New Delhi, June 30 : As the world contends with a global energy crisis, nuclear power has the potential to play a significant role in helping countries to securely transition to energy systems dominated by renewables, a new special report by the International Energy Agency (IEA) said on Thursday. In countries that choose to continue or increase their use of nuclear power, it can reduce reliance on imported fossil fuels, cut carbon dioxide emissions and enable electricity systems to integrate higher shares of solar and wind power. Building sustainable and clean energy systems will be harder, riskier and more expensive without nuclear, according to the new report, Nuclear power and secure energy transitions: From today's challenges to tomorrow's clean energy systems. Nuclear power is today the second largest source of low emissions power after hydropower, with nuclear plants in 32 countries. About 63 per cent of today's nuclear generating capacity comes from plants that are more than 30 years old, since many were built in the aftermath of the 1970s oil shocks. But a range of both advanced and emerging economies have recently announced energy strategies that include substantial roles for nuclear power as well as considerable financial incentives to invest in it. "In today's context of the global energy crisis, skyrocketing fossil fuel prices, energy security challenges and ambitious climate commitments, I believe nuclear power has a unique opportunity to stage a comeback," said IEA Executive Director Fatih Birol. "However, a new era for nuclear power is by no means guaranteed. It will depend on governments putting in place robust policies to ensure safe and sustainable operation of nuclear plants for years to come -- and to mobilise the necessary investments, including in new technologies. And the nuclear industry must quickly address the issues of cost overruns and project delays that have bedevilled the construction of new plants in advanced economies. As a result, advanced economies have lost market leadership, as 27 out of 31 reactors that started construction since 2017 are Russian or Chinese designs." In the IEA's global pathway to reach Net Zero Emissions by 2050, nuclear power doubles between 2020 and 2050, with construction of new plants needed in all countries that are open to the technology. Even so, by mid-century, nuclear only accounts for 8 per cent of the global power mix, which is dominated by renewables. Despite moves to extend the lifetimes of some existing plants, the nuclear fleet operating in advanced economies could shrink by one-third by 2030 without further efforts. While plant lifetime extensions require substantial investment, they generally yield a cost of electricity that is competitive with wind and solar in most regions. /IANS