Cooling for Thermal Generation in a Changing Climate

To strengthen their assets and operations against climate change related impacts, Ontario Power Generation (OPG) implemented adaptive measures in 2016, and subsequently released their first ever climate change plan more recently in 2020. Thermal power plants have large cooling needs, usually met by using nearby water or outside air. Climate change represents a significant challenge for these cooling processes, as it changes the baseline conditions, such as air and water temperature. To meet the challenge, the power sector must pay greater attention to technologies and design options that reduce the vulnerabilities arising from changes in regional climate.

This case study highlights various challenges and respective solutions implemented by three companies around the world. In Canada, Ontario Power Generation (OPG) invested in equipment to prevent clogging of water-intake structures due to ice particles suspended in the lake during freeze/thaw transitions. Then in 2020, OPG released its first ever climate change plan, which commits to using nature-based protection measures, such as, building wetlands to mitigate against flooding, wildfires and other extreme events. Beyond updating traditional technologies and processes, they will continue to integrate climate science and modelling into their investment decision and engineering processes, when considering future design and asset upgrades.

Understanding and Assessing Impacts

Climate change is expected to disrupt thermal generators around the world in multiple ways. The impacts of today’s climate on nuclear power-plant cooling are already felt in Canada. For example, one of the nuclear stations operated by Ontario Power Generation (OPG) on the shores of Lake Ontario is directly affected by seasonal climate fluctuations and their impacts on lake conditions, because it draws its water from the surface of the lake. The Pickering station recently experienced several episodes of unwanted blooms of Cladophora algae during periods of sustained high lake temperatures. In 2007, OPG had to shut down one of its reactors and reduce its power output because of clogged screens and filters in one of its water intakes. Climate change can also favour aquatic invasive species, such as zebra mussels, which stick to, and clog, water intakes and outlets. Overall, the risk to OPG facilities of higher water temperatures and other climate related hazards remains relatively low because its nuclear stations have large design margins. However, should new nuclear or thermal power-generation assets be commissioned in Canada, rising temperatures could become an important design consideration for cooling systems.

Identifying Actions

In 2020, OPG introduced its first ever climate change plan, titled, “Bulding a Brighter Tomorrow: Our Climate Change Plan”. The plan sets ambitious goals that will guide their promise to be a catalyst for efficient, economy-wide decarbonization, mobilizing expertise, suppliers, and industry partners to create a cleaner environment and more prosperous, resilient communities in Ontario and beyond. The plan includes climate change goals, solutions and an action plan for three time periods: 2025, 2040 and 2050.

Implementation

To manage seasonal climate fluctuations and their impacts on lake conditions, OPG runs specialized equipment in winter to prevent ice particles suspended in the lake from clogging the main screenhouse and the emergency water system. In their 2020 climate change plan, OPG commits to using nature-based protection measures like building wetlands to mitigate against flooding, wildfires and other extreme weather events. Beyond updating traditional technologies and processes, they will continue to integrate climate science and modelling into their investment decision and engineering processes, when considering future design and asset upgrades.

The climate change plan sets climate adaptation goals to be implemented by 2025, 2040, and 2050. For example, by 2025, climate change considerations will be embedded into established business processes to ensure resilience is a priority in the maintenance of their generating fleet and the operations of their business. By 2040, they will evaluate full-scale, nature-based solutions to reduce the effects of climate change. By 2050, they will address all generating asset-based climate vulnerabilities to ensure the continued production of clean, reliable power.

Outcomes and Monitoring Progress

Physical climate change adaptation can usually be implemented during either the design or operational phase of a power asset. One of the only options for coping with the impacts of rising temperatures and water scarcity on thermal generation is to build resilience into asset design. For instance, an appropriate water-intake system or cooling technology can help a power plant accommodate projected climate changes, and avoid output reductions and shutdowns. Locating power plants near the coast enables the use of seawater for cooling. Thermal generation units can be retrofitted with increased cooling capacity or with a new cooling system, although this is usually a very expensive option. Taking action on climate change adaptation sometimes requires making trade-offs between economic performance and resilience, especially when power plants draw water from scarce resources.

Next Steps

OPG plans to continue exploring and evaluating all available options to reach their sustainability and climate change goals.

Resources

Link to Full Case Study

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