4. INVESTMENT IN SALES-TYPE LEASES, NET

Under sales-type leases, Xi’an TCH leases the following systems: (i) BMPG systems to Pucheng Phase I and II (15 and 11 year terms, respectively); (ii) BMPG systems to Shenqiu Phase I (11 year term); (iii) Shenqiu Phase II (9.5 year term); and (iv) WGPG systems to Yida (15 year term). In addition, as of March 31, 2016, Erdos TCH leased power and steam generating systems from waste heat from metal refining to Erdos (five systems) for a term of twenty years. The components of the net investment in sales-type leases as of March 31, 2016 and December 31, 2015 are as follows:

	2016			2015
Total future minimum lease payments receivable	$	381,384,263		$	387,612,418
Less: executory cost		(91,850,486	)		(93,054,738	)
Less: unearned interest income		(150,638,976	)		(154,799,027	)
Investment in sales-type leases, net		138,894,801			139,758,653
Current portion		6,925,405			6,679,019
Noncurrent portion	$	131,969,396		$	133,079,634

As of March 31, 2016, the future minimum rentals to be received on non-cancelable sales-type leases by years are as follows:

2017	$	33,848,202
2018		32,687,426
2019		32,687,426
2020		32,687,426
2021		32,687,426
Thereafter		216,786,357
Total	$	381,384,263