Residential Grid-Tie Solar

Residential grid-tie solar is a term used to describe the type and size of a system. Modern solar electric systems convert the dc current produced by the solar modules (photovoltaic or pv) to ac "household" current through high efficiency inverters without the use of batteries, charge controllers, heavy switch-gear or cabling. When the sun is shining, the system is making power. A residential system is less than 10 kW while a commercial system is greater than 10 kW. Some residences have "commercial" sized systems while some businesses have "residential" sized systems. Grid-tie systems with back-up capabilities require components much like stand-alone or off-grid systems. The advances in technology and local incentives have made solar more attractive than ever to residential consumers.

Flush-mounted 4.7 kW grid-tie system

Below is a chart showing several installed residential system costs, rebates and tax credits. Installed means complete turn-key systems. Final cost includes all required system components, permits and shipping!

Residential Solar Grid-Tie System Examples

System Size	2.0 kW	3.5 kW	5.0 kW	7.7 kW
Average Cost¹	$16,300	$28,000	$39,250	$59,520
Utility Rebate²	$9,000	$15,750	$22,500	$34,650
After Rebate	$7,300	$12,250	$16,750	$24,870
Fed Tax Credit³	$2,000	$2,000	$2,000	$2,000
Final Cost	$5,300	$10,250	$14,750	$22,870

1. Average system cost is based on roof-top flush-mount installation. State and local sales taxes are not included.

2. Utility rebate assumes grid-tie installation within Black Hills (Aquila) or Xcel service territory. Current rebates paid are $2/watt equipment rebate and $2.50/watt REC payment. Array installation must be within 10% of calculated system output to qualify for full rebate amount.

3. Current residential Federal Income Tax Credit is 30% of system cost, capped at $2,000.

To calculate the energy produced from a grid-tie system, you can use the PVWatts application developed and maintained by NREL.