North-East facing plant (in Southern Hemisphere)

[Elisabeth]

Dear Andre,

I am doing a simulation for a utility scale solar plant in Queensland (Australia) and looking at the sensitivity to various parameters including orientation. The simulations I did gave me the following results:

- North facing = base case

- 10 deg West = -0.3% compared to base case

- 20 deg West = -1.1%

- 10 deg East = +0.3% compared to base case

- 20 deg East = -0.7% compared to base case

I was surprised that the difference was so minimal and more importantly, I can't understand why the production increases for the North-East scenario (10 deg East). All other inputs are exactly the same, I only rotated the scene. I checked the details of the losses and the key difference are the following:

Near shading:

North scenario 2.2%

East scenario 2.6%

IAM:

North scenario 2.6%

East scenario 2%

shading string:

North scenario 0.4%

East scenario 0.2%

So in other words, rotating the plant slightly East seems to increase slightly the shading loss (here, I modeled a 2MW block, on fixed frame, 20 degree tilt) but reduces the IAM loss. Do you know wether such result should indeed be expected in "real life"? And why?

Thank you

Elisabeth

[André Mermoud]

This may probably be due to a dissymmetry between morning and evening in your meteo data.

Or an horizon shade if any.

I don't see other explanations. However such low differences are not necessarily very significant

[Elisabeth]

I only just saw your response. Thank you Andre