Hobbit House is one of a few hawaii homes that is
truly off-grid and producing it's own power. Bill built the hybrid system over the years to
what it is today with 27 PV panels. He started with the 3000 watt windmill and a
few 12v florescent lights and added PV panels as the electrical needs grew. Ten
years ago we upgraded the refrigeration from a seven cubic foot propane RV
refrigerator to a 22 cu. ft side by side whirlpool electric one. The side walls
have twice the amount of insulation as a regular residential one. The pv system produces 1,200
watts and the windmill produces 3000 watts in a 20 mph wind; the best use of the
windmill is at night when the mountain down draft occurs. The wind is gentle all
night at about 5 to 8 mph which keeps the batteries topped off.
You can power your home by installing a solar electric off-grid system.
Off-Grid Systems include: 12-20 solar panels Off-Grid Inverter with charge
controller and a bank of batteries.
Average price can range between $10,000.00 - 40,000.00 depending on the size
of the Off-Grid System.
What exactly is "green power"?
Green power is a term applied to electricity that is generated from wind and
other renewable energy sources, such as solar, geothermal, biomass, and small
hydropower. Typically, the environmental impacts of these sources are quite
modest compared to those of coal and other conventional sources.
Hybrid systems--wind/photovoltaic, wind/diesel, and other
combinations--can often provide the most efficient and cost-effective option for
rural electrification. Photovoltaics (PV)--the direct conversion of sunlight
into electricity--is often used to supplement wind power since PV tends to
operate best in low wind months. Diesel generators or batteries can be used for
backup power and to maintain power production during low wind seasons.
Coal, the most polluting fuel and the largest source of the leading greenhouse
gas, carbon dioxide (CO2), is currently used to generate more than half of all
of the electricity (52%) used in the United States. Other sources of electricity
are: natural gas (15%), oil (4%), nuclear (19%), and hydropower (9%).
The ability to generate electricity is measured in watts. Watts are very small
units, so the terms kilowatt (1,000 watts), megawatt (1 million watts), and
gigawatt (1 billion watts) are most commonly used to describe the capacity of
generating units like wind turbines or other power plants.
Electricity production and consumption are most commonly
measured in kilowatt-hours (kWh). A kilowatt-hour means 1,000 watts of
electricity produced or consumed for one hour. One 50-watt light bulb left on
for 20 hours consumes one kilowatt-hour of electricity (50 watts x 20 hours =
1,000 watt-hours = 1 kilowatt-hour).
The output of a wind turbine depends on the turbine's size
and the wind's speed through the rotor. Wind turbines being manufactured now
have power ratings ranging from 250 watts to 1.65 megawatts (MW).
Wind speed is a crucial element in projecting turbine
performance, and a site's wind speed is measured through wind resource
assessment prior to a wind system's construction. Generally, annual average wind
speeds greater than four meters per second (m/s) (9 mph) are required for small
wind electric turbines (less wind is required for water-pumping operations).
Utility-scale wind power plants require minimum average wind speeds of 6 m/s (13
The power available in the wind is proportional
to the cube of its speed, which means that doubling the wind speed increases the
available power by a factor of eight. Thus, a turbine operating at a site with
an average wind speed of 12 mph will generate about 29% more electricity than
one at an 11-mph site.
Wind energy system operations do not generate air or water emissions and do not
produce hazardous waste. Nor do they deplete natural resources such as coal,
oil, or gas, or cause environmental damage through resource extraction and
transportation. Wind's pollution-free electricity can help reduce the
environmental damage caused by power generation in the U.S. and worldwide.
In 1997, U.S. power plants emitted 70% of the sulfur dioxide,
34% of carbon dioxide, 33% of nitrogen oxides, 28% of particulate matter and 23%
of toxic heavy metals released into our nation's environment, mostly the air.
These figures are currently increasing in spite of efforts to roll back air
pollution through the federal Clean Air Act.
Sulfur dioxide and nitrogen oxides cause acid rain. Acid rain
harms forests and the wildlife they support. Many lakes in the U.S. Northeast
have become biologically dead because of this form of pollution. Acid rain also
corrodes buildings and economic infrastructure such as bridges.
Carbon dioxide (CO2) is a greenhouse gas--its buildup in the
atmosphere contributes to global warming by trapping the sun's rays on the earth
as in a greenhouse. The U.S., with 5% of the world's population, emits 23% of
the world's CO2. The build-up of greenhouse gases is not only causing a gradual
rise in average temperatures, but also seems to be increasing fluctuations in
weather patterns and causing more severe droughts.
Particulate matter is of growing concern because of its
impacts on health. Its presence in the air along with other pollutants has
contributed to make asthma one of the fastest growing childhood ailments in
industrial and developing countries alike. Toxic heavy metals accumulate in the
environment and up the biological food chain.
Development of 10% of the wind potential in the 10 windiest
U.S. states would provide more than enough energy to displace emissions from the
nation's coal-fired power plants and eliminate the nation's major source of acid
rain; reduce total U.S. emissions of CO2 by almost a third and world emissions
of CO2 by 4 %; and help contain the spread of asthma and other respiratory
diseases aggravated or caused by air pollution in this country.
If wind energy were to provide 20% of the nation's
electricity--a very realistic and achievable goal with the current
technology--it could displace more than a third of the emissions from coal-fired
power plants, or all of radioactive waste and water pollution from nuclear power
The 6 billion kilowatt-hours currently generated by wind
plants in the U.S. each year displaced some 9 billion pounds (4.5 million tons)
of carbon dioxide, 23,500 tons of sulfur dioxide (64 tons per day), and 15,500
tons of nitrogen oxides (42 tons per day).
The high technology of a wind turbine is in just a few manufactured
components such as the blades. A wind turbine can actually be much simpler than
a diesel engine, and also require substantially less attention and maintenance.
Some types of small turbines can operate for extended periods, five years or
more, without any attention. With training and spare parts, local users can
support the wind turbine equipment they use.
Small wind turbines (ranging in size from 250 watts to 50 kW) are often the
least expensive source of power for remote sites that are not connected to the