The BBC Concert Orchestra’s evening of Americana, conducted by André de Ridder, began with Charles Ives’s Third Symphony and ended with Philip Glass’s first orchestral work, The Light. But it was built around a pair of UK premieres, the first of them effectively the last hurrah of the celebrations for the refurbishment of the Festival Hall organ – a concerto for the instrument, co-commissioned by the Southbank Centre from Terry Riley.

At the Grand Majestic, Riley’s concerto, was first performed earlier this year in Disney Hall, Los Angeles. It was written for Cameron Carpenter, who was the soloist here, too, and requires a large, rather lopsided orchestra, with six bassoons and five trumpets. A strange, shambling piece in three movements lasting 35 minutes, it references a vast range of musical styles, from boogiewoogie to baroque, Wurlitzers to oriental chant, all of them gathered together in rather shapeless, rag-bag fashion, with the organ rather stridently leading the way. For once, Riley’s musical open-mindedness seems to have got the better of his discrimination.

The other new work came from John Luther Adams, who may be far less well known on this side of the Atlantic than the composer with whom he shares two-thirds of his name, but whose music, consistently inspired by the beauties and the troubles of the natural world, occupies a very distinctive niche in American music today. Composed in 2007, Dark Waves is effectively a dark, compact precursor of the monumental Becoming Ocean, with which Adams won a Pulitzer prize earlier this year. It’s an 11-minute span combining layers of electronic and orchestral sound that move in and out of phase to generate a gigantic climax and then subside, all done with such subtlety and sophistication that it says far more than Riley’s piece in a third of the time.