Corrado Vinci asked:


To truly understand the benefits of green solar energy, you must first understand how solar energy is harnessed. There are two types of green solar energy-thermal and light. Thermal energy is considered passive solar. This type of green solar energy is harnessed through the design and materials used to construct a building. By integrating south facing windows and materials that retain heat, like brick and stone, you can lower your energy needs and build an energy efficient structure. The thermal energy produced by green solar energy is also used to heat water for solar hot water systems. The rays of the sun also produce light and radiation that can be captured by solar panels to create electricity.

The most popular use of green solar energy is for saving money. Although green solar energy systems can come with a large initial investment, they generally pay for themselves in a few years by providing either supplemental electricity or all of the electricity to your home or business. Building your own solar panels, participating in government refunds and net metering, in which you sell unused electricity back to the power company, can reduce the cost of implementing a green solar energy system. In addition, green solar energy systems require little to no maintenance after installation, as most have no moving parts.

The most important benefit of utilizing green solar energy is completely environmental. With polar ice caps dwindling away and climate changes creating tragic storms world wide, it is increasingly obvious that steps must be taken to decrease global warming and our dependence on fossil fuels. Green solar energy provides a clean energy alternative as it creates little pollution and does not contribute to global warming.

Solar energy panels have become more affordable in recent years making it a viable alternative energy option for savvy home owners looking for savings on their monthly utility bills and the environmentally conscious who also enjoy the financial advantage, but focus more on the benefits solar energy panels have on global warming and independence from fossil fuels.

If you are a beginner to the solar electric world, then you may be wondering what exactly solar energy panels are? It is really simple and yet fascinatingly complicated. Solar energy panels are also known as photovoltaic panels; photovoltaic meaning electricity from the sun. Solar energy panels work by collecting protons from the sun, which displace neutrons, and create a flow of electrons or electricity. An inverter converts the power generated by the solar energy panels from an AC current to a DC current making it usable in homes as a direct electricity supply.

You can use solar energy panels to heat your pool, workshop tools, greenhouse lights and fans or depending on you personal electric usage, your entire home or business. Most solar energy panels are designed to last 30-40 years and require little to no maintenance. Over the life-span of solar energy panels, the energy savings realized by the owner is enough to justify the initial cost of the system and prices are dropping more and more as a larger number of consumers express interest and make the change to solar energy panels or other renewable resources.

Solar energy panels for small applications can be purchased at your local hardware stores. These small versions are ideal for outdoor lighting, small water pumps and other outdoor tools. If you are purchasing a home size or business size system of solar energy panels it would be best to seek out a local retailer of solar energy panels or a green energy retailer in your area. There is also plenty of information available online about different solar energy panel providers.

Daniel Stouffer asked:


encouraging information for those homeowners who live in areas of the country covered with snow or, clouds due to frequent storms, for much of the year. The following article explains in some detail how how the sun angle effects solar energy out put in the form of electric for home solar power units. We will also document a few of the common components in a home solar energy system such as mounting units, sun tracking systems, and more.

The Sun’s Irradiance Throughout the Day

Many graphs and charts, found on the Internet via searching, show a solar cell module’s output when it faces south throughout the 4 days following the fall equinox. These graphs most often show a bell curve of the power output, where peak production occurs around 12 to 1pm with a morning ramp-up and a decline as the sun goes down. This is due to intensity of light as well as deflection. As the days get shorter, the total irradiation falls as expected. The sun no longer is directly square with the panels, since it is lower in the sky.

Panel Tracking Devices for Home Solar Energy Systems

The best way to get around this decline in energy output is to place the solar array on a tracking device to keep it in direct sunlight for more time throughout the day. Looking at a sunflower can give you a good idea. The sunflower wakes up in the morning facing due East to catch the morning sun. As the day progresses, the sunflower turns its head to track as much sunlight as possible. It’s perplexing why sunflowers grow so tall and sturdy? They soak up as much sun as possible.

There are two different types of tracking systems for residential solar energy units. There are other more creative choices, like mounting on fences or poles, but the following are most common.

1) Horizontal or flat mount array favors the summer months when the sun is highest.

2) Fixed angle at the optimum tilt angle yields the most kWh for a fixed array over the course of the entire year.

These two types of tracking systems create dramatically more exposure and higher sun hours all year long, but still more in the summer months. This relates to the overall need to calculate and take into account the total amount of energy required per month and per year then average out to the highest electric needs on a monthly basis. All of this data is included with the solar energy sizing estimates.

