The National Renewable Energy Laboratory (NREL) has for several years been gathering data on the U.S. solar energy market. Under the lab’s Open PV Project, solar installers from around the country voluntarily submit information on each installation they complete, noting metrics like solar cost-per-watt, system size and location.

While NREL readily admits its numbers aren’t perfect, the results do provide a glimpse at solar energy system pricing trends across the nation. And, now that 2010 is behind us, we can draw some preliminary conclusions about how solar buyers fared last year. Namely, we can see that the average going price for a solar panel installation in 2010 was $7.17 per watt.

It bears noting that this figure:

• Reflects total average costs across residential solar and commercial solar installations.
• Is a pre-incentive price, which means it doesn’t factor in any federal tax credits or grants and local solar rebates.
• Is a national average and as a result doesn’t reflect regional solar price variations.

NREL’s 2010 numbers confirm that the cost of solar energy systems continues to come down. It’s important to note, however, that solar rebates and other incentives are at the same time being reduced across the country, in places like California, Arizona, Massachusetts and New Jersey. Given that many state and municipal governments will continue to tighten their belts in 2001, this downward trend in solar rebates may well continue. So, while solar panels will likely be cheaper in 2011 than they were in 2010, the solar rebate available in your area may be smaller. This means waiting around to see if solar power costs drop further may not end up saving you any money.

If you’re even a little bit curious about solar power in America, the Open PV Project is worth a peek. Don’t miss their visualization of solar photovoltaic (PV) installations over time.