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Private Island Electricity

In a perfect world, your private island will already have electricity via an underwater cable running from the mainland or a larger island. In a less than perfect world, you might have no source of power at all.


You need to think about your power needs before you can determine your power supply. If you have a fully developed residence with all modern amenities including air conditioning, you’re going to need a powerful and expensive system, preferably with steady and reliable access to fuel. (You can forgo air conditioning if you build a house that takes advantage of cooling trade winds, where applicable.) You might power your island with a generator that runs for an hour or so a day, long enough to cool the freezer, do the laundry and charge the batteries. If your private island doesn’t already have electricity, three good options are available: solar, wind and generator power. Solar and wind power produce clean energy using environmentally friendly technologies. They do not produce pollutants or greenhouse gases. Nor do they leak any type of contaminates. You will likely end up using a combination of all three power sources.

Generator Power

In light of increasing power outages in North America caused by severe weather, brownouts and natural disasters, portable generator sales have taken off. In regular homes, generators are intended for backup power. On a private island, a generator might be your only source of power. Simply put, a generator burns fuel (gas, propane, diesel, or natural gas) to produce power. Generators are available in all shapes and sizes, depending on your needs. The generator converts power into electricity. That electricity can be used to power standard appliances and devices that normally run off of utility power.

The size and type of generator you need depends on what you plan on powering with your generator. Make a list of all the devices you plan on running. Find out the wattage requirements for each appliance and add it all up. That total is your “constant wattage”, the energy you will constantly need to keep the selected items running. Motor-driven appliances, such as refrigerators, freezers, air conditioners and furnace blowers require up to three times their normal wattage to start or to periodically cycle a compressor (that’s called your start-up wattage). Choose a generator that meets or exceeds your constant wattage needs and that also has a surge rating that meets or exceeds your start-up wattage needs. The generator that you purchase should be able to produce approximately 20-30% more than your calculation total.

Much like any tool or appliance, the better you maintain your generator, the more efficiently it will run and the longer it will last. On an annual basis, you can expect to change filters, oil and spark plugs, and service the engine. If you don’t have ready access to ample amounts of fuel, a generator isn’t the power source of choice. You’ll also want to be able to store significant amounts of fuel, in case you can’t make it to the mainland for any reason. If you’re running a small operation with conservative energy requirements, you might only run the generator for a few hours in the evening. While it’s running, you might pump water to the water tank, do the ironing, run the washing machine, and whatever else requires large amounts of power.

Harnessing the Wind

People have used wind energy for thousands of years, from sails on boats to grinding grain with windmills. Before you join generations of successful wind users, you need to make sure your private island has enough wind to use a wind turbine to generate power. Unless your power needs are very minimal, wind power should be considered as a supplemental form of energy rather than your main source. Wind is free (so far), but small wind turbines are expensive in relation to what they produce. The wind causes the blades to turn. The wind turbine is connected to a generator, which converts the motion into electrical energy. The energy is stored in a battery. The process is similar to charging a car battery.

Wind turbines come in all sizes, from those with rotors measuring a few feet across (used for battery charging on sailboats) to hundreds of feet tall. Odds are, you’ll be using a domestic wind turbine, which is usually 8 to 12 metres high with between two and five blades. The rotor is less than 4 metres in diameter, generating a few thousand kWh per year, more with ideal wind conditions. (An average household consumes about 4,000 kWh per year. A 4 cubic foot freezer might consume 200 kWh per year). Domestic wind turbines are a great independent source of energy when used to power small electrical devices. Most small turbines are used for charging batteries, to provide a reliable stand-alone power source where grid power is not available. The power generated can be combined with other forms of energy, such as solar power or electricity from a diesel generator.

Wind generators need “clean” wind to operate – constant from one direction without turbulence created from nearby obstacles. Wind can be affected by terrain like hills, trees and nearby buildings or structures. Some areas receive only seasonal wind in winter or in some coastal regions, the prevailing wind might be summer sea breezes. A very tall tower is best to capture strong winds, preferably built on a hilltop or on the coastline. But you’ll need to check on local regulations. You don’t want to get in the way of small aircraft. Also, close neighbours may not share your enthusiasm for wind generated power. Big turbines can be noisy! And they may not be suitable in areas with severe weather.

Solar Power

See that big bright orange ball in the sky? You can borrow its energy to power your private island home. Solar power uses light to generate electricity. Sunlight can be converted into electricity using solar panels. The electrical current is stored in a large battery, used to power things like lighting, vacuum cleaners, radios, fans and televisions. To supply your private island home with electricity, you would install photovoltaic (solar) panels on the roof. In the city, solar power is still more expensive than buying electricity from the power grid. But on a private island, solar energy is a very feasible alternative to grid power. Installing a solar energy system can only be considered expensive if there is a cheaper alternative. You might spend thousands of dollars to rig your house, but once the system is set up, you’ve got free power courtesy of the biggest star in our solar system.

Photovoltaic is the technology for direct conversion of light into electrical energy. The term comes from photo, which stands for light and voltaic which stands for electricity. A photovoltaic cell, also referred to as a solar cell, is composed of a thin round or square semi-conductive material such as silicon. When a number of solar cells are wired to each other and mounted in a support frame, it is referred to as a module. The current it produces is directly related to the amount of sunlight that hits it. When many modules are wired together, the arrangement is referred to as an array. They form a large solar panel; the type that you see on the roofs of homes and cottages. The larger the array, the more electricity it produces.

To calculate how many square inches you of solar panel you require for a house, you need to know how much power the house consumes and how much sun you get on average. Let’s say an average day generates 5 hours worth of solar power. You want to power the fridge, lights, computer, TV and washer. These things total 14,400 watts per day (24 hours). A solar panel can generate 350 milliwatts per square inch in 5 hours. Therefore, you would need about 41,000 square inches (or 285 square feet) of solar panel on your roof. These days, that would cost about $20,000. Purchasing a battery bank could double your costs. It’s an expensive one time investment, but you’re off the grid for good.