3.2. Energy Consumption Records#

Energy consumption records are the recent historical Load Demand. This information together with anticipated changes in consumption is used by the PCC model to predict future Load Demand. In PVPlant modelling, Solar Energy production offset Load Demand time-step to time-step. If the projected load-demand is not accurate, these inaccuracies accumulate as the Load Demand after Solar Offset will not be accurate, billing will not be accurate, and nor will any of the resulting financial modelling, leading to poor decision-making from inaccurate results.

3.2.1. Smart Meter Logs#

If the site has been upgraded to a 4 quadrant measuring smart meter then the client’s consumption information is collected remotely by its electrical supply authority, and stored in a database accessible by the client. Sometimes clients have not applied for access to this database.

Form Mandela Bay, Eastern Cape, an application form for access can be found here

When filled in, the application can be submitted to ecwin@mandelametro.gov.za.

For those unfamiliar with ECWin, once logged in:

  • Menus are found at the bottom in status line

  • Select Reports & Profiles

  • Select Profiles

  • Under entity selector select the devices, the Selected Items window will populate.

  • Under Timespan, select the month to yymm to review.

  • Keep the Chart type defaults - Profile Type = Standard and Data Class = Int Period.

  • Under layout and Selection - Press View.

  • In the Main data window switch between profile and Data.

  • In the Data tab, select Export values.

Smart meters log instantaneous P (kW), S (kVA) and Q (kVAr), every half hour. These records can be downloaded in monthly quanta. PVPlant requires the most recent year’s data, ending at the prior month.

Energy usage is calculated by treating the instantaneous value as if it was the value between the previous time-step and this. Energy (kWh, kVAh, and kVArh) is calculated by multiplying the instantaneous values by 1/2 hour, and treating them as the energy between the previous time-step and this time-step.

PVPlant’s time-step energy convention is energy values at a time-step and next. To be consistent, the smart meter’s logs time base nees to be shifted back by a half hour.

3.2.2. Billing Records#

If Smart Meter Logging is not available, then the next best (a far second) is the consumption values from billing records. Many assumptions are made as to the consumption profile, which detracts from an accurate consumption model. When using billing records, any following consumption and financial projections will not be definitive, and perhaps a guide or ballpark figures. The PCC model will attempt to flesh out a 17 520 record database from the values in 12 billing records.