so, how do I know if its in my calculation?

@modonn&craig  - it's an automatic calculation based on the province you live in, even before you enter your income and expenses, it will be there.

I already filed my return.  So I want to modify my return with the climate rebate.  When I click the box to get the climate rebate, go through the steps, and see how much I should get (a few hundred dollars), there is no change to my refund amount.  Why?

NEW - 2018 - Climate Action Incentive Credit (NB, MB, SK, ON only)

 The new refundable credit has no income cap but does have varying amounts by location. If you have a spouse, only one spouse makes the claim for the family (spouse and minor children). Software does it all for you – just enter a few details on your address and family. 

 You will be able to claim the Climate Action Incentive under the Provincial Deductions tab. Once that section has been completed, then the amount will calculate on line 449 of your Detailed Tax Summary Page, which is located in the Review Section after you open Bottom Line Tax Summary.

Please refer to the link below from TurboTax Tips to have a better understanding of this new credit and how it is calculated.

Climate Change Plan, Climate Action Incentive, Fuel Charges. How This Impacts Your Taxes. - https://bit.ly/2BJVS0L