A few issues:

• PVWatts / Single Owner NPV is negative. NPV is very sensitive to PPA price in the 4-5 cent/kWh range:

• For PV configurations, the default "Annual land lease cost" ui_land_lease of $100/yr and "Land lease escalation rate" om_land_lease_escal of 1%/yr from the Operating Costs page appear to be left over test values. I think these should both be set to zero unless we have a source for those values. This would increase the default PV / Single Owner NPV by about 10%. The ATB documentation mentions land lease is included in O&M cost and I could not find it broken out as a separate cost in the LBL report it cites.

• Although this is not necessary, it would be nice for the default IRR target and IRR target year to match the results for "Specify PPA price" mode so that if a user switches from Specify PPA price to Specify IRR target without changing any other inputs, they get the same results. This would be tedious to do because it requires running a simulation for all configurations -- something that could be done by LK script.

• For all FOM financial configs, retail rate inputs on Electricity Purchases page should have the following values in case user switches from PPA to retail rates.

  ur_monthly_fixed_charge = 0
  ur_ec_tou_mat = [ [ 1, 1, 1e+38, 0, 0.045, 0 ] ]
  ur_dc_enable = 0
  ur_dc_flat_mat = [ [ 0, 1, 1e+38, 0 ], [ 1, 1, 1e+38, 0 ], [ 2, 1, 1e+38, 0 ], [ 3, 1, 1e+38, 0 ], [ 4, 1, 1e+38, 0 ], [ 5, 1, 1e+38, 0 ], [ 6, 1, 1e+38, 0 ], [ 7, 1, 1e+38, 0 ], [ 8, 1, 1e+38, 0 ], [ 9, 1, 1e+38, 0 ], [ 10, 1, 1e+38, 0 ], [ 11, 1, 1e+38, 0 ] ]
  ur_dc_tou_mat = [ [ 1, 1, 1e+38, 0 ] ]
  

• Power Tower PPA price input of $0.13/kWh seems high. Calculated PPA price in SAM 2020.11.29 is $0.1032 with end of project IRR of 12.82% (which also seems high to me). Consult with CSP folks to see what default PPA prices / IRR they would like to see for CSP configs.

A few issues:

• PVWatts / Single Owner NPV is negative. NPV is very sensitive to PPA price in the 4-5 cent/kWh range:

• For PV configurations, the default "Annual land lease cost" ui_land_lease of $100/yr and "Land lease escalation rate" om_land_lease_escal of 1%/yr from the Operating Costs page appear to be left over test values. I think these should both be set to zero unless we have a source for those values. This would increase the default PV / Single Owner NPV by about 10%. The ATB documentation mentions land lease is included in O&M cost and I could not find it broken out as a separate cost in the LBL report it cites.
• Although this is not necessary, it would be nice for the default IRR target and IRR target year to match the results for "Specify PPA price" mode so that if a user switches from Specify PPA price to Specify IRR target without changing any other inputs, they get the same results. This would be tedious to do because it requires running a simulation for all configurations -- something that could be done by LK script.
• For all FOM financial configs, retail rate inputs on Electricity Purchases page should have the following values in case user switches from PPA to retail rates.

  ur_monthly_fixed_charge = 0
  ur_ec_tou_mat = [ [ 1, 1, 1e+38, 0, 0.045, 0 ] ]
  ur_dc_enable = 0
  ur_dc_flat_mat = [ [ 0, 1, 1e+38, 0 ], [ 1, 1, 1e+38, 0 ], [ 2, 1, 1e+38, 0 ], [ 3, 1, 1e+38, 0 ], [ 4, 1, 1e+38, 0 ], [ 5, 1, 1e+38, 0 ], [ 6, 1, 1e+38, 0 ], [ 7, 1, 1e+38, 0 ], [ 8, 1, 1e+38, 0 ], [ 9, 1, 1e+38, 0 ], [ 10, 1, 1e+38, 0 ], [ 11, 1, 1e+38, 0 ] ]
  ur_dc_tou_mat = [ [ 1, 1, 1e+38, 0 ] ]
  

• Power Tower PPA price input of $0.13/kWh seems high. Calculated PPA price in SAM 2020.11.29 is $0.1032 with end of project IRR of 12.82% (which also seems high to me). Consult with CSP folks to see what default PPA prices / IRR they would like to see for CSP configs.

I pushed the land lease fix to this branch.

I addressed some of the utility rate issues in #790 but need to upate theur_ec_tou_mat and the ur_dc_tou_mat

@cpaulgilman The calculated PPA price for PVWatts - Single Owner with the updated utility rates and a IRR target of 11% is 4.96 cents/kWh. Should we use that?

Would be good to have something close to the Detailed PV case -- if there's PPA price for a lower IRR that results in a positive NPV that would be good. Nitpicking here, so I wouldn't hold this up for that.

My default value for utility scale systems of $13/kW-yr does not include land payments. Should I increase that based on https://github.com/NREL/SAM-documentation/blob/master/Defaults%20References%20and%20Tools/Fall%202021/Copy%20of%20OandM%20TabularForm_Graphic.xlsx? I think land prep on the installation costs should remain the same.

If I increase the fixed O&M to $15/kW-yr (to account for land lease) and the PPA price to $0.048/kWh, I get a positive NPV for both Detailed PV-Single owner and PVWatts-Single owner.