Re: Solar. Wind gem and arch


Some days there is sun and no wind, other days (nights) there is wind and no sun.  This being the case, I question the value of a comparative study.  If you don't have sunshine, the data used to decide to not have a wind generator doesn't do you much good.

I have installed both solar panels and an Air Breeze wind generator on my Maramu.  I am about 2000 miles from completing my circumnavigation (basically following the wake of BeBe in the last five years), so I've experienced a variety of climactic conditions as well.

My first comment is that solar is definitely the most efficient source for renewable energy.  That being said, my experience has been that this great source is not a particularly reliable source for the majority portion of each day. Unless you are indeed tilting your panels on an hourly basis, the panels do not provide anywhere near peak output until around 10:00am and then fall off considerably at 3:00pm -that's five hours out of 24 of significant output.  Add to this overcast conditions and sail or mast/boom shadow (depending on point of sail or swing at anchor) and this "great source" has considerable limitations.  If you have installed your panels on a stern arch then this may be partially mitigated but then you have added the cost of the arch in your cost/benefit analysis.  Season of the year and  location on the globe plays a critical role in solar panel efficiency/effectiveness.

My second comment is that while a wind generator is a less efficient source of renewable energy, it can operate 24/7 and the investment is considerably less (my experience).  Seasons and location on the globe again play significant roles relative to the availability of wind but to a lesser extent in my opinion.  I couldn't count the number of times my house batteries were fully charged after a night of constant wind of 15 knots at anchor in the many places I visited.

My last comment is that solar panels and wind generators both have their limitations and therefore should be considered complementary.  Having one system and not the other will necessarily result in more occurrences of having to rely on your engine or genset than if you had both systems.  We all can agree that cruising demands redundancy in most systems so why not renewable energy sources?  While recently viewing Jimmy Cornell's last adventure through the Northwest Passage, I noticed that he relies on both solar and wind energy generation.  That would seem to be a significant endorsement for this level of redundancy.

Dennis Johns
s/v Libertad
Spice Island, Grenada
Maramu #121

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