So how much power do solar panels in the Seattle, WA area generate?

Since people sometimes ask me (or question me) about just how much solar power can be made in a "rainy" place like Seattle, I have decided to post a year's worth of data regarding the output of my panels. But first, notice the images above - they are average "normal" solar radiation levels from a variety of months for the Pacific Northwest (you can see that we get a lot of solar radiation in the warmer months, not so much in the colder months; in fact Seattle gets roughly the same amount of solar radiation as Houston, TX because we have two more hours of sunshine during the warmest time of the year, and only an hour or so less during the colder months).

The output I am sharing is from a 2.7 kilowatt array - my current array is now approximately 4.0 kilowatts after I expanded earlier this month (the additional panels came online on 8/5/10), and figures below represent the readings generated by my inverter and reported to Solar Oregon (the cooperative I sell my renewable energy production to - at 1 cent per kilowatt hour - for resale to power companies and individual customers that wish to subsidize the deployment of additional renewable energy installations). Also note the difference in my estimated output for August 2010 compared to August 2009:

August 2010 (2.7 kw system upgraded to 4.0 on 8/5) - 455 kwh
July 2010 - 335 kwh
June 2010 - 277 kwh
May 2010 - 290 kwh
April 2010 - 219 kwh
March 2010 - 199 kwh
February 2010 - 101 kwh
January 2010 - 45 kwh
December 2009 - 58 kwh
November 2009 - 54 kwh
October 2009 - 122 kwh
September 2009 - 242 kwh
August 2009 - 290 kwh

This period was a little bit unusual, I think, in that we had much sunnier weather in the colder parts of the year (when there are fewer hours of sunlight) and less sunny weather during the warmer parts of the year (when there is more), at least compared to average. In any case, you can see that my 12 month production of electricity adds up to 2,687 kwh of electricity. I will re-post next year's data with a full year of 4.0 kilowatt output.

How much is that worth, carbon offset wise? There are free online carbon calculators you can use to figure out how much carbon the output displaces, but this varies entirely on region (Seattle area gets the vast majority most of its power from renewable sources like hydro, wind, biomass, solar, and such). Using the average figures for the USA though (which is MUCH more coal dependent than anywhere in the state of Washington), my 2,687 kwh for one year of solar energy production results in 1,452 kilograms (3,194.4 pounds) of carbon staying out of the air. Given that my solar panels should be generating electricity for at least 30 years, that adds up to around 45,000 kilograms (about 99,000 pounds) for 30 years worth of production (add 30 - 50% or so to this since the estimated lifespan of the panels is 40 - 50 years). And note, this is comparing electricity used to power a home; if this electricity is used to power a vehicle that would otherwise be burning gas or diesel, the actual carbon reductions should be much higher (I don't have any estimates, sorry).

how much is all that power worth, cash wise? Given that my power company pays me for every kilowatt hour I push back to the grid, and I don't have to pay the power company for all the power I make and use myself, I am looking at well over $10,000 worth of electricity generated by the panels assuming power costs and average of 12 cents per kilowatt hour over the next 3o years (which is a very conservative figure - I would estimate it would cost more like 15 - 20 cents, on average, over that time frame... also note I am using the last 12 months as my figure for calculating, now that I upgraded my system, my actual output should be about 50% higher... so I could say $15,000+).

Anyway, I also receive subsidies from the state of Washington for producing solar power (equal to about $350 - $550 a year) and a small amount ($65 - $75 a year) from selling production credit to Solar Oregon. So there you go... a break down of just how much money my solar panels generate (in case you wanted to know, I estimate a 10 - 12 year ROI, given current incentives in Washington state). What else would you like to know?

Electric Cars and Solar Panels - woo hoo!

I wish I was a little less busy and a little more in the habit of posting. C'est la vie / what can you do? With the sound of Johnny Rotten and Sid Vicious blaring out of the speakers, I should be more inspired though. So let's try this...

Have you been following the news about the new "electric car invasion"? I have, obsessively. I am number four thousand something in line for a Nissan Leaf sometime late this year or early next year, the Chevy Volt should be rolling around streets in some parts of the country by the end of November (at least), Tesla is supposedly hard at work on a sexy new Model S (approximately half the price of the roadster) for 2012, Ford is bringing out an electric utility van (Transport) sometime in 2010, and an electric version of the Ford Focus for 2012 model year, Toyota is playing it safe and rehashing its Prius with a meager 14 mile battery only variant for sometime in the near future (2011?), Porshe is putting together a variety of monstrously powerful hybrid sports cars (that get good gas mileage), Fisker is perpetually just a few seasons away from bringing out their Karma, Coda has some Chinese electric cars just about ready to sell here (someday soon), Aptera's three wheeled car is another car made in San Diego county, CA, and just about every major car maker has something in the works for the next couple of years (even Honda, notoriously critical of electrics as part of the solution for ending our addition to oil, recently said it would make a plug-in electric car of some sort by 2012).

