Quote:
Originally Posted by wordwiz
I would guess about 156-280 watts per second on a sunny day when clouds are not blocking any radiation. This is at the equator, where banana trees grow well.
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When doing co-registration for remote sensing with EOS sensors, we obtain on average about 300 Watts/sq. meter for the given scenario. Using a measure of 4 sq. meters per plant brings the total to 1200W. The bulbs are at 1 meter from the plants and at peak output (factory fresh) are 2000W, but since energy drops off with distance we get about 1200W incident on the plants. Further, full power is only used part-time during 3 seasons and nearly full-time in the winter. Most agricultural sites of this type have free (deeded) water, power (e.g., geothermal), or both.
Growth is not enough. Farmers are trying to fruit these plants in a timely fashion -- 12 months or less brings an acceptable profit margin. The energy inputs used for poinsettias in a greenhouse, tomatoes in tunnels, cucurbitoids in warehouses, and fruiting bananas in orchid shelters are all different. Here in San Diego county, we don't bother with assisted lighting for poinsettias -- in fact we have the opposite problem so we use growth regulators.