Frequently Asked Questions (FAQs)
Contents
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When adding new Demand branches, why am I unable to select a different branch type?
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Can LEAP be used for developing a GHG inventory as part of National Communications to the UNFCCC?
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Can LEAP be used for non-energy sector GHG mitigation assessments?
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What is the difference between exogenous and endogenous capacity?
Answers to FAQs
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How do I speed-up calculations?
Make sure your computer has a minimum CPU speed of 1GHz and at least 2 GB of RAM. Computers with faster CPUs and more RAM will reduce calculation time. For a given PC, there are a number of things you can do to speed-up calculations:-
Reduce the number of scenarios calculated. Make sure that you are only calculating scenarios for which you wish to see results. To eliminate unwanted scenario calculations, go to the Manage Scenarios screen and uncheck the boxes attached to unwanted scenarios. Doing this will not affect the data entered for the scenario, it will just prevent you from seeing results for the scenario.
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Reduce the scope of calculations: Under the Settings: Scope screen, you can disable various parts of an analysis. At a minimum you must conduct energy demand analyses, but the following analyses are all optional: Transformation and Resources, statistical differences and stock changes, costs, environmental loadings and non energy sector emissions. Unchecking an option will not delete any data - it will only hide that data.
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Temporarily reduce the number of analysis years. You can temporarily reduce the number of years over which scenarios are calculated by going to the General: Settings screen, and entering an earlier End Year. Doing this will not affect any data you have entered, it will only reduce the number of years for which results are calculated. Later, when you wish to view results for all years, simply change the End Year back to its correct value, before viewing results.
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Choose to save results for fewer years: If you only need to see results every N years (e.g. every 2, 5, 10 or 20 years) you can greatly increase the speed of calculations as well as increase the speed with which each chart of table in Results View can be produced. Go to the General Settings: Years screen and change the value in the Results Every box to alter this setting.
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Reduce the number of regions calculated. In multi-regional data sets, go to the General: Regions screen and uncheck the check boxes in the Calculated column for any scenarios for which you do not wish to see results. As with scenarios, doing this will not affect the data entered, it will just prevent you from seeing results for the region. For a data set with many regions you want to switch on only one or two regions until you have got your model fully debugged,
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Why are some options disabled, such as the "Save" option?
Options are non-selectable (disabled) when they are not currently applicable. For example, the Save option may be disabled because no changes have been made to data since the last time you saved data. In addition, note that some options are disabled in the Evaluation version of LEAP (Save Data, New Area , etc.) To fully enable your copy of LEAP, you will need to enter a user name and registration code, under the Help: Register menu option. User names and registration codes are only made available to licensed users of LEAP. Visit the LEAP web site for information on how to get a license.
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What should I do if I encounter a problem or bug?
Should problems arise, please try and address the problems in the following order:
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Firstly, check to make sure that you have the most up-to-date version of LEAP. Use the Help: Check on Internet for Updates feature. If available, this will automatically install a newer version of LEAP on your PC. Your existing data will be preserved. Each newer versions of LEAP contains new features and bug fixes, so this may help solve any problems you are encountering. Note that the update normally requires that approximately 200 MB of data is downloaded, so you will need a reliable Internet connection to take advantage of this option.
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Next, check the discussion forums on the LEAP web site. Check to see if another user has already experienced (and hopefully solved) the same problem you are encountering. If you have not already done so, we suggest you register to use the site (which is free). This forum is also checked by SEI staff, so please post any technical support questions here rather than via email so that everyone can benefit from the answers.
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Finally, feel free to contact SEI directly. Please bear in mind that we can only provide technical support to licensed users - not to users of the evaluation versions of LEAP.
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Please see this web page for guidelines on posting questions to the LEAP forum.
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When adding new demand branches, why am I unable to select a different branch Type?
The current version of LEAP, does not allow you to mix branch types (categories and technologies) as siblings at a particular level. Therefore, once you have added one branch and set its type, all other branches added as siblings must be of the same type. An exception to this rule is that you may specify categories and aggregate energy intensity branches as siblings of one another. If you have mistakenly specified multiple branches of the wrong type, you must delete them before adding them once more and specifying the correct type. -
In a Transformation electricity generation module I have specified all my data but no generation occurs. Why?
Please follow this checklist to make sure that all data is entered correctly. This checklist assumes you are using a simulation-based approach. If trying to use an optimization approach, please refer to this introduction to optimization.-
First, check that the module does actually have some requirements. If there are no requirements then nothing will be generated! You can check this by viewing the Transformation: Requirements report in the Results View.
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Next, make sure you have specified some capacity data for the processes you expect will operate. You can specify capacity data using the Exogenous Capacity and Endogenous Capacity variables. Check to see how much capacity was build using the Transformation: Capacity report in Results View. Check also that processes are available for dispatch using the Maximum Availability variable. These values should be non zero.
