Carlos,
I consider myself a "pragmatic environmentalist" (and Libertarian, and adherent to Ayn Rands' theories of Objectivism... but that's another post, on another forum....). As such, I believe in making as small a "footprint" as practical. Key word there is "practical". I do what I can, and admittedly, a lot of what I "can" is afforded by a guy that has TONS of "coin" (who also is keen on being as un-impactive as his life allows). Harsh reality is, the major power companies on the Mainland (and that is ALL "mainlands") loose 66% of their generated power due to line-loss (the inherent loss of power due to the resistance of the power transmission lines). Meaning, when you consume a light-bulb's worth of power at your house, the power co had to produce three TIMES that amount of power at the source. That said, the power companies are able to generate that power SO efficiently that, even though we loose two-thirds of it, it is still produced cheaper and cleaner than WE can do "on sight" (that is, until we begin to develop efficient "neighborhood power generators", that will be able to generate power much closer to the consumer, hence negating the line loss problem--solar, wind, hydro and etc. notwithstanding). It's simply economies of scale.
I implement a system that allows us to live completely "AE", as we are totally without a grid to tie into. HOWEVER, I do consider humans to be at the top of the food chain. If I want/need to run an air conditioner, or desalinate salt water, or fill dive tanks, I'll fire up "Mr. Stinky" and be done with it. Others (most) in my 'hood simply run diesel generators 24/7/365. They have at least three generators each, of varying size, to enable more efficient usage, but a year has 8,760 hours in it, and every one of 'em goes onto their generators!
Now, as for your question. I have friends and family that occasionally have power outages (hurricanes, etc.), that often ask my advice on generators. They say they're gonna hop on down to Home Despot, and git themselves onea them thar lil' generators an' be READY for the next power outage (especially those further north, where the power outages are less frequent--fewer hurricanes, etc, but when they DO happen, HO-BOY!). My caveat is always the same. If you do that, you MUST exercise that lil' gas gennie at least once a month, else when you DO need it, it's gonna resent coming outta retirement. Small gasoline generators simply suck. Invariably, they run at 3600 rpm, to save weight and make 'em more portable. They use tons of gasoline, and yes, they ARE quite polluting. But hey, everyone drives a car, right? Propane generators tend to start much easier after a long hiatus, but they have the problem of using TONS of propane. In my not-so-humble opinion, the best option is to buy as small a DIESEL generator as is practical--too big can indeed be as bad as too small, as the diesel WANTS/NEEDS to run at load. If you need 20 kW, and purchase 35, the unit tends to idle along, never having a chance to work at load, consequently carbon builds up, and the unit begins to not like that (an analogy: if you don't exercise, yer arteries can harden up...). Get a unit that spins at 1800 rpm. Thinkabout it. The unit does it's mechanical voodoo HALF as often at 1800 than at 3600. Longevity and quieter operation is inevitable.
I have not fact-checked this, but a mentor of mine informed me that all smaller diesel engine blocks (four cyl. and below), are manufactured by either Kubota or Yanmar. Except for the Chinese diesels (which are about as popular as a pork chop in a synagogue, and should be avoided at all costs!!). Hence, if you buy a smaller Northern Lites, or Onan, or Cat, or whatever, the block is actually made by Kubota or Yanmar, then affixed to their alternator end. So, my logic has been, why not simply purchase the unit that has been mission-built by the manufacturer of said block? Well, that, and my very first diesel was a new Kubota garden tractor my pop bought new back in '79, and it is STILL going strong, even having survived the steeeep learning curve and harsh abuse my siblings and I put that lil' sucker through! So, I have a soft-spot for the Kubota line of machines. Every machine on my island is either Kubota diesel, or Honda gasoline. Makes for ordering spares easier. I have two Kubota generators (16 and 11kW), a Kubota-powered buggy made by Club Car (and this lil' beast is AWESOME! it's the Club Car 294--check it out!), a Kubota L-39 TLB (Backhoe--also mundo-awesome machine!!), two portable Honda generators, a Honda powered cement mixer, and even a Honda Z-50 minibike that I use to zip 'round the island! There may be a few more Hondas and Kubotas lurking around the Cay, but it's early, and I am only on my second cuppa joe... (oh yeah, and as for outboard motors, I have one word for you: YAMAHA.)
You have gotten some good advice from the earlier posters on this thread--most important is that electrons KILL, and yer planning on swimming in the deep end, so bone up on your knowledge.
Hey, another point... There are some really cool ancient generators out there--units that only spin in the 600 rpm range. They are HUGE, weigh tons, but they sit there goin' "chugida-chugida-chugida-chugida", and they actually sound like music to my demented ears. A REALLY fine website, well worth a coupla hours brousing, is Otherpower.com. These guys are a HOOT! Check out their "projects" page...
atb,
jcc
