May play a key role in regulating the relative amounts of cyclic and non-cyclic electron flow to meet the demands of the plant for ATP and reducing power. H(+) + NADP(+) + 2 reduced [2Fe-2S]-[ferredoxin] = NADPH + 2 oxidized [2Fe-2S]-[ferredoxin] Energy metabolism; photosynthesis. In the vicinity of the photosystem I in the non-stacked and fringe portion of the membrane. FNR is probably attached to the membrane by a specific binding protein. Belongs to the ferredoxin--NADP reductase type 1 family.