NRG brings largest US rooftop solar system online in Las Vegas

MGM Resorts International has expanded the rooftop solar array on its Mandalay Bay Convention Center in Las Vegas to become the largest in the country, as the casino operator prepares to make a final decision on whether to cut ties with the local monopoly utility and buy its own power – much of it renewable – on the open market.

NRG Energy and MGM this week announced the completion of an expansion of the rooftop PV system atop the Mandalay Bay Convention Center, which, at 8.3MW, is now the largest ever built in the US. On a sunny afternoon, the array is capable of generating one quarter of the electricity needed to run the entire Mandalay Bay Resort & Casino campus – or enough to power 1,340 average US homes.

New Jersey-based NRG Energy, a major US player in both utility-scale and distributed renewables, owns the PV system, and sells the power to MGM under long-term PPAs.

Minnesota-based Ten K Solar supplied modules, inverters and the racking system for the rooftop system’s expansion. The project’s first phase, of about 5MW, was completed in 2014.

The unveiling of the expanded array comes just a week before MGM is expected to finalise its decision to walk away from the monopoly utility NV Energy – owned by Warren Buffett’s Berkshire Hathaway – and turn exclusively to independent power producers for its electricity needs in Nevada.

MGM – which operates numerous hotels and casinos in Las Vegas, among them the MGM Grand, the Mirage, New York-New York, and the Bellagio – accounts for nearly 5% of NV Energy’s total power sales.

The decision to sever ties with NV Energy would not come cheaply: Nevada regulators have given MGM a green light on the matter, but have said it would need to pay a $86.9m “exit fee” to mitigate the impact its leaving would have on other power consumers in the state.

The rapidly declining cost of renewable power is seen as a major factor in MGM’s decision, with executive vice president John McManus saying earlier this year that the casino group would be “aggressively pursuing renewable energy sources” to cover its needs.

MGM is expected to announce its final decision next week and switch off its NV Energy-supplied power by autumn.