The AIM-listed firm, which earlier this year agreed to acquire a nearly 20% stake in NFCP, said the contract carried a sales value of €2.2mln and had now been executed by all parties.
EQTEC will receive €880,000 on financial close, with the rest paid subject to certain agreed milestones.
The project is the first part of the joint venture signed in May with California-based firm Phoenix Biomass Energy to develop biomass gasification power plants Stateside.
Under the contract, the UK company will provide equipment, engineering and design services to the project so it can produce synthetic gas of enough quality to achieve two megawatts of power on a continuous basis.
"We are delighted that we have finalised the sales contract with North Fork”, said Ian Pearson, EQTEC’s chairman.
Elsewhere in California, construction of the the NAPA power plant was planned to begin in 2019, but Phoenix had yet to receive the required permits, meaning construction was now expected to begin in the first quarter of 2020.
In lunchtime trading, EQTEC’s shares were 12.2% higher at 0.2p.