Chen Herzog 11/19/2015

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I need to incorporate a supply side limitation of the maximum hourly capacity of gas available to the market (in terms of mmbtu/hour).
In case gas demand exceeds availability, electricity generation using other fuels needs to be dispatched.
How can this constraint be added?

Taylor Binnington 11/20/2015
 

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Hi David,

In order to impose an hourly constraint on LEAP's electric dispatch, you'll need to divide each year into hourly time slices:

http://www.energycommunity.org/WebHelpPro/Supporting_Screens/Time_Slices.htm

Though this is technically possible, we almost always recommend against doing so. It's very taxing for LEAP's calculations, and is often an unnecessary level of detail for a scenario analysis that extends out twenty years or more. Instead, I'd suggest that you divide your year into time slices which capture the largest variations in gas supply, and aggregating your hourly data into those time slices. LEAP's time slices provide a great deal of flexibility for you to define slices for days, weeks, night vs. day, etc.

Once you've defined proper time slices, you would implement differing availability of gas using the Maximum Availability variable for your natural gas electricity generation process. This variable supports time-sliced values, which you can enter in one of two ways: using the built-in TimeSliceValue() function or by constructing a new "availability"-type yearly shape

http://www.energycommunity.org/WebHelpPro/Expressions/TimeSliceValue.htm

http://www.energycommunity.org/WebHelpPro/Supporting_Screens/Load_Shapes.htm

If you use the latter option, you'll be able to "Import Hourly Shape" from Excel, which will automatically assign your hourly data from one year to the appropriate time slice you've established.

Can I also ask - are you currently using LEAP, or just exploring what can be done with the tool? If you are currently using it, how did you acquire a license?

All the best,

Taylor

Chen Herzog 11/21/2015
 

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Thanks for your reply. I am currently evaluating LEAP using the freedonia example to understand how well it fits my needs.

My usage case has several processes (power unit technologies) that run on natural gas (combined cycle, open cycle, new combined cycle, cogeneration, etc.) along with additional processes that use other fuels.

There is a nationwide capacity limit in terms of total maximum gas supply (in terms of mmbtu/hour), due to a capacity limit of the gas pipeline infrastructure.
Once this limit is exceeded, other units (such as oil CT) need to be dispatched.

If I understand your suggestion correctly, using a maximum availability constraint on the process level will only work if I have a single gas based generation process, which is not the case here.

Any way to implement a time sliced availability constraint that will apply to the total supply of the gas resource to all relevant processes?

Taylor Binnington 11/23/2015
 

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Hi David,

To impose the constraint across more than one of LEAP's processes, I'd recommend assigning shares of the maximum hourly capacity to each separate plant (perhaps based on a ratio of their capacities). This way at least you can be certain that the total capacity constraint will not be violated, even if you are (to some extent) pre-determining how much power each gas plant may generate. There really isn't another way to impose resourceful constraints in LEAP on a sub-annual basis.

Hope this is useful,

Taylor