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The power grid produces as it is consumed. Energy production rises and falls in tandem with human activity, allowing electricity to flow continuously into homes and businesses. However, this flow can be interrupted.
If there is not enough energy to meet demand, there is a blackout. If energy demand drops suddenly and too much energy is being produced, generators are turned off to prevent equipment damage.
A successful power grid is flexible and responsive to demand. It must be able to rise to meet heavier loads and it must be able to slow down when demand drops.
This is never an easy task, but it is more difficult during extreme weather. Heat waves and cold snaps can cause spikes in demand as consumers crank up their heaters or air conditioning. Extreme weather can also impact some energy sources, namely wind power.
The Pacific Northwest has worked to incorporate both wind and solar power into the grid. But these sources do not respond to spikes in demand. Instead. They fluctuate based on the weather.
“While wind is a solid addition to the grid during normal temperature regime and when the wind is blowing, when it is the absolute hottest or coldest in our area, the wind does not typically blow, and hydropower must pick up the difference,” Paul Ocker, Chief of the Operations Division for the Walla Walla District, said.
Hydropower is reliable
In the Pacific Northwest, hydropower provides about 60% of the region’s energy needs. Because the river is always flowing, hydropower is always available to fill demand. In a hydroelectric dam, a generator unit can go from producing 0 to 100 megawatts in about two minutes, making it both reliable and flexible.
Because of this, hydropower is crucial during periods of extreme cold or extreme heat, when demand for air conditioning or heaters skyrockets. No other energy source can respond as quickly to the changing needs of the power grid.
“While I enjoy having solar panels on my home, I have learned that in summer we can have up to 18 hours of usable daylight to generate (not all at peak efficiency of course), but in winter, we can have as low as seven hours of usable sunlight. The efficiency of solar is also reduced by things such as clouds and wildfire smoke and of course in the nighttime hours, leading to increased uncertainty of providing power to people when they need it,” Ocker said.
Wind power drops during temperature extremes, and solar power is only available when the sun is shining. Because these sources are unreliable, the power grid turns to hydropower to pick up the slack.
“For every megawatt of wind on the grid, you need a megawatt of hydropower to back it up,” Chad Rhynard, Chief of the Technical Support Branch for the Walla Walla District, said.
When demand spikes
In January 2024, the Pacific Northwest experienced an intense cold snap, and, on Jan. 13, the Bonneville Power Administration had a record-breaking energy load of 11,396 MW. BPA was able to meet that demand using the region’s one nuclear plant and federal hydropower dams.
“The lower Snake River dams made major contributions to BPA's efforts to keep the lights on during the cold snap. Combined, Lower Granite, Little Goose, Lower Monumental and Ice Harbor dams peaked to more than 1,000 [average megawatts] each day from Jan. 13-16,” a news article published by BPA on Jan. 31, said.
The four lower Snake River dams are often called upon when there are limited options to meet high energy demands. Between June 25 and 30 of 2021, the Northwest experienced near-record temperatures. During this period, the four lower Snake River dams contributed energy production that ranged from 439 to 1,009 MW. For context, that’s enough to power between 300,000 and 700,000 homes!
In addition to energy production, the four dams provided another crucial element to the power grid: energy reserves. To avoid a blackout, BPA must have the ability to call on energy reserves when it needs them. For example, if generators on the grid go out of service unexpectedly, other generators must be available to increase their energy output instantaneously to ensure grid stability.
“Over this five-day heatwave, BPA transferred some reserve requirements to the four lower Snake River dams. At times, these four dams held 15% of BPA’s total required reserves, peaking at 220 MW. At their highest, these dams provided 1,118 MW of combined energy production and reserve capacity,” a news article published by BPA on July 22, 2021, said.
In 2022, the West Coast again experienced a serious heat wave, this time during the first week of September. California specifically found itself in need of additional energy production to support the high demand for air conditioning. This energy came from the Pacific Northwest, specifically from hydropower. According to the Public Power Council, “exports from the Pacific Northwest increased to 8,000 MW, the maximum volume that transmission paths to California can support.”
During this event, the lower Snake River dams provided crucial energy production capacity. This assistance peaked at 1,454 MW during the critical hours of energy demand on Sept. 6.
When generators fail
Hydropower’s role as a power reserve cannot be overstated. When other energy production sources go down unexpectedly, hydropower can ramp up fast enough to prevent blackouts.
In the first months of 2021, the lower Snake River dams were called upon to fill a gap in energy production. During this period, a deep freeze caused a spike in energy demand, but the gap widened abruptly when Chief Joseph Dam experienced an equipment failure and had to shut down.
“Technical issues at Chief Joseph Dam on the upper Columbia River impacted generation at the facility. Some of the electricity production and reserve requirements were transferred to the four lower Snake River dams, which are equipped to provide valuable operational agility and flexibility,” a news article published by BPA on June 16, 2021, said.
Chief Joseph is one of the largest dams in the Federal Columbia River Power System, and the production capacity of the lower Snake River dams was vital for preventing a blackout in the region.
In May 2018, Columbia Generating Station, the only nuclear energy facility in the Pacific Northwest, shut down when the main power transformers disconnected from the grid. CGS dropped from producing 1,158 MW to 0 MW in an instant. That’s enough to power over 800,000 homes! But, because of hydropower, the power grid was able to quickly adjust and make up the difference.
These are just a couple of examples of how hydropower’s flexibility has filled unexpected gaps in energy production. In North America, regional power grids are interconnected, and hydropower in the Pacific Northwest has been called upon to fill energy production gaps in places as far south as Arizona and as far north as Canada.
“A good electric storage system could help alleviate the uncertainty, but until we have that, our storage system is the water, which allows us to make hydropower and meet our society’s need,” Ocker said.
Time and time again, hydropower proves itself as both flexible and reliable. In both frigid winters and sweltering summers, hydropower dams can ramp up energy production to keep the lights on across the region.
| Date Taken: | 12.12.2024 |
| Date Posted: | 12.12.2024 16:21 |
| Story ID: | 487354 |
| Location: | WALLA WALLA, WASHINGTON, US |
| Web Views: | 71 |
| Downloads: | 0 |
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