In an era when Ludwig van Beethoven is so popular that any year might seem like a celebration, the 250th anniversary of the composer’s birth is bringing comprehensive presentations of his work throughout Philadelphia.

The Philadelphia Orchestra is hardly alone in playing the composer’s nine symphonies — but it adds a twist with a series of BeethovenNOW concerts at the Kimmel Center from Thursday to April 5 that include new American works either written by or mentored by composer-in-residence Gabriela Lena Frank.

Elsewhere, the Philadelphia Chamber Music Society has coordinated performances of all, scheduling all of Beethoven’s 16 string quartets and 32 piano sonatas with numerous artists this season. In fact, three A-list pianists were vying to play Beethoven’s longest piano work, Diabelli Variations Op. 120, said artistic director Miles Cohen. Mitsuko Uchida will perform the piece April 2.

“We’ve never done so many concerts of one composer,” Cohen said. “I think it proves that Beethoven is a composer people want to hear again and again. And I don’t know if this could work with any other composer. Haydn? Probably not.”

Part of the appeal of these concerts is following Beethoven’s artistic trajectory: Though Beethoven has long been categorized in early, middle, and late periods, his music often doesn’t adhere to convenient categories, and is often understood differently with the passage of time. Long considered minor Beethoven, the oratorio Christ on the Mount of Olives was revived earlier this year in performances led by Simon Rattle in London. An aria that disappeared from the opera Leonore has been reconstructed from sketches in a production by the Washington, D.C.-based Opera Lafayette.

Artists brought in by the chamber music society span generations, including pianistic veterans such as Richard Goode, 76, to Jonathan Biss, 39, both Americans who have performed and recorded Beethoven extensively. Some of the most distinguished Beethoven recordings come from the Austin-based Miro Quartet and the 24-year-old Canadian pianist Jan Lisiecki who are bringing fresh ideas to music the world has known for centuries.

Perhaps never has Beethoven sounded so different from one performance to another. The Philadelphia Orchestra concerts will be repeated at New York’s Carnegie Hall, its luxurious sound following a hugely successful Beethoven cycle by conductor John Eliot Gardiner and his Orchestre Revolutionnaire et Romantique that uses the lean, muscular instruments of Beethoven’s time and approximates the composer’s much-disputed, superfast metronome markings. Philadelphia’s Yannick Nézet-Séguin, who will record the symphonies with the smaller-scale Chamber Orchestra of Europe, takes a more moderate stance: “I’m not always with the metronome markings, but they remind us that with every bar, we need to remember that there’s nothing that is comfortable [in Beethoven’s music].

“Everything I do is rooted in the text," he said, “but — and this is going to sound weird — I don’t care if Beethoven didn’t intend the connections I’m finding.”

Often, Beethoven symphonies can sound like a series of movements from four different pieces — the Symphony No. 3 (“Eroica”), for example, with a funeral march in the second movement, and ballet music in the final movement. But Nézet-Séguin finds an overall unity in the piece and works to achieve it.

"I believe there's a narrative within the movement that should produce the same dramatic arc in the rest of the symphony," he said. "This is a deliberate choice for me."

Inclusion, dialogue, uniting society were philosophical tenets of Beethoven’s inner world. Though a highly problematic person in his outer world — in later years, the deaf, disheveled composer was mistaken for a vagrant — his Symphony No. 9 passionately extols universal brotherhood. In fact, Beethoven brings the exalted final movement of that symphony to a screeching halt for what sounds like a Turkish marching band. With the fad for Turkish music in Vienna long since passed, conductor Roger Norrington believes that Beethoven was saying that even former enemies — the Ottoman Empire had twice laid siege to Vienna — were part of that brotherhood.

That sense of inclusion is reflected in the new compositions for the Philadelphia Orchestra’s concerts. Frank was asked to write short pieces for all of them, but with a tight timeline, composers from her own West-coast-based Creative Academy of Music were asked for their own responses to Beethoven.

Beethoven’s Symphony No. 6 is one of the great nature symphonies, so Iman Habibi’s Jeder Baum spricht (Every Tree Speaks) will address climate change March 12, 14, and 15. Jessica Hunt contemplates Beethoven’s hearing loss alongside her own struggles with chronic illness in Climb (March 19, 21, and 22), alongside Symphonies Nos. 2 and 3. Beethoven had a romanticist’s sense of fate, and that’s what Carlos Simon will focus on in Fate Now Conquers (March 27, 28 and 29) with Symphonies Nos. 4, 7, and 8. For the climactic Beethoven Symphony No. 9 concerts on April 2, 4, and 5, Frank’s choral/orchestra work, Pachamama Meets an Ode, draws on her Peruvian heritage: Latin-American artists and craftspeople were known to surreptitiously incorporate aspects of their own culture when constructing Christian churches in the New World.

The companion pieces are all short — five minutes or so — and were rehearsed months ago to give the composers a chance to hear and to revise their works, if necessary. Frank points out that compositions will add more inclusivity to classical repertoire. “There have been waves of interest in classical music to hear underrepresented voices, whether women or people of color … and I think the BeethovenNOW concerts are helping to be part of this wave.”

These companion pieces won’t be part of the Carnegie Hall programs performed by the Philadelphia Orchestra. Frank expressed disappointment; she has been commissioned by and heard in Carnegie Hall in the past. “In planning the celebration,” wrote a Carnegie Hall spokesperson in an email, “the team decided early on that all the individual programs across this [Beethoven] series would be solely focused on music by Beethoven. While we think the approach taken in Philadelphia with the new commissions is also wonderful, we opted to focus on presenting all-Beethoven concerts....”

For the emerging composers, sharing stage time with Beethoven just in Philadelphia is probably daunting enough. Or maybe not. Says Frank, "You don't go into this profession unless you come to terms with hanging out with the greats."

IN CONCERT

Philadelphia Orchestra’s BeethovenNOW concerts

Four programs presented between March 12 and April 5.

Tickets: $52-$234

Information: 215-893-1999 or www.philorch.org.

The Philadelphia Chamber Music Society’s Beethoven concerts

Through April 22.

Tickets: $30

Information: 215-569-8080 or www.pcmsconcerts.