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Next, review the First Simulation Year and Dispatch Rule variables. The former controls the year at which LEAP switches over from dispatching based on the data you enter in the Historical Production variable to dispatching using the rules in the Dispatch Rule variable. If you are dispatching using the PercentShare rule, make sure you have entered the percentage share of each process in the Process Share variable. In the years before the First Simulation Year make sure you have entered some non-zero values for the Historical Production variable. Note also that if you have specified conflicting data (non zero Historical Production but zero Capacity) for some processes then LEAP will display an error during calculations.
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Finally, make sure that you have entered units and scaling correctly for the Capacity and Historical Production variables. For example, it is a common mistake to select an improper scaling factor, or to specify MWh when you mean to enter GWh. One way of spotting these mistakes is to look carefully at results and see if some (especially those produced in the years either side of the First Simulation Year) are much too big or much too small. A useful technique when looking at values that appear to be zeros (when you expect them to be non-zero) is to increase the number of decimal places in the Results View table by clicking the Increase Decimals (
) button. Sometimes non-zero values will appear that look like zeros when only showing one or two decimals. This is often a sign that a unit or scaling factor are incorrect.
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Can LEAP be used for life cycle analysis?
No. LEAP is best suited for integrated analyses. It is not intended for life-cycle analyses. Other modeling tools are available that take a life-cycle perspective including GEMIS and GREET for modeling well-to-wheel transport emissions. -
Can LEAP be used for developing a GHG inventory as part of national communications to the UNFCCC?
While LEAP uses many of the same calculation approaches and covers the same sectors that would be required for a national GHG inventory, it is a more complex tool than is required to simply do a static GHG inventory. For this task we recommend using the specific methods and accompanying spreadsheets developed by the IPCC. Where LEAP is most useful is in the preparation of energy-sector GHG Mitigation Assessments. This task generally builds upon the work of an inventory study, but rather than looking at historical emissions data, it examine possible future scenarios for emissions. This task requires the preparation of forward-looking scenarios: something that LEAP is very well-suited for. -
Can LEAP be used for non-energy sector GHG mitigation assessments?
LEAP is primarily an energy sector modeling tool, although it can be used for relatively simple calculations of non-energy sector sources and sinks. If the focus of your mitigation assessment is on the non-energy-related sectors of agriculture, forestry or land-use change then we suggest you use another modeling tool such as EX-ACT, CENTURY, or AgLU models. Note however, that you may still wish to incorporate the results from these separate analyses into the overall set of GHG emissions accounts in your LEAP analysis. This can easily be accomplished, especially for those of the above models that are spreadsheet-based. Results from these models can be imported into or linked to the non-energy branches in your LEAP area in order to provide a single comprehensive set of emissions results covering all sources and sinks of GHGs. -
What is the difference between exogenous and endogenous capacity?
Exogenous Capacity is capacity explicitly entered by the user, and is normally used to reflect existing capacity as well as planned/committed capacity additions and retirements. Endogenous Capacity values are those capacity values calculated internally by LEAP in order to maintain a minimum planning reserve margin. Endogenous capacity additions occur in addition to capacity specified in the Exogenous Capacity variable. Endogenous capacity is only available in scenarios where a module is using a simulation methodology. It is NOT used when a module uses least-cost optimization modeling. When doing an optimization, future capacity values are calculated internally. For more information, see this page on Specifying Capacity Data in LEAP. -
How Should I Cite LEAP in a report? Please refer to our citation guidelines. Please also consider sharing your reports with fellow members. Please contact us if you would like to do that.
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Share vs saturation units:
TLDR: Should neighboring branches sum to 100%? If so use share units!
Both saturation and share are a type of unit that can be used to specify an activity level in a demand analysis. Typically you will specify one absolute activity level (e.g. number of households) at a higher level and then use saturation and/or share units at lower levels in the Demand tree structure. Both share and saturation are always entered as percentage values.
Use share units when you have more than one branch and you want the total across the branches to sum to 100%. For example, if you have two branches for urban and rural households, use a share unit because the total across urban + rural needs to sum to 100%. Similarly, if you have more than one technology and the technologies are perfect substitutes (i.e. only one can be used in any situation) then use a share.
Use saturation units to represent market penetrations where the sum across neighboring technologies need not necessarily be 100%. For example, some households might own more than one type of cooking device (e.g. wood and charcoal and kerosene), so the sum of the market penetration of all those devices may well be more than 100%.
In both cases when using share and saturation, LEAP will check that any individual value is between 0% and 100%. If any values are negative or above 100% then LEAP will halt its calculations, report an error, and return you to the place where that error occurred. The ONLY difference between share and saturation units is that if you choose share for immediately neighboring branches, then LEAP will perform an extra check to test if all the values sum to 100%. If they do not it this will be reported as an error. When using shares, it is usually easiest to specify one of the neighboring branches with the expression Remainder(100). This will ensure that all the values sum to 100%. NB: You may not mix saturation and share units in immediately neighboring branches.
Tip: You can only edit units and scales when editing Current Accounts data. If these two columns appear grey/uneditable then use the Scenario selection box to select Current Accounts. Units are common across all scenarios and all regions.