Good morning, and thank you for joining the call today. In January, we had our annual update call prior to the earnings release, provides our investors, partners, customers and employees a recap of the prior year and provide an outlook for the upcoming year. Today, we'll provide an update to both our results for the fourth quarter as well as a reminder of our plans for 2019, which is really described in detail in the shareholder letter. I will just review a few highlights and then we'll open the floor for questions.
Some highlights for the fourth quarter in 2018, include fourth quarter gross bookings of $62.1 million versus $32.9 million gross billings in fourth quarter of 2017. The company 2018 had total gross billings of $184.8 million, a 42% increase versus 2017. We're really excited about the fact that we had our first positive adjusted EBITDA quarter in 2018 in the fourth quarter of $500,000.
The first positive quarter in the company's history. We've achieved that by delivering over 1,900 0 emission electric vehicles in the fourth quarter.
We also, in 2018, produced our first ProGen metal plate stacks, our metal stacks are 2.5x denser than our prior technology and offer 25% cost reduction at volume. And finally, production in first units utilizing Plug Power design and manufactured fuel cell membrane with the target building of over 400,000 membranes in the coming year. This year, we expect it to become the largest manufacturer of proton exchange membrane in the United States. That's not to say 2018 did not have some challenges, such as the unfortunate event that occurred in -- at P&G in May. Investigation is not complete. A Plug Power and the supplier of the carbon fiber tank have identified that the supplier had improperly qualified the tank to the ISO standards. Since the tank was improperly qualified, the supplier is completely funding a replacement program for approximately 3,000 tanks in the field. This program will have no financial impact to Plug Power. The work in 2019 will build upon our success in 2018. The majority of our revenue will be dominated by our material handling business.
Our success in building out this segment will allow us to achieve $235 million to $245 million in gross billings and adjusted EBITDA positive in 2019.
Our fourth quarter run rate for both gross billings and adjusted EBITDAS should provide investors a high level of confidence in Plug Power's ability to achieve these goals.
Additionally, 2019 will also include our ongoing improvements in service costs and hydrogen efficiency, coupled with an intense sales effort to expand this business in North America and Europe. Value proposition is strong.
Our service performance for our largest customers have been almost flawless and the pull for our products is increasing, especially in heavy usage applications like food distribution and automotive manufacturing. With 25,000 0 emission electric vehicles in the field, Plug Power is the most experienced company in providing fuel cell and hybrid solutions in e-mobility applications. E-mobility applications using fuel cells are ideal for heavy asset utilization applications like forklift trucks, delivery vans, ground support equipment, heavy-duty vehicles, autonomous-guided vehicles and aerial taxis. The benefits of fuel cells in e-mobility applications, include fast fueling, longer range, higher power density and simpler infrastructure for fleet vehicles. It could give our work in the past year with respect to membrane design, the manufacturing, stack development and our ProGen line have been focused on developing a suite of high performance, low-cost modules that can be easily adapted in a multitude of e-mobility applications.
As our business grows, these applications will represent a larger percentage of our revenue. In the coming year, Plug Power is committed to making 4 major business announcements, and I assure investors some of them will be new e-mobility applications. Paul and I are now available for your questions.