Solar PV technology has a huge potential to provide if not all, but bigger chunk of US electricity, which at this moment comes mostly from fossil-fuels such as Coal and Natural Gas, as well as some Nuclear and Hydro power, Still fossil-fuels provide most of our ever-rising electricity demand. While gas and coal are relatively cheap compared with other energy sources, they are polluting our atmosphere with ‘green-house’ gases. Also due to rising energy demand, cost of gas, coal and oil keeps rising, with no limit in the foreseeable future.

Solar on the other hand produces clean, ‘free’ energy in form of electricity, heat, and light. Although benefits of solar are enormous, so is the initial capital investment, which without additional incentives becomes not so attractive to the end user. Fortunately US government, as well as many other governments through-out the world see great potential and need in renewable energy and offer end-user the financial rebates and incentives to promote the widespread of renewable energy, which in turn reduces the cost of such technologies.

Here we will review rebates and incentives offered by Federal, State and local governments, as well as utility companies and other organizations in Massachusetts, Connecticut and Rhode Island (Note: Due to recent budget deficit and slow economic conditions in RI, most of State-sponsored renewable-energy incentives are temporarily suspended – we will keep a close eye on the situation and post updates as news become available).

Federal Tax Rebates for Solar PV: Commercial and Residential

Commercial:

Federal Government offers Tax rebate for solar and other renewable-energy installed on your building. You can claim 30% Business Energy Tax Credit in the year of installation and a 5-year accelerated depreciation thereafter. No maximum cap for Solar PV, while other technologies may have a limit.

Residential:

For residential Solar PV systems, the Federal Tax Credit is 30% percent with $2000 cap.

Note: Current Federal Tax Credits for renewable-energy are set to expire on December 31, 2008. Unless they are renewed before expiration, Tax credits will be reduced to 10%. Currently, Big-Oil companies receive over $1.5 billion/year in Federal Tax Credits from US government for oil exploration and drilling in the Gulf of Mexico. These same companies that had over $130 billion profits (net income after all expenses and taxes paid) in 2007. This money can be use to the advantage of the people of the United States in form of Renewable Energy Bill, which President Bush promised to veto, if it passes in the senate. We urge you to call your Senator, State Representative, Governor, and other officials as well as Presidential Candidates, and tell them that we, the people, demand support for renewable-energy.

State Tax Rebates, Incentives and Grants for Solar PV

Each State has a different Solar Rebates and Incentives Program, and to eliminate any confusion, we list them under each state’s respective page. This programs are designed for residents and businesses located in each state to take advantage of all the great benefits of Renewable Energy, and to help out the environment.

Massachusetts Solar PV Rebates overview

MA Solar PV Rebates for Residential installations

Calculating your Mass. Residential Solar PV Rebates

MA Solar PV Rebates for Commercial installations

Connecticut Solar PV Rebates – Section Coming Soon

Rhode Island Solar PV Rebates: Apparently, due to excessive budget deficit in RI, there is no renewable-energy rebates available at this time. This is very unfortunate, and we try to do anything we can (which is not a lot, as this matter is in hands of RI policy makers) to bring those rebates back. To find out what is being done or how you can contribute to these and other renewable-energy initiatives, visit Apeiron Institute – a group of volunteers and activists of Sustainable way of life in RI and surrounding areas.

If you live or do business in RI, you are paying a Renewable-Energy charge on your electric bill. Fight for your right to access of a State-sponsored Solar PV rebates program, to which you and EVERY customer of electric companies in RI contributes every month. Yet your money goes somewhere else, while the National ‘Greed’ keeps on hiking your electricity rates. Contact RI Governor and the members of state senate and tell them you wand the Renewable-Energy Program back!

