How does solar power work?

A solar energy system creates usable power from sunshine. The two most commonly used types of solar energy technology in the Midwest are photovoltaic (PV) panels and solar thermal collectors. PV uses sunlight to generate electricity. It’s the same technology found on pocket calculators, just on a larger scale. Thermal solar uses sunlight to heat water, usually for a hot water supply.

PV panels contain a semiconductor material (typically silicon-based) which converts sunlight into direct-current (DC) electricity. Solar Electric systems generate electricity silently and without any moving parts. Sunlight falls on the solar array (blue, on the roof), generating DC electricity. That DC electricity is converted into household 120V AC electricity by the inverter (blue & gray, on the wall). The AC electricity is fed into your electric meter and circuit breaker panel (gray, on the wall). The electricity either goes to your appliances and lights, or to the grid, or some to each. This all happens silently and automatically every day.

At night and during cloudy weather, the solar system’s output is reduced or stopped; your building then gets electricity directly from the utility grid. You’re always connected to the grid, so you can have as much power as you need, any time you need it, regardless of whether the solar system is able to put out any power.

When the solar system can put out power, it goes to reducing your usage at the time, or, if there is excess, to spinning the meter backwards, counting down your electric use and bill.

Solar Electricity is one of the fastest growing energy technologies worldwide, growing over 35% each year for the last 8 years. Not actually a ‘new’ technology, the first solar panel was put into use in 1954. Most of the bigger solar manufacturers have over 20 years of experience in producing and refining their products. Some have over 40 years of experience.

How does solar power connect to the electrical grid?

In grid connected systems, the AC electric current can be routed directly into the home or business, or routed to the electric grid via a two-way meter. In “net metered” systems, the meter runs forward when the home or business is using more power than is generated by the solar panels. It runs backwards when the solar panels are generating more power than is being consumed on-site. This type of metering is available from many utility companies.

Does solar power make sense for my building?

There are several factors that go into whether or not solar is a good fit for your home or building:

  • Does your roof get much sun exposure?
  • What’s the condition of your roof? What material is it made of?
  • Does solar make sense for your budget?
  • Is your building energy efficient?

The first question should always be whether your building is energy efficient. Energy efficiency upgrades should always precede or accompany solar investments. These are often very cost effective, but less in vogue than solar electricity. They include lighting upgrades and replacing refrigerator and other equipment or appliances with more modern and efficient products.

Next, do a solar spot check on your own. Is your roof shaded by trees or other buildings? If your roof is sloped? Is there a south-facing slope? If there is an uninterrupted southern exposure, your home or building may be ideal for solar PV.

​What incentives are available?

​There is a 30% federal investment tax credit (ITC) for solar energy systems in place until December 31st, 2016. Both residential and commercial customers can take advantage of this tax credit. This credit has been extended through 2020, but the credit rate will reduce each year.

In addition to the federal ITC, many states, counties, municipalities and utilities offer rebates or other incentives for solar energy technologies. Iowa is currently offering an incentive tax credit for half of the federal credit toward the total project cost, with limits of $20,000 for commercial and $5,000 for residential systems.

For Iowa residents, the federal and Iowa state tax incentives combine to offset 45% of the cost of a residential solar PV system. Individuals receive this credit in the form of a tax break, which reduces tax liability. This tax break can be taken all at once or spread out across multiple years.

Commercial and agricultural customers can also depreciate their arrays for additional tax benefits. The amount you can depreciate depends on your tax bracket. Solar is eligible for a 5-year recovery period.

What are the economics of an average residential solar system?

The economics of residential solar vary significantly depending on solar policies and incentives available and different market conditions. Module costs (hard costs) are typically only about half of the total installed costs. These have been dropping significantly since 2000 due to a global supply glut and technological improvements. Soft costs (system design and installation) vary depending on the size, location, and design of a system.

Every rooftop is different, and Moxie Solar can provide the best information on what it will cost to go solar for your home or business. Once our customers begin exploring their options, they often find that the total up-front cost of solar is less relevant than the financing terms, return-on-investment, and cash flow calculations.

Moxie Solar has teamed up with financing partners that offer incredibly low interest rates. For many home owners, financing a solar array for their home means immediate cash savings on monthly bills.

Depending on who it is, your utility company may “net-meter” your production. This means that any extra power your array produces is banked for the future. You then receive a credit toward future energy bills or receive a check. Just imagine the electric company paying you, instead of the other way around!

What happens to solar panels when it’s cloudy or raining?

Photovoltaic panels can use direct or indirect sunlight to generate power, though they are most effective in direct sunlight. Solar panels still work even when the light is reflected or partially blocked by clouds. Rain actually helps to keep your panels operating efficiently by washing away any dust or dirt. If you live in an area with a strong net metering policy, energy generated by your panels during sunny hours will offset energy that you use at night and other times when your system isn’t operating at full capacity. Naturally, cloud cover reduces the amount of solar radiation reaching the panels, but the system will produce some electricity and/or heat on all but the most overcast days.

