Well that's just it, Over the long run Alberta has proven that it is not able to run a balanced budget[0][1][2] and the only times where it has come close have been achieved through a combination of high oil prices, the selling off of municipal and provincial assets which ultimately cost Albertans more in the long run, and heavy cuts to infrastructure and social spending that are merely deficits of a different kind.
At the same time the development of the O&G industry put great strain on existing infrastructure with schools massively underfunded, understaffed and with too many students[3] and the Alberta capital of Edmonton not having a new hospital constructed since 1988 while the population has nearly doubled.[4]
The NDP win in 2015 was a complete aberration that is unlikely to be repeated in the future. From 1971 to 2015 the Progressive Conservatives held power until the combination of electorate fatigue towards their rule and a schism in the party lead to a vote split that enabled the NDP to win. the price of oil promptly shit the bed[5] causing the return of massive deficits and this combined with sustained attacks on the provincial NDP inaccurately painting it as anti O&G industry lead to a narrow NDP defeat and the return of the PCs reborn as the UCP. To look at it another way with the UCP in office until at least 2027 that means that we're looking at conservatives running Alberta for 52 of 56 years or 93% of the time.
It's also noteworthy that in the past twenty years the only Premier to successfully complete a full term and not have to resign in disgrace or be ousted by the party has been the NDP leader. Every other conservative Premier has stepped down before completing a full term. Functionally what's occurring in Alberta is that the Premier is picked at the conservative party leader convention and many centre or centre left Albertans buy party memberships to have a say in the leader because they understand that the actual provincial election does not determine who the leader is.
Your question about why O&G companies care so much about solar and wind production is a good one, I think it's a combination of two things -- One they view the success of it anywhere as a threat to their continued existence and two they have truly bought into the propaganda that their industry puts out about climate change so they're in complete denial about the necessity to move away from hydrocarbon extraction. Alberta was making great strides to move towards renewable energy but those moves were squashed by the UCP in the past few years when they implemented an outright moratorium on new projects which scuttled a lot of projects and has effectively neutered the industry in Alberta as investors are now seeking more politically stable regions for their investments[6] despite Alberta having tremendous potential for solar and wind production[7].
Much of Southern Alberta is located in a region known as Palliser's Triangle[8] which is susceptible to periodic droughts. With much of the region dependent on glacier fed rivers that originate in the Rocky Mountains it is only a matter of time before those glacier sources dry up and ground water sources prove to be insufficient for the burgeoning population of Calgary and the agriculture industry. Tough decisions will need to be made and the current UCP leader's ambitions to double the population of Alberta by 2050[9] may just not be tenable.
[0] https://www.policyschool.ca/wp-content/uploads/2018/10/50-Ye...
[1] https://en.wikipedia.org/wiki/Alberta_budget#Historical_budg...
[2] https://www.cbc.ca/news/canada/edmonton/alberta-s-5-2b-budge...
[3] https://calgaryherald.com/news/in-a-crisis-hundreds-of-schoo...
[4] https://edmontonjournal.com/news/politics/alberta-puts-2m-to...
[5] https://en.wikipedia.org/wiki/2010s_oil_glut
[6] https://www.cbc.ca/news/canada/calgary/solar-wind-investment...
[7] https://natural-resources.canada.ca/energy-sources/renewable...
[8] https://en.wikipedia.org/wiki/Palliser%27s_Triangle
[9] https://edmonton.citynews.ca/2024/08/09/alberta-government-b...