Massachusetts State Tax Rebates, Incentives and Grants for Solar PV

In 2008, Governor Patrick’s administration passed a new Solar Electric Photo-voltaic Initiative for the Commonwealth, which includes Solar rebates for residential and commercial Solar PV installations, as well as rebates for other renewable-energy technologies. This new program will allocate $68 million over next four years (2008 – 2011). Here is a brief summary of rebates for Residential and Non-Residential (Small and Large Commercial, Non-Profit and Government) solar PV systems.

List of Massachusetts residential solar rebates:

Moderate Home Value varies by county and ranges from $300,000 to $400,000. If your home value is equal to, or less-than your county’s Moderate Home Value (determined by municipality), you are eligible for this rebate.

Main obstacle that is holding the wide-spread of solar PV is the long ROI (return on investment) that in some situations may exceed 10 years. Fortunately, US federal government and local and state governments have a multitude of incentives and rebate programs for solar and other renewable energy projects.


Purpose of this Solar PV system design guide is to help you squeeze the most efficiency out of your home solar system, making it collect as much sun light as is available throughout the year.


Solar guide quick navigation:

• Is solar PV for you? – Planning a Solar PV System
• Designing Solar System for you – Estimate how many KW solar system will you need, & how much electricity it will produce.
• How to choose solar equipment? – Learn which solar PV panels, inverter, and control units you should choose.
• Cost of Solar PV – Compare prices of solar systems installed by integrator or do-it-yourself.

After reading this Solar System Guide, you will also learn how to minimize power losses due to electrical resistance of the wiring, how to choose the right type of solar panels and inverter, and how much of solar PV capacity (system size) you will need for your home or small business, and what kind of solar rebate you will be eligible for.

All of the above may dramatically increase your ROI and reduce the time that your solar system pays for itself. But first things first lets plan out your Solar PV system.

A rack-mounted Solar Photovoltaic system installed on a flat roof

Planning a Solar PV system for home and small business:

Before we begin, first and foremost – you need to figure out if your site can accommodate a solar pv array so that it operates at or near its rated efficiency. If your site conditions (roof of your home or business, backyard, etc) will limit the electricity production even by 20-25% – everything else is irrelevant and solar is probably not for you.

Step 1 – determining if your site can accommodate a solar photovoltaic system

Southern Exposure: Solar PV systems operate by converting sun light into electricity, so the first thing they require is enough sun light through-out the year, with as little obstruction or shading as possible. If you plan to use solar system that will be fixed (usually a roof mounted solar array), you will need to position it so that it faces South. In this case your solar PV system will collect as much sun light as possible, as the sun will move from East to West.

Shading: During the year, the sun is positioned very different, depending on the season – in the summer the sun is up high and in the winter it is very low. You need to consider this as this has a potential to make your system very inefficient. Solar Pathfinder is used by solar professionals to determine the position of the sun during the year and to find any shading that will obstruct the sunlight to the Solar PV Panels. Using a pathfinder you could determine weather it makes sense to have a solar system installed at your location and if you would need to remove some of the shading – eg. cut down some trees or move your neighbor’s house 20 feet to the left .

It is unlikely that a homeowner will have a Solar Pathfinder handy, but using just common sense, you can get a good idea if you have to much shading or if your location is perfect for the installation of a Solar PV system.


Angle or slope for solar panels: Depending on where you live or plan to install your solar system, an angle or incline of the panels may have a significant effect on electricity production. Here in New England the sun is at about 20 degrees to the earth surface and at about 45-50 degrees during the summer. If you plan to have a fixed solar systems installed in MA or at the similar longitude, ideal angle for your panels would be 30-32 degrees. As you above down south, the sun is higher in the skies so it is better to lower the angle of solar panels. At equator, solar panels can lay flat on the ground and will get maximum electricity production. At north or south pole, they should stand up vertically.

