Thinking About Going Solar?
Don't Forget The Tax Credits, Too
1. Heating From The Sun - The Basics
2. Sell Back Your Solar Electricity
3. How Solar Works
4. What You Need To Start (tax credit info)
1. Heating From The Sun - The Basics
The process of heating your home with the sun is hardly new. Since the dawn of humankind the sun has been used to provide needed warmth. But modern technology has completely transformed the way that can be done, even from the methods used a few generations ago.
In the 1920s some municipalities supplied hot water to homes by large storage tanks that were heated by the sun. As the unit cost of electricity and gas decreased, such applications became relatively too expensive to compete. But old ideas often become new again, with a twist. Modern hot water heating systems using solar power have now been in use for more than 30 years.
But what's even newer are ways of heating your home using solar energy that go well beyond simple windows. It's certainly possible to just allow sunlight to stream into a window. But that often leads to areas of the home that are too bright. It generates areas that are too warm, while others receive too little heat.
Modern solar heating systems can redirect solar energy to provide an even, comfortable temperature throughout the house.
Some such systems use water or a salt water mixture. The tubes and channels that contain the liquid sometimes lie in small parabolic mirror-type troughs that concentrate the sun's rays to raise the water temperature. That's how many solar water heating systems work (minus the salt, of course). But that same technology can be adapted to supply home heat.
In one application, a series of tubes runs under wooden, clay or other materials used for flooring. By design, the heat gradually flows through the flooring and rises up into the air to provide a comfortable interior environment.
Such problems are not as rare as they may seem. In climates where the weather becomes quite cold in the winter, water inside pipes does sometimes freeze and break the pipe. Yet, at the same time, there are many such cold days that still supply plenty of sunshine that could be used in a solar heating system.
2. How Solar Power Works
Solar power, particularly when it's used to provide home electricity needs, may seem like a relatively recent invention. And it's true that large, cost-effective panels that form the core of most systems have only been in use for about that past 30 years. But the underlying method they employ goes back to 1839, when it was discovered by Becquerel. He found that shining sunlight on an electrolytic cell would produce a current.
Other scientists built on that work very well. In fact, while Albert Einstein is most well known for the Theory of Relativity, he received his 1921 Nobel Prize for something quite different. According to the Nobel organization it was 'for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect'. His paper on the subject was written in 1905.
The photoelectric effect is essentially similar to what solar power enthusiasts and workers know as the photovoltaic effect, the principle Becquerel first found. When light, in this case from the sun, strikes certain materials it knocks loose electrons from their associated atoms. Those moving electrons create a current that can flow through the material to provide electrical power.
Those materials today are typically some type of doped silicon. 'Doping' is another way of saying that other elements are deliberately introduced. In other applications, those impurities would be undesirable. In solar power, they're essential. Pure silicon has its uses, but it's not a good conductor of electricity. Adding phosphorus in just the right way, for example, turns them into semiconductors.
Certain specialized applications use gallium-arsenide or other materials, instead of silicon. But because of their relative rarity the cost is much higher. Silicon is a major component of ordinary sand and hence plentiful.
The silicon-phosphorus compound is arranged in layers, then connected to a grid to enhance the flow of electricity. It reduces the resistance losses. Then terminals are installed to allow for the electricity to flow into the home electrical system. The whole assembly is covered with glass to protect it and forms what's known as a PV (photovoltaic) cell. Those cells are then arrayed into a module. Modules can then be connected together into a complete system.
Those modules comes in various sizes that determine how much electricity they generate. All other things being equal, the larger the area, the more power they can produce. Naturally, the larger panels tend to cost more.
Though the solar energy reaching the surface (at the equator) is about 1,000 watts per square meter, not all of it is usable energy. A square meter is a square whose sides are a little larger than three feet - it's about 10.7 square feet. Apart from losses due to latitude, atmosphere, dust and other natural factors, the modules themselves only convert with about 10-15% efficiency.
The growth of solar power as a practical energy production method depends heavily on increasing that efficiency and lowering the costs of production. To a degree, that efficiency is bound by certain difficult-to-get-around physical constraints, so most of the research efforts involve attempts to lower the manufacturing costs.
When or if that happens, solar power applications may well become even more commonplace in homes and businesses than they are today.