There are single axis tracking solar systems that track the sun from east to west. There are also dual axis tracking solar systems that track both from east to west and up and down, following the sun’s altitude and azimuth to optimize production throughout the season. In the winter, the sun is much lower in the sky than in the summer therefore solar energy systems that can tilt up or down have a greater chance of catching all of the sun’s energy.

Forms of Sun Irradiance

The sun reaches the solar panels in various paths, not just directly from a sun’s beam being directly overhead. Because of this fact, there may be good generation of solar electricity on even overcast days or when you would not think the sunlight is of proper intensity.

There are three types of irradiance. 1. Diffuse Irradiation: Scattered light comes from the whole sky. Diffuse is completely absent on a crystal clear day with no clouds or haze and is highly available on cloudy hazy days or in places with lots of smog.

2. Direct Irradiation: A beam of sun light goes straight from the sun to the solar module and directly interacts with the solar cells

3. Reflected Light (i.e. the Albedo effect): This is light that is reflected or scattered by the ground or nearby surfaces like trees or other buldings. Snow gives off a lot of this albedo light and grass or dirt gives off very little.

Sun Path Diagrams and Home Solar Energy Systems

A sun path diagram plots the position of the sun throughout the year. This is very useful when designing and installing solar arrays, to optimize the performance by determining the best angle and to avoid shadows from trees, vents, other buildings, etc. Understanding where the sun traces across the sky at your home, allows you to place your solar energy unit in the correct location. You can also determine if you may need to supplement your solar power system with a tracking device.

Expanding Options for Residential Solar Energy

New solar energy technology is continually coming to market that takes the idea of solar power to a new and simpler levels. Homeowners, while it is very useful to know the nuts and bolts of solar power systems, do not have to know the level of detail as presented in this article. New solar technology and home solar panel rental services provide energy efficiency and better control of power consumption. These solar power rental programs enable electric services that are more responsive, more reliable, and more renewable.

Daniel Stouffer asked:


You’re most likely not an electrical engineer so you’ll find that the terms for residential electricity more than confusing and nonsensical at times. The following article explains the terms associated with home electricity and defines the general electrical concepts found in residential solar electric systems. The majority of this article defines on the important terms, principles, and technical definitions that will be further explained in relation to home solar power in another article.

The intent of this article is to help you to understand enough about electricity so that you can understand the technology used in solar photovoltaic (PV) systems. You most likely will review a lot of information and learn many new solar energy terms when you begin the process of purchasing or renting a home solar power system.

When you start researching residential solar energy systems, or even taking a close look at your electric bill, you hear a lot about kilowatts and kilowatt hours. You may have used these terms mistakenly as the same thing in the past. The ideas are really very similar. Both terms are just a measure of relative electricity sizes.

However, they are very different measurements, as you will learn through the electricity definitions included here. In order to understand what they mean, you also need to understand a few basic concepts about electricity.

When talking about electricity, you will be using terms like power and energy. The average person often uses these terms interchangeably in daily speech along with current, potential, charge, electrons, and even photons. You might have learned about all of these electricity terms way back in high school. In use as part of your daily life, you may have confused their meaning.

Common Residential Electricity Terms

Here are the most important electricity concepts you need to know when you begin the process of purchasing or renting a solar energy system for your home. It may be surprising to you that the actual meaning of a few of these is not quite what you expected.

Power: The rate at which work is performed or energy is provided. Power is the amount of energy required or expended for a given unit of time. It is measured in watts (W).

Energy: The actual work done by solar panels installed on your home. In other words, energy is power supplied over a period of time. It is typically measured in joules or watt hours (Wh).

Potential: The capacity of an electric field to do work (i.e. to provide energy). This is similar to the height of water behind a dam. It has capacity to do work. The higher the water, the more potential energy that is available. Potential is calculated and measured in volts.

Current: A passage or movement of materials charged with electricity. This is not unlike the speed of water flow in a river. It is measured in amperes (I or in common terms amps).

Resistance: The characteristic of a material, substance, object, or circuit to limit the passage of electricity. Items letting electricity to pass with low resistance are called conductors and materials that resist electricity from flowing are called insulators. Resistance is measured in ohms (R).

Charge: A property of some subatomic particles, i.e. the charge on an electron (subatomic particle is negative). Charge determines how subatomic particles interact. Electrically charged matter is influenced by and produces electromagnetic fields. Having strengths that can be measured, a charge has two states; either negative or positive.

