Kyle Roadman, EPUD General Manager
Hello Emerald Customer-Owners,
I’m back with another post related to the future of our Northwest power supply system. Today we’ll examine renewable energy: how it differs from traditional power resources and why its current limitations prevent it from being a full replacement.
Part 3: Renewable Energy – Part of the Portfolio But Not a Replacement
There’s no doubt renewable energy has come a long way and is a valuable component of a balanced power supply system. However, it must be stated that today—here in 2025—the intermittent nature of wind and solar resources is simply not a 1-1 replacement for legacy resources.
Pointing out the reasons why requires drawing a distinction between electricity delivered “on demand” and that delivered “as available”. Legacy power resources (coal, gas, nuclear, and hydropower) can be delivered on demand at all times of day and night. We call this type of power “firm” or “dispatchable” and the predictability helps operators keep the grid stable. Which, in turn, leads to lower and less volatile pricing.
Renewable power, on the other hand, is dependent on short-term weather (the wind must blow or the sun must shine). Although our industry has become much better at forecasting when this will happen, these sources of power will always require some type of backup option to keep the grid reliable. Traditionally, this backup has been provided by legacy resources, most notably natural gas and hydropower.
A typical power supply system might look something like the following, where the horizontal axis represents each hour in a day and the vertical axis represents megawatts of energy:
Each component in the chart represents the following:
- Black line (top): Total energy demanded on the system throughout the day.
- Blue area: Hydroelectric resource providing a “firm” (largely constant) amount of energy.
- Purple area: Natural gas resource that flexes up and down on demand (“dispatchable”).
- Green area: Wind resource that moves up and down as available (“non-dispatchable”)
- Yellow area: Solar resource that shows up in daylight hours (“non-dispatchable”)
Clearly, the heavy lifting here is done by the hydroelectric and natural gas supply. The renewables show up to the party when they feel like it, but it’s the other resources that are counted on to be reliable around-the-clock and ramp up or down.
Moreover, because renewable power only generates some of the time, it requires us to massively overbuild to achieve the same amount of total electricity generation. The chart below shows what’s known as “capacity factor” (or how often each resource type produces power compared to its maximum output):
Source: U.S. Department of Energy
This shows that wind and solar power only generate about a third of the time. Solar power in Oregon is far worse, with just a 16.6% capacity factor statewide (and likely closer to 10% west of the Cascades).
What does this mean in practical terms? To generate the same amount of annual energy as a “firm” resource like natural gas or nuclear, solar projects must be built 3-5X as large (think 3-5X the amount of land or 3-5X the number of solar panels).
In fact, the land use requirements for replacing existing Northwest resources with wind and solar would be 20 to 100X the area of Portland and Seattle combined:
Source: E3 Study: Resource Adequacy in the Pacific Northwest
Even with this massive overbuilding, other resources would still be required when the sun doesn’t shine and the wind doesn’t blow. This is particularly true during extreme cold weather events, when wind and solar both tend to produce zero output. This unfortunate phenomenon is so well known it’s been given a cute German nickname: dunkelflaute. Meteorologists call it anticyclonic gloom.
Whatever the label, the fact that wind and solar power don’t produce when we most need it is a huge problem for grid reliability. Never was this more apparent than during the January 2024 cold spell when hydropower picked up all the slack.
Given these characteristics and the continued rush to remove legacy resources from the grid, it’s no wonder the system has become more volatile.
Finally, assuming we did want to massively overbuild on renewables, our ability to do so is far from certain. Although the U.S. is a leader in many areas, building new infrastructure is not one of them. Between land use and environmental laws, trying to permit new power resources and the transmission that goes with them is a major challenge.
Here’s a recent example close to home. For years, the State of Oregon and the Federal Government have been looking to site offshore wind projects along the Oregon coast. All the interested parties seemed to agree this would be a useful application of our natural resources. However, when the auction was to be held for developers to move the idea forward, it only took a few interests speaking out to get the entire thing canceled:
Source: OPB
This is far from an isolated case. In fact, the Northwest seems to be particularly good at holding up any new renewable energy projects. Our backlog is the highest in the nation:
Source: https://www.motive-power.com/gridlock-visualizing-the-u-s-clean-energy-backlog/
All of this is to say, as we rush to remove legacy resources from the Northwest power supply system:
- Our only current options to replace them are intermittent renewable resources.
- This adds volatility and cost to the system.
- Replacements are unlikely to be built at anywhere near the scale required.
How does this reality play out over time? As luck would have it, our neighbors to the south have provided a real-world case study for us look at.
In the next post: what we can learn from the California experience.
Please stay safe,
