Can overcast Seattle be a solar-powered city? Is it even worth trying?

Climate Lab is a Seattle Times initiative that explores the effects of climate change in the Pacific Northwest and beyond. The project is funded in part by The Bullitt Foundation, Jim and Birte Falconer, Mike and Becky Hughes, University of Washington and Walker Family Foundation, and its fiscal sponsor is the Seattle Foundation.

Let’s get the bad news out of the way, quick like with a Band-Aid.

Western Washington is one of the worst places in the contiguous United States for solar energy. Perhaps even the worst place.

That might not come as a huge surprise. The whole rainy aesthetic is a core part of the identity out here, after all. But it sure hasn’t stopped people from slapping solar panels on their roofs anyway.

Since 2019 the statewide installation of solar panels has grown 15% each year, said Reeves Clippard, a board member with the Washington Solar Energy Industries Association. And according to Seattle City Light, the solar scene has more than doubled in the city since 2018. There are now more than 8,860 rooftop installations across the utility’s coverage area.

Renewable energies like solar, wind and hydropower are essential as Washington rushes to rid its energy grid of fossil fuels, which generate greenhouse gasses and exacerbate the worst effects of climate change. The Clean Energy Transformation Act requires utilities to supply customers with 100% renewable or non-emitting energy by 2045.

And more solar is on the way. The state will see more than $156 million from the federal government for rooftop and other solar projects. Gov. Jay Inslee called the windfall “heaven sent,” late last month. That’s also on top of federal tax credits for solar panels and any other local grants or incentives floating around.

Despite all that growth and cash, solar power accounts for less than 1% of Washington’s total electricity demand. That’s one-tenth of the power generated by wind farms and one-fiftieth of the electricity from hydropower.

That begs the question, are solar panels worth it in Western Washington? Before we answer that, let’s explore the different types of solar projects.

What are the different types of solar projects? 

Let’s separate the technology into two categories. One is utility-scale projects (think huge arrays in sunny places), and then there’s the smaller stuff: rooftop and community solar, meant to power individual homes or communities.

Large and expensive solar projects can generate large amounts of power, and would be worthwhile in Western Washington if (and that’s the key word here) they check all the right boxes, said Mel Clark, president and CEO of the CleanTech Alliance, a clean-technology industry group operating across the United Sates and Canada.

Of course, the thing has to make financial sense for utilities and developers to consider it.

Finding the right spot for a large project can be a difficult, time-consuming and controversial process.

The location will influence when the project would be able to generate electricity, Clark said. Some places are sunnier than others.

According to the National Renewable Energy Laboratory, Western Washington ranks at the lowest amount of solar energy per square meter in the United States.

Then you’ve got to determine whether existing transmission lines can carry the electricity from the array to customers, Clark said.

Does the site have space for battery storage or other renewables like wind turbines? Are there local, state or federal incentives?

These are a few of the considerations.

And so, you ask, how often do the sun and the moon align to make a large-scale solar project worthwhile in Western Washington?

They haven’t yet, really.

Large solar projects in Washington, tracked by the U.S. Energy Information Administration, are all out east. Even then, there are only six. For context, Oregon has 113 solar projects, Idaho has 11 and Montana has 8.

That’s not to say solar projects won’t pop up west of the mountains in the future, but to give you an idea of the challenges involved.

Solar just isn’t really worth it here for bigger projects, Don MacKenzie, an associate professor of civil and environmental engineering at the University of Washington, said in an email. Land and labor costs are higher and the sun doesn’t shine as much.

Utilities and developers would be better off spending their budget on projects eastward or on a different form of renewable energy, he said.

What about rooftop and community solar? 

Here’s where it might make a little more sense.

First, these are one of the few actionable ways you (yes, I’m talking to you) can directly influence the energy grid. Chances are you can’t build a wind turbine in your backyard and you sure can’t build a hydropower plant there either. But if you’ve got the right conditions at home, you can put up solar panels.

Money is still a factor but Clippard, also chief strategic officer and co-founder of A&R Solar, said the cost has dropped precipitously over the past decade or so. Now, a residential rooftop solar system costs about as much as a car, he said.

Whether that’s an economy or luxury car is up to you and your bank account, Clippard said.

And the panels do work, Clippard said. They’ll lower your utility bill and generally can pay for themselves about halfway through the warranty period, perhaps 10 or 15 years in.

On the whole, rooftop and community solar projects in Western Washington likely reduce greenhouse gas emissions, MacKenzie said. They’re just a more expensive way to do it.

There are a few larger rooftop projects in the region, like at Ikea in Renton, on top of the Harborview Medical Center or even on Decatur Island. 

But even for some of the larger community projects, utilities like Puget Sound Energy are looking to the east.

So what’s solar’s place in Western WA’s energy future?

Rooftop and community solar projects might not be the solution, Clark said. But they’re absolutely part of the solution. Especially as energy demand is expected to increase sharply in the years ahead.

“We are going to need more generation, that’s the flat truth,” Clark said. “We can’t turn away from a proven tech that’s getting rapidly cheaper.”

Plus, there are a few extra benefits of rooftop and community solar in Western Washington. These projects are increasingly accompanied by battery storage, meaning they can store power and tap into it as needed rather than just when the sun is shining.

Installing solar panels on top of existing houses or businesses also means you’re not cutting into farmland or green space.

Sure, rooftop panels won’t generate as much electricity but little projects do add up and pave the way for more to follow, Clark said. The option also gives people and businesses something they can do today; it’s a chance to be part of the solution.