Thursday, May 26th, 2016
by Elizabeth Scribner, Solar-Powered Homeowner
As of this moment, I am relaxing in a 72-degree living room, courtesy of the hot sun baking outside, as a solar-powered air-conditioning unit and solar-powered central fan expertly deliver cool air throughout my house. With the sun as our primary power source, watching TV in the evening or making coffee in the morning have become truly guilt-free pleasures as we produce more energy than we need without the worry of spewing harmful toxins into the air or contaminating precious drinking water with coal waste.
Some people choose to spend money on luxury cars, kitchen remodels, or even exotic vacations, but when the promise of energy bill savings, reliable back-up power, and a chance to do something good for the environment presented itself it early 2015, my husband and I took the solar power bait and never looked back. When we first started looking into having a solar power system installed on our roof, the technology seemed like a black box with a lot of unknowns in terms of actually getting it on my roof and making sure it worked. My husband and I knew of only one person living in the Birmingham area with solar on his roof. We soon discovered, however, that the process was very straightforward and the technology actually rather simple.
Step One: We hired someone to survey our home for its solar potential, which Google will actually do for you now, free of charge, with the expansion of Project Sunroof into the Southeast. Project Sunroof analyzes the tilt and orientation of your roof, along with shading factors, to determine whether or not your home or business is a good candidate for solar power. Local experts can also provide a more detailed shading analysis of your roof using a device called a solar pathfinder, which provides hourly and monthly shading data. Below are pictures of the solar pathfinder results for our home:
The figure on the left is an image of the actual solar pathfinder at work, which reveals whether or not we have shading from 5:00am until 7:00pm each month of the year. Ideally, a roof is shade-free between the hours of 9:00am and 3:000pm, twelve months a year, which we very nearly accomplished if not for a very tall pine tree and equally large magnolia infringing upon our solar potential during the winter months when the sun is low. (As an environmentalist, I haven’t the heart to cut them down and no longer fear I need to after surviving our first solar-powered winter with no blackouts!). The figure on the right breaks down the percentage of daily sun our roof receives per month once shading is taken into account.
It turned out our home was an almost perfect candidate, facing just 16 degrees east of due south and high up on a hill with very little shading. Google’s Project Sunroof also reached the same conclusion, with the majority of my roof appearing a blazing yellow color (see picture below). Still, we needed to involve the local experts because there are other factors like the age and support structure of the roof, along with the existing electrical system, that needed to be considered before making the solar plunge.
Step Two: Once we’d been convinced that solar power was a good choice for our home, we reached out to our local utility, Alabama Power, to learn more about their policies for interconnecting solar panels with their utility grid. With a bit of paperwork, the process is straightforward: (1) e-mail residential solar contact at Alabama Power, (2) receive necessary paperwork, (3) submit paperwork and wait for APC approval. At the time we engaged with APC, there were four items of paperwork to complete: a Contract for Electric Service, a Purchase of Electric Energy agreement, an Interconnection Agreement, and a Parallel Generator Installation Certification (to be completed by a licensed electrician after installation). Below is a breakdown of the different APC rates for residential customers, along with their associated costs of interconnecting with the grid:
In order to capture the full financial benefit of a grid-tied solar power system without net metering as a local utility incentive, it is important to properly size a system so that a residence or building uses all of the solar power it produces. In our case, however, we intended to put as many solar panels on our southward-facing roof as possible. Given our energy-conscious lifestyle, combined with the lack of net metering and the $35 monthly fee we would be facing to grid-connect with APC, we concluded that an off-grid solar power system presented the best scenario for financial payback in our case. Add to that the benefit of having a reliable source of power in the event of a grid failure, which I appreciate more after watching everything in my fridge spoil during a 48-hour utility blackout just weeks before our solar power system was up and running!
Step Three: Regardless of whether you choose a grid-tied or off-grid solar power system, it is important to perform a load analysis to determine when and how much power you are using on a daily basis. Data on historic usage is available through APC’s website and is generally the most informative because it can tell a customer how much power they are using on a daily basis, each month of the year. However, in the case of an off-grid system like ours, a more detailed analysis was required in order to determine which appliances we could reliably take off-grid and how large of a battery bank we would need to survive the darkest months of the year without a solar power outage.
