solar_pv_system_size

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Work out the solar PV system a UK home needs: the capacity in kWp, the number of panels, the battery to go with it, and what it would do to the electricity bill. This runs the MCS arithmetic backwards. The other solar calculators here each answer one question about a system somebody has already specified. This one starts from what a household uses and arrives at the system that covers it, which is the question a householder actually has. The chain is short and every link is published. Annual consumption sets the generation the array has to make. The MCS irradiance dataset behind MIS 3002 says what one kWp makes on that roof, which gives a capacity. Capacity divided by panel size gives a panel count, rounded up, because panels come whole. The MGD 003 tables then say how much of that generation the household will use and how much it will export. Only the postcode and the roof direction are required. Direction is a compass point, not an angle: 'S', 'SE', 'SW', 'E', 'W', 'NE', 'NW' or 'N'. Give the annual consumption from a bill if it is known, since the 3,500 kWh default is only the British average. Shading can be described in words instead of measured, and a roof area caps the panel count where the roof is the constraint. No cost is assumed. Installed prices vary far too much between houses to guess at, so a payback figure appears only when a cost from a real quotation is supplied. Use this to size a system or to sanity-check a quotation. Use 'solar_pv_output' instead when the capacity is already known and the question is only what it will generate. Method from MIS 3002. These calculators follow the published MCS methods, for understanding a system and checking a quotation. Anything that gets installed still needs a design and a site survey from a certified installer.