Field: An effect produced by an electric charge that exerts a force on charged objects in its vicinity.

Electron: A negatively charged subatomic particle. The current is caused by the movement of electrons from different energy levels within its atomic structure.

Photon: An elementary particle that is the carrier of electromagnetic radiation of all wavelengths. The photon is different from many other elementary particles, such as the electron, because it has no mass. That means that it travels at the speed of light across the vacuum of space. Trillions and trillions of photons are blasted out from the sun every second.

Upgrading Your Home to Solar Power

To understand solar electric systems and how they work, you first need to understand the basic principles of electricity. This means learning the language used to explain these principles. In our next article which is a ongoing series related to renewable energy, we will dive into understanding the language of residential solar electric systems.

Understanding the most common electricity terms and technical jargon is a crucial initial step related to the process of renting or purchasing a residential solar energy system. You should feel comfortable talking with solar industry experts about your home solar options. In future articles, we will dig deeper into the details and emerging options for home solar power systems.

Cooler Planet asked:


Solar power energy systems are not inexpensive. That said it’s important to compare them within context of other types of home improvement projects. Home buyers and realtors view a solar photovoltaic or solar hot water heating system as a significant value-added improvement – similar to adding a deck or remodeling your kitchen. Plus unlike a deck or kitchen remodel, you also gain one-up on your power bills. Here are some foolproof ways to estimate the cost of a solar photovoltaic or solar thermal system and to figure out if a solar energy system makes sense for you.

Six Easy Steps To Estimate Cost of a Solar Power System

Solar power energy systems are not inexpensive. That said it’s important to compare them within context of other types of home improvement projects. Home buyers and realtors view a solar photovoltaic or solar hot water heating system as a significant value-added improvement – similar to adding a deck or remodeling your kitchen. Plus unlike a deck or kitchen remodel, you also gain one-up on your power bills.

Solar power systems often get an additional financial boost as well: many jurisdictions and utilities across the USA offer attractive financial incentives to drive down the upfront capital costs associated with a solar power system.

Here are some foolproof ways to estimate the cost of a solar photovoltaic or solar thermal system and to figure out if a solar energy system makes sense for you. Let’s start with a home photovoltaic (PV) system.

Step 1: Estimate your home’s electricity needs

To get started, it’s good to have a sense of how much electricity you use. You’ll have a better point for comparison if you find out how many kilowatt hours (kWh) you use per day, per month, per year. Your utility bill should include that information.

Of course, the utility bill will also display your costs and many utilities include a graph that displays how your monthly energy use/cost varies throughout the year. That helps you estimate where your highest energy use is and at what time of year.

New Home Construction

If you are constructing a new home, then you’ll need to estimate your demand based on the type of equipment you plan to install and your home’s square footage. The pross call this “your load”.

To figure out your anticipated load, create a table to record the watt use for each appliance. Each appliance – be it a water heater, electric light, computer, or refrigerator – should have a nameplate that lists its power rating in watts. Or you can get the information from the manufacturer’s website.

Some labels list amperage and voltage only; to obtain watts multiply the two together (amperage x voltage = watts). In another column, record the number of hours each appliance is expected to operate. Then multiple the watts and hours together to estimate watt-hours used per day. Since it’s hard to anticipate all electric loads (it may get tedious scouting out every toothbrush and mobile phone cell charger), you might want to add a multiplier of 1.5 to be safe.

Step 2: Anticipate the future

In 2005, average residential electricity rates across the USA ranged from about 6 to nearly 16 cents per kilowatt hour depending on where you lived. Average retail and commercial electricity rates have increased roughly 30% since 1999 and the upward trend will likely continue especially as costs for the coal and hydropower used to generate that electricity rise as well. So think about your home electricity needs and present and future cost in relation to one another.

Step 3: How much sun do you get?

The Florida Solar Energy Center has conducted a study to examine how a 2-kW photovoltaic system would perform if installed on a highly energy efficient home across the continental USA (http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-380-04/).

The study accounted for all factors that impact a PV system’s performance such as the temperature effect on the photovoltaic cells, the amount of sun peak hours in various regions, and the efficiency of inverter to convert solar derived energy from DC to AC.

As the study implies, solar photovoltaic systems work just about anywhere in the US. Even in the Northeast or in “rainy Seattle”, a pv system can pencil out if designed and installed properly. In New York or New Jersey, a one kilowatt system should produce about 1270 kilowatt hours of electricity per year, in Seattle, a one kilowatt system should produce about 1200 kilowatt hours per year. In the Southwest, of course, those ratios will be much greater.

