Nature of Operations	12 Months Ended
Dec. 31, 2015
Nature of Operations.
Nature of Operations	1. 1. Nature of Operations Description of Business Plug Power Inc., or the Company, is a leading provider of alternative energy technology focused on the design, development, commercialization and manufacture of hydrogen fuel cell systems used primarily for the material handling and stationary power market. We are focused on proton exchange membrane, or PEM, fuel cell and fuel processing technologies, fuel cell/battery hybrid technologies, and associated hydrogen storage and dispensing infrastructure from which multiple products are available. A fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity and heat without combustion. Hydrogen is derived from hydrocarbon fuels such as liquid petroleum gas, or LPG, natural gas, propane, methanol, ethanol, gasoline or biofuels. Plug Power develops complete hydrogen delivery, storage and refueling solutions for customer locations. Hydrogen can also be obtained from the electrolysis of water, or produced on-site at consumer locations through a process known as reformation. Currently the Company obtains hydrogen by purchasing it from fuel suppliers. We provide and continue to develop fuel cell product solutions to replace lead-acid batteries in material handling vehicles and industrial trucks for some of the world's largest distribution and manufacturing businesses with a primary focus on North America. We are focusing our efforts on material handling applications (forklifts) at multi-shift high volume manufacturing and high throughput distribution sites where our products and services provide a unique combination of productivity, flexibility and environmental benefits. Our current product line includes: GenDrive, our hydrogen fueled PEM fuel cell system providing power to material handling vehicles; GenFuel, our hydrogen fueling delivery system; GenCare, our ongoing maintenance program for both the GenDrive fuel cells and GenFuel products; ReliOn, our stationary fuel cell solution providing scalable, modular PEM fuel cell power to support the backup and grid-support power requirements of the telecommunications, transportation, and utility sectors; and GenKey, our turn-key solution coupling together GenDrive or ReliOn, GenFuel and GenCare, offering complete simplicity to customers transitioning to fuel cell power; and GenFund, a collaboration with leasing organizations to provide cost efficient and seamless financing solutions to customers. We provide our products worldwide, with a primary focus on North America, through our direct product sales force, leveraging relationships with original equipment manufacturers, or OEMs, and their dealer networks. Through July 31, 2015, we were a party to a joint venture based in France with Axane, S.A. (Axane), a subsidiary of Air Liquide, under the name HyPulsion, to develop and sell hydrogen fuel cell systems for the European material handling market. On July 31, 2015 we purchased all of Axane's equity interest in HyPulsion and now hold 100% of such interests. See note 4 regarding our acquisition of the remaining ownership of HyPulsion. Prior to the acquisition the Company had a zero basis in its equity investment. We were organized as a corporation in the State of Delaware on June 27, 1997. Unless the context indicates otherwise, the terms "Company," "Plug Power," "we," "our" or "us" as used herein refers to Plug Power Inc. and its subsidiaries. Liquidity Our cash requirements relate primarily to working capital needed to operate and grow our business, including funding operating expenses, growth in inventory to support both shipments of new units and servicing the installed base, funding the growth in our GenKey "turn-key" solution which also includes the installation of our customer's hydrogen infrastructure as well as delivery of the hydrogen fuel, and continued development and expansion of our products. Our ability to achieve profitability and meet future liquidity needs and capital requirements will depend upon numerous factors, including the timing and quantity of product orders and shipments; attaining positive gross margins; the timing and amount of our operating expenses; the timing and costs of working capital needs; the timing and costs of building a sales base; the ability of our customers to obtain financing to support commercial transactions; our ability to obtain financing arrangements to support the sale or leasing of our products and services to customers and the terms of such agreements which may require us to pledge or restrict substantial amounts of our cash to support these financing arrangements; the timing and costs of developing marketing and distribution channels; the timing and costs of product service requirements; the timing and costs of hiring and training product staff; the extent to which our products gain market acceptance; the timing and costs of product development and introductions; the extent of our ongoing and new research and development programs; and changes in our strategy or our planned activities. If we are unable to fund our operations with positive cash flows and cannot obtain external financing, we may not be able to sustain future operations. As a result, we may be required to delay, reduce and/or cease our