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People ask me where we will put all the solar panels when everyone drives an electric car and heats their homes with heat pumps. The curiosity is whether solar panels are going to ruin millions of square miles of farmland, or are they going to be just something that gets installed on top of buildings.
To get a sense of what is needed, here are some back-of-the-napkin calculations about the solar you would need if you lived a typical all-electric life, and some idea about whether you could install it on your home.
The average person in Snohomish County drives about 7,000 miles each year, and there are about 2.6 people per household. The average household drives about 18,200 miles a year.
The average electric vehicle gets about 2.8 miles per kilowatt (kWh) hours, which is the amount of electricity you buy from the Snohomish County Public Utility District (PUD). For example, the PUD sells electricity for about 12 cents per kWh. For your driving, you would need about 6,500 kWh each year.
Most people in Washington heat with electricity, and the minority that heats with gas burns about 51 therms of gas each year. About five to 10 of those therms are wasted up the chimney, so the actual number of therms used for heating is about 46 or less.
A therm has the same energy as 29.3 kWh. For heating, a heat pump generates about 3.5 times as much energy as it draws in electricity. To produce 46 therms of heat, a heat pump would use about 385 kWh.
The average home in Washington uses about 27.7 million BTUs of electricity for all purposes other than home heating (and driving). That’s about 8,100 kWh.
Altogether, a typical all-electric home in Washington needs about 15,000 kWh of electricity each year.
In Western Washington, a home gets about 1,000 kWh each year for each kilowatt of installed generation capacity. You can buy a solar panel with 0.44 kilowatts of capacity. (Older panels have lower capacity.) That 0.44 kilowatt panel would produce about 440 kWh each year.
You could generate the 15,000 kWh you need with 34 panels. That 0.44 kilowatt panel covers about 20 square feet. You would need panels that cover about 700 square feet of your rooftop, which is completely doable for most single-family homes.
About half our energy will come from wind
Wind farms will generate about as much electricity as solar. Electricity from wind costs about the same as electricity from solar, and wind can generate through the night, reducing our need for batteries. It would work well if the average home in Washington generated half of their electricity with about 17 solar panels and got the rest from wind farms.
Solar farms use 2% as much land as ethanol-corn farms
Not everyone can install solar on their rooftops. Apartment towers like the tall towers in downtown Seattle do not have enough rooftop for the solar their residents need. Another challenge is single-family homes that never get sunlight. For those homes, some of their electricity will come from solar installations on fields.
As long as we’re using fields to generate energy, some folks would rather grow corn to turn into ethanol. If you want to use farmland to create energy to drive cars, you can cover it with corn that is then transformed into ethanol, or you can cover 4% of your corn fields with solar panels to get the same amount of transportation.
An acre of corn field in the Midwest can be turned into about 550 gallons of ethanol. Ethanol has less power than gasoline. Those 550 gallons are the equivalent of 386 gallons of gas. The average U.S. vehicle gets about 25 miles to the gallon, so one acre can drive a car about 10,000 miles each year.
An acre of solar in the Midwest generates about 200,000 kWh per year. The average EV gets about 2.8 miles per kWh. That means an acre of Midwestern farmland covered in solar panels can power a car about 560,000 miles each year.
As Bill McKibben has pointed out in Here Comes the Sun, solar panels on 2% of an acre would drive cars as far as a full acre of corn. And solar panels require no fertilizer, pesticides or watering.
Solar panels increase crop yields
Solar and agriculture are not an either/or deal. You can have both together. In many places, solar panels increase the productivity of fields. Some solar farms are providing pasture for livestock. Plants need sunshine, but many plants thrive better with less sunshine than is available.
For example, you have heard of “shade-grown” coffee. Even in the Northwest, many gardeners can tell you about the plants in their gardens that thrive in partial shade.
In the Midwest, with our current global warming, many corn fields dry out before the corn can be harvested. Some shade could even help even corn in the Midwest.
Growing produce under solar panels that shade the plants for part of the day allows farm workers to stay in the shade as they harvest the crops. That’s a huge deal as climate change pushes temperatures higher.
Solar panels reduce evaporation
In some places, solar panels are being installed over irrigation canals and reservoirs. Keeping water in the shade reduces how much evaporates, and as droughts worsen with climate change, that’s a big help.
The bottom line: We will put the solar panels on top of our homes, businesses, canals, reservoirs, parking lots, and over our crops and pasture lands. Many farms will install solar panels to improve crop yields and protect workers.
Nick Maxwell is a certified climate action planner at Climate Protection NW, teaches about climate protection at the Creative Retirement Institute and serves on the Edmonds Planning Board.
Thank you, Nick!
Great article! I love the comparison to ethanol. Also it is very important to explain to people that farming can thrive in coexistence with solar panels and irrigation canals conserve water with solar panels above. I loved that book by Bill McKibben … Here Comes the Sun. The bottom line is that Solar is the cheapest form of energy which is why it is spreading across the globe and in poorer places like Pakistan and Africa. Now we need community solar here in Edmonds for those with too much shade like me. Maybe you can write an article about that Nick.
Never was a fan of ethanol as it really turned out to be nothing more than a boondoggle tax credit for Big Agri-Biz. That, and the energy consumed producing the corn-to-ethanol itself far outweighed the energy produced by the ethanol blended gasoline.
But then Solar is no panacea either. The usual suspects rave about the panels and conveniently/purposefully ignore the rare-earth metals strip mining that must be done in mostly 3rd world countries to produce the components for said panels which are then worthless in as few as 15 years.
Interesting that this analysis didn’t include the incredible increase in electrical demand resulting from AI (artificial intelligence) engines. AI appears to be expanding at an exponential rate and is being integrated into all aspects of our lives.
