Solar Power for Houses: Your Residential Solar Power System

Have you always dreamed of having a house powered by the sun? Perhaps you are seriously thinking about it, but want to know more about your options. When most people think about solar power, they think of the classic solar panels that produce electricity. These are solar photovoltaic panels. But solar photovoltaics are not the only way to use solar energy.

Solar hot water: uses the sun to heat your water instead of fossil fuels. There are several different types of solar hot water systems available. They are usually lower tech and cheaper to install than household solar photovoltaic systems, although pricing varies widely with the type of system chosen.
Pro: cheaper to buy than photovoltaic
easier to DIY than photovoltaic
Con: will only give you hot water
too heavy for some roofs
cheapest varieties don’t work in freezing temperatures

Solar swimming pool: this is actually a very inexpensive way to heat your swimming pool. It pays for itself within a few years.
Pro: short payoff time
Con: only heats your pool water

Solar thermal: technically this includes both solar hot water and solar swimming pool systems, as well as solar cookers. It also refers to heating air by the heat of the sun.
Pro: cheaper than solar photovoltaic for the amount of energy produced
Con: heat only, won’t give you electricity

Passive solar/solar architecture: designing or renovating a house so that it gains the maximum benefit from the sun’s heat, while not getting overheated during the summer.
Pro: adds very little to cost of a new house for major reductions in heating needs
Con: hard to retrofit

Solar cooker: uses the sun to cook food. It tends to cook food more slowly – can be compared to a slow cooker. Very easy to DIY compared to other solar options. They are also inexpensive to buy.
Pro: easy to DIY
cheap to buy or make
Con: needs sun to cook food
won’t do anything other than cook food
cooks food slower than most cooking methods

Solar photovoltaic: solar electricity created using the classic solar panels. A full system for your house is expensive compared to other solar power options, but it’s more versatile. It is also possible to buy very small systems intended for charging cell phones for laptops. These are very much cheaper.
Pro: extremely versatile as electricity can be used for almost anything
Con: more technically complex than other solar methods
more expensive than other solar methods for the amount of energy acquired
high-voltage electricity produced makes DIY photoelectric more hazardous than other solar power projects.

For decades, residential solar has been available but has been too expensive for most people with fossil fuel powered energy so easily available. Now that the world is facing climate change and fossil fuel depletion, the equation has changed. Solar photovoltaic systems have tumbled in price since the 1970s when they were so expensive, becoming a realistic option for many more people today.

The costs of a solar photovoltaic system are front-loaded. Once you have bought and installed the system, all you have to do is maintain it to have a free source of electricity. While the world around you grapples with energy prices that oscillate wildly, you’ll be laughing. Even better, that energy is renewable and far better for the environment than electricity from coal or natural gas. Natural gas may be cleaner than coal, but it’s still a fossil fuel and is therefore nonrenewable and gives off carbon dioxide when burned.

Residential photovoltaic systems are usually under warranty for 20 years and should last 25-30 years. Some last much longer. The first photovoltaic system in the USA is still operating – it was installed in 1954.

If you want a system that includes batteries, the batteries will not last as long as the photovoltaic panels or other parts of the system and must be replaced. Battery lifespan varies dramatically depending on how often the batteries are used, how deeply the batteries are discharged, and if they are ill-treated by overcharging or being subjected to unsuitable temperatures. Some types of batteries also require maintenance which consists mainly of adding distilled water at appropriate intervals.

The USA compared to other countries

Solar power is growing in popularity in the USA, as is true in many places around the globe including such disparate locations as Germany and China. With the increasing popularity has come a drastic fall in prices. Some retailers sell solar photovoltaic modules for well under $2.00 per watt. There have also been changes in the way that solar installations are funded. There are a few companies such as SolarCity in California that will install a system on your house for no money down and then charge you a lower rate for a combination of lease on the system and the electricity you use.

The fall in price and increased diversity in payment options mean that if you took a look at solar energy earlier and dismissed it because it was too expensive, it is time to take another look.

Many places in the USA are very sunny and need air conditioning in the summer, which makes solar energy an excellent option. An example would be Southern California. You get more electricity from a solar panel in a sunny place than you do from one that is in a cloudy area, or that is shaded some of the time. Given this, you have to wonder why solar electricity is more used in Germany when the USA is far better suited to it.

The answer lies in government policy. Germany got into the renewable energy game early, supporting solar power with feed-in tariffs. The USA has done far less to encourage people to buy solar systems, and what they have done they have only started recently. It is now time for the USA to play catch up, and it’s having some problems scaling up its industry ie. Solyndra.

