Optimal solar panel direction for best financial investment return

[gb88]

I am looking to install solar panels but trying to identify which direction to face. From what i have read north is the obvious direction for getting the maximum sun, though I am not sure that it makes the most financial sense. My largest energy costs are likely to be in the afternoon when tarrifs are at their highest and when my house is likely to use the most energy. Facing the solar panels north is likely to result in good energy generation mid morning into the afternoon, which is not necessarily when i am likely to need it. I wonder if it is worthwhile turning some of the panels slightly to the west so that they are likely to capture more afternoon sun so therefore off set the high electricity rates and more in line with when i would be using electricity. Does this make sense? is there any information around on how much solar energy a panel is like to absorb over the course of the day (hour by hour) based on its direction.

[Marty]

Hi Greg

I agree with your thinking. I have spoke about it here previously:

Adelaide Solar Power | Optimal panel direction

Hey @John_FC This is an interesting one, because intuitively I would say NE. It will clearly give you more sun throughout the year, by my rough calculations an extra 1500kWh per year (9200 vs 7700 for the SW roof). Assuming an average roof pitch of approx 25 degrees, you’ll get about 25kWh per day on average from the NE roof, and 21 from the SW roof. However, the fact that you use most of your power after 5pm puts an interesting spin on it. It really depends on how much power you use when, as …

It does depend on a number of factors. Namely:

• Your feed in tariff and cost of electricity
• When you use your energy (as you already mention)
• Your roof direction

Regarding the last one, it’s often best to lay the panels flat on whichever is your best roof. It’s cheaper to put more panels up than to perfectly optimise the panel direction. This is one of the reason that it is a good idea to oversize your inverter.
https://forum.cleanenergyreviews.info/t/ch-9-how-big-a-solar-system-should-i-get-oversizing-the-inverter/162

What is the layout of your roof like?

Let me know your thoughts.

Cheers
Marty

[gb88]

i have a relatively flat roof, open on all sides. i have been trying to understand if i should turn some of the panels so that they are slightly facing north west. to enhance the amount of energy they may generate in the afternoon when charges are at their highest. It would be good to understand what sort of power generation north facing panels generate over the course of the day, then compare that to having some panels either tilted north east or north west to see if that improves their generation capability at the time of day that costs or usage is at its highest. I am not necessarily after generating the most power from my solar solution but rather getting the greatest value out of it.