Thank you for joining the first quarter conference call today. Today, we issued our first quarter Shareholder Letter, which provides details about our first quarter performance, as well as our outlook for the remainder of the year.
Let me start by saying that we are disappointed with our growth billing numbers during the first quarter and we shift 65% more GenDrives units this quarter versus the first quarter 2018, gross billings were down. It is important to note that the first quarter gross billings declined because of the timing of closing of project financing deal. The deal closed six days post the close of the quarter and represented a significant portion of our revenue gap. A positive in our financials is the improvement of the EBITDA versus prior quarter. Even at a lower gross billing level, EBITDA improved by over $3 million, based primarily on lower service costs.
Looking forward, we’re expecting gross billings of between $55 million to $60 million in the second quarter, reflecting over 100% sequential growth.
The first half is in line with our previous guidance or approximately one-third of our revenue in the first half. Today, we are reiterating our guidance for the year $235 million to $240 million in gross, bookings positive EBITDA for the full year 2019 and four major announcements during the year, some of our announcements are tied directly to our ProGen line. In the first quarter, we launched our new 30 kilowatt ProGen hydrogen engine for e-mobility applications. The ProGen product line offers a pre-engineered modular and scalable architecture that makes it simple for use by customers. The offering reiterates Plug Power goal of playing a meaningful role in ongoing vehicle electrification on a global basis.
Our modular ProGen hydrogen engine provides distinct advantage over battery electric vehicles, especially in applications which require high asset utilization, as well as long range. The [indiscernible] is starting to generate considerable customer interest globally.
One of the four major announcements will be associated with our ProGen line, and will be announced in May post our customers' announcements. Contracts have already been executed for this program and we look forward to sharing more information in near future.
Now, I’d like to open the line for questions.