Going Solar: What You Need to Know
Going Solar: What You Need to Know!
If you’re thinking about solar for your home, you may not know where to start. You’ll have to ask yourself a lot of questions and consider several different options before you get started. Thanks to Anne-Catherine Dargis and the folks at PV Power, we’re able to provide a list of those questions for you!
# 1: How big should my system be?
PV systems are sized based on three key components.
- What is your home’s consumption and how much do you want to offset? You can see your electricity consumption on your electric bill. For ComEd customers, it is listed on the left-hand side of the bill. This will tell you what you’re using each month. You can also perform a DIY Energy Audit to help find ways to lower your consumption. The best way to keep costs low is to reduce consumption and increase efficiency as much as possible before adding and solar panels to your home.
- How much space do you have? In Chicago, PV modules will most likely be mounted on your roof, so you’re limited by the space you have available without obstructions such as parapets, air conditioners, skylights or chimneys. To estimate the space you have for solar modules, remove a 3ft perimeter from the outside of the roof, and count out an area that is three times the height of any obstructions. So, if you have a 2ft tall roof vent, you shouldn’t place modules within 6ft of it. (See more on shading issues below)
- What is your budget? As mentioned earlier, the best way to keep costs low is to reduce consumption as much as possible. In doing so, you reduce the number of solar modules you need, thereby reducing upfront costs. Budget constraints may limit the total energy you’re able to produce, so choose a budget you’re comfortable with and shop until you find systems that strike the right energy offset-to-cost balance for you.
# 2: Should I have a grid-tied or off-grid system?
The most common type of solar installation for an urban residence is grid-tied or on-grid, meaning your home remains connected to your current electricity provider. Solar modules will create electricity as long as the sun shines during the day. Then, at night or while the sun is hidden behind clouds, the home will use power from the electric grid. The two biggest components of a grid-tied system are PV modules and an inverter.
Off-grid systems are typically used as back-up power or in remote settings. They include a battery bank to provide power during the times when there is no sunshine. There are more components in a battery-based system, including a charge controller to regulate the batteries’ charge rate and an inverter to convert the direct current (DC) to alternating current (AC) to be used by your appliances.
# 3: Where should I put my panels?
Several factors should be considered when you are choosing the place to install a solar system:
- Solar power systems installed in the Northern Hemisphere are most efficient facing south.
- Any shading from overhanging trees or nearby structures can negatively affect the performance of solar panels, so every effort should be made to make sure that there is no shading where the panels are mounted. (See more on shading below)
- The PV panels should be mounted at an angle perpendicular to the sun to maximize exposure.
Based on the criteria listed above, the following mounts can be used.
Roof Mount
Stand-off mounts are the most commonly used roof mounting system. A stand-off mount consists of a pair of rails onto which the panels are clamped parallel to the roof with a small gap between the modules and the roof to allow good air flow. Panels operate most efficiently when kept cool. The other types of roof mount are direct mount, which mount the panels directly on the roof; rack mount, which supports the module array on a metal frame; building integrated photovoltaic (BIPV) mount, which are integrated into the building and replace standard building materials; ballasted mounts, which use concrete blocks to hold the array in place.
Ground Mount
Ground mounting is often chosen when the system is too large to be mounted on the roof and the site has enough land to accommodate the array. The mount is a frame that is bolted to footings, which can be fixed or adjustable to allow maximum sun exposure.
Bracket Mount
Angle brackets are attached to the exterior walls or roof of the building and a compatible pair of brackets attached to the module, thus joining the brackets and securely attaching the module. This is only suitable for a single module.
Pole Mount
This system is often used when the array can’t be mounted on a building. The array is mounted on hardware, which is then bolted onto a pole. The pole is secured in a hole filled with concrete. The size of the pole and amount of concrete will depend on the array size, the type of soil and wind speeds.
Tracking Mount
As its name suggests, this type of system tracks the sun’s movement across the sky to achieve maximum exposure of the array to the sun’s rays. Single-axis tracking mounts only follow the sun’s azimuth (the location of the sun east and west of true south), whilst double-axis mounts follow both the azimuth and the altitude of the sun. The mount is placed on a pole, which must be cemented into firm foundations to bear the weight and withstand the wind.
# 4: Do I have shading issues?
The vast majority of solar systems installed today are connected in series. Whatever happens to one panel in the series affects every panel in the series. So, if one panel gets shaded, the output current will drop, which leads to the current drop of the whole string. To maximize the efficiency of the array, it is therefore critical to avoid shaded areas when mounting modules if at all possible.
# 5: Estimated Payback on an Average Home
Payback is difficult to calculate since it depends on so many variable factors, such as the module and inverter efficiency, SREC (solar renewable energy credits) availability and utility rate inflation. However, to give you an idea of what you can expect from a solar installation, we have done a calculation for an average home with a system size of 4.14kW. You can also use this Solar Power Calculator to get some estimates based on your homes electricity usage.
The component cost for a system this size is estimated at $23,501. Illinois rebates lower the cost by $6,321 and the federal tax credit will further reduce the cost by $5,154, making the total net cost $12,026. ComEd customers can currently sell SRECs to New Jersey and Pennsylvania. The current value of an SREC in Illinois is roughly $250, and a system this size produces 5.32 SRECs per year. So, SRECs are worth $1,330 annually. The graph below shows the payback timeline for the system just described:
This payback visual does not include additional costs, like installation, permits and shipping, but will give you a good idea of what you could expect. The visual below gives a cost breakdown of a typical solar installation. So, based on the component cost of $23,501, installation would be around 12 %, or $2,800.
Another thing to keep in mind when considering solar for you home, is the increase of resale value. According to a study done by ICF Consulting (“Evidence of Rational Market Valuations for Home Energy Efficiency,” www.icfi.com/Markets/Community_Development/doc_files/apj1098.pdf), every $1 reduction in annual energy costs would increase a home’s value by $20.73.
# 6: How does the cost of solar energy compare to the electricity I’m getting now?
To be better able to compare the cost of solar to your utility provider, here is a breakdown of the cost per kWh. The total system size is multiplied by the number of sun hours per day, the number of days in the year and the expected life of the system, which is 25 years.
| 4.14kW | System Size |
| 4.4h | Average Sun Hours per Day in Chicago |
| 365 | Days per Year |
| 25 years | System Life |
| 166,221 kWh | Total System Output over System Life |
The total component cost divided by the total energy produced will tell us the cost per unit of energy produced:
$12,026/166,221kWh = $0.072
Currently, ComEd customers are charged $0.090 per kWh of electricity consumed. Utility rates are inflating at roughly 6-8% annually.
# 7: What should I do next to get started?
There are lots of resources for Chicagoans who are looking to go solar. To learn about financial incentives that may apply to your project: DSIRE Incentives for Illinois and DSIRE Federal Incentives. Call PVPower at 866-274-0642 to get setup with an installer, or call our trusted installer partners in Chicago:
| Meyer Electrical Construction Inc. |
P.O. Box 220578
Chicago, IL 60622-0578
P 312.829.9009
F 312.829.9494
info@meyelecco.comCronan Graf Corporation
2215 S. St. Louis Ave
Chicago, IL 60623
P 773.273.9526
Solar Power and the Environment
So, we’ve told you about what to consider when considering solar for your home and we’ve walked through some of the expected costs and returns of the systems. Another thing to consider when thinking about whether or not solar is right for you, is the environment and the impact reducing your electricity consumption can have. Because fossil fuels are the most used mean of generating electricity and because of the known harmful byproducts and emissions that are released from burning fossil fuels, you can have an impact on slowing the effects of global warming by generating some of your own electricity in a clean and renewable way.
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