Around 50 Unite union members at the Stonebyres, Cruachan and Glenlee hydro-electric power stations have voted to strike by 84.6%, on an 86.7% turnout.
The Drax Hydro workers also voted by 92.3% to take action short of a strike, which would involve an overtime ban.
They include engineers, plant controllers, as well as mechanical and electrical craft workers.
The strike action days are expected to take place from mid-March, with Unite making an official announcement next week.
The vote for strike action, and action short of a strike, follows the rejection of an offer (8%), which is significantly below the current rate of RPI inflation at 13.4%.
Drax Hydro's latest accounts showed that it made £2.3m of profits in 2021.
The trade union predicts the strike action in Scotland in conjunction with a separate pay dispute involving Unite members at the Drax power station in Yorkshire could lead to the UK facing power cuts. Unite has announced nine days of strike action at the Yorkshire plant from late February into April.
Unite general secretary Sharon Graham said: “Drax Hydro is a profitable energy company and it can afford to pay its workforce significantly more than the current offer.
“It is also part of a wider Drax Group, with underlying earnings for last year projected to be around a staggering £680m; this is a classic case of corporate greed and now the UK faces a threat of power cuts due to Drax’s greed.”
The Drax Group generates around 11% of the UK's renewable energy and a fifth during peak periods.
Elaine Dougall, Unite regional co-ordinating officer, said: "The pay offer on the table by Drax Hydro is unacceptable.
“Unite will not tolerate real terms pay cuts and our members are determined to get what they deserve - it should not have needed to come to this point as the parent group is awash with hundreds of millions in profit.”
Drax responded that the industrial action would not put electricity supplies at risk, adding that plans were in place to ensure all its sites remained safe.
A spokesman for the company said: “We are deeply disappointed that Unite is planning to go forward with this unnecessary action, which will see colleagues lose money instead of securing a significant pay rise.
“Drax remains open to dialogue with Unite to avoid industrial action.“
Separately, energy regulator Ofgem recently announced that following an investigation, Drax Pumped Storage - a subsidiary of the parent group - paid a fine of £6.12m for breaching the Generation Licence by submitting excessively expensive bids to turn down its generation in the balancing mechanism.
As a result of Ofgem’s compliance work, the company admitted to having breached its licence, specifically the Transmission Constraint Licence Condition, which prohibits generators from being paid, or seeking to be paid, an excessive amount during times of transmission system constraint.
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