6.	Solar Energy Systems, net

Solar energy systems, net consists of the following (in thousands):

	June 30, 2015			December 31, 2014
Solar energy system equipment costs	$	1,610,120		$	1,406,478
Inverters		148,714			123,910
Initial direct costs		48,809			36,279
Total solar energy systems		1,807,643			1,566,667
Less: accumulated depreciation and amortization		(176,161	)		(143,028	)
Add: construction-in-progress		64,246			56,584
Total solar energy systems, net	$	1,695,728		$	1,480,223

All solar energy systems, construction-in-progress, and inverters have been leased to or are subject to a signed Customer Agreement with customers. The Company recorded depreciation expense related to solar energy systems of $16.5 million and $32.0 million for the three and six months ended June 30, 2015, respectively, and $12.9 million and $24.9 million for the three and six months ended June 30, 2014, respectively. The depreciation expense was reduced by the amortization of deferred grants of $3.5 million and $7.1 million for the three and six months ended June 30, 2015, respectively, and $3.5 million and $6.9 million for the three and six months ended June 30, 2014, respectively.