Getting Started in Solar

Because we have solar panels at Terra Dei Homestead at Lutherlyn, people sometimes ask us for tips about getting started on putting up their own solar panels. We recently had a chance to talk about this with our solar installer, John Younkin of Blue Roof Farms. Here is what we learned from him:

Currently, the average payback period is about 12-14 years. You will make back in electric bill savings what you paid for the solar installation in about 12-14 years. (That estimate does include some payback from tax credits, which non-profit organizations do not qualify for; so for non-profits like churches or schools the payback time would be a little longer.)

Most solar systems today are grid-tied – this means you are still connected to the power company as well as to your solar panels. Sometimes the solar panels provide all the electricity you need, or even more, and sometimes you need to draw electricity from the power company. This eliminates the need for batteries to provide electricity when the solar panels are not producing. It also means that during the  times when a solar system is producing more electricity than needed, it can sell the extra back to the electric company. Off-grid systems are available too but grid-tied systems are less expensive and very convenient.

Solar panels DO produce electricity even on cloudy days (although a sunny day will produce a lot more, obviously).

Do a rough estimate of the number of solar panels you want and the cost. Solar panels and installation currently cost about $1,300-$1,500 per panel. This is overall cost which factors in the costs of additional equipment like inverters and wiring as well as installation, and of course the panels. Most residential customers need somewhere around 24-36 panels to supply all their electricity. (See below for more on how to estimate how many panels would supply all your electricity.) BUT, how many panels you want to install is up to you – you don’t have to install enough panels to provide ALL your electricity. Because the system is grid-tied, you could provide half your electricity from solar panels, and half from the electric company, or whatever you’re ready for. You also don’t have to install all the panels you want all at one time – you can install some first and add more later.

To estimate how many solar panels would supply all your electricity: 

• Find out how many kWh (kilowatt hours) you use per year. This is usually printed on the lower left corner of your electric bill.
• Divide kWh per year by 365 to find kWh per day.
• Divide kWh per day by 4.2 – this is about how many hours a day provide power, on average, in western PA. This tells you how many kilowatts your solar panels need to produce. (If you are in a different geographic area, this number may be different for you.)
• Multiply kilowatts by 1,000 to find watts. Now you know how many watts your solar panels need to produce.
• Divide the number of watts by the amount of watts each panel produces to find out how many panels you’d need to supply all your electricity. (There is a wide range of how many watts solar panels produce. Our installer is currently using panels that produce 415 watts each, so you could divide by 415 for this estimate.)
• Multiply your final result by 1.2 to account for panels not producing exactly the number of watts they’re rated for.

To summarize:

kWh per year divided by 365 = kWh per day 

kWh per day divided by 4.2 = how many kilowatts your panels need to produce in western PA

kw times 1,000 = how many watts your panels need to produce

watts divided by 415 = how many panels would supply all your electricity

number of panels times 1.2 to make sure you have enough

(These calculations assume that your system will be grid-tied.) 

Example:
The average US household uses 11,000 kWh per year, so let’s use that for our example, although actual usage varies widely, and the usage of a church, business, school, etc., will be very different than household usage.

11,000 / 365 = 30.1 kWh per day
30.1 / 4.2 = 7.2 kw (panels need to produce this many kilowatts)
7.2 x 1,000 = 7,200 watts (panels need to produce this many watts)
7,200 / 415 = 17.3 panels needed
17.3 x 1.2 = 20.76, round down to 20.
Someone using about 11,000 kWh per year will need 20 panels to provide all their electricity in a grid-tied system.

20 panels x $1,500 = $30,000 

Check with your power company - find out what they need for an interconnection agreement. This is an application to the electric company to install a solar system.

Check with your local municipality – ask what you would need to install solar panels. (Ask about ground installation and roof installation, in case you aren’t sure which you will do.) They will tell you what kind of permits or inspections you will need. Each municipality’s requirements are different.

Contact a solar installer. A good solar installer will walk you through all of the above – calculating how many panels you need and what type of system, giving detailed estimates of costs, taking care of the interconnection agreement and local permitting, as well as figuring out how to situate panels on your property and installing the panels and system.

Advertisements you see offering “free” solar panels to homeowners are for solar leasing companies. If the company puts up solar panels on your property, you don’t pay for the solar panels, but you then pay the leasing company for your electricity. It’s a legitimate business model, not a scam, but it’s not necessarily a good deal for homeowners. The benefits are that homeowners don't have any of the up-front costs of installing solar (which is the biggest barrier for many people), and it increases the overall use of solar power. But with a lease like this homeowners also don’t realize any of the long-term savings of having solar panels, which could be significant over decades of not paying anything for electricity with solar panels owned outright. It’s not really free, because you pay the leasing company for your electricity; but it is accurate that you don’t pay for the solar panels.   

Financially, solar panels are fully viable (they pay for themselves in electric bill savings well before the end of their useful life span of 25-50 years), and have been since at least 2003, even here in cloudy western Pennsylvania! In addition, of course, they provide electricity from a renewable resource and cause far less pollution than typical electricity-generating power plants. Getting your electricity from solar panels is a great way to care for the earth!

John can be reached at solar@bluerooffarms.com and www.BlueRoofFarms.com.