction.

  • Electricity tariff -  is the price you pay per unit of electricity to your energy utility and is measured in a currency of kilowatt-hour (R/kWh).

  • Eskom - is a government-owned organisation that generates and distributes electricity in South Africa. It is responsible for the nation's power grid.

  • Feed-in tariff - a tariff that is paid to you by the local municipality / Eskom for the extra power generated from your solar system that can be fed back into the national grid.

  • Financed solar - refers to a financing scheme for solar adoption. Rather than consumers paying for the switch to solar immediately, they can do it over time but still benefit from immediate savings.

  • First-year energy savings - are a critical metric that measures the savings a solar installation will give in the first year.

  • Grid-tied solar systems - also known as on-grid or connected to the grid, this is any solar system that connects to the national grid, Eskom. It is important to note that these systems cannot operate without being connected to the grid therefore, power outages such as load shedding will still affect these systems from operating if there is no battery storage.

  • Ground mount - is when solar panels are secured to a mounting structure that is connected to the ground with steel beams or another type of metal post. Ground mounts make a great alternative for someone who doesn’t have enough usable roof space or just prefers to not have panels mounted to the roof.

  • Irradiance - The direct, diffuse, and reflected solar radiation that strikes a surface.

  • Inverter - is a device that changes (inverts) direct current (DC) to alternating current (AC). Solar panels initially produce power as DC, so the inverters change it into AC to feed your appliance or the grid.

  • String inverters - are inverters that connect to a series (string) of solar panels. They convert power from DC to AC for the entire solar system for each series of panels; they have shorter cables and are located near the panels. String inverters have a small capacity and are what residential properties use.

  • Central inverters - are high capacity inverters that are larger in size, use longer wires and convert more power than string inverters. Central inverters are for large utility-scale installations such as large commercial or utility (power station) sized solar systems. They offer more efficiencies and economies of scale. They are not for residential use.

  • Kilowatt (kW) - measures how much power is consumed or required at an instantaneous moment in time.

  • Kilowatt-hour (kWh) - is a measure of how much power you are using per hour over a set period of time.

  • Kilowatt peak (kWp) - is the peak power of a PV system or panel. Solar panel systems are given a rating in kilowatt peak (kWp) which is the rate at which they generate energy at peak performance.

  • Mounting system - also known as solar module racking, are the railings, frames and any other structures that enable the solar panels to sit atop a roof or building.

  • National Energy Regulator of South Africa (NERSA) - is the regulator for the energy sector in South Africa. It oversees the electric, petroleum, and gas energy sectors.

  • Net metering - is a billing system that enables solar energy producers (residential and commercial) to sell energy to the grid.

  • Off-grid - is a system that isn't connected to the electrical grid and requires battery storage or a generator in order to operate.

  • Peak demand / load - The maximum energy demand or load in a specified time period.

  • Photovoltaic (PV) - are devices that use sunlight to generate electricity. They use semiconductor material and convert light into direct current (DC) electricity.

  • Power / utility grid - is the network that delivers electricity from the producers to the consumer. The power grid consists of generator stations, transmission lines and towers, and individual consumer distribution lines.

  • Power optimisers - take the DC electricity generated, then connect and optimise it for the inverter. Its purpose is to increase the conversion rate and efficiency of DC to DC energy. Power optimisers are useful in challenging solar installation conditions like a roof with partial shade or multiple orientations.

  • Power-Purchase Agreement (PPA) - or long-term electricity supply agreement is a contract between a power producer and a customer that enables the use of a solar system for a set tariff in return. Most often the agreement includes the insurance, performance monitoring and operations and maintenance of the solar system. 

  • Production - The amount of sunlight (solar radiation) that is converted into electrical energy using solar cells in the form of a solar panel.

  • Roof rental - is a form of solar site lease. The solar services provider pays a fixed monthly payment to the property owner for the use of the building’s roof space, which also produces solar energy for the property. The property owner pays the solar services provider for the energy used based on their current electricity tariff, while all other costs, such as system maintenance, operations and insurance are covered. 

  • Roof structure - the trusses, beams, tiles and any other frame that make up your roof.

  • Rooftop or roof mount - rooftop solar is the most popular type of solar installation, this is when the solar panels are installed directly onto the roof.

  • Small scale embedded energy (SSEG) certification - is a power generating facility (under 100MVA) located on a residential, commercial or industrial site where it is also consumed or wheeled. It usually refers to renewable power generation, such as photovoltaic, wind turbine and biogas power generation. The certificate is a regulatory demand for anyone that generates electricity for others. National Energy Regulator of South Africa (NERSA) is the issuing authority.

  • SSEG tariff rates - is a payment structure that charges and compensates consumers for using SSEG. An SSEG tariff consists of a fixed charge, consumption charge for drawing from the grid, and compensation for what it feeds into the grid.

  • Solar carport - solar panels that are installed on top of a carport / shelter providing shade for parked vehicles and generating electricity from the sun.

  • Solar lease / solar rental - is a financial arrangement wherein the consumer doesn't own the solar panels but pays a periodic (usually monthly) fixed fee to use them.

  • Solar modules - or solar panel is a collection of connected photovoltaic (PV) cells.

    Solar panels:

    • Monocrystalline (Mono) - are monocrystalline solar cells made from a single source of silicone, making them more efficient. They have an octagonal shape and uniform colour.
    • Polycrystalline (Poly) - are a blend from multiple silicon sources and are slightly less efficient. They are blue in colour but up close, the texture and colour are uneven.
    • Thin-film amorphous - is less costly and less efficient than poly or mono panels. Thin-film panels use a thin layer of conductive material on a backing plate made of glass or plastic. They are used for large-scale commercial applications. Because they are thin layers on plastic, they are also more flexible and are what you find on foldable panels.

     

  • South African Photovoltaic Industry Association (SAPVIA) - is an organisation consisting of government agencies and private players advocating for a solar energy future in South Africa.

  • Stable grid - is a state wherein there is equilibrium between the energy produced and consumed. A power grid must respond to volatility in voltage and frequency disturbances, or there will be service disruptions like blackouts.

  • System size - or solar system size refers to the amount of peak DC installed; its measurement is in kiloWatts (kW).

  • Wheeling - is an electric power transmission system that enables the transportation of electrical energy from an energy generator through an established grid network to a remote end-user.  Not all solar energy users can have their panels onsite; wheeling enables solar power generated in the plains of Cape Town to be transmitted (through Eskom grid) to a company in Johannesburg CBD.

  • Yield - or specific yield (kWh/kWp) refers to the amount of energy (kWh) that the installed solar panels (kWp) produce over a year.  The yield can vary according to location, module selection, module orientation, and efficiency, among other factors.

Solar tech is an expanding industry, and you will come across more terms and innovations along the way. With the above terms, you will, at the very least, have a basic understanding of the industry.

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