Welcome back. For now, the problem of what to do with worn-out renewable-energy equipment is hardly the most pressing question when it comes to the energy transition. Questions such as how to make steel without burning coal, or how to heat people's homes without gas, get more airtime—and all the proposed solutions tend to boil down to stepping up the supply of renewable power. The U.N.'s recent climate-change mitigation report was clear that any route to net-zero relies on massively expanding🔒 the number of wind turbines and solar panels in existence. 

Right now, the numbers aren't rising enough to limit the damage of climate change, but even renewables' current rate of expansion is plenty fast enough to be storing up a big waste-disposal problem for the future. As the solar panels and lithium-ion batteries manufactured during the current clean-energy boom get to the end of their lifespans, the lack of large-scale recycling processes will be a concern for equipment suppliers and project owners who will have to dispose of them. They want to show they are solving environmental problems, not creating new ones. 

This week we're looking at how the wind-power industry is approaching one recycling headache—what to do with old turbine blades. Stay tuned for more stories on this theme.  

This week: Gas from garbage; Canada's carbon-credit rush; SEC sues Vale over dam disaster. 

Wind-turbine blades reborn as cement. Turbines are mostly made of easily recyclable steel. But the blades, made of hard-to-separate composite materials, are a waste-disposal headache. Blades that reach the end of their operational lifespan or are replaced with more efficient models often end up in landfill. One answer to this growing problem is to send the blades to cement factories, where they are burned in kilns to make clinker, a key ingredient in the building material. 

Burning blades causes air pollution and greenhouse-gas emissions—hardly perfect from an environmental perspective. Lawrence Bank, a research engineer at the Georgia Institute of Technology, said the practice “contributes to an inherently unsustainable solution.” 

But the wind-power, waste-management and building-materials companies driving this emerging business say it causes less emissions than would arise if the blades were sent to landfill and more conventional fuel were used to make cement. Eventually, new designs could allow materials to be harvested from old blades and reused in new ones, but those efforts are some way from fruition. Many of the blades that are being taken down from turbines in ever-increasing numbers look destined to end their lives in a cement kiln.  

Waste Management taps thirst for fuel from trash. The biggest landfill operator in North America said it would invest $825 million over the next four years to turn methane from garbage dumps into biomethane, a natural-gas substitute. As well as using the fuel, known as renewable natural gas, to power its own vehicles, Waste Management expects to sell it to consumers that are willing to pay more for fuel that improves their environmental credentials. 

New Canadian gold rush. Nearly a dozen startups are expected to go public🔒 on Canadian exchanges to finance carbon-credit purchases or invest in ventures that generate credits, according to banking and exchange officials. Among the ventures seeking to tap booming demand for emissions offsets are companies promising to distribute cook stoves, grow new forests and prevent threatened deforestation. 

Investing crazes in Canada's public markets haven't always ended well. When the country legalized recreational marijuana in 2018, markets took off, only for valuations to slump. There have been some high-profile financial frauds, too. But the carbon market needs speculators to fuel its growth, according to Josh Crumb, founder of Base Carbon, which listed on Toronto's NEO exchange in March and earns credits by investing in projects designed to benefit the climate. 

More from the Sustainable Business Forum. Experts shared their views on environmental, social and governance priorities at a WSJ Pro event last week. Here are some of the takeaways.       

💡 C-suite involvement. Harmit Singh, executive vice president and chief financial officer at Levi's, said ensuring that the chief executive and other top executives are involved in sustainability matters should be a priority. Nancy Pfund, founder and managing partner at venture-capital firm DBL Partners, had a simpler rule of thumb. The sustainability chief "should report to the CEO,"🔒 she said.

💡 Integrating climate risk. Vanessa Havard-Williams, head of environment and climate change for Linklaters, said the regulatory landscape is at "peak mess,"🔒 as companies get to grips with mandatory reporting requirements. The challenge for companies is to move away from managing sustainability risks through a standalone corporate-responsibility function and integrate the work across their businesses, she said. 

💡 Assess risks early. Elizabeth Seeger, managing director of sustainable investing for KKR, said the private-equity firm looks for "gating issues" early in its investment process.🔒 That means looking for risks that could rule out an investment, such as exposure to weapons of mass destruction, but also factors that aren't necessarily red flags but may require careful risk management, such as investments in a healthcare company that sells to a vulnerable population. 

SEC's Vale suit points to focus on sustainability reports. The Securities and Exchange Commission sued Vale over how the Brazilian mining company disclosed its mining-safety practices before one of its dams collapsed in 2019, killing 270 people. The SEC said Vale misled investors🔒 about the risks posed by its dam, manipulated dam-safety audits and issued sustainability reports that said the company followed the “strictest international practices” for dam safety. 

The SEC’s focus on what Vale wrote in sustainability reports is a new tactic for the agency, which says investors increasingly factor environmental issues such as climate change into their decisions. Vale said this month it is committed to paying reparation to affected parties and would contest proceedings it believes are without merit.

📅 Join us at the WSJ Risk & Compliance Forum on May 10 for a discussion on navigating sustainability regulations. You’ll hear from Carrie Christopher, director of ESG and climate at Splunk, and Mardi McBrien, managing director of accounting standards body the IFRS Foundation. Register for a free ticket using the code wsj100 via this link.

Tech giants may be using conflict minerals from the Democratic Republic of Congo due to the misuse of a widely used certification system. (Mining.com)

Warren Buffett has pushed back against investors who want to force Berkshire Hathaway to do more to reduce greenhouse gas emissions. (New York Times) 

Volatility in economic activity during the pandemic illustrates how tightly economic growth is tied to emissions. (Fitch) 

Investors refused to back resolutions demanding stricter fossil fuel financing policies at three U.S. banks. (Financial Times)

U.S. regional banks are teaming up to tackle climate risk. (Climate Risk Review) 

Broken charging stations are slowing the spread of electric vehicles. (Wired)

A new Department of Energy-backed group is trying to make vehicle-to-everything charging—in which car batteries send power to homes or the grid—mainstream. (Canary) 

The U.S. Occupational Safety and Health Administration is struggling to adapt to the way climate change is making jobs more perilous. (Grist) 

A mask for cows that captures methane from their burps won a design award. (Bloomberg)