"access to energy is a basic human right"

"Every home in South Africa deserves to have access to solar energy"

"Breaking the shackles binding us to crippling electricity tariff increases"

Solar Solution Size

How we will determine what size solar solution you need

Our research indicates that the Storage-Enabled Solar Solution is the product of choice for most South Africans.  We've designed our own standards and protocols for sizing such a system, taking into consideration all the complexities involved, such as the users’ load profile, the geographic location and variations in municipal tariff structures.


  • Load Profile:

    This refers to the amount of energy consumed in a home (or school) at hourly intervals over a period of 24 hours, seven days a week per month per year. This allows us to ascertain the kilowatt hours consumed at various times of the day and ultimately the amount consumed on a daily and monthly basis. In the past, this would require monitoring systems to be installed and managed for months before any meaningful data could be evaluated. Blackwood Power’s analysts have circumvented this tedious procedure by constructing probability consumption curves based purely on an analysis of a users last six months electrical bills. In essence, users will fall into one of three different profile groups; Low, Medium or High, broken down into seasonal variations between Summer, Winter and combined Spring/Autumn profiles.


  • Geographic Location:

    The important variables contained here refer to the peak sun hours experienced by the property at different times of the day, taking into consideration the orientation of the roof hosting the solar panels, the roof pitch and shading effects caused by trees or structures. An inescapable fact is that some areas of South Africa are better suited for solar installations than others and geographic location plays an important part in helping us to decide where and when we’ll be prioritising our installation roll-out.

    B&W Best Solar SA Map

  • Municipal Tariff Structures:

    Different municipalities charge different rates for electricity and even within a single municipality it may charge a variable rate depending on user consumption. Blackwood Power has captured the tariffs for most municipalities throughout South Africa, allowing us to evaluate and compare regions, which has helped us to plan and design our installation roll-out strategy.




Sizing Calculator


Blackwood Power has built an enormous database that contains the relevant variables that determine what size solar solution is required for a specific location. The calculator draws on the Load Profile probability curves generated for a particular household (or school), imports the information obtained from the Geographic Location and plots the Municipal Tariff the property falls within. All that is required from the operator is to input the end-user’s average monthly electricity bill and select the relevant municipality from the drop-down menu. The tariff is computed against the other variables and a solar size, represented by the number of 250 watt solar panels required to provide an optimum solar solution, is calculated.

Once the tariff is measured against an individual user’s consumption profile, we ascertain if that specific individual falls within a financially viability zone; those who have a high consumption and pay high tariffs are considered to be in the “Distressed Zone” whilst those paying low tariffs and have low consumption will fall within the “Stay Zone”, meaning that the user should not consider a solar solution for economic reasons but should rather stay until new electrical tariffs push them to a higher zone.