Size of your roof: If you plan to have a ground-mounted solar system, this will be irrelevant as there is usually enough room to have a decent size systems installed. If like most other people you plan to have solar panels installed on your roof, depending on the number of Kilowatts you plan your future solar system to be, you may need a considerable roof area. If you have a large roof and you are thinking about metal roof, a Roof-Integrated Solar PV System such as standing seam metal roof with Uni-solar panels is a very good choice providing you with a long lasing roof and slick-looking yet efficient amorphous-silicon thin-film solar panels. This babies require more space to produce the same amount of electric power, but are a better choice from the perspective of roof / solar system longevity and integration.

Lets assume that now you have performed a site inspection and determined that it would make a good place to have a solar systems installed. Maybe you will have to trim some trees, but over all, you have a decent size south facing roof with a good 35 degrees angle and no or very little shading going from east to west.

Step 2 – figuring out the size (in Watts) of your future Solar PV System:

This will surprise many people, but solar PV systems are priced in Watts or Kw – NOT in Sq. Ft.

Every second person calling us about Solar Roof, asks me: “how much is solar per square foot”. Truth is – I can’t answer this question and frankly, no one can. The question it self is wrong, but here is the right answer: Cost of solar will be determined by the system size measured in KW. Here I will explain how many kilowatts of solar you may need or want, and below you can find out how much it will cost.

How many Kilowatts do I need? – This is actually simple, but pay attention to the theory behind it all.

Electricity production of your solar system depends on how many “sun-hour-days” you have in your area. In Massachusetts and surrounding states (Connecticut, Rhode Island, Southern NY) we have an average of 4.2 – 4.5 hours of sunlight (sun hours) per day annually. This accounts for rainy and cloudy days as well as long, sunny summer days and short winter days.

Most households in the US consume on average 750 kWh (kilowatt-hours) per month. Assuming a 4.5 sun-hour-day in your area, 1 Kilowatt solar pv system should produce 4.5 kilowatt-hours of DC electricity per day. Per month it will produce 135 kWh DC. Now this DC electric current has to be converted to AC, so that your home appliances could use it. Inverter takes care of this part, as well as making your solar panels working at optimal production. However as any electrical device it has resistance sou there will be power losses. Average modern inverter loses 3% of electricity due to resistance, while total power loss can be as much as 7-10% or more, depending on how well or poorly your system was designed.

Basically to become completely independent from your Utility company you will need produce about 750 kWh of AC electricity. With 4.5 sun-hour-days you will need 6 kW solar PV array (5.83 kW to be exact, but bear in mind that this is all relative) which is optimally designed and is placed in optimal location – no shading, perfect angle, etc. This is the best case scenario.

So what size solar system will YOU need?

When considering installing a Solar PV system, you as home or business owner will need a to know the future size of your solar system in kW ( 1 kilo watt is 1000 watts) and the cost associated with this solar system. You also need to establish your current annual electricity usage and decide if you want to reduce or completely eliminate the use of electricity that you purchase from your utility company.

First, gather your electric bills for the last 12 months, record your total electricity consumption – the number of kW-hours, and your the total amount you had to pay, excluding any late fees and other miscellaneous fees. Divide your total cost by the total number of kWh – this will give you real cost per kWh.

In Massachusetts, average cost of electricity for residential use is 19-24 cents per kWh, and 15-17 cents per kWh for commercial use. Both are set to increase by 20% in near future, as announced in April 2008, by local utility companies.

Designing a Solar PV system, tailored for your need

To make best use of your solar system, you will need to capture as much sun-light as possible, therefore the best location to place your solar system is on the south-facing side of the roof. You also want them to be installed at a certain angle – about 20-30 degrees.
Assuming the 4.5 hours of sun per day, a 1 kW Solar PV system will produce 4.5 kWh per day, and 135 kWh in a 30-day month (4.5 x 30 days). Please keep in mind that the energy produced is in DC volts, and when it goes through the conversion into AC, you lose about 20-25% of that electricity.

Average household electric consumption is 750 kWh per month for a single family home. To cover 100% of this consumption with solar electricity, you will need about 8 kW solar PV system. 135 kWh DC x 8 = 1080 kWh – 10% = 972 kWh AC at 100% production output of solar panel. Note that ALL solar panels loose an average of 0.5% of production output per year, or 10 % through its 20-year warranty period.

