Upgrade to a grid-tied solar PV system
Small scale embedded generation (SSEG)
SSEG refers to renewable power generation under 1 Megawatt, located on residential, commercial or industrial sites. SSEG systems are connected to the wiring on the customer’s premises, which is in turn connected to, and supplied by, the municipal electrical grid - thus these generators are considered to be ‘embedded’ in the municipal electrical grid.
Most of the electricity generated by an SSEG user is consumed directly at the site. However, there may be times when generation exceeds consumption, and typically a limited amount of power is allowed to flow onto the municipal electrical grid. One of the major advantages of such a municipal electrical grid connected system is that it eliminates the need for backup batteries that stand alone (or off-grid) systems require.
Solar photovoltaic (PV)
Solar PV panels that are mounted on the roof of a residential, commercial or industrial building are SSEG installations that convert solar energy into usable electricity. A PV system is made up of solar cells that are connected in a way that points them toward the sun, which an inverter then converts from direct current (DC) into usable alternating current (AC).
The size, layout and configuration of a solar PV system will differ, depending on the use of the system, size of the building, the energy demand and consumption pattern (load profile) and the ability of the municipal electrical grid-operator to allow the system to be grid-tied and feed back onto the municipal electrical grid.
Feeding-in to the Municipal Grid
Many municipalities across the Western Cape already have the rules and tariffs in place for feeding into the grid when installing a PV system. The remaining municipalities across the province are being supported by the Western Cape Government and GreenCape to design and implement appropriate feed-in tariffs and approve the necessary regulations. The below table indicates the status of the municipalities which allow SSEG.
To find out more details on the municipalities that have the necessary legal framework click here.
It’s important to note that feeding-in requires permission from the municipality. However, installations that are off-grid don’t require permission. The below document provides more details:
For a more detailed outline of the requirements for a safe and legal rooftop PV installation in the City of Cape Town click here. This is a good guideline to follow and the general steps would apply in most other municipalities in the Western Cape that allow SSEG.
For an info sheet which explains the SSEG tariff in the City of Cape Town click here.
The Solar PV System
The figure below provides an indication of the layout of a solar PV system connected to the City of Cape Town's municipal grid.
The same components will be used in all solar PV installations, with a similar set-up in most municipalities which allow feed-in.
Understanding the Costs and Benefits of Solar PV
It’s important to remember that PV is not an all-encompassing solution.
Solar PV does:
- Provide price security for customer.
- Provide electricity supply security for customer.
- Provide additional supply in supply- constrained areas.
- Promote changes in the customer load profile, thus adding options for other energy security options.
- Support Eskom with room for maintenance by removing some of the demand on their systems.
- Add diversity to the South African energy mix.
BUT Solar PV does not:
- Stop load shedding.
- Reduce peak demand. There’s a misalignment between peak PV generation (midday) and average peak demand (early morning and late evening), unless battery storage is installed.
- Protect against rising cost of peak-time energy, unless battery storage is installed.
The cost of installing a solar PV system is driven by the following elements:
- the solar panels,
- the inverter, and
- the balance of system costs (installation and commissioning and project development).
The equipment components of the solar PV system make up the majority of the overall cost, with the solar panels and the inverter accounting for almost 80% of total costs. The installation, commissioning and project development account for the remaining 20%.
The financial viability of solar PV is dependent on a number of different factors:
- Installation size: larger projects produce cheaper electricity as fixed costs, such as design and specification, are spread over more panels.
- Technology choice and exchange rate: prices still vary and some components need to be imported.
- Location, roof type and direction: influence the amount of sun reaching the solar panels.
- Financing model: depends on the client's risk profile or financial standing.
- Current electricity tariff: solar PV's viable increases as electricity tariffs increase.
- Consumption patterns: Eskom charges a peak charge during periods of highest use (typically, in a business context, during the day). Generating one’s own electricity (also most effective during sunny periods) results in greater savings.
Below is a table which provides a Solar PV price benchmark for SSEG systems. Please note that this is approximate as at June 2018.