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Monday, May 25, 2009

HSA, the future of fusion (solar) power

Replacing all of the electricity used in a typical home with photovoltaic panels is presently not cost effective--too expensive. We use too much electricity. The panels cost too much. But there is another way to look at residential solar. Installing just enough panels to offset your refrigerator and dryer can be viewed as a fancy refrigerator or dryer system. Two of your biggest electricity hogs can essentially become zero fossil energy use appliances.

This is something you will be envied for. Compared to driving a gas hog SUV for show or a poseur pickup truck, this idea, let's call it hybrid solar appliances, or HSA, is an example of an environmentally benign status symbol. Sure they will be pricey, but so are the industrial sized stainless steel ranges, fridges, dishwashers, and the granite countertops found in today's $40,000 (on average) designer kitchens.

The panels will have about twice the lifespan of a typical appliance and by the time you have to replace them in twenty years or so, they will cost a fraction of what you paid for your first ones. I use the word hybrid a lot because, like the word bio, it creates a warm fuzzy feeling in most people.

The concept can be extended to your water heater. Solar hot water panels supplementing your hot water tank can be viewed as one fancy hot water appliance, again driving one of your biggest energy hogs to close to zero fossil energy. Solar panels are very visible and therefor make excellent status displays. You can also put the controller in your parlor to entertain and impress guests.

That pretty much leaves things like lights, computers, and various phantom loads. It's easy and cheap to radically reduce the power used by these things. Replace incandescent lights with curly bulbs, or curly bulbs with much more expensive diode bulbs. Use sensors to control many lights and use timers on fans. There are all kinds of smart power strips available now that will turn off your various charger transformers when not in use. There's even a widget that will power down your computer when it detects you have departed.

Another way to view grid-tied residential solar is that, as far as the power company is concerned, it's equivalent to turning off electric appliances. They can't make money off you if you don't use their product.

The latest solar power plants are using concentrated solar rays to create molten salts that are stored for later use to heat steam to turn turbines that spin generators to make electricity. They can generate electricity for extended periods of time when the sun isn't shining.

Studies have shown that with a properly designed electric grid, wind and solar power can be combined to keep the lights on because when the sun isn't shining the wind is always blowing somewhere, or vice versa.

I just read an article in Science, which mentioned that load-peaking natural gas power plants are now more expensive than solar:

A power plant using natural gas can be quickly fired up or shut down to provide extra electricity when needed, like say on hot sunny days when airconditioners are being used. Coal fired plants cannot easily be turned off and on because it takes a lot of effort and expense to get the coal burning. They are designed to run continuously.

The sun is a giant fusion reaction. The future will be determined by how efficiently we capture its power. I will be cutting my home's electric use in the coming months and will keeping readers abreast of developments and projects.

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(photo credits frielp and The Lebers via the Flickr Creative Commons license).


  1. Another water heater energy diversifier is a heat pump. I have been using one the past year and really like the idea of getting away from using electric resistive heating for water heaters. This would work well in conjunction with solar hot water, especially in climates such as Wisconsin where large spans of time can occur with little direct solar radiation. Estimated energy savings with a heat pump over resistive heating is 50%-this is the same estimated savings in electricity that solar hot water systems claim for Wisconsin's climate.

  2. Good point, Shawn but be careful. A heat pump water heater will cool the air around it so if you put it inside your home's insulated envelope, your hot water bill will go down but your home heating bill will go up (in the winter). No problem in the summer where is will act like an air conditioner stuffing heat into your insulated water tank. I'm thinking of using one in my unheated basement that never gets very cold so there is still plenty of heat for a heat pump to get at.

    A test of one of these in Seattle in the winter did not go as well as in other cities because our water in the winter comes from snow melt and arrives very cold.


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