operations and/or seek bankruptcy protection. We have experienced and continue to experience negative cash flows from operations and net losses. The Company incurred net losses attributable to common shareholders of $55.8 million, $88.6 million and $62.8 million for the years ended December 31, 2015, 2014, and 2013, respectively, and has an accumulated deficit of $993.9 million at December 31, 2015. During the year ended December 31, 2015, cash used in operating activities was $47.3 million, consisting primarily of a net loss attributable to the Company of $55.7 million, coupled with net outflows of operating assets and liabilities of $8.9 million. The investment in working capital primarily was related to inventory procured to meet our backlog requirements. On December 31, 2015, we had cash and cash equivalents of $64.0 million and net working capital of $88.5 million. By comparison, at December 31, 2014, cash and cash equivalents was $146.2 million and net working capital was $167.0 million. Net cash used by investing and financing activities for the year ended December 31, 2015 included purchases of equipment and payments on capital lease and finance obligations. In addition, during 2015, the Company signed sale/leaseback agreements with the Company's primary financial institution (M&T Bank or the Bank) to facilitate its commercial transactions with key customers. These agreements represent the sale of the Company's fuel cell systems, hydrogen infrastructure and agreements to provide related extended maintenance to the Bank. The Company then leases the fuel cell systems and hydrogen infrastructure back from the Bank and operates them at customer locations to fulfill Power Purchase Agreements (PPAs). These operating leases require, the Company to maintain cash balances in restricted accounts securing its lease obligations. Cash added to these restricted accounts was $14.2 million during 2015. Cash received from customers under the PPAs is used to make lease payments back to the Bank. As the Company performs under these agreements, the required restricted cash balances are released, according to a set schedule. At December 31, 2015, the Company has seven PPA's that are connected to these sale/leaseback agreements. Remaining lease payments to the Bank associated with these agreements are $26.1 million and have been secured with restricted cash. Also, cash associated with sales of future revenues is required to be recorded as financing obligation on the consolidated balance sheets and accordingly represents a financing cash inflow. With regards to the master lease agreement with the Bank, the Company has a financial covenant, which requires a minimum level of unrestricted cash of $50 million. The Bank currently has remaining contractual lease payments fully secured through a combination of restricted cash and pledges on funds escrowed for future service by the Company. The covenant is maintained in association with the residual exposure of the Bank, which stems from tax benefits taken by the Bank that could be recaptured should the underlying assets not be deployed for five years. This residual exposure at December 31, 2015 amounted to approximately $15 million, and the exposure decreases with the passage of each year. Should the Company's unrestricted cash fall below the aforementioned minimum level, the Company is entitled to remediate the requirement through the provision of additional restricted cash to the secure the outstanding residual tax exposure of the Bank at that time. Additional sale/leaseback agreements have been entered into with other financial institutions, however, they were structured differently in that they required prepaid rent or security deposits in addition to restricted cash. Prepaid rent and security deposits related to sale/leaseback transactions with these other financial institutions as of December 31, 2015 were $12.1 million and restricted cash was $32.6 million. Prepaid rent and security deposits are classified as operating outflows (and noncurrent assets on the consolidated balance sheets). Remaining lease payments associated with these agreements are $27.9 and have been secured with restricted cash, security deposits and prepaid rent. During 2014, we received gross proceeds of $176.7 million from three underwritten public offerings. Net proceeds after underwriting discounts and commissions and other estimated fees and expenses were $165.7 million. In addition, during 2014 we received $18.3 million from the exercise of previously issued common stock warrants. To date, we have funded our operations primarily through public and private offerings of common and preferred stock, a sale/leaseback of our building and our previous line of credit. The Company believes that its current cash, cash equivalents, cash anticipated to be generated from future operations and, to the extent exercised, cash generated from the exercise of outstanding warrants will provide sufficient liquidity to fund operations for at least the next twelve months. This projection is based on our current expectations regarding product sales and service, cost structure, cash burn rate and other operating assumptions. Also, see note 17 Subsequent Events regarding the closing of a loan facility with a specialty finance company on March 2, 2016.

