In the modern world power production and its sources play the fundamental role in economic development and state security. In the 20th century electricity demand was provided with fossil fuel power plants and the greatest breakthrough was done by nuclear power. Nowadays many countries including Ukraine face the challenge of nuclear power replacement before or after its operation expire date with new sources of renewable age. The purpose of this paper is to show whether cost competitive utility scale solar PV power plants deployment in Ukraine could help in replacement nuclear power in till 2035. Thus the core objectives of this paper is to assess the electricity demand in Ukraine till 2035 caused by nuclear power phase out as well as the cost-competitive potential of utility scale solar PV power plants to cover such demand, barriers and policy instruments for realisation of such potential. These objectives were reached by data collection method and comparison approach of nuclear and solar PV power costs as well as assessment of current and suggested incentive solar PV support instruments. This research shows that current balance of Ukraine electricity mix and electricity generation in peak load period as well as current incentive solar PV policy will constrain PV deployment in Ukraine after 2020 and would not make considerable impact on nuclear power replacement. Nuclear power with its base load function and low flexibility are strongly colliding with solar PV power and will constrain REN development in Ukraine. Only investment oriented changes in solar PV policy could partly bring positive results to nuclear power replacement with solar power by 2035.