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Backtracking Performance Ratio

With backtracking, trackers can show a significantly higher performance ratio (PR) than standard tracking, even when the energy yield is similar. This is a consequence of the PR defintion:

\[ PR = \frac{E\_Grid}{GlobInc \times PnomPV}\]

Where E_Grid is the energy injected into the grid, GlobInc is the total irradiance in the plane of incidence (POA irradiance), and PnomPV is the nominal power of the PV system. In a backtracking system, GlobInc is reduced due to intentional misalignment of the trackers (see cosine effect). This artificially boosts the PR, because the loss from misalignment is not reflected in the PR.

In contrast, non-backtracking systems have optimal GlobInc, but experience mutual shading. This shading loss is counted as a system loss and is included in the PR calculation, leading to a lower PR.

It is therefore advised to use a different metric to compare systems, such as the Produced energy (E_Grid) of the Specific Production.