I actually did this step of the process myself. Armed with a clipboard and the knowledge that Amps x Volts = Watts, I walked through every room in my house, diligently recording the wattage of each appliance down to the radio alarm clock on my nightstand. I estimated the number of hours we used the appliance each day, multiplied this number by the appliance’s wattage, added up all the products, and arrived at a total daily consumption for my home. I was shocked to learn how much energy the incandescent overhead lights in our kitchen and family room consumed and quickly replaced them with 7-watt LEDs. The dryer, oven, and central air-conditioning unit were also huge energy draws, but having already upgraded to some of the most energy-efficient versions of those appliances, there was nothing we could do about that. We decided to leave those three appliances on the utility and take everything else in our house off-grid, which includes, among many things, our pool pump, our washing machine, our dishwasher, and all the lights and outlets in our home. I often joke that the worst-case scenario for us in the event of a utility outage is that I am stuck using the solar-powered toaster oven to bake a casserole, and I may have to hang my laundry to dry. A solar-powered window air-conditioning unit and central fan can cool my house efficiently during the summer months, and we rely on gas heating in the winter.
Step Four: After determining which appliances we intended to take off-grid, we engaged a solar system designer and local electrician to take care of the design, permitting process, and installation. An important step in the design phase is meeting with the local permitting board to ensure that the solar power system adheres to local electrical and building codes.
Step Five: Once we got the green light from the local permitting board, we placed our equipment order and eagerly awaited the big day when we could finally break ground on this much-anticipated energy upgrade. The components can take anywhere between 2 and 4 weeks for delivery, and depending on the size and complexity of the system, installation times can vary between 3 and 7 days for most residences. Because we were working with multiple contractors at the time and didn’t have the benefit of a turnkey solar system provider like Eagle Solar & Light, our installation actually took several weeks. However, unlike many home upgrade projects, installing a solar power system is relatively painless in terms of inconvenience because all the work takes place on the roof, attic, utility closet, and other uninhabited parts of the residence. My one-year-old continued to sleep peacefully through her morning and afternoon naps, while my 3-year-old asked with excitement each morning, “Mommy, are the solar panel men coming today?” By the end of the install, she was a solar power expert: “The sun makes electricity, and the electricity makes the lights work,” she explains to anyone who visits for a tour. Below are some pictures of the finished roof array:
Step Six: Like the purchase of any cool new technology, it is important to take the time to learn how the solar system works. At first I was incredibly intimidated looking at all the blinking lights and breaker switches and numbers on the display monitor, but I soon learned that, like using an iPhone or any new computer application, understanding the basics of a solar power system isn’t rocket science. I spent about an hour with our solar system designer walking through all the components and taking notes, and then I was ready to go! Below is a flow chart of the various components of our solar power system and their roles in keeping the lights on:
The best part about our solar power system is that the manufacturer of the equipment, Outback Power, provides free online monitoring of system, accessible through any computer, tablet, or smart phone. There are three basic numbers that interest me at any given time (and I check them regularly and with great interest like a kid with a new toy): (1) How much power the system is generating (reported in kW), (2) How much power our home is using (also reported in kW), and (3) the state of charge of the battery (reported in volts or more useful, a percent state of charge). Below is an image of the display I see every time I login to the online monitoring:
According to the above graphic, on September 25th, 2015, at 1:54pm, we were harvesting 5.2 kW of solar power, using 0.9 kW, and our battery was at a 74% state of charge. The online monitoring also provides great historical data by days, weeks, months, and even years, which is great for monitoring system performance and tracking seasonal trends.
Step Seven: Now we get to enjoy our solar power system and the energy savings along with it! The three appliances left on the utility—oven, dryer, and central cooling unit—have lost power several times in the months since we installed our off-grid system, whereas we haven’t experienced a single energy blip in the solar part of the house, even during the darkest weeks over the Christmas holidays. I would barely notice a utility blackout were it not for my neighbor’s generator noisily coming on and often waking me up during middle-of-the-night power outages. Once of the great things about an off-grid solar power system is that it functions as a back-up generator, minus the noise and fuel-cost (the sun is free!). It is also working all the time and saving us money on our power bill. We have seen out power bill cut by over 50% most months, and we expect to pay off the system within its lifetime of 20-25 years. However, for us, the best part is that we feel good about all the carbon emissions we are offsetting. To date, the use of our solar power has avoided putting 5,287 pounds of C02 into the atmosphere—a toxin primarily responsible for some of the poor air quality we suffer in Birmingham and a likely culprit for my daughter’s recurrent asthma. We are educating our children about the importance of energy conservation and trying our best to do what we can to reduce our carbon footprint. To learn more about our particular solar power system and current status of solar power in the state of Alabama, you can watch Southern Exposure’s short documentary film On The Horizon, by Lauren Musgrove. Dennis Pillion also wrote an interesting and informative news piece on Al.com about the potential of solar power in Alabama, which discusses and includes pictures of our solar power system.