Green Living - Tips & Advice for Living a Greener Lifestyle

SOLAR POWER

What's not to love about solar power? It's free, clean, and available every day. And you don't have to live in California or the Australian outback to harness the power of the sun. The costs of solar systems have come down 80%+ over the past two decades, and as more consumers take to solar the costs are falling still. There are a variety of solar power options available, and it's important to understand the benefits and costs of each option.

How Solar Power Works

Solar power is produced by using photovoltaic (PV) cells to capture the energy of the sun and convert it into electricity. The basic unit of the system is the solar cell, which are connected together into modules. PV cells are comprised of semi-conductors, most often made of silicon (like the chips used in computers). The semiconductors absorb power when they are struck by light. These modules or panels of PV cells are what you see installed typically on the roofs of homes and businesses. The electricity created by the solar system is DC or direct current, and the electricity we use in our homes is AC or alternating currents. Thus solar systems include an inverter which changes the DC current into useable AC current. Installing solar systems is a complicated technical process and most people will benefit by using contractors skilled in solar technology and electrical installation.

Home Solar Power Systems

There are two main forms of solar systems for residential use: the “grid-tie” system and the “off-grid” or stand-alone system. In a grid-tie system, a home has solar cells but is still connected to the local power grid. The home solar system includes solar cells installed on or near a home that collect the sun's energy and convert it into DC electricity. Then the inverter converts the DC power into AC power, which can then be used directly in your home.

Electricity produced by the solar cells that is not used immediately in the home is returned to the power grid. When this happens your electricity meter literally spins backwards as you are passing energy to the grid. You are also building a credit on your power bill. This is called “net-metering”. The benefit of the grid-tied system is that it does not include expensive batteries to be installed in your home for the storage of power; the grid acts as the storage system and your home and the grid exchange power as you need and produce it.
Off-grid or stand-alone systems are typically used in remote locations where standard grid-based power is not available. These systems are more expensive, but do allow for complete electrical independence. These systems require deep-cycle batteries for storing the electricity as well as a charge controller to assure the flow of electricity from the cells does not over-charge the batteries.
For a solar system to work well it needs an unobstructed view of the sun. In the United States, typically the best orientation for solar panels is to the south as the sun is in the southern half of the sky (lower in the winter and higher in the summer).

Solar panels can either be attached directly to a slanting roof, or bolted onto frames on flat roofs. If your roof is not a good option, then panels can also be mounted on the ground. They can either be placed on a fixed mount frame or on a “tracking mount” that follows the sun across the sky.


Solar Water Heaters

A solar water heating system is fairly simple. You install solar panels, typically on your roof, and the sun heats the panels. Then these solar collectors heat a fluid in pipes held in the interior of the panel boxes, and that fluid is transported into the house where it heats water in a storage tank. The system can include a pump which circulates the transmission fluid from the roof to the water tank and back again, but pumpless systems are also available. In areas where freezing isn't an issue, systems can heat your water directly. In most places a type of antifreeze is used and the fluid and water do not mix.

One convenient and less expensive option if you live in a warm climate is a solar batch collector. Water is simply pumped up to a solar storage tank on the roof and heated by the sun. Then you just use the hot water as needed. (But you need to make sure you have a roof that is strong enough to support the weight of the stored water and the tank.) These units cost less than $1000. Another great way to save energy and money if you are a pool-owner is to use solar power to heat your pool.


Solar Power Costs

The cost of a solar system depends on the size of your home, the orientation of your property, and your electricity needs. But for a standard medium-size house it can run from $20,000-$40,000 before rebates.

However, many state and local governments offer incentives for solar installation that can significantly reduce the costs. Rebates coupled with federal tax credits can knock thousands off of your initial investment, sometimes cutting it in half! Be sure to check with your local government for these offers.

One way to cut the cost of a solar electric system is to reduce your electricity use before installing the system. Such measures as replacing light bulbs with compact fluorescents and upgrading old appliances can cut your electricity use (and also your solar investment) in half. You'll spend a bit of the savings on the new items, but you'll have that brand new stainless refrigerator you've been craving too. Low Impact Living's In-Home Environmental Assessment program will help you understand what cuts can be made before you go solar and therefore save you thousands of dollars.

You can also finance solar installation using home equity. This approach offers the possibility of making you “cash flow positive” from day one, especially if you live in an area that has high power prices, good exposure to the sun, and solid local rebates.

If the cost of a full house solar system is daunting, a very attractive option can be heating your water with the power of the sun. A solar water heating system will save a typical California family $1000 in power costs. The payback period on these units is typically under five years.

Other great lower-cost solar options are distributed solar applications. You can get attractive solar lights to illuminate your yard or garden. You can also power a nice fountain or heat your pool using solar energy.