Living Off the Grid
The "Grid" is the network of wires that supply most of today's people with electricity and communications. Here on the Big Island, the grid generally follows the main highway that belts the island. From there it branches into some communities, however, it does not go everywhere. Living off the grid simply means that you do not depend upon it for electricity or phone/internet service. Some people live off the grid because it is too far away, while others choose to let it pass them by for independence, economic, and environmental reasons. Living without utility supplied electricity can be challenging for those of us who have come to take it so for granted, but it is an option.
Hawaii is a prime location for alternative energy enthusiasts. The climate, (at least at moderate and low elevations), is very hospitable to humans. We need not expend huge amounts of energy to warm up or keep cool. People travel from all over the world to grab a little Hawaiian sunshine, which is usually available in some abundance in most areas. The low latitude of Hawaii means that the winter Sun will never ride so low in the sky as to not be useful for energy production. Some areas of South Hawaii are known for their windiness. Commercial wind powered electric generators are found on the South Point peninsula.
Solar Water Heaters
Consider that the overhead Sun sheds about 750 Watts of power (broad spectrum) on to every square meter of Earth surface. That's a lot of juice! Unfortunately we humans have yet to figure a way to capture most of that. A fairly efficient capture system is to paint a surface black and just have the Sun heat it. You can run water across this hot black surface (usually within a pipe) and you have a solar water heater. Real solar water heaters usually have an insulated storage tank to hold the hot water after the Sun goes down. Solar water heaters are fairly common in Hawaii. Even if you are on the grid you may consider a solar water heater. The electric utility offers sizable rebates on your installation of an approved system by certain contractors. One word of caution; investigate how much Sun your property actually receives. Many higher elevation locations cloud over almost daily due to clouds that form around our mountains. This daily cloud effect may impact your solar energy collecting ability.
You have probably heard of solar cells. You may have owned a calculator or some other device that used these to charge its battery. Large collections of solar cells (a solar panel) can be used to convert the Sun's energy directly into electricity and charge a battery. The battery can then be used to power lights, entertainment equipment, or most anything electrical. One problem with solar cells is that they are quite inefficient , that is, they can only convert a small portion (about 15%) of the sunlight they receive into electricity. That 750 watts of available Sun power per square meter ends up being about 100 Watts of electricity. This could be overcome by using a huge number of solar cells. That, however, is problematic because solar panels are still quite expensive. What most people do is buy as large a system as their budget will allow and then use the collected energy very frugally.
As mentioned above, there are commercial wind powered electric generators here in Hawaii powered by the plentiful wind found in some areas. The south part of the Big Island, especially the southern Kau district is known for its windiness. Wind powered electric generators can be purchased for home use. You should be able to purchase a small wind generator somewhere in the $600 range that produces up to 400 watts of electricity (when the wind is blowing!) . That compares quite favorably to solar panels. On the down side, wind generators have moving parts and moving parts all eventually wear out. Still, wind generators work when the Sun isn't shining and combining a wind generator system with a photovoltaic system is a popular choice among many off griders.
If you produce your own electricity from photovoltaic panels or wind generators, you will need to store the energy in batteries. These are usually deep cycle lead acid batteries (12 Volt). This means your available electricity is in the form of direct current (DC). In order to power your alternating current (AC) appliances, the DC from the batteries has to be converted to AC using a device known as a power inverter. Power inverters have an efficiency problem of their own. They are not 100% efficient in the converting process and always lose some energy as heat. It is thus advisable to avoid using them where possible by utilizing 12 Volt DC appliances, and lights. These are fairly common as they have had a long term usage in the RV world. Batteries require periodic replacement, are fairly expensive, and pose environmental problems. Alas, there is no perfect solution.
Most people who have solar energy systems have a gasoline powered generator to help supplement their energy needs. The generator is usually placed in a sound baffling box some distance from the house. Gas generators are noisy and expensive to run, but you will probably want one if you live off the grid. Many people use propane for water heating, cooking, and even refrigeration. Propane can be purchased from several distribution points and delivery is available.
We are lucky to have alternative power specialists right in Ocean View at Solar Works. Dan and Donna Durgin have been helping people live off the grid here for years. Check with them for some real expertise. Note that home wiring in Hawaii is legally done only by a licensed electrician. Low voltage wiring has its own requirements and potential hazards. Get advice from an expert!
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