1. 1. Nature of Operations

Description of Business

Plug Power Inc., or the Company, is a leading provider of alternative energy technology focused on the design, development, commercialization and manufacture of hydrogen fuel cell systems used primarily for the material handling and stationary power market.

We are focused on proton exchange membrane, or PEM, fuel cell and fuel processing technologies, fuel cell/battery hybrid technologies, and associated hydrogen storage and dispensing infrastructure from which multiple products are available. A fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity and heat without combustion. Hydrogen is derived from hydrocarbon fuels such as liquid petroleum gas, or LPG, natural gas, propane, methanol, ethanol, gasoline or biofuels. Plug Power develops complete hydrogen delivery, storage and refueling solutions for customer locations. Hydrogen can also be obtained from the electrolysis of water, or produced on-site at consumer locations through a process known as reformation. Currently the Company obtains hydrogen by purchasing it from fuel suppliers.

We provide and continue to develop fuel cell product solutions to replace lead-acid batteries in material handling vehicles and industrial trucks for some of the world's largest distribution and manufacturing businesses with a primary focus on North America. We are focusing our efforts on material handling applications (forklifts) at multi-shift high volume manufacturing and high throughput distribution sites where our products and services provide a unique combination of productivity, flexibility and environmental benefits. Our current product line includes: GenDrive, our hydrogen fueled PEM fuel cell system providing power to material handling vehicles; GenFuel, our hydrogen fueling delivery system; GenCare, our ongoing maintenance program for both the GenDrive fuel cells and GenFuel products; ReliOn, our stationary fuel cell solution providing scalable, modular PEM fuel cell power to support the backup and grid-support power requirements of the telecommunications, transportation, and utility sectors; and GenKey, our turn-key solution coupling together GenDrive or ReliOn, GenFuel and GenCare, offering complete simplicity to customers transitioning to fuel cell power; and GenFund, a collaboration with leasing organizations to provide cost efficient and seamless financing solutions to customers.

We provide our products worldwide, with a primary focus on North America, through our direct product sales force, leveraging relationships with original equipment manufacturers, or OEMs, and their dealer networks. Through July 31, 2015, we were a party to a joint venture based in France with Axane, S.A. (Axane), a subsidiary of Air Liquide, under the name HyPulsion, to develop and sell hydrogen fuel cell systems for the European material handling market. On July 31, 2015 we purchased all of Axane's equity interest in HyPulsion and now hold 100% of such interests. See note 4 regarding our acquisition of the remaining ownership of HyPulsion. Prior to the acquisition the Company had a zero basis in its equity investment.

We were organized as a corporation in the State of Delaware on June 27, 1997.

Unless the context indicates otherwise, the terms "Company," "Plug Power," "we," "our" or "us" as used herein refers to Plug Power Inc. and its subsidiaries.

Liquidity

Our cash requirements relate primarily to working capital needed to operate and grow our business, including funding operating expenses, growth in inventory to support both shipments of new units and servicing the installed base, funding the growth in our GenKey "turn-key" solution which also includes the installation of our customer's hydrogen infrastructure as well as delivery of the hydrogen fuel, and continued development and expansion of our products. Our ability to achieve profitability and meet future liquidity needs and capital requirements will depend upon numerous factors, including the timing and quantity of product orders and shipments; attaining positive gross margins; the timing and amount of our operating expenses; the timing and costs of working capital needs; the timing and costs of building a sales base; the ability of our customers to obtain financing to support commercial transactions; our ability to obtain financing arrangements to support the sale or leasing of our products and services to customers and the terms of such agreements which may require us to pledge or restrict substantial amounts of our cash to support these financing arrangements; the timing and costs of developing marketing and distribution channels; the timing and costs of product service requirements; the timing and costs of hiring and training product staff; the extent to which our products gain market acceptance; the timing and costs of product development and introductions; the extent of our ongoing and new research and development programs; and changes in our strategy or our planned activities. If we are unable to fund our operations with positive cash flows and cannot obtain external financing, we may not be able to sustain future operations. As a result, we may be required to delay, reduce and/or cease our operations and/or seek bankruptcy protection.

