New York Times cov­er­age of changes in the clean ener­gy indus­try.

It was just last sum­mer that SunEdi­son was a Wall Street dar­ling, the very air around the fast-grow­ing com­pa­ny seem­ing to shim­mer with potential.

SunEdi­son was, after all, a red-hot com­pa­ny in a red-hot space — renew­able ener­gy. Its mar­ket cap­i­tal­iza­tion reached near­ly $10 bil­lion, putting it on a par with the likes of Wynn Resorts of Las Vegas. Among the believ­ers bet­ting on its stock was the hedge-fund heavy­weight David Ein­horn of Green­light Cap­i­tal. With plans to buy Vivint Solar for $2.2 bil­lion, SunEdi­son appeared unstoppable.

And then the com­pa­ny went super­no­va. Its shares fell from around $32 last sum­mer to 34 cents this week. Mr. Ein­horn furi­ous­ly tried to dump his stake in recent weeks. In ear­ly March, Vivint said, “thanks, but no thanks” and exit­ed the deal with SunEdison.

On Thurs­day, to the sur­prise of no one, SunEdi­son filed for bank­rupt­cy — one of the largest in a series of recent green-ener­gy failures.

There is a time­less ele­ment to SunEdison’s swift demise: an exec­u­tive with an Icarus com­plex chas­ing a fast-grow­ing mar­ket embarks on an aggres­sive strat­e­gy fueled by cheap debt. Soar. Crash. Burn. Repeat.

Yet the col­lapse rais­es a big­ger ques­tion: Can renew­able-ener­gy com­pa­nies be prof­itable? Can green make green?

The answer, of course, is yes. Just as soon as they cross over a fun­da­men­tal hur­dle: find­ing a strat­e­gy that actu­al­ly works.

“We haven’t total­ly fig­ured out exact­ly what the busi­ness mod­els are going to look like, for who wins and who los­es,” said Jason Bor­d­off, direc­tor of the Cen­ter on Glob­al Ener­gy Pol­i­cy at Colum­bia University.

Sig­nif­i­cant­ly, though, the sud­den decline in oil prices isn’t large­ly to blame. The dif­fi­cul­ties run much deep­er, echo­ing indus­tri­al col­laps­es of ear­li­er eras — the tele­com-indus­try boom and bust of the 1990s and ear­ly 2000s, and dis­rup­tive cycles before that.

On the sur­face, the var­i­ous green-ener­gy com­pa­nies all seem to be pur­su­ing dif­fer­ent strate­gies. But there is a uni­fy­ing prob­lem they have yet to over­come: Find­ing enough cus­tomers to sup­port the cost­ly infra­struc­ture they must first build.

SunEdi­son is far from being the only trou­bled green-ener­gy business.

Aben­goa, which grew from a small elec­tri­cal equip­ment com­pa­ny in Seville, Spain, to a multi­na­tion­al solar and bio­fu­el giant, is in restruc­tur­ing pro­ceed­ings in the Unit­ed States and abroad. Solazyme, a once-promis­ing mak­er of algae-based bio­fu­els, has aban­doned the ener­gy mar­kets and changed its name in favor of focus­ing on ingre­di­ents for per­son­al care and food prod­ucts for com­pa­nies like Unilever and Hormel. And NRG has pulled back from its head­long rush into alter­na­tive ener­gy as it restruc­tures to focus on its con­ven­tion­al oper­a­tions after the ouster of its chief exec­u­tive, David Crane.

Pho­to

What’s remark­able is that these lead­ing ener­gy com­pa­nies are strug­gling at a time when reg­u­la­to­ry, pub­lic and investor sup­port for the renew­able-ener­gy indus­try has arguably nev­er been greater.

On Fri­day, world lead­ers are sign­ing the Paris agree­ment on cli­mate change, a sweep­ing com­mit­ment to low­er car­bon emis­sions that prac­ti­cal­ly requires that renew­able devel­op­ment be steeply ramped up. At the end of last year, Amer­i­can law­mak­ers extend­ed impor­tant tax cred­its for green ener­gy sev­er­al more years, while in recent days, the Sen­ate approved a broad ener­gy bill that would fur­ther pro­mote clean power.

More­over, investors around the world sank hun­dreds of bil­lions of dol­lars into clean-ener­gy tech­nolo­gies last year even as the prices of com­pet­ing fos­sil fuels — oil and nat­ur­al gas — tumbled.

Though devel­op­ment in renew­able ener­gy climbed in the last 15 years, the indus­try is still wide­ly con­sid­ered to be in its ear­ly stages. Nonethe­less, there has been a race among com­pa­nies to devel­op, com­mer­cial­ize and even­tu­al­ly pros­per from what many see as one of the largest tec­ton­ic eco­nom­ic shifts in decades.

Last year, Chi­na start­ed con­struc­tion on a mas­sive solar farm in the Gobi desert that is expect­ed to gen­er­ate enough pow­er to light up one mil­lion homes. Dong Ener­gy is devel­op­ing a multi­bil­lion-dol­lar wind farm off the York­shire coast that could even­tu­al­ly pow­er even more.

And in the Unit­ed States, the fed­er­al gov­ern­ment recent­ly approved a major new trans­mis­sion line to move wind-gen­er­at­ed elec­tric­i­ty east from the Great Plains.

