The DPS is nothing more than a measure of how strongly the wind speed depends on the time of day. It can't say anything about why the wind speed does that. In the Antarctic winter, the DPS should be zero because there's nothing about the time of day that could influence the wind speed. On the Hawaiian coast, the DPS is probably quite high becau

During the same simulation, HOMER shows that the excess energy produced is 85.3%, while it also shows that there is a capacity shortage of 49%. If there is excess energy why it does not use it for minimizing the capacity shortage? The excess energy and the capacity shortage do no happen at the same moment. This result is expected, for example, if

What is the mathematics model to calculate daily, hourly, of wind speed and load demand data ..... when put the resource data input to HOMER program and then the plot button clicked ..... Can you make a description about the HOMER calculation process? The steps of the wind speed data synthesis algorithm are as follows: 1. Generate a fir

What data can I get from other sources to put into HOMER Pro? There are two major options. Option 1: Use long-term monthly averages If you have a large dataset, you could calculate the long-term average wind speed for each month of the year, enter those monthly averages in HOMER Pro's Wind Resource Inputs window along with the long-term Weibull

What start up condition are we trying to achieve? Currently I have the web service creating a document that can be File->Import XML into the Homer program. Something I kind of had a problem with is that you can't see the data until you say that there is a PV or a wind turbine. Should the Homer XML just include these? Should it also force Homer

I use the Power = Power Coefficient x 0.5 x Swept Area x Air Density x Velocity3 to do the calculation which has the different answer from what I get from HOMER. If you use the same formular, could you please tell me what value of the Power Coefficient do you take? HOMER does not use that approach to calculate the wind turbine output because t

If we are using pitch regulated turbines, I guess the best option would be to give sea level wind speeds for our desired wind power classes. We would have to set the elevation to be 0 in our inputs to Homer. How would that affect the other Homer calculations? The elevation affects nothing except the wind turbine output, so setting it to zero

Does HOMER use any algorithm to compensate this variation per hour? That's a good question. No, HOMER does not attempt to account for variation of the wind with the time step. It simply assumes a constant wind speed throughout the time step, which as you say slightly underestimates the power in the wind. But this conservative assumption is u

A suggestion for further development: in the tracking model it's not foreseen the single axis tracking with the pivoting axis north-south oriented with the panels that look to the east in the moornig and to the west in the afternoon. You can model that situation in HOMER by setting the PV tracking system to "Horizontal axis, continuous adjustme

I am interested in the software Homer and would like to know whether I could use this software to compare the outputs of a vertical axis wind turbine (VAWT) and horizontal axis wind turbine (HAWT) of the same rating. Could I use Homer to estimate the power output for VAWTs? Yes, you can model vertical axis wind turbines in HOMER. The default

I'm trying to use HOMER and I couldn't find an option to cap the availability of the wind turbines in the system. For instance in the systems in Alaska, the turbines are down about 20% of the time for maintenance. Can you think of a way to have HOMER incorporate this fact in its calculations? Would scaling any output invaliditate the results? Y

I am interested in the feasibility of a tilt up grid connect wind farm that creates ac and converts it using the windyboy inverter and a large bergey or sw wind power wind turbine can homer help me with direct grid connect systems? The converter seemed to do ac-dc dc- ac but not ac-ac.... HOMER can model both AC and DC wind turbines. If you ar

I was working with Homer, trying to modelate a litle Wind Park (20 MW). In the report of the systems never apears that the park reach the nominal power rate of 20 MW. Why? HOMER multiplies the power curve by the air density ratio, which is correct only for stall-regulated wind turbines. Unfortunately it is not able to do the air density corre

Does Homer extrapolate between values in the power curve? Yes, HOMER interpolates within points of the power curve, so it would be happy if you specified only a few points.

