Solar Energy Systems, net

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



	June 30, 2017			December 31, 2016
Solar energy system equipment costs	$	2,793,188		$	2,459,856
Inverters	287,833			260,011
Initial direct costs	134,325			117,587
Total solar energy systems	3,215,346			2,837,454
Less: accumulated depreciation and amortization	(359,288		)	(303,305		)
Add: construction-in-progress	95,202			95,217
Total solar energy systems, net	$	2,951,260		$	2,629,366

All solar energy systems, construction-in-progress and inverters have been leased to or are subject to signed Customer Agreements with customers. The Company recorded depreciation expense related to solar energy systems of $29.2 million and $22.5 million for the three months ended June 30, 2017 and 2016, respectively, and $56.8 million and $42.9 million for the six months ended June 30, 2017 and 2016, respectively. The depreciation expense was reduced by the amortization of deferred grants of $1.8 million and $3.4 million for the three months ended June 30, 2017 and 2016, respectively, and $3.8 million and $7.4 million for the six months ended June 30, 2017 and 2016, respectively.