Being eco-friendly may be admirable, but it comes with a
price, and it is not always as crystal-clear as one believes.
We rely heavily on non-grid energy, including wind and solar
power. However, renewal energy sources
such as ours require energy storage, and, specifically, battery storage. While there are advanced battery technologies
on the market (e.g. batteries for hybrid vehicles), as well as large wet-cell
storage batteries (such as those in forklifts and indoor industrial cleaning
equipment), the most prevalent, and therefore, the lowest-priced units are
conventional deep-cycle marine 12-volt batteries. These typically cost from $80 to $200, with
only modest storage and cranking amperage.
The primary advantage of marine batteries over vehicle
batteries is their capacity to be discharged to low levels and recharged
often. However, “often” is subjective,
with most of the commercially available units being rated for a few hundred
charging cycles, at most. These
batteries also do not like to be frozen, but really detest excessive heat.
In order to supply minimal energy, such as the energy to
light two compact fluorescent bulbs four hours each day and a small bar
refrigerator (drawing 90 watts, with a surge of 800 watts), you will consume
2,280 (2.3 kw) watts each day. Now
consider that a small solar panel produces 13-18 watts (some of the single
panel retail units produce 30w) under optimal conditions. In northern latitudes, hours of summer
daylight average 15 hours, but typically generate only about 60% of that in
sunlight sufficient to “max out” the solar panel. With three panels, you will produce 405 watts
– less than 20% of what you need. A
small wind turbine may produce 40% of what you need, if you live in an
environment where the wind is very frequent, and of sufficient strength to
power the turbine. Typically, the marine batteries attached to your collectors are
rated for 800-1000 CCA. Obviously,
unless you expand your generation and/or storage network, you will need to use
a charging system on the batteries.
Because each of the batteries is being discharged the
equivalent of 100%every eight hours, you will require a battery array of at
least three batteries, just to produce your daily minimum energy requirement. Ultimately, most of us will require
electricity for television or sound equipment, charging cell phones and
laptops, power for small fans, and so on. With minimal energy, though, your
three-battery array will be fully discharged and recharged 100 times from June
to September. That is the normal
lifespan of the battery!
This year, we experienced near-record heat and sunlight
throughout our summer. While that is
great for our solar panels, heat is more damaging to the batteries than cold,
and reduces their ability to be recharged (and hold a charge) significantly.
We used an eight-battery package. However, almost weekly, we needed to refill
the cells, as the electrolytic acid evaporated.
The sunlight did its damage, too, destroying one battery. Of the eight, only one battery now holds a
significant charge, even though I de-sulphated the batteries regularly. Five of the batteries were three years old or
less, with the other three being four years old. Seven batteries will need to be replaced.
At a cost of $90 per battery, our outlay will be $630, plus
taxes. We used nearly $100 of generator
fuel to supplement our renewable energy supply.
In four months, our lighting costs will be $700-800, factoring in the
wear and tear on equipment.
Now, we have batteries that need to be recycled and spent
fuel that polluted the air. If we had
relied on our hydro-electric grid for energy, at a cost of $0.08 per kwh, we
would have spent less than $130! Did we
really do the environment and our pocketbook a favour?
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