The USA and China – solar industry interactions

There is a gap between the interests of solar installers and the interests of solar manufacturers. Solar installers like the fact that they can get cheap solar modules from China, as lower prices mean more people are installing solar systems. American solar manufacturers are having trouble dealing with the low prices of the competition. There is some currently some antidumping litigation going on between the U.S. and China. There is some basis to it, as one of the reasons the Chinese panels are so cheap is because they are not recycling things that would have to be recycled by law in the USA. The pollution has been bad enough there has actually been protests against some of the factories. To protest in China is not a minor decision.

What this means for the home owner looking for a solar system is that you should be aware that while Chinese solar photovoltaic modules are cheap, they are also less environmentally friendly than US or German manufactured panels.

Recent solar photovoltaic developments

Solar photovoltaics are still improving. Thin film solar collectors are a relatively recent development that increases the range of things solar photovoltaics can be used for as it bends without breaking. For example, it is possible to buy solar photovoltaic shingles. Thin film is also generally the cheapest solar photovoltaic material per watt, making it a very practical choice.

There are also experimental solar photovoltaic cells including multi-junction cells, and cells based on other materials than silicon. If you can get hold of these at all, they’re much more expensive than silicon-based solar cells. You could wait for these to come out and drop in price, but experimentation and commercialization take time, and the amount of time is highly unpredictable. It could be many years until they are actually available at a price you are willing to pay.

Given the current situation with lowered prices and improved technology, if you can afford to go solar, I’d say do it!

The need for solar power

The Earth is facing a multi-headed environmental crisis. These problems may seem enormous, but we are not powerless.  There is a great deal we can do to take control over our impact on the Earth and its biosphere.  The tools to do so are not yet to be invented.  We already have them, and they’ve been available for years.  We just have to do the work to change the way we do things. One of the main dangers is climate change, which is currently being driven by fossil fuel extraction. This means we need to reduce fossil fuel use drastically.

But we will still need a power source. This is where solar power comes in, along with wind, small hydro, biomass, geothermal and other renewable energy sources. Some include nuclear, but I’m not going to get into that debate right now.

Solar power, in both its thermal and solar photovoltaic forms was discovered many years ago.  It has been used in various ways since – you’ve probably used a solar powered calculator, tried to burn something with a magnifying glass when you were a kid, and seen photographs of spacecraft with their solar panel wings. We can do far more with it than we have so far.

In its thermal form, people have been making use of solar for far longer – think solariums, greenhouses and orangeries. Then of course there’s plants and photosynthesis. Starting with cyanobacteria and other algae, they’ve been using it for at least 3.5 billion years!

Solar power’s two flavors: solar thermal and solar photovoltaic

Solar photovoltaic transforms light from the sun into electricity.  If you want to light your home with solar, you need to use solar photovoltaic.  This form of solar energy is more versatile than solar thermal since you can use electricity for almost anything, but is also more technically complicated and expensive to install for the amount of energy produced.

Solar thermal uses the sun’s energy in the form of heat. It is frequently used in the form of solar hot water systems, as well as pool heating, greenhouses for growing plants, solar cookers, solar dehydrators, and passive and active heating for the house. Solar thermal is a lot easier and more practical as a DIY project than solar photovoltaic.  The materials are often cheaper and less technically complicated.  It’s also safer if you have less skill with electrical circuits, since you aren’t working with high voltage electricity.

Why solar power is practical, and how to make it work for you

Solar photovoltaic power has undergone major improvements in recent years and has become a lot more affordable.  There are now many solar photovoltaic modules with a price of under $2.00 per watt.  This is vastly better than even a year ago.  There have also been changes in the way solar is marketed – a few power companies are offering to install solar photovoltaic systems on your house for free, and then charging a set price for electricity produced that is lower than their standard electricity rates.  This makes residential solar a possibility for many people who would not have been able to afford solar on their own.

With the exception of a very few power companies, most of the costs of solar photovoltaics are up front, one time costs.  If you go this route, you pay a large sum at the beginning but then have free electricity thereafter.  Under modern circumstances of fluctuating energy prices and a changing climate, this is an excellent investment if you have the money. If you’re off the grid using a generator, you can save a lot of money over time if you go solar.

If you have rather less money but have skill with building things or electronics and some basic equipment, there are also kits for making solar panels and solar installations.  Remember that solar thermal is usually easier and safer as a do it yourself project than solar photovoltaic.

