SAM logic for renewable energy use?

Hi,

I have a strange situation going on with SAM and I don't know why SAM is giving me a different output.

First, let me give you some more information: I made 2 cases and both are identical to one another with only the load power (in the energy usage section) as a difference. In my first case I had a certain load x and for my second case I had a certain load  x + y. So basically the same load, but with extra load power added to it. 

The weird thing is that in the output of my SAM in the statistics section, it mentions that for the hourly data the electricity from the system to load is higher in case 1 compared to case 2, while the load power is lower in case 1.

How is that possible? Could you please help me, because I have been looking at this for a long time and I can't find the cause of this.

Thank you in advance.

Kind regards,

Michiel

Hi Michiel,

Have you looked at the Time Series tab on the Results page to see what is happening on an hour-by-hour basis? The annual sums of hourly values don't really provide very much information about how the model is meeting the load using grid and PV power.

Best regards,
Paul.

Hi Paul,

I added the pictures of the graphs in the time series tab. It seems to me that in case 1 there goes much more energy from the PV-system to the loads during the summer months compared to case 2. I still don't understand why it is like that though. I would think that because of added loads you take more energy from the PV-system in case 2.

note: The spikes in case 2 represent the charging of electric trucks.

Kind regards,

Michiel

Paul Gilman wrote: Hi Michiel,

Have you looked at the Time Series tab on the Results page to see what is happening on an hour-by-hour basis? The annual sums of hourly values don't really provide very much information about how the model is meeting the load using grid and PV power.

Best regards,
Paul.

Hi Paul,

Thanks for your response, I added the graphs from the time series tab in attachments. What I clearly notice is that in case 1 the electricity usage form the system to load is much higher from April till October compared to case 2.

Also something I should note that can also be of big importance is that in case 1 I started with putting the monthly enery usage as an input since that was all I had to work with. Then I enabled the "normalize supllied load profile to monthly utility bill data" option. For case 2 I used the load profile from case 1 and added extra load to it that would represent the charging of electric trucks at certain time intervals. I did not enable the "normalize supplied load profile to monthly utility bill data" option here.

Kind regards,
Michiel 

Hi Michiel,

Would you mind attaching a copy of the .sam file(s) and weather file you used for the analysis in both cases? It is hard for me to tell what is happening only from the results in your screenshots.

Best regards,
Paul.

Hi Paul,

Thanks for the offer, but I finally figured it out. I enabled the  "normalize suplied load profile to monthly utility bill data" option in case 1 and consequently only used the values form the "energy usage" in this case as a base for case 2, plus additional charging energy from the electric trucks. I think because I didn't use a scaling factor in case 2 the renewable energy usage amounts were much less compared to case 1. I calculated the correct scaling factor and finally got realstic values! 

Thanks for all the help Paul!

Kind regards,
Michiel