According to market convention, when pricing an instrument on electricity, a lot is calculated as the number of megawatt hours (MWh) in that instrument's delivery period. That is, a lot in an instrument that is based on the September 2009 forward contract will necessarily have a different number of MWh (720) than an instrument based on the October 2009 forward contract (744). Accordingly, the lots of different instruments are not the same.
To support this market convention, when you price an instrument on electricity, once you have defined its underlying forward contract the system displays the number of megawatt hours (MWh) in its delivery period in the pricing page (next to the Delivery field).
This number also represents the MWh in one lot. So, if the number of megawatts in the instrument is 720, if in the Volume field you enter 3 lots and then toggle the field to be displayed in MWH, the system converts the number of lots as follows: 3 * 720, i.e., 2160.
Because a lot of electricity is defined as the number of MWh in the instrument's delivery period, it is important to note the following for an instrument based on electricity:
In the Portfolio page, if you are displaying the results in lots, although the Delta Forward in lot result and the Gamma in lot result are displayed for each individual instrument, they are not displayed for the total portfolio.
In the Portfolio page, the Buckets window (which accessed by clicking the Buckets button) does not show results for the Delta FWD in Lots column.
This is because the results in lots between different instruments cannot be summed, as each lot has a different underlying number of megawatt hours.
There is a feature whereby you can define whether or not to show results in lots. This is set via the Customize menu > Default Settings tab > Show results in lots dropdown list. If you set this setting to Yes, and in the pricing page you toggle the volume to be displayed in lots, when you next click Calculate, the results are displayed in lots.