The best reference on probability transformations I know is: Graham VA, Hollands KGT, Unny TE (1988) “A time series model for Kt with application to global synthetic weather generation”, Solar Energy, 40 (2), 83-92 Section 2 of that paper covers probability transformations. I can give you a rough description though. A probability transformation

I think if you set HOMER up so that measured wind data is set at say 10 meters but hub height is 50m, then HOMER scales automatically. Yes, HOMER will scale the wind speed to account for the wind shear between the anemometer height (which you enter on the Wind Resources Inputs window) and the wind turbine hub height (which you enter on the Wind

I am wondering if HOMER can deal w/ changing temperatures and pressures? the one thing the Arctic has going for it is that the air density can be up by as much as 20% in the winter... Unfortunately HOMER doesn't consider the effect of varying temperature and air density on the wind turbine.

I know the annual average wind speed in my site. To calculate energy from a wind turbine i have to know the weibull parameter K.Is there any way to calculate this from only annual average wind speed. Please inform me. The average wind speed and the Weibull k parameter are two independent variables. There is no way to determine one from the oth

Wind resources are usually measured in 10-minute intervals. HOMER input is limited to 1 hr. This requires a great amount of data modification in order to import the data. Even an application that would accept the 10-minute data and then compress it to 1 hr average would be a nice feature. Actually, HOMER is no longer limited to 1-hr timesteps,

I have a question about Step ten: Add sensitivity variables in the HOMER help. What is scaled annual average and what is the difference between the Annual Average which HOMER automatically calculates after we add Wind Monthly Average? Using the Scaled Annual Average input box for a HOMER variable allows you to adjust the size of an annual avera

Please look up 'synthetic wind data' for a description of how HOMER generates hourly wind speed data from monthly averages.

The wind power class refers to an average wind power density range at a particular height above ground. For example, power class 4 means that at 50 m above ground, the average wind power density is between 400 and 500 W/m2. The average wind power density is a function of the wind speed distribution and the air density. Where the table shows the

Does HOMER take into account the outdoor temperature to correct the air density in the wind power calculation or is the "actual density" refer to the height above see level density adjustment only? There are two ways that you can adjust for colder temperatures. One would be to figure out what the equivalent altitude would be for the same densi

How can HOMER recognise that rated wind speed, when i just put see performance curve into? So it's a good question why the maximum wind power output is greater than the reported wind power capacity. The reason is related to the shape of the power curve and the way HOMER extrapolates from it. The power curve for that turbine slopes up at 20 m

I want to ask for your help about the "advanced parameters" in HOMER. Because I'm not sure whether I can get a correct answer from local metereological department. The parameters that are already in the HOMER files for "advanced" parameters of wind data are the default values. These are what we always use, except in very unusual cases where t

Wind resource inputs - autocorrection factor and diurnal factor I found difficult to interpret. If example of values and the effect upon an average resource profile were given then it may assist me to make a decision The Help system does have some explanation of those terms. If you look up 'autocorrelation factor' in the index you'll see a de

The wind turbine power curve I have from the University of Minnesota shows the cut out speed at about 31 or 32 m/s. The wind curve you sent me cuts out at 25, which makes my hydrogen and electricity way more expensive. Is there a good reason why it cuts out earlier? Way more expensive?? In your case 2a and case 2b files the wind speed exceed

When Homer runs its simulation does it take in consideration the wind turbine height? Yes, HOMER takes the hub height (tower height) into account when calculating the power output of the wind turbine. You enter the anemometer height and the wind shear properties in the Wind Resource Inputs window. You enter the turbine hub height in the Wind

Is it possible to add custom wind turbine outputs? You can click "New" next to the turbine type drop-down box on the Wind Turbine Inputs window to create your own wind turbine with its own power curve.

You do not need to multiply the manufacturer's power curve by the wind probability. Just enter the true power curve showing the turbine's power output versus wind speed. Every hour of the year, HOMER will calculate the output of the wind turbine that hour based on the wind speed that hour. If the wind resource was measured at a different height

What would be the best wind turbine option (from the available library) to cover a demand in the order of 100 MW in an wind-diesel hybrid system? There is no simple answer to the question of which turbine is best suited to a particular application. It is almost always necessary to model the system with several types of wind turbines, and to co