We have experienced and continue to experience negative cash flows from operations and net losses. The Company incurred net losses attributable to common shareholders of $55.8 million, $88.6 million and $62.8 million for the years ended December 31, 2015, 2014, and 2013, respectively, and has an accumulated deficit of $993.9 million at December 31, 2015.

During the year ended December 31, 2015, cash used in operating activities was $47.3 million, consisting primarily of a net loss attributable to the Company of $55.7 million, coupled with net outflows of operating assets and liabilities of $8.9 million. The investment in working capital primarily was related to inventory procured to meet our backlog requirements. On December 31, 2015, we had cash and cash equivalents of $64.0 million and net working capital of $88.5 million. By comparison, at December 31, 2014, cash and cash equivalents was $146.2 million and net working capital was $167.0 million.

Net cash used by investing and financing activities for the year ended December 31, 2015 included purchases of equipment and payments on capital lease and finance obligations. In addition, during 2015, the Company signed sale/leaseback agreements with the Company's primary financial institution (M&T Bank or the Bank) to facilitate its commercial transactions with key customers. These agreements represent the sale of the Company's fuel cell systems, hydrogen infrastructure and agreements to provide related extended maintenance to the Bank. The Company then leases the fuel cell systems and hydrogen infrastructure back from the Bank and operates them at customer locations to fulfill Power Purchase Agreements (PPAs). These operating leases require, the Company to maintain cash balances in restricted accounts securing its lease obligations. Cash added to these restricted accounts was $14.2 million during 2015. Cash received from customers under the PPAs is used to make lease payments back to the Bank. As the Company performs under these agreements, the required restricted cash balances are released, according to a set schedule. At December 31, 2015, the Company has seven PPA's that are connected to these sale/leaseback agreements. Remaining lease payments to the Bank associated with these agreements are $26.1 million and have been secured with restricted cash. Also, cash associated with sales of future revenues is required to be recorded as financing obligation on the consolidated balance sheets and accordingly represents a financing cash inflow. With regards to the master lease agreement with the Bank, the Company has a financial covenant, which requires a minimum level of unrestricted cash of $50 million. The Bank currently has remaining contractual lease payments fully secured through a combination of restricted cash and pledges on funds escrowed for future service by the Company. The covenant is maintained in association with the residual exposure of the Bank, which stems from tax benefits taken by the Bank that could be recaptured should the underlying assets not be deployed for five years. This residual exposure at December 31, 2015 amounted to approximately $15 million, and the exposure decreases with the passage of each year. Should the Company's unrestricted cash fall below the aforementioned minimum level, the Company is entitled to remediate the requirement through the provision of additional restricted cash to the secure the outstanding residual tax exposure of the Bank at that time.

Additional sale/leaseback agreements have been entered into with other financial institutions, however, they were structured differently in that they required prepaid rent or security deposits in addition to restricted cash. Prepaid rent and security deposits related to sale/leaseback transactions with these other financial institutions as of December 31, 2015 were $12.1 million and restricted cash was $32.6 million. Prepaid rent and security deposits are classified as operating outflows (and noncurrent assets on the consolidated balance sheets). Remaining lease payments associated with these agreements are $27.9 and have been secured with restricted cash, security deposits and prepaid rent.

During 2014, we received gross proceeds of $176.7 million from three underwritten public offerings. Net proceeds after underwriting discounts and commissions and other estimated fees and expenses were $165.7 million. In addition, during 2014 we received $18.3 million from the exercise of previously issued common stock warrants.

To date, we have funded our operations primarily through public and private offerings of common and preferred stock, a sale/leaseback of our building and our previous line of credit. The Company believes that its current cash, cash equivalents, cash anticipated to be generated from future operations and, to the extent exercised, cash generated from the exercise of outstanding warrants will provide sufficient liquidity to fund operations for at least the next twelve months. This projection is based on our current expectations regarding product sales and service, cost structure, cash burn rate and other operating assumptions. Also, see note 17 Subsequent Events regarding the closing of a loan facility with a specialty finance company on March 2, 2016.