Danny Williams, centre, smiles at a signing ceremony in St. John's that also involved Nalcor CEO Ed Martin, left, and Nova Scotia Premier Darrell Dexter. (CBC)

An ebullient Danny Williams says the Lower Churchill deal he signed Thursday is so good, he would put his own money on the line.

Newfoundland and Labrador will need to raise $4.4 billion to pay for its share of the Lower Churchill deal, which will see power generated at Muskrat Falls in Labrador and then piped first to Newfoundland and then to Nova Scotia, through underwater cables.

Asked by CBC News to describe how financially risky the deal is, Williams replied: "I would take my own money and put it in if I could."

Williams, a lawyer and former cable television mogul whose personal fortune is in the hundreds of millions, said the new deal will finally allow Newfoundland and Labrador to move past a ruinous contract on Upper Churchill power with Quebec.

The two provinces plan to harness the power of Muskrat Falls, on the Churchill River, to create electricity. (CBC)"It's part of the reason why I got involved in politics," Williams told reporters Thursday, minutes before he and Nova Scotia Premier Darrell Dexter signed a long-term contract to develop the 824-megawatt Lower Churchill project.

The $6.2-billion Lower Churchill deal is not quite as Williams had hoped. Left undeveloped for now is the 2,200-megawatt site at Gull Island on Labrador's enormous Churchill River.

But Williams said the deal, which gives Nalcor 51 per cent ownership of transmission and Emera the remaining 49 per cent, is a fiscally responsible move.

Williams said the 1969 Upper Churchill deal, which allows Quebec to collect almost all of the profits from the sale of power, is the type of giveaway that has guided his own political choices.

"[Today] is the day, hopefully ... when Newfoundlanders can finally let go of the Upper Churchill and say, 'Done. It's over,'" said Williams, who then immediately added the fight over the Upper Churchill is not quite finished.

"A word of caution. We're not giving up on redress."

Later, speaking to hundreds of observers who gathered at a hotel ballroom, Williams said Thursday " will go down in history as the day that finally eclipses that day back in 1969 when the Upper Churchill agreement was signed."