Of course, you might be more interested in other renewable energy options. There will be more articles on these subjects on this site soon.

There are a lot of ads for build-your-own solar panels on the internet, including on this site. I have no control over what ads do or do not appear, but felt a bit of research as to whether DIY solar panels were possible or cost effective was in order.

Solar Panel Price Comparisons

When sites say ‘build solar panels for under $100!’, they often seem to be comparing the materials cost of the homemade panel to the cost of an entire solar photovoltaic system which (for a house) usually includes multiple panels, an inverter, a charge controller and sometimes batteries. This is not comparing the same thing. A true cost comparison would be one of two things: the cost of the entire system, or the cost per watt of power produced by a single panel.

The full cost for a DIY solar photovoltaic system includes the number of panels that you wish to build as well as buying or building all the other parts of a system. Also include your time that you will be spending building the panels and mounting racks and then wiring and installing everything. A single solar panel by itself is not much use for home applications without an inverter and charge controller, and one solar panel will not power an ordinary house. Costs for solar panels are usually a little over 1/3 the price of an installed system, so while they are a major component they are not the only component.

Comparing Solar Panel Prices: Price Per Watt

The usual method of comparing the prices of solar panels is price per watt. For example, if a 60 watt panel is built for a materials cost of $104.85, as the maker of mdpub.com did, the price per watt is $1.75. The average price per watt for a commercially made module of over 125 W is $4.39 as of September 2009. Prices for smaller modules are generally higher per watt, so the home-made panel looks pretty good. So yes, it is possible to build a solar panel for less money than you would pay for commercial one. But there are several caveats:

• This is presuming no materials were ruined while you learned how to make the panel
• This is presuming that you manage to make the panel work properly
• This is counting your own labor cost as $0
• This is assuming the you do not have to buy soldering equipment or paint, plexiglass, wire, or screws in order to make the panel since the author of this site had them on hand
• The person who made the solar panel used as an example has also built a wind turbine and a jet engine

DIY Installation of Solar Photovoltaic Systems

Once you have made your panels, will you be installing and wiring everything yourself or will you get someone else to do it? The level of skill required is an important consideration because installing solar photovoltaic systems means working with electricity, which has a certain amount of inherent danger involved. On-grid residential solar power systems usually involve high-voltage electricity, which increases the danger if you do zap yourself.

So is Building Your Own Solar Panels For You?

I would not want to try this myself, nor do I have the equipment I would need. If you have to go and buy the equipment and then teach yourself how to use everything I would not advise attempting to do it yourself. If, on the other hand, you are an electrician with a large workshop looking for a project, building your own photovoltaic system might be worth another look.

Sources:

http://www.mdpub.com/SolarPanel/index.html

Cassandra Sweet. Sept 8, 2009 Let the Sun Shine. The Wall Street Journal

Solar module retail price environment Sept. 2009

Passive solar heating is a great way to provide much of your home’s heating for free. Almost every home gets some solar energy coming through the windows, but there is a vast difference between the average house and a home heated with passive solar energy.

Building a new house that is passively solar heated is not significantly more expensive than building a normal house. This makes passive solar the most cost-effective form of solar power for the new home. Every new home should be built using passive solar techniques because home heating and cooling needs can be reduced greatly – potentially to zero in certain circumstances.

All this sounds wonderful, but there is one caveat: you must find a good architect who understands passive solar design. Some architects do not understand how to do it properly and mistakes made during the building process may prove costly later.

Passive solar heating covers a wide range of strategies, including passive solar thermal hot water heaters such as the batch and thermosyphon, but it’s usually used to describe heating the house air and structure.

Direct Passive Solar Heating

The simplest form is direct passive solar heating. This involves big windows on the south side of the house. The sunlight falls onto a dark surface with a high heat storage capacity such as a masonry floor or wall painted a dark color. Water is sometimes used instead – this involves water contained in glass or transparent plastic. It has slightly different properties than solid walls, but the basic idea is the same. The wall or floor absorbs energy on sunny days, and releases it at night or on cloudy days when things get cooler.

Of course, you don’t want the house to overheat in the summer. This is generally avoided by building overhangs over the windows. In the winter the sun is at a low angle and comes in the window. In the summer, especially near midday, the sun strikes the overhang and doesn’t come into the room. This leaves the room much cooler.

