According to this CBC article, Elections Alberta will announce the official results from the May 5 Alberta election on May 15th.
After polling day, returning officers are tasked with doing an official count of the votes, which is a way of checking that all the addition of the votes from the numerous polling stations has been done correctly and that all the ballots have been accounted for.
You can read about the procedures undertaken at the official count in sections 136-138 of the Election Act (Alberta).
Usually the official count is an administrative formality, but on May 15th all eyes will be on the official count for the electoral district of Calgary – Glenmore, where there was a tie after the unofficial count on polling day between the PC candidate and the NDP candidate.
If the official count confirms that there is a tie in Calgary – Glenmore, the returning officer for that electoral district is required pursuant to section 144(5) of the Act to apply for a judicial recount.
If the result is still tied after the judicial recount, then pursuant to section 147 of the Act it heads to an appeal which is heard by the Court of Appeal.
Finally, if the result is tied after the appeal, the returning officer is required by section 148(8) of the Act to declare that no candidate was elected for the electoral district, which triggers a by-election under section 149 of the Act.