Couple builds solar-powered home just off Hilton Head Island

Living off the grid means living independently without support from public utilities. It's a lifestyle that's growing for several reasons, but primarily among homeowners who want to save money and to become better stewards of the earth's resources, according to Nick Rosen in his 2007 book "How to Live Off-Grid." But sometimes, there's no choice and living off the grid is born of necessity. That is exactly what happened when Tom and Mary Donald set out to build their home on Old House Cay Island, which is approximately one mile off of Hilton Head Island.

They were looking for a water-oriented property in the area and soon came across this little island for sale. It was water-oriented for sure, but there wasn't a dock, a house or any power on the island.

As a matter of fact, when Tom first visited the island, he had to swim from the boat to get on shore. He says it's been an adventure to build a house on his own island, but adds: "I'm now ready for a little less adventure and ready to enjoy it."

Relaxation should be easy now, since the house was completed last summer Their 1,800 square foot, two-bedroom, 2.5-bathroom home is outfitted with all the modern amenities, thanks to the power of the sun.

Photovoltaic energy generated by the sun provides energy for all the lights and appliances, for the flatscreen TV which plays movies (no cable service is available on the island), and to run the air conditioner during the hottest days of the summer. There is a solar thermal water collector on the roof which provides hot water for domestic use.

A well provides water to the house - it was one of the couple's first projects to test the feasibility of living on the island.

The sun's energy is captured by an array of solar panels on the south side of the roof. The power is collected and stored in 4 DC batteries in a bin under the house.

When the power is needed, it is converted into AC power for regular household use. The power collected and generated is more than sufficient for the needs of their home, which Tom Donald attributes to "highly energy-efficient appliances" in the house.

There is a backup generator if the need should arise but thus far, it hasn't. "We made it through the peak demand of the summer, so I think we are okay," Tom Donald said.

He said his experience in the contracting business (he's the owner of Carolina Contractors) helped him build and outfit his island weekend get away home.

The couple lives in Hilton Head Plantation.

"Initially, we built a three-story deck structure to test out solar and wind power sources," he said. "The wind power in our case was not as beneficial as solar power."

Also, the town's zoning board wouldn't allow the windmill to be put up."

Tom Donald and local architect Merrill Pasco designed the house together. Now looking back at the design and function of the sustainable energy sources, Donald says "I wouldn't do it any differently."

Donald says, "If you have the option to be on the grid, it is definitely cheaper."

It can cost anywhere from five to 10 times more in start-up costs to live offgrid, he said.

There are federal tax rebates and in some states, incentives for creating renewable energy sources. In California and New York, residents can