nonrefundable tax credit and payroll withholding

Hello all, I have been searching for some time and have found little help. I asked an expert here via live chat and they gave conflicting information with this article (found here). So I am going to ask here for a socong opinion. 


Last year I paid about 14,000 in federal taxes (via withholdings on my paychecks) and owed about 500 because of untaxed stock profit throughout the year. This year I am looking at taking advantage of the Residential Clean Energy Credit (5695 part 1). By my estimate, I will be eligible for 18,000 in a nonrefundable tax credit (60,000 x 30% for a geothermal system).

 

Do nonrefundable tax credits offer a refund of taxes withheld throughout the year? In my above example, I would receive a refund of 14,000 for taxes paid throughout the year and have 3,500 left on the nonrefundable refund that may be rolled over to next year, or does it only apply to the 500 that I owe potentially rolling over 13,500 to the following year?