OPPD EXPLAINS ROOFTOP SOLAR SYSTEMS
As the price of rooftop solar installations decreases and technology improves, the option of going solar becomes more attractive. This is enhanced by the fact that Congress extended a 30 percent federal tax credit for residential solar installations through the end of 2019.
However, choosing a home solar panel system is a big decision with a lot of information to process and choices to make. Here are answers to some questions you may have when considering an investment in rooftop solar.
Rooftop Solar Q&A
What are the components of a rooftop solar system?
There are many variables when it comes to the actual solar installation, but the main components of a typical system include:
- Solar photovoltaic (PV) panels that use sunlight energy to generate electricity. The panels are connected to a main inverter or multiple microinverters.
- An inverter or microinverters that change the direct current (DC) gathered by solar panels to alternating current (AC) so it can be used as household electricity. Inverters connect to the circuit breaker panel, where power is supplied to your sockets and outlets.
- Racking that secures the panels to your rooftop. Proper mounting is crucial to prevent roof damage and ensure stability, especially in extreme weather conditions.
Is that all I’ll need for a home solar system?
It depends on whether you’re connecting to a utility grid or going off-grid. Here are some additional components needed for each situation:
- A specialized electric meter is necessary for a grid-connected system. This will allow you to receive incoming energy for backup purposes and to export surplus energy to the utility company for credit.
- Batteries or a battery pack can be used to store backup energy for times when the sun is not shining. This is optional if you get backup energy from the grid.
- A generator will be needed if you are off-grid in order to supply energy during periods of low solar output or high electricity use.
Is my roof right for solar?
PV panels can be installed on most roofs. These are important factors in determining the cost, size and efficiency of your installation:
- Direction: South-facing roofs are the most productive for solar, followed by west- and east-facing structures. North-facing roofs often are ruled out due to lack of direct sunlight.
- Shade: Sun should hit your panels for five or more hours daily. It’s a problem if trees or other obstructions block the sun from shining on your roof.
- Pitch: The ideal angle for solar panels is 30 degrees but they can be installed on roofs ranging from zero to 45 degrees. Tilted racks are used to mount solar panels on flat roofs.
- Size: The average amount of contiguous space needed for a residential solar installation is 500 square feet.
- Type: Asphalt shingles or corrugated metal are the best surfaces for mounting rooftop solar systems. Installation on slate or tile is more complex and expensive, and wood shingles are sometimes ruled out due to fire hazard.
- Age: If your roof needs to be replaced within five years, you should consider doing it before installing solar panels. Removing and reinstalling solar panels in order to replace the roof is costlier.
Are there different types of rooftop solar panels?
Nearly all PV panels are made of crystalline silicon and have a life expectancy of approximately 25 years. Here is a list of the most common kinds of residential solar panels:
- Monocrystalline panels are made from top-grade silicon and have the highest efficiency rate (15-20 percent), perform well in low-light conditions, are space-efficient and are the most durable. While monocrystalline panels are more expensive than other options, they usually come with a 25-year warranty.
- Polycrystalline panels, also known as multi-crystalline, are manufactured using a simpler, more cost-effective process. Made with less pure silicon, they have a lower efficiency rating than monocrystalline panels (13-16 percent) and therefore require a larger installation with more surface coverage for equivalent performance.
- Thin-film solar panels are made and sold more cheaply than crystalline-based solar cells. However, their lower efficiency rating (13-14 percent) means you will need significantly more coverage space to achieve similar energy production. Thin-film panels also tend to degrade faster than their counterparts and have shorter warranties as a result.
How many solar panels will I need?
A number of variables help determine the size of your rooftop solar system. These include:
- How many kilowatt-hours you use per month.
- What percentage of power you want to offset with solar.
- The efficiency rating of the solar PV panels you’re considering.
As a matter of comparison, the average residential solar system is five kilowatts (5 kW), which translates to approximately 20 high-efficiency solar panels.
Will a rooftop solar system save you money?
Yes, but how much you’ll save and how quickly you’ll be able to offset the cost of your solar system depends on a variety of factors. Hours of daily sunlight, size and angle of your roof, solar panel efficiency, household energy use and local electricity rates all affect your bottom line.
There are online solar calculators that can help you estimate how much a residential solar installation might save you. These calculators also will come in handy when comparing contractor quotes for a solar PV system.
Are there operational costs of residential solar systems?
Solar PV panels require little maintenance, are very durable and have no moving parts to break down. Any damage that might occur should be covered by your solar system warranty. Nevertheless there are some fees that will arise during the lifespan of your solar PV panels.
- Inverters last about 10 years and cost between 10 and 20 percent of the total system price to replace.
- Annual inspection of panels can be arranged through your contractor for approximately $150.
- Cleaning of panels can be done by the owner or by a contractor for about $150.
- Homeowner insurance premiums may go up slightly as a result of increased coverage needed to account for the cost of your solar system.
What about solar rebates, tax credits and incentives?
In addition to federal renewable energy tax credits, each state has its own residential solar regulations. While Nebraska does not have the most robust renewable energy regulations, residents are eligible for certain tax incentives and credits.
Here are other perks that make purchasing a home solar system more attractive:
- Net metering is a program that allows power company customers with solar systems to sell surplus energy back to the utility for credit on their electric bills. Nebraska utility companies like OPPD have strong net metering programs.
- The federal solar tax credit allows you to deduct 30 percent of the cost of installing a solar energy system from your federal taxes.
- Zero-down, low-interest solar loans are becoming increasingly common. For instance, a fixed rate of 4 percent for 15 years can help maximize your solar savings and influence your decision to go solar.
Will a solar system increase the value of my home?
This is contingent upon a number of factors such as if the solar system is owned outright or leased, age and condition of the roof and solar system, preferences of prospective purchasers and energy costs in the area.
OPPD's Energy Portfolio
OPPD utilizes an Integrated Resource Plan as a way of promoting a diverse energy portfolio that includes clean and renewable sources of energy. If you are not in the OPPD service area, check with your utility to see if any renewable energy programs are available.