Sunlight is important for solar, but even cloudy areas are great for solar energy. It doesn’t matter as much where you live, whether it’s the Northeast or Southwest. What matters more is your roof (or property, if you’re thinking of a ground system). As long as your roof is free of shade and faces the South, East, or West, you’ll get plenty of sunshine for panels.

The array pictured on the right produces over 5,000 kWh each January.

How much roof space do solar panels need?

On average, for every kilowatt (kW) installed, a home solar system takes up about 100 square feet. Most residential solar systems are between 3 and 6 kW, so an average solar system takes between 300 and 600 square feet.

What is the best type of roof for solar panels?

The perfect roof for solar could be described as made of composite and not too steep, with unobstructed space for the solar panels. That said, solar works on many kinds of roofs, with the exceptions of slate and clay tile roofs. Wood shake roofs, flat roofs, and concrete tiles are a little more difficult to install on, but can be done.

How many solar panels are needed to provide power for an average home?

​PV systems can be designed to generate the majority of the electricity used in your home, or just a portion of it. In general, your solar system will not be designed to offset 100% of your electricity needs. This is because it makes more financial sense to get some of your electricity from solar energy and the rest from your utility company (i.e. in the daytime, solar electricity is bountiful but utility electric rates may be at their peak; at night, your system won’t produce any solar energy, but you can use cheaper, off-peak electricity from the utility company).

For a Midwest example, the average residential home uses approximately 720 kWh of electricity per month. A 3.5 KW PV system would offset more than half of the average household’s electricity consumption. This size solar system would require about eighteen 200-Watt PV panels.

The size of your solar system depends on a number of factors:

  • How much electricity your home uses
  • Angle, pitch, and direction of your roof
  • Unobstructed roof space that is available

Should I consider a ground mounted solar system?

If your roof isn’t optimal for solar and you have ground space, you might choose a ground-mounted solar system. People commonly choose ground mounted systems if the roof doesn’t work (faces the wrong direction, made of the wrong materials, etc.) or if they have a lot of space on their property. Moxie Solar offers best-in-class ground mount systems that are durable and reliable.

Will solar panels work if my roof isn’t new?

In general, we recommend that your roof be less than 15 years old if you decide to go solar. Your home solar system will last for twenty years or more, so you’ll need to have at least twenty good years left on your roof. If your roof needs to be replaced or repaired, it’s best to do so before you get solar, so you don’t have to remove and re-install the panels later on. However, it is possible to do a roof replacement or repairs once you have solar.

Can my homeowners association (HOA) stop me from installing panels on my home?

Usually not. An HOA may try, but in many states, this is not allowed. However, HOAs may ask you to modify the design and/or location for aesthetic reasons as long as the changes don’t significantly impact solar electricity production (a decrease greater than 10%) or cost more than $2,000.

How does a solar energy system benefit me personally?

  • It reduces your energy bill, and in many cases the utility company will buy back any extra electricity you generate.
  • Federal, state, and utility financial incentives are available in many areas.
  • It adds to the value of your home.
  • You gain energy independence.
  • Perhaps most importantly, it’s a good investment in a sustainable future for yourself and your loved ones.

How can solar improve national security?

Currently, the US depends on fossil fuels, especially oil, from potentially unstable or unfriendly countries. These supplies are vulnerable to political upheaval, trade disputes, embargoes, and other disruptions. In 1973 we imported only about 34% of our oil, and yet the 1973 oil embargo was a serious blow to the economy. Today we import over 53%, and are more vulnerable every year. Solar energy can help reduce this dependency, making our economy, our nation, and our families more secure.

How can solar help the economy?

Right now the US has to import oil and natural gas to cover our energy needs. The cost adds up to many billions of dollars, and all of that money leaves the country. Solar energy is generated locally. Moxie Solar installs panels that are made in the U.S. The energy dollars stay at home, creating economic growth and benefiting your community. Solar power also offsets the total consumption of fossil-fuels, which benefits everyone through the laws of supply and demand.

What regular maintenance do I need to do?

With systems that we recommend, very little. PV systems are inherently very low-maintenance, requiring the system owner only to wash the solar modules down with water when they get dirty so light can get through.

How long will my system last?

If properly installed, it should last 30-40 years. Systems that were installed in the 1970’s are still fully operational today. Technology has evolved so the systems from the 1970’s may not be as efficient as today’s technology.

What is a kilowatt hour?

This is what you pay for when you buy energy from the local utility company. A kilowatt-hour (kWh) is a unit for measuring energy. It is, as its name suggests, one kilowatt of power used over a period of one hour.