Well, you're right, it was a long time ago, but let's see if we can't figure this out. I don't recall the details of the Homer sensitivity analysis, but I can speak to the general concept. You need to keep in mind that the underlying problem (microgrid design) is highly nonlinear. Unlike some nonlinear problems, this one is characterized by a lot of discrete nonlinearities. So the change in one variable could pop you over into another completely different domain. Say for example the by-back price for excess electricity was much less than the retail price being displaced. If your current design is below net zero, then the economics might look very favorable, and an incremental increase in capacity has a positive economic impact. However, if you increase the generation capacity above net zero, then the the economics are quite different and an increment increase could easily have a negative impact. Does this sound like the problem you're having? Hope it helps. JFG

@@johngardner2979 Wow thanks so much for replying! Your explanation is really helpful. So when you set the sensitivity variables to different values, is it that the chart is showing you those set values as if they are the base case? So each combination of variables is its own case? Basically, I was expecting that as you change the values, the respective lines retained their gradient and just shifted laterally left or right, depending on if the value was set to be higher or lower. So that's why I was really confused when the line did that whole flip. But I guess that has do with the non-linearity you talked about. Ok so the variables in question are the grid (retail) price and wind speed as relates to the NPC. When I increase the grid purchase price above a certain value, a portion of the wind speed gradient (the higher speeds) flips from positive to negative, meaning that high wind speed goes from increasing the NPC to decreasing it. I was assuming that wind speed and capacity are linearly correlated (I was thinking inversely proportional so that as speeds rise, less capacity is needed) but from your explanation I'm guessing it's not that simple. I'm thinking what I need to do is figure out the possible reasons why high wind speeds might increase or decrease the NPC. I was thinking that the only factor was wind capacity (high wind speed -> less capacity-> lower NPC) but maybe it's more than one factor. So for example, at higher grid prices, when high wind speeds decrease the NPC it could be because the model favours less wind capacity AND less grid purchases. Or at lower grid prices, when high wind speeds increase the NPC, it could be because of increased grid purchases, or increased capacity to capitalise on a sellback rate, or a combination of the two ??? Can you tell me if I'm thinking along the right lines? Sorry for the long paragraph. Lol typing this out helped me to think. Thanks a lot for the help though. I'll keep trying to wrap my head around it.

The second input to the 'stickslip' function is the velocity of the block. The acceleration will be computed by taking the sum of forces and dividing by mass. Does this help?

@@johngardner2979 Yup got it. Thanx!

For an offset slider crank, then the R1 vector would have both x and y components (the y being the offset) but the rest of the analysis works fine.

Martha: Thanks for the kind words about the video. This might be an easier conversation to have outside of the KZbin comments pages. You should be able to find my email through my university web site.

Hi Mark: It's based on "Renewable and Efficient Electric Power Systems" by Gil Masters, 1st edition. There's a new edition out that doesn't treat this area (load duration curves) nearly as well. I suspect Dr. Masters did that because this analysis doesn't do a very good job of integrating wind and solar so it's less relevant now than it once was.

John Gardner thanks! Will get that book. Any idea on the best state university for phd in renewable energy planning?

It's "Efficient and Renewable Electric Power Systems" by Gil Masters: www.amazon.com/Renewable-Efficient-Electric-Power-Systems/dp/1118140621

Thank you very much. Also I would like to ask if you can recommend any other books for LCOE models for electricity generation. I am masters student currently studying economics without having a previous economics degree.

I appreciate the comment. This was one of my earlier lectures, before I started using the headset. Hopefully I'll have time soon to re-record it.

+afif 76 : ressource solaire est spécifié via latitude et de longitude. Si vous ne disposez pas de données de charge primaire, alors vous pouvez faire évoluer la charge par défaut disponible pour le logiciel. I hope this helps. I used Google Translate since I am afflicted with mono-lingualism.