Renewable Energy in Action — Island Green Living

I find it very hard to believe that people still scoff at renewable energies, whether it is solar, wind, wave, hydro, tidal, or geothermal. They not only work well, they help us cut down on the use of fossil fuels and reduce emissions.

A case in point is my little house on Lovango Cay. I use only about 12 kiloWatts (kW) per day, times 30 days per month = 360 kW. At the current WAPA rate of about $0.34 cents (and going back up!), my average monthly WAPA bill would be $122.40, or $1,468.80 a year.

However, I have not paid a WAPA bill in more than 15 years because I live 100 percent off grid.

Yes, I have my investment costs of around $8,000 for solar and wind power, and I have bought batteries twice, at about $2,500 each time. So I have spent close to $13,000 over 15 years.

With WAPA I would have spent $1,468.80 x 15 years = $22,032 (actually more, because WAPA rates have been much higher at times). At a minimum, I have saved $9,032.

Plus, when WAPA goes out I still have power!

When my batteries get old and it’s time to replace them, I take them to a recycler who ships them back to the States to be properly recycled. They refund me $10 per battery too!

Besides my solar panels I also have a 400-watt wind generator that helps keep the batteries topped up most nights. For our rare all day rainy days (about a week per year), I have a small 2-kW Honda generator that uses hardly any fuel and is fairly quiet too.

A minor drawback of storing your energy in lead-acid batteries (the same kind used in your car) is the need to monitor the battery charge level at least daily. Your batteries should be kept in a 100 percent state of charge at all times. A 24-volt battery system is at 100 percent when batteries are at 24.6 volts, not at 24 volts. If you keep your batteries in the 100 percent charged state, they will last you many years. I have a digital meter indoors that displays the voltage so I know if they are getting low.

I also check the water level in my batteries about every two months and check for corrosion on the connections. With this minimal maintenance, I get about seven years out of my battery banks.

Other types of batteries do not need maintenance as often, but they too have drawbacks. For instance, absorbed glass mat batteries are just like lead-acid batteries, but you never have to add water. They are more expensive, however, and if you overcharge them they will fail very quickly.

Lithium ion batteries, including the Tesla “Power Wall” batteries, are very expensive per kW and can heat up and catch fire if overcharged. Also some of the usual brand-name inverters and chargers (Schneider/Outback and SMA) do not work well with lithium ion batteries. They are a good product, but they are still very new being used in renewable energy, and as a result, some systems are having problems that could be easily avoided with a different battery type. I think in a few more years’ time, the pricing for lithium ion will drop and they will be better designed for renewable energy use.

Dan Boyd for TW websiteFor a cleaner tomorrow, For a greener tomorrow !
Dan Boyd
Lovango Cay