When temperatures are at their worst, the flexibility and reliability of Northwest hydropower assures you can cool down or heat up your home with a few clicks of the thermostat or the flip of a switch. 

As people turn up their fans and air conditioners during heat waves or crank up their heaters and electric blankets during cold snaps, demand on the power grid can soar to record levels. Without the massive generating capacity of hydroelectric dams, and their ability to readily convert water into energy, there simply wouldn’t be enough dependable power to meet those electricity demands and keep the lights on

Jump-starting the grid

Hydropower is up for the challenge presented by extreme temperatures thanks to its agile, flexible and reliable nature. If severe conditions such as snowstorms and wildfires cause major outages, hydropower is one of few resources – and the only renewable energy resource – that can jump-start the grid after a blackout. This process – known as a “black start” – ramps up operations of a power plant from a completely unenergized state without drawing on the electric grid for external power. In minutes, hydropower plants can power up other generating plants and restore power to the grid. 

Hydropower: The perfect complement to wind

Wind and hydropower are both low-cost, renewable energy sources. But unlike hydro, wind turbines are an intermittent power source, which means it is dependent on a fuel source that is not always available. The wind doesn’t always blow, and wind turbines usually can’t produce power unless there is a minimum breeze of 6-9 mph. 

Most of the region’s wind generation is located on the east side of the Cascade Mountains, where it is commonly windy. But when extreme weather conditions – hot or cold – hit the Northwest, wind generation tends to plummet. Why does that happen? Most of the time, noticeable temperature and pressure differences on either side of the mountains, known as gradients, cause winds to blow from west to east. During a regionwide extreme weather event, those temperature and pressure differences shrink, bringing normally windy generating locations to a standstill. 

When wind generation is low, hydropower can quickly ramp up to make up the difference and keep the region’s power supply and demand in balance. With more variable renewable resources like wind and solar rapidly coming online, hydropower’s role as a balancing resource is more important than ever.

The big Rs: Reliability, resiliency, redundancy and reserves

With their ability to quickly ramp up or down at any time, dams can reliably provide power at a moment’s notice to keep the grid stable during extreme winter and summer temperatures. Another key characteristic of hydropower that makes it reliable is its efficiency. Hydropower plants can convert as much as 90% of the available energy from falling water into electricity, so they are especially critical when resources are tight during extreme weather events. 

Hydropower supports a resilient grid in the Pacific Northwest due to the diversity of hydroelectric generation across the region, which gives operators options during a crisis as they work to maintain grid reliability. As an example, if one area experiences operational or technical challenges, the grid is designed with redundancies to deliver power from other locations. 

Hydropower also has the advantage of storage thanks to reservoirs. During the frigid January 2024 winter storm, the output of the FCRPS ramped up during the day to meet the high demand for electricity, but at night during light-load hours, water was held back to maximize power generation later when it was needed most. 

No matter the daily forecast, hydro facilities provide stability and significant grid resilience, powering the Northwest through whatever weather is thrown our way.