Feb 16 (Reuters) - Transcanada Corp TRP.TO
* Says expects to retain sufficient commercial support from shippers to underpin Keystone XL pipeline project
* Says some KXL shippers may increase or decrease volume commitments
* Says $8 billion is most recent cost estimate for Keystone XL, will look to refresh that in 2017
* Says does not anticipate being ready to start construction on KXL until well into 2018, construction will take two years
* Says no plans at this point for an open season on Keystone XL capacity Source text for Eikon: ID: Further company coverage: TRP.TO