Power and Energy Values

  • Paul Gilman
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03 Dec 2014 18:59 #2804 by Paul Gilman
Power and Energy Values was created by Paul Gilman
In the new SAM results, the energy values are being displayed with the units MW/kW...power units. Are these energy or power units?
The time series values are average power values. What we called "hourly energy" in older versions of SAM was technically the average power over one hour, which was equivalent to kWh/h, so we used the shorthand kWh as the units for hourly results.
Because the new version of SAM can perform subhourly simulations (providing you have subhourly weather data), we changed the units for time series results to power to be more precise. For a 15-minute time step, it would not be correct to use kWh as units for the average power over each time step.
Best regards,

Paul.

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  • George Aluru
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04 Dec 2014 13:22 #2805 by George Aluru
Replied by George Aluru on topic Power and Energy Values
Thanks Paul. I find it confusing when I am dealing with annual energy values denoted in MW. In this case do you mean it is the average power over one year?

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  • George Aluru
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04 Dec 2014 14:18 #2806 by George Aluru
Replied by George Aluru on topic Power and Energy Values
Can I safely assume that the value reported as energy is indeed the annual value of energy in kWh or do I have to manipulate it with a factor to get this?

Thanks again

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  • Paul Gilman
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04 Dec 2014 18:30 #2807 by Paul Gilman
Replied by Paul Gilman on topic Power and Energy Values
Dear George,

The monthly and annual energy values should be in kWh. For example, for the annual value:

annual_value [kWh] = SUM(average_power) [kW] * hours_per_time_step [h]

Some of the SAM developers are concentrating solar power engineers and are accustomed to referring to electrical energy as "kW" and thermal energy as "kWh," which is why you might see kW units for some electrical energy metrics in SAM. We will try to change those for the next SAM update.

Best regards,
Paul.

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