Average residential solar installation is 2-4 kW system which usually eliminates 50-70% of electric power that you purchase. How ever those installations are still dependent on additional electricity.

Commercial solar installations can range from 10 kW to over 1 MW (1 megawatt = 1000 kW). Commercial Solar PV systems can supply power to the building they are installed on or they may be a so called solar farm – or a solar power plant supplying electric power directly into electric grid. For purpose of this guide, we will concentrate on smaller, roof-top solar installations for individual home or business use, as solar farms topic goes way beyond the scope of this guide, and is considered a power utility for taxes and other purposes.

Step 3 – How to choose equipment for your solar system:

This is the most difficult part, as there is no right answer to this question. However there is a general guideline to follow, which will help you choose the longest-lasting and best performing solar panels, inverter(s), control units, production monitors, etc.

This part of our solar guide will be the most confusing part also, as I will go over equipment and the solar systems sizes and how to pair different components and to get the best solar pv rebates, all at the same time.

Lets begin: to avoid as much confusion as possible, we will pretend that we are designing a 3 KW solar system for residential installation, in Massachusetts. Some of the variables will be different for your state, but this will be a good reference point for you.

Basic metrics for choosing solar equipment (or any electronic equipment for that matter) is such that you don’t want to be an early adaptor. You want to buy a 2nd or even 3rd generation stuff (inverter for example), which is a very safe bet that all the bugs of first / second generations were worked out and equipment performs at maximum efficiency. You also want to get UL rated equipment, or your electrical inspector will never sign off on the permits. A good example of such inverter is the Sunny Boy 2500, which is a 3rd generation, tried and true work horse which also offers one of the best expandability and efficiency. This is not to say that other inverters are bad – you should use the 2nd/3rd generation metric and do your due diligence.

You also need to keep in mind that average life-span of the inverter is 7-10 years while it’s cost is up there (on average you can expect to pay just under $1 per watt of the inverter’s capacity). If you plan for a big solar system, it is better to have many smaller inverters than one big inverter. If a small inverter dies, others are still performing, and your system is only partially down and it is a LOT cheaper to replace one $3000 unit, out of 5, than one $15000 unit.

For our hypothetical solar system we will choose one of the more simple inverters from Sunny Boy, rated at 3000 or 3500 watts. There is never and exact number of watts produced and in the first year, your Solar system WILL produce about 10% more than its rated capacity. You want to utilize that and also don’t want to “overload” your inverter: this is a little confusing – inverter will only accept as much electricity as it’s rated capacity – not more, so anything extra will just disappear.

A slightly larger inverter will allow for some future expansion of your solar systems.

Cost of Solar PV systems:

National average cost to install a Solar PV system ranges from $9 to $12 per watt or $9000-12000 per kW DC (direct current) of solar system installed, with smaller installations being at the top for this price range due to fixed costs such as equipment, setup, installation, permits and paperwork.

Most expensive component of the solar PV system are the solar panels themselves, however equipment such as inverter (which converts DC into AC and feeds it into your meter) also add considerable amount to a smaller size PV systems. Therefore for a 3 kW residential solar system, the cost will be around $11 per watt or $33000 total system cost when using conventional solar panels

Fortunately the $33000 price tag is not you actual cost, as many states have a wide range of rebates for solar PV installations as well as federal tax credits, available for both commercial and residential systems.

ROI and pay-off period for Solar PV

For purposes of this guide we will use two hypothetical solar PV systems – one being a 4 kW residential system and the other being a 25 kW commercial system. To simplify this guide and to avoid any confusion both of those systems are installed in Massachusetts. This way we know exactly what the MA state rebates are for each system and what the local electricity costs are from N-Star and National Grid utility companies. These two utility companies have the widest presence in MA market.