Solar Power for Houses: Your Residential Solar Power System

Increasing energy conservation and energy efficiency are the most cost effective ways to reduce the amount of money you pay for energy.  Before you invest in alternative energy sources, you should check that your house uses as little energy as possible while still allowing you the lifestyle you want.   Of the two approaches, the simpler is energy conservation.

Energy conservation involves using less energy by doing things like turning off the lights when we’re not in the room.  There is no upfront cost to such actions, although they do typically require behavior changes.

Ways to reduce your power use through energy conservation

• Turn all lights out when you leave the room
• Set your computer to fall into hibernation mode when it is not in use
• Unplug appliances when not in use, or get a power bar and turn the power bar off at night
• Buy a timer for your home’s thermostat so that your home will be warm when you’re home and moving about and cooler at night and when you’re at work
• Turn your home’s thermostat down a couple of degrees Celsius and wear a sweater – presuming your home is not leaky enough that you’re wearing a sweater anyway and freezing cold besides
• Turn the TV off if you’re not watching it

Basically, if you aren’t using it, it shouldn’t be on.

Energy efficiency involves using appliances that can do the same amount of work with less energy.  It does not involve you changing your daily behaviour.  The classic example is replacing incandescent lighting with compact fluorescent, but it goes far beyond this.  The largest use of electricity in many homes is heating.  By insulating the house, the amount of energy required to heat the house is reduced.

Cheap ways to reduce your power use through energy efficiency

• Replace incandescent bulbs with compact fluorescents
• Insulate your hot water heater
• Insulate your hot water pipes
• put plastic film over windows during winter

More expensive, but very useful

• Buy an energy-efficient refrigerator if your current fridge is more than 10 years old
• Insulate your ceilings, walls and floors
• Replace single-glazed windows with double or triple glazed windows

Of course, if you really want to increase energy efficiency there are a variety of methods for passive solar heating, but that is beyond the scope of this article.

When you install that new appliance…

I once lived in an apartment where the landlord had replaced all the windows with new windows that were supposed to be much better insulated and lose less heat.   However, he had installed them badly and there were gaps between the windows and the frame.  One of the gaps was so large you could see right through it to the outside.   Because of this, the house would not stay warm despite the new windows and the landlord complained about his energy bills to us.  Meanwhile, we complained that we were always cold.

This shows the importance of installing new energy efficient objects correctly.  If installed incorrectly, the object may well work badly if it works at all, and you may have done a lot of work and spent a lot of money for no energy savings.  So do it right the first time!

Pros

The most obvious advantage to solar energy is no operational carbon emissions.  Other advantages include reduced dependence or even complete independence from fluctuating energy markets and efficient power generation in areas that do not have access to a power grid.  In areas that do not have access to the power grid, it is frequently cheaper to buy a photovoltaic system than it is to pay to extend the grid, or to buy and run a diesel generator.

While energy prices have gone down recently with the global recession, it is unlikely that they will stay down.  When the economy improves oil prices will likely go back up, and energy prices in general will probably follow.  Once your solar panels are set up, the vast majority of your costs have already been paid, and rising electricity prices will be something that happens to other people.

In certain areas of the USA, there are programs that will let you lease solar Grid-tied Systems. This eliminates the high start-up cost problem if you are lucky enough to live in one of those areas.

Cons

There are also disadvantages to solar photovoltaic power.  Solar energy requires sunlight.  Photovoltaics do not produce power at night, and the amount of power they produce on cloudy days is much reduced from what they produce in sunlight.  They also produce more electricity during the summer than in the winter.  This is an advantage if your air-conditioning bills are higher than your heating bills, but in colder climates this is a disadvantage to solar power.  In climates with many cloudy days, power output is reduced from its full potential, which means that your initial investment takes longer to pay back than you might expect from tests in Spain or California. 

Purchasing and installing a solar system involves a substantial outlay of capital.  Prices for solar photovoltaic sytems are falling, but the cost is still prohibitive for many people.

Sources:

Home Power Magazine http://www.homepower.com/home/

Solar Photovoltaic Cost and Price Trends Retrieved May 16, 2009 http://www.solarbuzz.com/StatsCosts.htm

The exact pros and cons of photovoltaic solar power depend partly on whether you have a grid-tied system or an off-grid system.  So, what exactly are those pros and cons?

Off-grid Solar

Off-grid solar systems require substantial maintenance because of the battery banks necessary for storing electricity.  These batteries require occasional replacement and can be a fairly expensive investment on top of the solar panels.  However, if you live far from the power grid it can be far cheaper to have a solar system than to pay for connection to the grid.  Also, if the grid goes down your power source will not be affected.

Grid-tied Solar

Grid-tied systems without battery backup are the cheapest to set up for most people.  They do not offer any protection if the power grid they are tied into goes down, but they do offer the possibility of selling excess power to the local power company provided that the power company is set up to accept that.  This should be checked before you set up a Grid-tied solar Power System.

Grid-tied Solar with Battery Backup

It is also possible to set up a system that is Grid-tied but has a backup battery bank.  This is considerably more expensive than the standard batteryless Grid-tied System, but it means that if the grid goes down you will not have a power outage due to that failure.

In the end, which system is best depends on your needs and how you plan to use your photovoltaic array.  Photovoltaic power is not a one size fits all technology, and while the array of options in systems can be confusing, at least it gives you a good chance of obtaining a system that suits your needs.  More information on solar power and photovoltaic systems can be found at http://www.homepower.com/basics/solar/, as well as many other places on the web.