Trombe Walls (Indirect Gain) and Solar Spaces (Isolated Gain)

There are two other major passive solar heating strategies, Indirect Gain and Isolated Gain. The most common Indirect Gain method is the Trombe Wall, and the most common Isolated Gain method is the solar space.

Trombe walls involve a thick wall painted a dark colour. An inch or so in front of it is glass. Sunlight enters through the glass and is absorbed as heat by the wall. The glass helps prevent heat loss, and wall slowly releases the heat into the rest of the house. Again, a Trombe wall is placed on the south side of the house.

A solar space is basically a glassed-in space on the south side of the house. They are also sometimes known as solar rooms or solaria. Solar spaces can act as greenhouses, and they are sometimes referred to as greenhouses. However, they are not the same as greenhouses designed to grow plants.

The glass is vertical, and there usually isn’t glass overhead. This is so that the glass can be shaded in the summer to avoid overheating. It also means the plants that grow there have less light than they would in a true greenhouse, although more than they would in your house. Since they are attached to the house, you may not want to grow large numbers of plants in it if you’re allergic to mildew. However, if you’ve always wanted a greenhouse,why not use it to grow plants?

These three types of passive solar heating are the most commonly used. While the systems describes here are simple and this overview is simple, there’s a lot more to passive solar design when you really start looking deeply into the subject.

Sources:

Arizona Solar Center

US department of energy: energy efficiency and renewable energy. Passive solar home design.

People turn to solar power for several different reasons:

• High energy prices
• Climate change
• Fossil fuel depletion
• Solar energy costs are coming down

When these factors are taken into account, it’s no wonder that people are going solar. Here are some more data on each:

High Energy Prices

While we’ve been hearing most about high oil prices over the past few years, electricity prices have also been going up in many places. When combined with the price of solar photovoltaics coming down, solar looks a lot more practical than it used to. The recession may have lowered energy prices temporarily, but how long will that last? The volatility in energy prices also makes solar power attractive because you don’t get left vulnerable to energy price spikes when you produce more electricity than you use.

Climate Change

Operating a residential solar power system does not produce CO2. While some CO2 is produced during the making of solar panels and other elements of the system, there are vastly lower emissions than from the production of electricity from oil, gas, or most especially coal. Thus, every solar photovoltaic array very slightly reduces the likelihood of catastrophic climate change.

Fossil Fuel Depletion

The easiest, cheapest oil gets used first. Most oilfields and wells being brought into use now produce oil that is difficult to access or process in some way. This tends to keep oil prices high. It looks increasingly likely that we have hit Peak Oil, which means diminishing supplies of oil in the future no matter how much oil exploration and development we do.

While most electricity does not come from oil, prices for all forms of energy are linked and are likely to become increasingly so as more electric vehicles are made, and even more so if Coal-to-Liquids technology is used on any large scale. In the US, coal is the largest source of electricity. If Coal-to-Liquids plants are built to compensate for Peak Oil, this would increase the price of coal, and therefore that of electricity.

Coal supplies are not endless and it looks increasingly likely that there may be less recoverable coal than commonly thought. This is likely to raise electricity prices in the future. In such an environment renewable energy sources, including solar, look better and better.

Residential Solar Energy is Becoming More Affordable

The current recession has resulted in people buying less. During the high oil prices, producers of solar panels and other components vastly increased capacity. When the recession hit, they found themselves with excess solar photovoltaic systems, components, and raw materials. Prices dropped.

The USA is about to start giving larger rebates for solar which will help increase affordability for a very large, affluent market. This is likely to increase demand for solar energy, which might prevent lowering of prices in the short term, but will likely reduce them in the long term by increasing the capacity of industry. China has also started manufacturing solar panels, which is likely to reduce solar panel price due to economies of scale and cheaper labor in that country.

In California there is at least one company that offers leases of solar photovoltaic systems with guaranteed electricity prices lower than that of some utilities in that area. This increases affordability of solar by eliminating the high start-up costs of home solar systems which act as the largest barrier to going solar for many people.

More Information:

Fossil Fuel Depletion, Peak Oil and Energy Prices:

The Oil Drum

Richard Heinberg’s Museletter

Heinberg, R. 2009 Blackout: coal, climate and the last energy crisis. New Society Publishers.

Trends in Renewables and Renewable Energy News:

Renewable Energy World

This job requires tolerance of heights, strength to lift heavy objects
and knowledge of how to install electrical objects safely.

