On January 15, 2009, the Company entered into an "Exclusive Patent and Know-How License Agreement Including Transfer of Ownership" with the Energy and Environmental Research Center Foundation, a non-profit entity (“EERCF”). Under the terms of the Agreement, the Company has been granted an exclusive license by EERCF for the technology to develop, make, have made, use, sell, offer to sell, lease, and import the technology in any coal-fired combustion systems (power plant) worldwide and to develop and perform the technology in any coal-fired power plant in the world.

On April 24, 2017, the Company closed on the acquisition from EERCF of all patent rights, including all patents and patents pending, domestic and foreign, relating to the foregoing technology. A total of 42 domestic and foreign patents and patent applications were included in the acquisition. In accordance with the terms of the License Agreement, the patent rights were acquired for the purchase price of (i) $2,500,000 in cash, and (ii) 925,000 shares of common stock of which 628,998 shares were issued to EERCF and 296,002 were issued to the inventors who had been designated by EERCF. The shares issued were valued at $518,000 ($0.56 per share), representing the value as of the closing date.

Patent costs capitalized as of December 31, 2018 and 2017 are as follows:

Amortization expense for the years ended December 31, 2018 and 2017 was $201,200 and $136,083, respectively. Estimated annual amortization for each of the next five years is approximately $201,200.