3. Sell Back Your Solar Electricity
One of the hurdles any homeowner considering solar generated power has always faced is the high upfront cost. Powering the average home using the sun's energy requires fairly large solar panels. Most panel systems cover most of the south facing roof of the house. But the cost of the panels alone can easily be around $10,000-$16,000. Add batteries, installation and related costs and you are looking at an initial investment of anywhere from $32,000 to about $50,000.
Many find the cost worth it in order to be independent of the local utility company. In rural areas, power outages are common. Wind storms knock trees onto the lines. Transformer blow outs are common. Many components of such systems are decades old and there's too little income or other incentives for the power company to upgrade. Having an 'off-grid' system provides at minimum a backup during times when the power is out.
Given that the pay back on home solar panel systems can be 20 years or more, some may still see the initial cost as too high. They feel compelled to endure the occasional blackout.
But upfront purchase of the total system isn't the only option today. There are various loan, lease, rebate or grant systems that can offset part or all of the cost.
Federal tax rebates or outright payments help somewhat. Special legislation in most states allows utility companies to enter arrangements that can reduce the cost of solar power. Some contracts and systems allow for purchasing back any excess solar power. If your system generates more than your home needs, the difference goes into the utility grid. You receive a rebate on your bill.
Many companies will subsidize part of the cost by offering a discount for homeowners who install a solar power system. Not many companies will pay you to purchase less of their product or service. But the crazy quilt of regulations in electricity generation gives the utility company a financial incentive to do just that.
There are a few companies just now starting up that promise to lease equipment. That opens the option of lowering the major share of the upfront cost of solar systems. Just as when leasing a car, the total cost over time may be slightly higher. But lowering the initial investment from $50,000 to $1,000 puts a solar power system within reach of many more people.
Most people today own their home for less than seven years. That's one of the major reasons mortgage companies can offer the flexible rates and terms that have become common in the past 15 years. That fact affects the feasibility of installing a solar system as well.
4. What You Need to 'Go Solar'
To implement solar power to heat and power your home requires a number of relatively expensive items. But those items can be cost effective over the long run. Still, going solar the right way requires the right technology and some planning.
First, you need to estimate how much electricity you require to run your home. If you plan only to supplement your power needs, that's fine. Then just calculate the percentage you want to offset.
A glance at your electric bill can make the task easy. Most utility bills will show a chart of month by month usage throughout the year. You can average the total, or use the peak demand. If you plan to go 'off grid' - stop using power from the utility company completely - focus on the peak.
Those numbers will allow you to estimate how many and what size PV modules you need. PV is short for photovoltaic, the method almost all solar cells use to convert sunlight into electricity. It's a matter of simple arithmetic to match the area of your south-facing rooftop section to the number and size of modules needed.
Each module will generate a certain amount of power at a given cost. When connected the right way the modules add up, so finding the total output (and cost) is equally easy. For a modest-sized home, the cost of panels is somewhere around $10,000-$16,000 at current prices. But keep in mind when planning the expense that there are tax rebates and other programs that will help you offset the amount invested.
But the modules have to connect to something. The connectors, clamps, wires and other components add to the total. They vary considerably. And don't forget to add installation costs. Most homeowners don't have the skill to build the system themselves.
The sun doesn't shine all day every day. It's dark at night, obviously. Rain and heavy cloud cover will reduce the amount of insolation, as it's called. Other uncontrollable factors reduce the amount of sunlight available. So, almost anyone going 'off grid' will want a battery storage system. Those not taking the complete plunge can draw power from the local utility company during those times.
If your system generates more than you need at any given time, some utility companies will enter into an agreement to buy any excess you put into their system. That's usually done technically by running your meter backwards when you're supplying the utility company. It normally runs forward as you draw power from their system.
Naturally, they'll insist on inspecting your system before finalizing any agreement. In fact, most municipalities will require that you have your system inspected and approved even if you go entirely off grid. They need to ensure that it's implemented in a way that's safe for local lineman. During power outages they have to assume there's no power running through the lines. Your system has to be installed in a way that guarantees that.
Between panels, batteries, installation costs and other expenses most modest-sized solar panel systems will cost in the neighborhood of $32,000-$50,000. Some less, some more. That cost should be offset against what you would pay for electricity from the power company over the lifetime of the system, usually about 20 years without substantial replacements. Don't forget here are tax credits available too!
But costs are coming down and efficiency is improving as time goes on, as the price of electricity continues to rise. It may well be worth your while to have a solar powered electrical system for your home.