The title suggests the topic to be concerning the placement of the solar panels needed to generate the electricity required without damage to the climate. Nick seems to have stayed on topic.
Excellent article, Nick! In Europe, esp. Germany and Switzerland, we see much farmland with solar panels. I hope to learn which work best with livestock and/or crops.
So educational and informative as usual, Nick. Thank you!
That is a BIG napkin!
I always enjoy your thoughtful articles, Nick. Our house is situated in shade beneath 12 large fir trees, so solar is not an option for us, but I am seeing several of our sunnier neighbors adding solar panels to their homes. At least for now we must be satisfied with our decision to upgrade to a heat pump. And we are inching closer to the purchase of our first EV. Keep the faith, my friend.
Really appreciate all these articles, Nick. Please keep them coming.
Nick, I am happy with my 28 solar panels and they generate what was promised by the installer. But there is no way in Washington that 15 mWh is “completely doable for most single family homes”. I have a relatively large unobstructed south facing roof that generated 8.9 mWh in 2025. Adding additional panels did not make sense because of lower generation due to shade, but 34 panels would have produced 10.9 mWh, which is 72% of what you said. Most single family houses in Western WA are smaller and shaded. PUD would have all the data to tell you how many houses generate 15 mWh per year, but the data will not show that it is doable for most. My guess is your data came from areas with more sun and less shade.
What was the power output promised by the installer of your 28 panels? Was it 440 watts? My 18 panels are about 15 years old and their output is not that strong. Words like approximate, most, about, and average indicate there are many moving parts in this discussion. Mr Maxwell’s article provides a comprehensive look at the scope of a realistic solution for the adequate supply of renewable electricity. For me a takeaway from his work is that individual homeowners, to the extent that they are able, will be integral to this solution.
Thanks for sharing your solar panel performance!
We installed our solar panels 10 years ago, and their capacity is well under 440 kW per panel. Capacity has increased. When did you install your panels? What capacity do they provide?
I linked to the estimate from Seattle City that I was counting on. It also sounds like you have shading on your panels. You won’t match the City Light estimate if you have more shading than they expect.
Even in your location, with your shading, and with panels that work as well as the ones you got, you would need 47 panels to generate 15,000 kWh. 3 feet by 6 feet is a big panel. 47 panels that are 3′ X 6′ would cover 850 square feet. What is the footprint of your house? Do you have 850 square feet of floor space on the ground floor? If you have a roof with a lot of gables and towers, you might have to have some framing installed to handle all the panels. There is a home on Main st in Edmonds between 9th and 8th that has framing like that.
And you really only want to generate about 750 kWh/year. Plan on getting the other 750 kWh from wind.
You are doing great!
Sorry about the typo. You are currently generating 8,900 kWh (8.9 MWh). You only need to generate 7,500 kWh. (Not 750) Leave the other 7,500 kWh to wind. You’re doing great.
Nick — this is unrelated, but do you have any data on how much power Bitcoin mining uses in our state?
As always, a great article. I am on the fence, we have extremely tall trees and use gas heat (becoming more and more expensive un WA State). I think our list if improvements is moving to a heat pump and mini split system then perhaps to solar – I just get concerned about the initial capital outlay and payback period if we sell and downsize. I suspect, on our lot, it would accommodate 4 zero lot line homes or small garden style homes, so I am not sure I’ll ever recoup the initial costs. Our neighbors installed a full array and they seem extremely pleased with theirs, I just wonder if the proverbial juice is worth the squeeze. If natural gas continues to increase, it certainly changes the dynamics and at the pace of cost reduction of equipment (offset by labor and installation increases currently), it may begin to make more sense. Certainly with minisplits, I need to weigh the additional cost. The three or four weeks a year we actually need AC doubles our electric costs when we run the portable units (that are horribly inefficient and extremely cumbersome). I always enjoy these thoughtful and fact based articles!
Hi Nick,
I really appreciate your articles and the depth of research you bring to them. This comment is a bit off-topic, but I’d like to suggest a couple of future pieces that could help inform the community and support the city’s long‑term planning.
The wastewater treatment plant recently added an environmentally friendly carbon‑recovery stage before discharging into Puget Sound. A clear, accessible article explaining how this upgrade works—and the environmental and financial benefits it’s delivering—would be incredibly valuable. As I understand it, this facility is the city’s largest consumer of gas and electricity, so helping residents understand the return on this investment seems worthwhile.
It would also be helpful if you explored options for heating Yost Pool more efficiently and sustainably. Any analysis or recommendations you could offer would give the city and the public a stronger foundation for future decisions.
Both topics could make a meaningful contribution to the community’s understanding of these important systems.
Thank you
Thanks, Jim!
I very much appreciate suggestions. Each month, I turn to writing the next column and find I have 20 different topics I would like to share about. If someone says, essentially, “I would like to hear about idea number 14”, that makes it easier for me to focus.
The wastewater treatment plant is great topic. I recently dug into pyrolysis for the Snohomish Climate Reality group. I’ll give it some attention. Not next month, but probably sometime this year.
HEATING YOST POOL is a great topic, especially since it’s related to heating water in your own home. One analysis found that you could install six solar panels on your home, or you could much more cheaply replace an electric resistance water heater with a heat pump hot water heater and end up with the same reduction in how much electricity your family took from the grid. And, if you have a natural gas hot water heater, you can’t cancel your natural gas without first replacing it.
Thanks!
Nick,
Consider finding out what method of solid reduction (pyrolysis??) is planned for the Lynnwood Wastewater project being designed now. The process occurs in our Edmonds neighborhood, plus we share 11% of the costs. Currently, solid waste is hauled away for treatment.
Nick S
Got it.
Thanks, Nick!