Geothermal Royalty Costs, Drilling Costs, and Capacity Factor

henry.johnston@nrel.gov
Topic Author

27 May 2021 07:48 #9635 by henry.johnston@nrel.gov

Geothermal Royalty Costs, Drilling Costs, and Capacity Factor was created by henry.johnston@nrel.gov

Hello,

I've been comparing SAM to GETEM, and I have 3 questions/observations.

1. When using SAM, how do I enter Royalty Costs? In GETEM, BLM Royalty rates are entered as follows:
a. 1.75% through year 10
b. 3.5% after year 10
2. SAM drilling costs are much lower than in GETEM. For example, if the well is 2500 m deep, per well drilling costs are as follows:
a. SAM: ~$2M
b. GETEM: ~$4M
3. I haven't been able to adjust the Net Capacity Factor in SAM. I've tried using the System Availability Constant Loss, but it doesn't seem to impact Net Capacity Factor.

Thanks,

Bud Johnston

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pgilman

01 Jun 2021 11:46 - 01 Jun 2021 11:47 #9646 by pgilman

Replied by pgilman on topic Geothermal Royalty Costs, Drilling Costs, and Capacity Factor

Hi Bud,

There seems to be a bug in the capacity factor calculation for the Geothermal model. We will fix this issue for the Fall 2021 version of SAM. As a workaround, please use this LK script to calculate the correct value. To use it, click Open script on the File menu, paste the following lines of code into the script editor and click Run.

Code:

AEP = get('annual_energy'); // annual energy SAM output, kWh
Pmax = get('system_capacity'); // system capacity SAM input, kW
CFsam = get('capacity_factor'); // capacity factor SAM output,%

CFcalc = AEP / 8760 / Pmax * 100; // capacity factor equation, %

outln(CFsam); // capacity factor SAM output, %
outln(CFcalc); // capacity factor calculated, %

You can enter the royalty costs on the System Costs page as an operation and maintenance cost at the bottom of the page. You'll have to convert the costs to one of the available units $/yr, $/kW-yr (kW of nameplate capacity), or $/MWh (MWh of annual production). Click the small blue and grey button next to the input to convert if from a single Year 1 value to a table of annual values and then click the Edit button to type a values in the table for each year.

As for drilling costs, the default values in SAM may be out of date. You can modify the values in SAM to match the assumptions in GETEM.

Best regards,
Paul.

Last edit: 01 Jun 2021 11:47 by pgilman.

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henry.johnston@nrel.gov
Topic Author

03 Jun 2021 14:44 #9654 by henry.johnston@nrel.gov

Replied by henry.johnston@nrel.gov on topic Geothermal Royalty Costs, Drilling Costs, and Capacity Factor

Hi Paul,

Thanks for the informative response. Another related issue is the System Availability Constant Loss parameter. Changing this parameter doesn't seem to impact annual energy generation.

Regards,

Bud

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pgilman

03 Jun 2021 17:32 #9655 by pgilman

Replied by pgilman on topic Geothermal Royalty Costs, Drilling Costs, and Capacity Factor

Hi Bud,

Thank you for pointing that out. I've created an issue for both of these problems in the SAM GitHub repository, and we'll try to those both fixed for the Fall 2021 version of SAM.

github.com/NREL/SAM/issues/630

Best regards,
Paul.

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