The pay is usually about 15 to 23 dollars an hour. The whole solar sector is a high growth sector of the economy, and job prospects are bright. A high school education is usually expected, along with some construction experience and an apprenticeship or trade school education. However, the exact things employers look for vary somewhat. I culled the list below from actual job ads:

Things employers look for when hiring solar installers are:

• Ability to lift heavy objects (approx. 30-50lbs)
• Ability to work in a variety of positions
• Ability to work in hot sun and awkward spaces
• Not afraid of Heights
• Ability to interact with clients
• Attention to detail
• Ability to keep records and understand documentation
• Driver’s license and clean driver’s record
• Construction-related experience

Knowledge of Computer Software, OSHA safety regulations, and ability to understand blueprints is also often required.

Sources:

SolarInstallerjobs.com

A Day (or Three) in the Life of a Solar Installer

Places Hiring Solar Installers:

Standard Solar

SolarCity

Rec Solar

Batteries are an important component of off-grid and many grid-tied residential solar power systems. They are used to store excess electricity produced by the photovoltaic panels for times when they are producing less electricity than needed, such as at night. Batteries are used in both off-grid applications and in grid-tied battery-backed systems. Batteries for off-grid are usually sized to last through normal use on three cloudy days.

The batteries in grid-tied residential solar power systems are used for backup when the grid goes out. There are usually fewer batteries in these banks because they are only used for backup rather than being used every single night.

The three main types of solar batteries are all lead-acid batteries. However, they are very different from the batteries used in a car because they are deep cycle batteries. This means that they can be drained much more deeply of their charge than shallow cycle batteries such as those used in cars. Car batteries will not stand up to the strain that a residential solar power system will place on them.

Batteries Suitable for Residential Solar Power Systems

Flooded Lead-Acid Solar Batteries

Flooded lead-acid batteries are the cheapest type of lead-acid batteries commonly used to store solar power. They also have the longest life, but require regular maintenance. Distilled water must be added as necessary to replace that lost during charging, and because they are not sealed they must be kept clean and there is a danger of spillage.

Absorbed Glass Matt Sealed Lead-Acid Solar Batteries

These are sealed, and therefore do not require regular maintenance as flooded lead-acid batteries do. They are a newer invention and so far less widely used than flooded lead-acid.

Gelled Electrolyte Sealed Lead-Acid Solar Batteries

These are freezing resistant and are typically used in unheated spaces. They must be charged slowly in order to avoid decreasing capacity, making them better for grid-tied backup than for off-grid uses.

Sources:

Homepower.com

Solar-Batteries.net

There are three main types of solar panel for sale at present: monocrystalline, multicrystalline, and thin film panels. A fourth, sometimes known as vaporware, is sometimes mentioned in the media, but does not yet exist. There is no one best solar panel for every purpose, but each type of solar panel has its own advantages and disadvantages.

Monocrystalline Photovoltaic Panels:

Pros:

• Most efficient, especially in low light conditions
• Less space required for the same amount of power
• More durable than Thin Film

Cons:

• Most expensive per watt
• Production process uses more silicon and more energy
• Rigid

Polycrystalline/Multicrystalline Photovoltaic Panels:

Pros:

• Lower price than Monocrystalline
• Higher efficiency than Thin Film

Cons:

• Higher price per watt than Thin Film
• Rigid
• Lower efficiency than Monocrystalline

Amorphous/Thin Film Photovoltaic Panels:

Pros:

• Cheapest per watt
• Can be made flexible
• Harder to break
• Uses less silicon and less energy during manufacture

Cons:

• Degrades faster
• Lower efficiency
• More space required to produce the same amount of electricity

Vaporware?

This doesn’t actually exist yet, but if it ever does, it will be photovoltaic material that you spray onto a substrate which then becomes a photovoltaic panel.

In Practice:

The type of application has a major impact on which type of solar panel is best for you.  If you want to have solar panels on a backpack where the panels have to be flexible, your only choice is Amorphous/Thin Film panels.  However, if you require the largest possible amount of electricity from the smallest area of solar panel and do not care about it being flexible, then Monocrystalline photovoltaic panels are best.  The choice is up to you.

For More Information:

Northern Arizona wind and sun

Solar Sphere

Solar thermal and solar photovoltaic power are similar in that both use the sun as an energy source, and both are renewable. However, there are quite a few differences between them, including price, type of energy output, and the things that energy can be used for in your home.  The table below should give you a good idea of the pros and cons of both types of solar power.

Prices are global average for July 2009 and are US denomination. They exclude rebates your government may give. They assume the system is grid-tied.

http://www.solarbuzz.com/solarindices.htm