Solar Panels: Go Off Grid Now?

If you install solar panels on your home, can you go “off grid” and never have to deal with the electric company again?  Being energy independent is a nice thought.  No more triple digit electric bills.  No more hassle with the utility companies for any reason.  Is this possible for you and your family?  It depends on where you live, and how much money you’re willing to commit to maintain your own energy system.

First, consider where you live.  Are you in a part of the world that gets lots of sunlight all year long, or do you have lots of gray and overcast days?  Even when you install solar panels on your home, they only create electricity while the sun is shining on them.  That means you have to use batteries to store electricity in order for it to be available at night and during overcast days.

Here’s where your system can start getting expensive.  You’ll need to buy and maintain enough large DC (direct current) batteries to store enough electricity to get you through one to three days of cloudy weather.  You’ll need plenty of storage space for all of those batteries, and you’ll have to plan for the expense of replacing them periodically.

It’s also a good idea to keep a backup generator just in case you have a long stretch of cloudy weather that lasts beyond your battery storage capacity.  Your generator will need fuel, so you’ll have to store that, too. Generators usually use either gas or diesel fuel.  But that seems to defeat the purpose of a solar panel system, so you’ll probably want to use biodiesel.  So, yes it is possible to got “off grid”, but it’s not a simple or cheap project.

For most people, it makes more sense to look into “net metering”.  Find out  if it’s offered by your local electric utility company.  Net metering is a great way to cut down on your electricity bills, yet still have power available at night and during long spells of gray, cloudy days.  Net metering allows you to credits back from the electric company for excess electricity that your solar panels produce during the day.  Then you simply use the electricity from your local utility company at night and on days when there is not enough direct sunlight.  You won’t need to store banks of DC batteries in your basement or garage.  You won’t be completely “off grid”, but you can save significant amounts of money on your monthly electric bills.  Some months you may even have a zero balance.

So if you live on a large parcel of land and have an extra barn or outbuilding to store your DC batteries in, going “off grid” could be a reality for you.  But if you live in a subdivision, have no basement, and you’re already parking your car on the street because the garage is too full, “net metering” will probably be your best bet.

Revealed Solar Energy: Active or Passive?

Solar energy is a hot topic in the news these days.  But if you’re not already familiar with the terms, it can be confusing.  What’s the difference between active and passive solar energy systems?  And which one is better?

Active solar technology uses electrical or fuel-driven mechanical equipment to perform some of its functions.  For example, some solar swimming pool heating systems use electric pumps to move the heated water from the coils in the solar panels into the pool.  Large off grid solar electrical systems that provide 100% of the electricity to buildings usually use diesel or gas-powered generators as part of their backup systems.

Some solar electric systems use motors to allow their photovoltaic arrays to track the sun’s movement throughout the day in order to maximize the amount of sunlight they capture.  Grid-tied solar electrical systems are also considered to be active systems because they rely on the electric company as a backup source.

Passive solar technology does not use additional mechanical or electrical devices to deliver heat or electrical energy. There are no additional fuel or utility costs, and no added environmental impacts.  For this reason, many people think that passive solar technology is superior to active solar technology.

The most common passive solar application is solar water heating.  A truly passive solar hot water system can provide enough hot water for washing and bathing. It usually consists of a collector tank located on a south or west-facing wall or on the roof, and a plumbing system that delivers the water using gravity.  These types of systems are most successful in moderate climates where temperatures don’t get cold enough to cool the water in the storage tank.

It’s also possible to combine passive and solar energy systems to get the benefits of both.  Any of the active systems that use electric motors can also use solar cells to create the electricity.  For example the motors that  move photovoltaic arrays can easily be powered by solar cells.  And solar cells can also power the electric pumps that move the water in solar swimming pool heaters, and in water heating systems used in buildings.

Some active solar electric systems, like off grid systems, need external generators.  They are part of the system to provide backup energy during long periods of cloudy days when there is no direct sun.  Solar cells won’t work under those conditions.  But it’s still possible to stay green by using bio-diesel fuel to power the generator.

How Do Solar Panels Work?

There are two basic types of solar panels.  One kind makes electricity, the other kind generates heat.  It’s important to know which kind you need for the job you have in mind, because they are not interchangeable.  But both kinds can save you money and help you live a greener lifestyle.

Solar thermal collectors use the sun’s energy to heat water and other fluids, like oil. They typically use plastic tubing, hoses or coils in the panel.  The liquid runs through the coils and is heated by the sun.   These types of panels are ideal for heating swimming pools, spas, hot tubs and hot water for homes and businesses.  They can also heat building interiors by using baseboard heating units and hot water flooring systems.  Once they are installed, there is usually no need for additional heating fuels.  But the systems usually require some kind of motorized pump to circulate the fluids.

Solar photovoltaic cells create DC (direct current) electricity.  Most typically, they use semi-conductor material (silicon) in the panel, which interacts with sunlight to create electricity.  The electricity then can be used to power computers and appliances, or the entire house, if you build the system big enough.  The electricity is only generated from the panels during the day when they are interacting with direct sunlight.

In order to use a photovoltaic system at night or during cloudy days, the electricity must be stored in a battery storage system.  You can use inexpensive lead-acid batteries (like you car uses), but you will need to make sure they are filled with distilled water in order to maintain their charge.  You can also use more expensive batteries.  Sealed AGM (absorbent glass mat) batteries don’t require maintenance to retain their charge.  Gel batteries are good choices for cold climates because of their freeze-resistance.

Both the thermal collector and the photovoltaic systems typically use glass panels to encase their collection systems, and both require access to direct sunlight.  The panels are ideally situated in a location that faces south and allows maximum exposure to sunlight during the entire day.   They can be used anywhere to harness the sun’s energy, but they are less effective in regions that typically have a lot of cloudy days throughout the year.

Even in mostly sunny regions, it’s always a good idea to add a backup generator to both kinds of solar panel system.  Backup generators can be fueled  with biodiesel to maintain your green lifestyle.  And the generators can be used if your battery storage fails, or whenever there is an unexpected stretch of cloudy days.