{"id":2795,"date":"2018-05-18T09:00:55","date_gmt":"2018-05-18T13:00:55","guid":{"rendered":"https:\/\/kneedeepinit.com\/?p=2795"},"modified":"2019-09-01T09:49:52","modified_gmt":"2019-09-01T13:49:52","slug":"sound-of-sunshine","status":"publish","type":"post","link":"https:\/\/kneedeepinit.com\/sound-of-sunshine\/","title":{"rendered":"The Sound of Sunshine"},"content":{"rendered":"\n

This is a follow-up to the previous post<\/a> about our solar power backup system. Fair warning: this post contains a lot of technical jargon, but it’s necessary to answer some of the questions our technical readers have. It’s a challenge to satisfy a broad audience, so if this isn’t your thing, we understand. In fact, Deb says her eyes glaze over at some of this. But I’m going to  dig in a little on the technologies, technical aspects of how to size the system, that sort of thing. Either way, if you haven’t already, I urge you to read the previous post<\/a> first to get the bigger picture. Go ahead, I’ll wait… Done already and want more? OK, let’s go!<\/p>\n

Not long ago, my good friend Paul tried to convince me that solar power is going to ride a slope like Moore’s Law<\/a> did with computer chips during our illustrious technical careers. As many of you know, the law was named after the founder of Intel, Gordon Moore, who observed and predicted in 1965! that there would be a doubling of transistors in an integrated circuit every year for the next decade. A decade later, he revised it to every 2 years, and this proved to be very accurate for many decades to come. Some other big-shot at Intel muddied the message some as he pegged the doubling time at 18 months, because the transistors were getting faster as they got smaller, so performance<\/em> would double in 18 months or so.<\/p>\n

But Gordon Moore was right for a long, long time. In any case, many people including Mr. Moore, predict it will end it’s reign by 2025, and some are even calling it done now, in 2018. So is solar next to ride that crazy exponential curve?<\/p>\n\t\t\t\t\"Graph\n\t\t\t\t\t\tCredit: https:\/\/www.cringely.com\n

I really don’t know but I argued, because I like to argue with Paul, that I’ve only seen photovoltaic efficiency go from 8% when I first heard the term \u201cphotovoltaic<\/a>\u201d in the 80’s, up to around 24% for production panels today. So that’s a doubling and a half in around 35 years, which doesn’t say to me \u201cthis thing is really taking off!\u201d. Efficiency in this case means how much electrical energy you get (out of the photocells) vs. how much light energy you put in (from the sun). Now research level solar cells are producing electricity at over 40% efficiency, so there is definitely hope for real gains in the future. Add to that the investment dollars that tech companies are making, and the fact that China has taken over the production of these things and driven down the cost, and the picture gets brighter all the time. Besides, what do I know? I’m the only person I know who lost money on that shining star of high tech Apple (AAPL)<\/a>!<\/p>\n\t

Fortunately I’m not trying to solve the world’s big energy problems, I’m just trying to solve our little energy problem in our little house on this little island. Because of the really unreliable power delivery here since Hurricane Maria, we need some backup power. As mentioned in the previous post, when power was knocked out on the island by Hurricane Maria, the Federal Emergency Management Agency (FEMA) and the U.S. Army Corps of Engineers (USACE) supplied big loud gasoline generators to all the key businesses on the island. And homeowners added to the noise with their own generators. I don’t fault them, but frankly, the noise is a bit ugly amongst all the beauty that is Vieques.<\/p>\n

So, we wanted a backup power system, but what were the requirements? Any engineer knows you have to start with the requirements, the customer need if you will, to know what to build. In this case, the customer (which is us) needed or wanted the following:<\/p>\n

Need:<\/p>\n