Ontario Hydro hasn't existed since 1998 but with an estimated market cap of about $31.8 Bn, Hydro One would be a little pricy for a government of any colour.
Forgetting the merits.........
The Province of Ontario is currently the 47% owner of Hydro One, and its share value is included in the above.
So the outstanding equity is worth 16.85B
But in any re-aqusition, If this were done with an eye to reforming Ontario Hydro, you could use the assets of Ontario Power Generation.
This only works if you intend to retain a public float, but that is plausible with or without a dual-class share structure. Many of Canada's biggest private firms separate out voting control from the wider class of shares.
So if the object were simply public control, as opposed to immediate 100% ownership........I don't think its hard to imagine how to do this or find the money.
The important question though is 'why''? That's not a critique or an endorsement, simply, one needs to know the purpose to evaluate any policy merit (or lack thereof)
OPG doesn't have a public valuation. There have been different estimates in recent years based on available data and reported net income. At the low end, its worth as little as 6B, but that seems very low.
At the high end, its ~30B.
Looking at the broad picture, if I were considering investing in it, subject to a host of ifs and buts, I would peg it at close to an 18B value if given a market float.
So it would be the junior partner in a re-merged Ontario Hydro, but it could realistically result in a zero cash deal in which the Province had a 66% controlling interest.
Add some cash, and you can push that number higher at moderate cost.
Whether any of that is a good idea is a different question entirely.