SOLAR SYSTEMS 2019
How They Work and How Much They Cost
This is an especially good year to consider upgrading with a residential solar-power system for two reasons: the cost has never been lower and the 30% federal tax credit starts to disappear in 2020. Understanding how solar systems function will help you to determine the desirability of that investment.
How Solar Works
Every rooftop solar system has four essential components and an optional fifth.
Solar panels have photovoltaic (PV) cells that turn radiant energy from the sun into direct-current (DC) electricity. Each standard-size panel is 65 by 39 inches (5.4 x 3.25 feet), weighs around 40 pounds, and is typically rated for output at 300 watts. To install an average-size residential system that produces six kilowatts (kW) of electricity, you’ll need 20 panels covering an area of 500 square feet and weighing about 1,000 pounds with mounting hardware. All-weather panels are durable for at least 25 years. Rain removes most grime, but annual inspections may include professional cleaning.
A mounting system secures that half-ton array to the rooftop. Most roofs can handle the weight, while older ones may need reinforcement, but this is definitely not a DIY job. Ideally, the roof has a pitch of around 30 degrees, is unobstructed by trees, and faces south because east-west orientations can be about 15% less productive.
An inverter converts that DC electricity into the standard alternating-current (AC) that powers electrical devices. A performance monitor tracks how much electricity is being produced and used. Data is displayed on a wall unit and can be transmitted to an off-site service accessible online or with an app.
The performance monitor also keeps tabs on excess electricity being fed back to your local utility because you’re not off the grid yet, nor do you really want to be. Instead, it’s a two-way street: you’re both a producer and consumer as part of a net-metering system. For every kilowatt-hour (kWh) of electricity you generate but don’t immediately use (typically during the afternoon), you get a credit for sending it out on the wires for redistribution where it’s needed. Those credits are cashed in when you’re producing less than you’re using (morning/evening peaks, all night long and during inclement weather). There’s also an annual cycle of summer production versus winter usage. This ebb and flow results in either a credit surplus that can be carried forward according to utility policy or a deficit requiring a small power bill that’s far less than what you’re paying now on the one-way street of consumption only.
So why can’t you just keep all the power you create, use it as needed, and get entirely off the grid? With current technology, electricity is much cheaper to produce and distribute than it is to store. Hence, the optional component of your system: solar batteries. Until there are major breakthroughs in storage capacity, current batteries serve as little more than emergency back-ups and can add 50% to your total price.
HOW MUCH SOLAR COSTS
The good news is that the declining price of solar panels plus a growing number of competing installers have combined to make residential solar-power systems more affordable than ever. As an example using nationwide averages, the 20-panel/6-kW system described above has a gross cost today of around $20,000, including all equipment, permit, and installation charges. Deduct $2,000 for the rebates offered in many states, subtract the 30% federal tax credit from that subtotal and another $1,000 for state credits where applicable, and you’ve got a bottom-line cost of just $11,600.
OK, that’s a big chunk of change, but consider this: you’re paying $100 or more a month for electricity now, which is $1,200+ a year or more than $30,000 over 25 years. But, if your system hits the sweet spot of producing roughly the same amount of power that you consume annually in a net-metering system, your monthly bill will be $0—a total savings of about $18,400. And, several recent studies have shown that a residential solar system can raise a home’s market value by up to 4%; for a $300,000 property, that’s an increase of $12,000 on day one. If you can’t afford the entire up-front cost, there are financing options and even leasing plans. But, under current law, the 30% federal tax credit available in 2019 will decline by 4% each year in 2020 and 2021, expiring altogether for residential solar in 2022 unless the program is renewed, which is ironic because rooftop solar systems are renewable-power sources that enhance American energy independence, create skilled jobs, and may help to save the planet.