Clean energy investments - In 2009 and 2011, we built a total of 29 commercial clean coal production plants to produce refined coal using Chem-Mod’s (see below) proprietary technologies. On September 1, 2013, we purchased a 99% interest in a limited liability company that has ownership interests in four limited liability companies that own five clean coal production plants. On March 1, 2014, we purchased an additional ownership interest in seven of the 2009 Era Plants and five of the 2011 Era Plants from a co-investor. For all seven of the 2009 Era Plants, our ownership increased from 49.5% to 100.0%. For the 2011 Era Plants, our ownership increased from 48.8% to 90.0% for one of the plants, from 49.0% to 100.0% for three of the plants and from 98.0% to 100.0% for one of the plants. We believe these operations produce refined coal that qualifies for tax credits under IRC Section 45. The law that provides for IRC Section 45 tax credits expires in December 2019 for the fourteen plants we built and placed in service in 2009 (2009 Era Plants) and in December 2021 for the fifteen plants we built and placed in service in 2011, plus the five plants we purchased interests in that were placed in service in 2011 (2011 Era Plants).
Depreciation - The increases in depreciation expense in 2015 compared to 2014 and in 2014 compared to 2013 were due primarily to the purchases of furniture, equipment and leasehold improvements related to office expansions and moves, and expenditures related to upgrading computer systems. Also contributing to the increases in depreciation expense in 2015, 2014 and 2013 were the depreciation expenses associated with acquisitions completed during these years.
Our investment in Chem-Mod generates royalty income from refined coal production plants owned by those limited liability companies in which we invest as well as refined coal production plants owned by other unrelated parties. Based on current production estimates provided by licensees, we believe Chem-Mod could generate for us an average of approximately $4.0 million to $5.0 million of net after-tax earnings per quarter.
For all plants that are not under long-term production contracts, we estimate that we will invest, on average, an additional $7.0 million per plant to connect and house each of them. For those plants that will have majority ownership co-investors, the average additional investment will be $3.5 million. We currently have $2.2 million of commitments related to our refined coal plants. Additionally, we further estimate that we could invest approximately $40.0 million to redeploy the remainder of the refined coal plants in 2016 and into 2017, before any co-investor contributions.
On September 19, 2013 we entered into an unsecured multicurrency credit agreement (which we refer to as the Credit Agreement), which expires on September 19, 2018, with a group of fifteen financial institutions. The Credit Agreement replaced a $500.0 million unsecured revolving credit facility (that was scheduled to expire on July 14, 2014), which was terminated upon the execution of the Credit Agreement. All indebtedness, liabilities and obligations outstanding under the previous facility were fully paid and satisfied, except for outstanding letters of credit which became letters of credit under the Credit Agreement.
In connection with our investing and operating activities, we have entered into certain contractual obligations and commitments. See Notes 7, 13 and 14 to our consolidated financial statements for additional discussion of these obligations and commitments. Our future minimum cash payments, including interest, associated with our contractual obligations pursuant to our note purchase agreements and Credit Agreement, operating leases and purchase commitments as of December 31, 2015 are as follows (in millions):
The amounts presented in the table above may not necessarily reflect our actual future cash funding requirements, because the actual timing of the future payments made may vary from the stated contractual obligation. Outstanding purchase commitments in the table above include $81.6 million related to expenditures on our new corporate headquarters building. In addition, due to the uncertainty with respect to the timing of future cash flows associated with our unrecognized tax benefits at December 31, 2015, we are unable to make reasonably reliable estimates of the period in which cash settlements may be made with the respective taxing authorities. Therefore, $15.7 million of unrecognized tax benefits have been excluded from the contractual obligations table above. See Note 16 to our consolidated financial statements for a discussion on income taxes.
On May 13, 2014, our stockholders approved the Arthur J. Gallagher 2014 Long-Term Incentive Plan (which we refer to as the LTIP), which replaced our previous stockholder-approved Arthur J. Gallagher & Co. 2011 Long-Term Incentive Plan (which we refer to as the 2011 LTIP). The LTIP term began May 13, 2014 and terminates on the date of the annual meeting of stockholders in 2021, unless terminated earlier by our board of directors. All of our officers, employees and non-employee directors are eligible to receive awards under the LTIP. The compensation committee of our board of directors determines the participants under the LTIP. The LTIP provides for non-qualified and incentive stock options, stock appreciation rights, restricted stock, restricted stock units and performance units, any or all of which may be made contingent upon the achievement of performance criteria. A stock appreciation right entitles the holder to receive, upon exercise and subject to withholding taxes, cash or shares of our common stock (which may be restricted stock) with a value equal to the difference between the fair market value of our common stock on the exercise date and the base price of the stock appreciation right. Subject to the LTIP limits, the compensation committee has the discretionary authority to determine the size of an award.
During 2014, cash awards related to the 2011 provisional awards with an aggregate fair value of $17.6 million (411,000 units in the aggregate) were vested and distributed to employees under the Program.
Chem-Mod is determined to be a variable interest entity (which we refer to as a VIE). We are the controlling manager of Chem-Mod and therefore consolidate its operations into our consolidated financial statements. At December 31, 2015, total assets and total liabilities of this VIE were $10.3 million and $0.9 million, respectively. At December 31, 2014, total assets and total liabilities of this VIE were $10.2 million and $1.2 million, respectively. For 2015, total revenues and expenses were $72.1 million and $3.0 million, respectively. For 2014, total revenues and expenses were $69.1 million and $3.0 million, respectively. We are under no obligation to fund Chem-Mod’s operations in the future.
Since commitments may expire unused, the amounts presented in the table above do not necessarily reflect our actual future cash funding requirements. See Note 13 to our consolidated financial statements for a discussion of our funding commitments related to our corporate segment and the Off-Balance Sheet Debt section below for a discussion of other letters of credit. All of the letters of credit represent multiple year commitments that have annual, automatic renewing provisions and are classified by the latest commitment date. Funding commitments in the table above includes $31.4 million related to expenditures on our new corporate headquarters building.
Off-Balance Sheet Debt - Our unconsolidated investment portfolio includes investments in enterprises where our ownership interest is between 1% and 50%, in which management has determined that our level of influence and economic interest is not sufficient to require consolidation. As a result, these investments are accounted for under the equity method. None of these unconsolidated investments had any outstanding debt at December 31, 2015 or 2014 that was recourse to us.
We and our principal domestic subsidiaries are included in a consolidated U.S. Federal income tax return. Our international subsidiaries file various income tax returns in their jurisdictions. The foreign earnings (losses) before income taxes were $(52.1) million in 2015, $3.4 million in 2014 and $45.9 million in 2013. Earnings before income taxes include the impact of intercompany interest expense between domestic and foreign legal entities. Foreign intercompany interest expense was $107.0 million in 2015, $76.5 million in 2014 and $16.6 million in 2013. Domestic intercompany interest income was $107.0 million in 2015, $76.5 million in 2014 and $16.6 million in 2013. Significant components of earnings before income taxes and the provision for income taxes are as follows (in millions):
We have audited Arthur J. Gallagher & Co.’s (Gallagher) internal control over financial reporting as of December 31, 2015, based on criteria established in Internal Control - Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) (the COSO criteria). Gallagher’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control Over Financial Reporting. Our responsibility is to express an opinion on Gallagher’s internal control over financial reporting based on our audit.