Climate Change Assessment for Hydropower Project Licensing

After initiating a study of climate change impacts on its operations more than a decade ago, Manitoba Hydro incorporated climate change impacts into the environmental assessment and economic assessment of the 695 megawatt (MW) Keeyask Generating Station, located on the lower Nelson River of northern Manitoba. Research shows that changes in climate and hydrological conditions can increasingly affect the future operation, performance and safety of existing hydropower assets. Regulators recognized the necessity to ensure that the new facility would operate effectively and efficiently under climate change, namely, periods of prolonged drought and changes in seasonal water cycles, precipitation, evapotranspiration, radiation and wind. Manitoba Hydro conducted studies about historic climate trends, and developed future climate scenarios, which was incorporated into the regulatory approvals and environmental licensing process.

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Understanding and Assessing Impacts

The Keeyask Project is a 695-megawatt (MW) hydroelectric generating station that is being developed in a partnership between Manitoba Hydro and 4 Manitoba First Nations: Tataskweyak Cree Nation, War Lake First Nation, York Factory First Nation, and Fox Lake Cree Nation. Working together, the Partners are known collectively as the Keeyask Hydropower Limited Partnership. It is located approximately 725 km north of Winnipeg on the lower Nelson River. Well aware of its dependency on climate and streamflows, Manitoba Hydro incorporated the assessment of future climate into its business strategy and resource planning. During the last decade, the study of climate change has become an integral part of several environmental and economic assessments. To assess the potential impacts of climate change, the company’s team of climate-savvy engineers selected five out of 109 Global Climate Model (GCM) simulations to represent future changes in average system inflows through the 2050s—the equivalent of a 35-year planning horizon. The selected projections cover 90% of all the climate simulations’ uncertainty and range from a 9.6% reduction in overall inflows to a 28% increase. To integrate this hydrological assessment into an economic-feasibility analysis, the change signals from the five simulations were added to the observed long-term streamflow database record. The resulting five future stream flow scenarios were then fed into the Simulation Program for Long-term Analysis of System Hydraulics (SPLASH) to estimate average annual revenues. With 70% of the initial 109 climate model projections showing increased inflows, the analysis attributed a higher likelihood of increased revenues to the plan which included Keeyask.

Identifying Actions

Manitoba Hydro’s climate change team—part of its Water Resources Engineering Department— took an anticipatory approach by addressing climate change in the project’s Environmental Impact Statement (EIS) and Needs for and Alternatives to (NFAT) business case. The EIS considered three aspects of climate change:

  1. The effect of the environment, including climate, on the Project;
  2. The effect of the Project on the environment, including greenhouse gas (GHG) emissions; and
  3. The sensitivity of the assessment to climate change.

While the first two were requirements of the federal EIS Guidelines, the latter was done by the Partnership as a precautionary approach to assess whether the environmental assessment conclusions would hold for future climate conditions. Manitoba Hydro chose to develop and strengthen climate-related capacity in-house, eventually assembling a team with the appropriate knowledge and aptitude. Manitoba Hydro became an affiliated member of Ouranos in 2007 to benefit from a large climate database, participate in joint projects and to tap into the experience of other climate experts.

Implementation

The project team prepared reports on the past and projected climate conditions at the sites of new or modified infrastructure. These reports supported the company’s case for climate resilience during environmental review and licensing process for projects such as the Pointe du Bois spillway replacement, the Bipole III transmission line, Lake Winnipeg Regulation and the planned Manitoba-Minnesota Transmission Project (MMTP). Whenever climate-related questions arise in the company, the in-house team responds, and it drives the company to look further into adaptation to climate change. Consequently, Manitoba Hydro, will explore additional steps to better factor climate change impacts into long-term planning. These include exploring future changes to seasonal water-supply variations, droughts, energy demand and peak demand forecasting. Finally, after considering recommendations made by both the Clean Environment Commission (CEC) and Public Utilities Board (PUB), in 2014 the Province of Manitoba issued a licence to the Keeyask Hydropower Limited Partnership for construction.

Outcomes and Monitoring Progress

During the PUB hearings, external expert reviewers scrutinized the company’s analysis. Concerns included that the resolution of the climate models used was inadequate and that the company’s analysis focused exclusively on mean annual runoff and did not address changes to the seasonal cycle and in the severity of drought. However, the rebuttal of the criticism presented little difficulty as it addressed issues that Manitoba Hydro’s climate change team had considered extensively in their studies, for example, the fact that the runoff variable they used integrates changes in precipitation, evapotranspiration, radiation and wind. Shortly after the regulatory hearings for the licensing of the Wuskwatim Generating Station, the company established the Hydrologic and Hydroclimatic Studies Section. Embedded in the Water Resource Department, the section is responsible for providing specialized engineering and expertise across the corporation in the areas of climate change impact studies, hydrology, watershed modelling and inflow forecasting with a focus on environmental studies, resource planning, regulatory review, operations, licensing and technical support during planning, design and construction. The company’s understanding of its climate dependency has increased substantially over time and eventually this knowledge was required to be incorporated into regulatory processes.

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