If you crave an alternative to filling you car with gas (or diesel), you won't have long to wait. Even if you can't afford one of these new electric cars, unless something goes horribly wrong, or falls terribly flat, within about 5 - 10 years cars that can be powered by electricity at least part of the time should be within a couple thousand dollars of the cheapest gasoline cars. But what about all the electricity these cars will consume, and how about those big huge batteries... won't these just create new problems?

Of course they will, but I believe these problems are FAR easier to solve than those presented by our continued use of petroleum as our primary fuel for transportation.

I recently installed an additional 1.4 kilowatts of solar panels on my roof (bringing my total maximum output to just over 4 kilowatts of power, or about 3,700 kilowatt hours of electricity per year given my home's location, roof orientation, and typical weather patterns around the Seattle area). As I mentioned I am in line to get an all electric Nissan Leaf sometime in the next 9 months or so. The Leaf has a 24 KwH battery (meaning it holds that much electricity), which is just a little less than 100% of the total output of my 4.0 kw solar array on a sunny summer day - about 25-26 KwH. The estimated distance a Nissan Leaf can travel on one kilowatt of electricity varies drastically, but we can safely say it could go between 4 and 7 miles per kilowatt hour. That means my solar panels can power the leaf for between 14,800 to 25,900 miles of driving per year - more than I will ever drive my electric car, most likely (by the way, in case you are wondering, the ROI on using solar panels to power an electric car is at least 40% faster than using solar panels to power your home, given current gas and electric prices in the Seattle area, according to my estimates). Why do I mention this?

Probably the biggest problem associated with us switching to electric cars is our antiquated electricity grid. It is terribly inefficient, bleeding much of the power we generate into the ether. But, the closer the means of production is to the building, or car, consuming the electricity, the less of that electricity gets lost to transmission. This is why localized power generation should be a primary component of our effort to transform our aging grid - they are simply much more efficient. So, problem (almost) solved - if most people who buy electric cars also buy (or subsidize) solar, wind or other localized power production, there won't be much of an increase in demand for electricity to power these cars. And even if they don't install a few kilowatts of solar or wind on their property or subsidize the cost of installation of it elsewhere in their region (through "green power programs" offered by most major utilities), the current capacity of our power production network could handle the power demands of millions of electrically powered plug in cars (for comparison, one electric car would draw roughly the same amount of power as 4 or 5 plasma TV sets, when charging).

But what about the battery issue? Won't all those batteries mean lots of environmental destruction by mining of lithium and cobalt, etc.? Well, yes... but compared to the damages wrought by drilling for oil (see Gulf of Mexico, Exxon Valdez, Oil spills after first Gulf War, any number of oil spills in Africa, Asia, South America, North America, most of the oceans, etc), refining, transporting, and cleaning up the air, sea, and land after burning it... the use of batteries is much cleaner and much more sustainable than using oil. For starters, the lithium ion batteries that will power the coming generation of electric cars will be useful as power storage for each car for at least 10 years, probably more like 12 - 15. After the batteries reach the end of their useful life as storage for the cars, they can be reused in stationary power systems as back up or supplemental power sources when power usage exceeds standard output, regionally. And if these batteries are not used in this fashion, lithium ion batteries can be recycled much as lead acid car batteries are now (in fact they may be even easier to recycle).

The bottom line is that battery powered cars will not solve all our problems, nor will they (alone) get us off our oil addiction. Likely, we need additional alternatives as well - sustainably made biofuels and eventually hydrogen (which, when used in fuel cells, could essentially be designed to slot directly into the battery storage compartments on today's electric cars - since hydrogen fuel cells powered cars are electric cars that have a fuel cell to generate electricity rather than a battery array to store electricity from the grid). But battery electric cars will get us moving toward a greener tomorrow, and along with investments in better, more efficient mass transportation, better resources for bicycling, and other less carbon intensive forms of travel, they will be a key part of our transition away from oil.

But what do you think?