Speaking at a news conference, Tusk said grid operator Polish Power Grids (PSE) had assured the government there was no need to declare a so-called capacity market alert period, a mechanism used to call reserve power generators into operation when electricity supplies come under strain.
"According to the experts, there will be no need to call on reserve generation because the situation is under control," Tusk said.
He told reporters that the country's Kozienice and Połaniec power plants had earlier reduced output from some generating units because low water levels limited the amount of cooling water available.
Tusk said that on Tuesday the available reserve margin in Poland's power system had briefly fallen below the required level, but added that the situation was not expected to recur on Wednesday.
The prime minister said Poland's electricity and district heating systems had faced a challenging year because of unusually severe weather, including a colder-than-normal winter followed by two heat waves.
'The energy system is safe'
"We remember the July heatwave well, and now we have the August heatwave with record temperatures," Tusk said. "However, I can assure you that the energy system is safe."
He argued that Poland's energy security depends on diversifying power sources and said renewable energy was playing an increasingly important role.
"On days when some power plants have to limit electricity production because it is too hot, photovoltaic installations are generating more electricity than ever," Tusk said.
"The fact that we now have a significant amount of electricity from solar power and wind turbines makes our system relatively secure," he added.
He told reporters that Poland also needed further investment in onshore wind farms to help balance the electricity system, saying offshore wind projects remained important but were relatively expensive because of their scale and construction costs.
Tusk also said Poland had benefited from the integrated European electricity market during the heatwave.
"Although Hungary and Romania also have very high demand today, there is enough electricity available in Europe for Poland at critical moments," he said, adding that Poland has previously imported electricity from Germany, Sweden and the Czech Republic.
The Polish Institute of Meteorology and Water Management forecast temperatures above 40 C in parts of the country on Wednesday, prompting the highest-level heat alerts across much of central, southern and eastern Poland.
Tusk on Wednesday urged employers to protect workers from the intense heatwave, warning that the extreme conditions posed a health risk.
Source: IAR, PAP