Solar contractors in your area can help determine the best size for your solar photovoltaic system.

Step 4: Size your system

In general, solar photovoltaic systems sized between 1 to 5 kilowatts are usually sufficient to meet the electricity needs of most homes. One advantage of grid-tied systems is that you can use solar PV to supplement or offset some of your electricity needs; therefore you can size your system to match your budget and always add to the system later if needed.

Also as a side note, here’s a rule of thumb to remember to help you estimate the physical space your PV system might need: one square foot yields 10 watts. So in bright sunlight, a square foot of a conventional photovoltaic panel will produce 10 watts of power. A 1000 watt system, for example, may need 100 – 200 square feet of area, depending on the type of PV module used.

Step 5: Know your rebates

Many states and local jurisdictions offer rebates, tax credits and other types of incentives to homeowners for installing residential photovoltaic and solar domestic water systems. To view a comprehensive database of the incentives available for renewable energy visit http://www.dsireusa.org.

At the Federal Level, you can take advantage of a 30% tax credit (of up to $2,000) for the purchase of a residential solar system at least until December 31, 2008.

Step 6: Run the numbers

Although the cost for a solar PV system will depend on the size of the system you intend to install, your electricity rate, the amount of kilowatt hours you expect to generate, and the state/local rebates/tax credits that may be available, the formulas for calculating the returns are pretty much the same.

For those who appreciate having the formulas, use the ones listed below to do a quick ballpark estimate of how much a solar photovoltaic system might cost you.

Retail Price for Solar Photovoltaic System

+ Building Permits

- $2,000 Federal Tax Credit

- State or Local Tax Credit or Rebate

- Utility Rebate or Other Incentive

= Net Investment

Kilowatts of electricity generated from PV per year

x Kilowatt hours used per year

= Annual Kilowatt energy from the PV system

Annual Kilowatt energy from the PV system

x Current Residential Electricity Rate

= Annual $$ Saved

Yearly Excess PV Energy Produced

x $$ credit applied per watt

= Annual Value from Net Metering

Of course, a more accurate assessment can be made by a pro. Work with a solar power contractor to size and price the right system for you. As is true with any major purchase, don’t hesitate to ask for several bids from different contractors.

Many solar power providers will provide you with a comprehensive estimate. Helpful information to know includes:

- Total cost to make the system operational (labor cost for design and installation and equipment costs)

- Equipment (Make and Model)

- Warranty info

- Permit costs, if needed

- Tax, where applicable

- Federal tax credits

- State or local jurisdiction tax credits or rebates

- Utility rebates

- Expected Renewable Energy Certificates or Net metering credits

- Expected operation and maintenance costs

- Projected savings

Solar Thermal (also called Solar Hot Water)

Solar thermal systems capture the sun’s energy to heat water and are one of the most cost-effective renewable energy systems. They are used to heat hot water tanks and/or a heating system. A solar pool heating system is another type of solar thermal system designed specifically to heat a pool or hot tub.

Generally it’s worth investigating the economic viability of installing a solar hot water system if you have an electric water heater with utility rates of at least 5 cents per kilowatt hour and have tax credits or rebates available. (It may even be worth changing out a gas-powered water heater if your costs are at least $8/million BTU).

The formulas for costing out a solar water heater system are similar to estimating the cost for installing solar PV system. Many solar energy professionals can help you determine what system might work best for you.

Heating Your Swimming Pool with Solar Power

Although few jurisdictions provide financial incentives for using solar energy to heat a swimming pool or hot tub, in general, using solar power to heat your pool is a “no-brainer” from a return on investment standpoint.

The electricity used to heat a pool during the swimming season often amounts to the same amount of energy that homes-without-pools consume over a year. Combining a solar thermal system to generate heat for the pool with a solar thermal pool cover to retain the heat generated can further maximize efficiencies and extend your swimming season.

Most installers recommend that a solar collector used to heat a pool is sized at roughly half the square footage of your pool surface area. Solar thermal panels typically last 10 – 20 years and come with a 10-year warranty.

How long it takes to break even on the cost of your solar power pool system depends on where you live. In California or other parts of the Southwest, you’ll break even in 1 to 3 years but places as “far north” as Canada, a solar pool heating system pencils out over a slightly longer period of time.