But all good bub­bles burst. What is hap­pen­ing in renew­able ener­gy now has sim­i­lar­i­ties to the telecom­mu­ni­ca­tions bub­ble of the 1990s. Led by hard-charg­ing exec­u­tives seek­ing big pay­days, giants like World­Com, Glob­al Cross­ing and Adel­phia start­ed far-reach­ing acqui­si­tion and cap­i­tal-expen­di­ture pro­grams — burn­ing through bil­lions of dol­lars — to buy cable com­pa­nies or bury long-haul fiber-optic cable under land and sea. They were all chas­ing expect­ed high demand and soar­ing rev­enues from the dawn of the Internet.

Those rev­enues even­tu­al­ly mate­ri­al­ized, but they came too late for the first movers of the rev­o­lu­tion. After cre­at­ing a broad­band glut, and buried under moun­tains of debt — let’s not for­get the var­i­ous account­ing scan­dals and frauds — the many com­pa­nies col­lapsed into bankruptcy.

But the infra­struc­ture they cre­at­ed lived on. Last week­end, when you binge-watched the fourth sea­son of “House of Cards” or streamed your own cook­ing show on Face­book Live, chances are bet­ter than not that your data zoomed through at least some of those networks.

In that case, it turned out that if you build it, they will indeed come. But as many renew­able ener­gy com­pa­nies are learn­ing, build­ing it costs dearly.

Even before SunEdi­son, the land­scape of green ener­gy com­pa­nies was lit­tered with failed strategies.

Dozens of solar-focused com­pa­nies around the globe have dis­ap­peared, through bank­rupt­cy, insol­ven­cy or just shut­ting their doors, since 2009 when prices for solar pan­els plunged as com­pe­ti­tion from Chi­na increased.

Among the high-pro­file fail­ures was that of Solyn­dra, a solar mod­ule man­u­fac­tur­er, which became a sym­bol of green ener­gy ambi­tions gone awry for the Oba­ma admin­is­tra­tion after it burned through $527 mil­lion in gov­ern­ment loans.

Part of the conun­drum for these com­pa­nies is that the most effec­tive way to cut costs has been to grow, to take advan­tage of economies of scale, cer­tain forms of financ­ing and gen­er­ous sub­si­dies that were set to expire.

But with all that growth has come debt, and an inabil­i­ty to show a prof­it, even if the com­pa­nies are cre­at­ing value.

“Clear­ly in a mar­ket that has had a lot of growth, you are going to have some com­pa­nies — and in this case many com­pa­nies — that try to do too much, too fast,” said Shawn Kravetz, founder of Esplanade Cap­i­tal, which invests in solar pow­er. “We’re going to con­tin­ue to see a shakeout.”

The vul­ner­a­bil­i­ty to shift­ing con­di­tions has been evi­dent for indus­try lead­ers like SolarCi­ty and Sun­Pow­er, com­pa­nies whose stock prices can swing wild­ly with ener­gy mar­kets and pol­i­cy changes.

But it is espe­cial­ly the case at SunEdi­son, where its chief exec­u­tive, Ahmad R. Chati­la, set about expand­ing, seem­ing­ly in all direc­tions at once.

With roots in mak­ing com­po­nents for solar pan­els, SunEdi­son aimed to become the world’s largest renew­able ener­gy devel­op­ment com­pa­ny. It bought ven­tures in wind and ener­gy stor­age, looked to increase man­u­fac­tur­ing, entered big new mar­kets and cre­at­ed new sub­sidiaries known as yield­cos to help it raise cheap­er financ­ing by buy­ing the projects it developed.

That strat­e­gy was fur­ther com­pli­cat­ed by ques­tion­able account­ing and opaque finan­cial report­ing — SunEdi­son has received an inquiry from the Secu­ri­ties and Exchange Com­mis­sion and a sub­poe­na from the Jus­tice Depart­ment — that con­found­ed even experts in the field.

”This is going to be a big indus­try glob­al­ly, but we’re stum­bling and bum­bling to get there,” said Erik Gor­don, a clin­i­cal assis­tant pro­fes­sor at the Ross School of Busi­ness at the Uni­ver­si­ty of Michi­gan. “If they weren’t try­ing to beat each oth­er to the next rooftop they wouldn’t be need­ing to do this finan­cial engineering.”

Still, indus­try ana­lysts and exec­u­tives say that despite the fall of SunEdi­son, the future for renew­able ener­gy is bright.

Indeed, there are a few stal­warts in the renew­able-ener­gy race.

Take First Solar. The com­pa­ny, which sup­plies solar pan­els and devel­ops solar farms, has had its share of trou­bles. It has been the tar­get of share­hold­er law­suits claim­ing it hid big prob­lems and mis­rep­re­sent­ed its prospects. Its stock, at $62 a share, is a far cry from its bub­ble-peak of $311 in the spring of 2008.

But by adopt­ing a slow­er-growth strat­e­gy and reduc­ing debt, First Solar is a rar­i­ty in the green-ener­gy indus­try. It is prof­itable. Last year, the com­pa­ny made $546 mil­lion on $3.6 bil­lion in revenue.

For now, First Solar may be an anom­aly, par­tic­u­lar­ly amid uncer­tain­ty around the pres­i­den­tial elec­tion and the pol­i­cy stances of can­di­dates like Hillary Clin­ton and Don­ald J. Trump on renew­able ener­gy sources. Some warn that a lull could set­tle over the indus­try in the short term.

“The Sec­re­tary Clin­ton per­spec­tive on lots of dis­trib­uted clean ener­gy couldn’t be more dif­fer­ent than the Trump view,” said Daniel M. Kam­men, the direc­tor of the Renew­able and Appro­pri­ate Ener­gy Lab­o­ra­to­ry at the Uni­ver­si­ty of Cal­i­for­nia, Berke­ley. “That could mean huge­ly dif­fer­ent things for the growth of the industry.”