Williams Partners LP (NYSE: WPZ) has agreed to sell its interest in the Geismar, La., olefins plant and associated complex, to NOVA Chemicals for $2.1 billion in cash.

The deal will give NOVA 100% control of Williams Olefins LLC, owner of an 88.46% interest in the complex, after its expected closing this summer.

It also secures a long-term fee-based revenue stream for the partnership, with Williams Partners subsidiaries enter into long-term supply and transportation agreements with NOVA to provide feedstock to the plant through the partnership’s Bayou Ethane pipeline system.

“The Williams Olefins transaction and these announced new supply and transportation agreements fortify our focus on natural gas market fundamentals, reduce our commodity margin exposure and secure our fee-based Gulf Coast transportation business—all consistent with Williams’ strategy to allocate capital to its core, natural gas-focused business,” said Alan Armstrong, CEO of Williams Partners’ general partner. “When the Williams Olefins transaction closes, we expect to be at 97% fee-based revenues driven largely by natural gas volumes. Today’s announcements further strengthen our financial position to support Williams’ peer-leading, low-risk growth portfolio.”

Williams Partners will use the cash proceeds from the transaction to pay off its $850 million term loan and to fund a portion of the capital and investment expenditures that are a part of the partnership’s growth portfolio. The MLP said it would update its financial guidance at its Analyst Day event on May 11.