With a transition underway in the global energy industry to reduce greenhouse gas emissions and stem climate change, countries are looking at ways to ensure a continuous 24/7 supply of clean electricity while avoiding power blackouts and disruptions to other critical facilities, such as public transport and medical care.
Nuclear power is one solution, as the International Energy Agency noted this week in a commentary on how the Covid-19 crisis also highlights the need for a secure and flexible electricity supply.
As countries increasingly turn to solar and wind to generate electricity, flexibly operated nuclear power plants (NPPs) can provide a reliable stream of low carbon power as well as fill the output gaps left when variable renewable sources (VREs) lack sunshine or wind. Likewise, NPPs can adapt their power production when renewable generation varies. This balancing act, known as non-baseload operation, can ensure the supply of power and limit the risk of disruptions by enhancing the reliability of the electrical grid.
But this flexibility comes at a cost. Most existing NPPs are best run at full or “baseload power” because with high upfront costs but very low operating costs, their economics depend on running close to capacity over many years.
“Flexible operation results in higher operation and maintenance costs, and the magnitude of those costs will depend on the grid system’s flexibility needs,” said Nikhil Kumar, a contributor to a forthcoming IAEA report on the economics of flexible operation and Managing Director at U.K.-based Intertek, an assurance, inspection, product testing and certification company. “These costs increase as the depth and periodicity of load following increases.”
France, where NPPs provide almost three-quarters of the country's electricity, has years of operational experience adjusting output based on electricity demand. Around two-thirds of France's NPPs utilize load following and frequency control on a regular basis, which helps minimize the days per year in which electricity generation exceeds demand.
Germany also uses load following and frequency control to respond to market demand and ensure grid stability. Load following NPPs have helped integrate greater shares of variable renewable sources, which produced almost half of Germany’s electricity last year and are expected to further expand in years to come.
“The outstanding issue in many power markets is what kind of value to assign to these services for the grid,” said Victoria Alexeeva, an energy economist at the IAEA. “In the absence of an adequate valuation for such services, nuclear power’s economic competitiveness is reduced,” added Nesimi A. Kilic, an IAEA nuclear engineer.
Amid the clean energy transition, electrical grids may face different challenges.
Last August, for example, the UK suffered its most severe power outage in more than a decade — a blackout of between 15 and 50 minutes for more than a million customers that disrupted some passenger trains and caused a temporary loss of power at one hospital and airport. In a report last month, Germany’s grid operators said the country may need to import electricity at times in the coming years as firm sources such as coal and nuclear are retired.
The IAEA supports countries in understanding all relevant aspects of flexible NPP operation through publications, workshops and technical meetings, including one held in Phoenix in the U.S. state of Arizona in December 2019. Around 60 plant operators, regulatory officials and policymakers from 10 countries discussed “future energy needs and proactive actions that would ensure nuclear power plants continue to provide clean, affordable and reliable power to people around the world,” said Robert Bement, Executive Vice President and Advisor to the Chief Executive Officer at Arizona Public Service, which hosted the meeting.
The IAEA is also working with governmental and non-governmental bodies, including the Flexible Nuclear Campaign for Nuclear-Renewables Integration. The campaign—a project of the Clean Energy Ministerial led by the Nuclear Innovation: Clean Energy Future (NICE Future) initiative — seeks to model revenue for flexible NPPs, including costs and technical requirements.
“A clear understanding of how flexible integrated energy systems — that include both nuclear and renewable energy—can meet our future energy needs must be developed and communicated,” said Kelly Lefler, a Senior Advisor at the U.S. Department of Energy’s Office of Nuclear Energy. “Technical meetings and other initiatives by the IAEA and the Clean Energy Ministerial bring together governments, research institutions, non-governmental organizations and industry to explore innovative clean energy solutions with nuclear power.”
