LEAP

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Topic: Least Cost Optimization ModuleSubscribe | Previous | Next

Asim Amjad 4/17/2017

Respected Sir

I am currently working on Least Cost Electricity Generation Module. I am facing
some issues regarding O&M cost. The O&M cost (Reference table is attached) is not available in separate fixed O&M and variable O&M cost.
I am using this O&M cost in Fixed O&M variable in LEAP. Kindly suggest
and advise.

After putting these values in NGCC, WIND, COAL and HYDRO, I have received an
error when clicking Analysis view. The error file is attached.

Looking forward your valued response. Regards

Taylor Binnington 4/19/2017

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Hi Asim,

Occasionally, useful data sources group all O&M costs into a single cost per kW of installed capacity. But this assumes a level of capacity utilization, which you will need to recover if you wish to enter both fixed and variable O&M separately. In other words, your table provides you with the variable OM_total in the following equation:

OM_total ($/kW) = OM_fixed ($/kW) + OM_variable ($/kWh) * 8760 (h) * CF

...where CF = the average annual capacity factor of the technology. LEAP requires both OM_fixed and OM_variable separately.

I can't speculate as to the cause of the warning you see in the third screenshot without more information. Have you included any constraints on the amount of allowed capacity which could prevent LEAP from constructing enough to satisfy capacity requirements?

Best,

Taylor

Dorji Yangka 5/8/2017

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Hi taylor

(sorry Asim for coming in between),

I also get the same diagnostic message.

I have linked the 'maximum capacity' to the 'exogenous capacity' for each power plant, which I guess is practical.

To add to Asim queries, my questions are:

Does it imply that optimization did not work? why do we get this diagnostic message?

When I don't put a constraint on the 'maximum capacity', then for some of the future years the model chooses capacity level beyond the exogenous capacity. Your valuable support will be much appreciated.

thank you,

Dorji

Taylor Binnington 5/9/2017

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Hi Dorji,

I'm not quite sure why you would want to constrain total installed capacity to the values which you have entered in the Exogenous Capacity variable. This implies that LEAP would never build any new power plants that are not described entirely through exogenous capacity.

if this were the case, it's quite possible that the optimization routine would be unable to build sufficient capacity to meet requirements (as the diagnostic message indicates). This does not mean that the optimization "failed", but only that the contraints kept enough capacity from being built.

Hope this is clear,

Taylor

Dorji Yangka 5/12/2017

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Hi taylor,

thanks for your kind response.

the reasons for putting a constraint on the maximum capacity:

1) the default value is 'unlimited', without putting a constraint, the model chooses the cheapest power plant beyond its resource yield level - which is not practical;

2) upon linking the 'maximum capacity' to the resource 'yield', the model still choses the cheapest power plant beyond the resource yield;

3) the restriction works only by linking the 'maximum capacity' to the 'exogenous capacity'

I don't understand, why the model don't import electricity (whatever the import cost may be) in case of 2) above to meet the demand rather than building the cheapest power plant beyond the resource yield. I am attaching my excel sheet.

Look forward to your kind support.

Thank you,

Dorji

Attachments:

DY_power gen issue.xlsx [7]

Taylor Binnington 5/17/2017

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Hi Dorji -

LEAP's transformation calculations (including its optimization routines) are not sensitive to resource yields or reserves. They will not automatically obey resource constraints.

I still don't know why you would set your Maximum Capacity equal to Exogenous Capacity, for all power plants. This is the same as using LEAP only to perform dispatch of a fixed set of power plants which you write into the Exogenous Capacity variable. If you are worried about exceeding your resource constraints (take, for example, your limit of 33.55 PJ/year of solar irradiance), then I would recommend including an expression like the following, in your Maximum Capacity variable:

Resources\Primary\Solar:Yield[MWh] * Process Efficiency / Maximum Availability

This expression would calculate the output capacity, in MW, given an assumed efficiency and (annual) availability. This will ensure that no more capacity is built than there is solar energy to fuel, but it would presumably also allow some new capacity to be built beyond your Exogenous Capacity.

Best,

Taylor

Dorji Yangka 5/18/2017

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Hitaylor,

thanks for providing me with the expression to control building of power plants within the resource yield.

I shall use it and get back to you in case of issues.

What I fail to understand is that - why does not the model import electricity when domestic resource has limit due to yield/reserve and also constraint posed by availability factor in case of run of the river scheme? why do the model say - no primal feasible solution? (there is no emission constraint in this case)!

look forward to your valuable and continued support.

thank you,

Dorji Yangka

Taylor Binnington 5/19/2017

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Hi Dorji,

LEAP may import electricity for a few different reasons.

If the "Shortfall Rule" (more about these here) for the electricity generation module's output fuel is set to import remaining requirements, then any remaining requirements which the module cannot satisfy with its processes/power plants will be filled with imports. These electricity imports "enter into the tree" at the same location as the module. Note that you may forbid these imports by choosing "Requirements remain unmet" in the module's output fuel properties.
Even if imports are forbidden in each of your transformation modules, LEAP may still import fuel in the Resources branches. You may right-click on a fuel under the Resources branches to view its properties, and select "Any remaining requirements stay unmet", to forbid imports at this level in the tree.

In either case, it's important to realize that just because LEAP is unable to satisfy requirements for a fuel (by transformation, domestic production or imports), this will not automatically affect the demand or other requirements for that fuel. LEAP will simply mark remaining requirements as "unmet", after all of its calculations have resolved. So this means that domestic resource yields or reserves will simply tell LEAP which requirements can be met using domestic sources, and which need to be imported (or unmet, if you have manually forbid importing of these fuels).

Second - the "no primal feasible solution" generally means that you have assigned two or more model constraints which directly conflict with one another. A simple example would be setting the Minimum Capacity Addition variable for an (optimized) transformation process to zero, while also setting the Minimum Capacity variable to something greater than the Exogenous Capacity. This tells LEAP that it must build new capacity to satisfy one constraint, but cannot build any capacity due to another constraint - hence, no solution.

Best,

Taylor

Dorji Yangka 5/31/2017

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thank you Taylor.....

cheers,

Dorji