The margin between national demand and available capacity is still low or negative (particularly in peak hours), and power stations are under strain, such that surges in demand, which are common during winter, or drops in supply, often a result of a lack of coal for power plants, result in another phase of rolling blackouts. The government and Eskom are currently planning new power stations, at cost to the South African consumer. The power utility plans to have 20,000 megawatts of nuclear power in its grid by 2025.