SDC SAP PV 2005 and 2009 Online Calculation (version 1.1) of Annual Solar Contribution

The Energy Software Online Calculation based on the United Kingdom Government's Standard Assessment Procedure (SAP) for Energy Rating of Dwellings (2009 Edition). Results are provided for comparison with the manual calculation for SAP. All results below should be checked against the published manual calculation where mission-critical.

The following calculation provides a theoretical annual thermal energy yield figure generated from a typical solar photovoltaic system (PV) fitted in the UK. This figure is used as part of a longer assessment within the ‘Standard Assessment Procedure’ (SAP) which is intended to provide the UK government with an average estimate of energy of a whole house which is independent of geographical location as well as individual electrical usage. SAP also provides a general basis to report carbon dioxide mitigation.

The resulting figure on this site is intended as a comparative guide and should be checked against the published manual method before using this to complete a full SAP calculation. The calculated figure shown here should not be used alone as indicative solar performance as other factors will be required in SAP for the complete analysis of the electrical energy system. For example electrical appliance efficiency is not considered here.

The calculated SAP figure for solar PV will have reduced accuracy in the following cases:

• Complex shading and string layouts
  
• Coastal, mountainous or extreme UK latitudes
  
• Non-domestic properties
  
• Off gridsystems
  
• Systems not meeting UK Wiring Regulations guidance
  
• Multiple arrays and inverter combinations
  
• Extreme inverter or module values
  
• Time periods less than a whole year

Full details are available from BRE in the official SAP documentation. For reference the formula used on Electricity produced per PV array (kWh/a) = 0.8xkWpxSxZpv. The calculated values (Combined (SAP 2005 and 2009)) shown here in bold are automatically calculated when the boxes are completed. If you require further clarification of the terminology and units used for the SAP calculation, you are recommended to read Appendix M of the SAP document which can be viewed for SAP 2005 or SAP 2009.

For those interested in more detailed calculations, simulation software is highly recommended. This allows you to take into account shading and degredation over time, ultimately providing far more accurate and reliabile projections of output for decision making. Which PV*SOL is for me

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