Updated May 21, 2018

How California's residential solar mandate could misfire

Workers install solar panels on homes in Corona, California. Photo: Will Lester/Inland Valley Daily Bulletin via Getty Images

Earlier this month, the California Energy Commission mandated that all newly constructed low-rise residential buildings must include solar power

Why it matters: While California prides itself on its leadership on climate change and innovative energy technology adoption, this decision is likely to misfire. Forcing people to install solar panels may actually exacerbate grid problems, creating negative secondary impacts without meaningfully greening the electricity system.

Most experts agree that the electricity grid will become more decentralized, with generation coming increasingly from customer-sited equipment. But even Elon Musk, a vocal proponent of solar roofs, believes that ultimately the grid will still get two-thirds of its supply from large, central generating plants, in part because electricity is much cheaper to produce at scale. Rooftop solar, given its cost disadvantages and small market share, is not the most cost-effective avenue to greening our electricity supply. 

In fact, in California, there is a mounting problem of too much solar during the sunniest parts of the day, which cannot then meet the system's demands when the sun goes down, barring expensive storage solutions. This means that the value of solar energy produced by these panels will actually decline as more are installed. 

Some experts also warn that the mandate will increase housing costs at a time when prices are beyond the reach of many lower-income people. It would be cheaper for homeowners, and more cost-effective overall, to focus on solutions to current problems, including well-placed storage that addresses the challenge of after-dusk solar supply.

The bottom line: The California Energy Commission has made a mistake. It makes sense to require new homes to be energy efficient and solar-ready, but California's climate goals would have been better served in this case by more informed regulation.

Ron Dizy is managing director of the Advanced Energy Centre at MaRS.

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World coronavirus updates: Italy becomes 2nd country to exceed 100,000 cases

Data: The Center for Systems Science and Engineering at Johns Hopkins, the CDC, and China's Health Ministry. Note: China numbers are for the mainland only and U.S. numbers include repatriated citizens and confirmed plus presumptive cases from the CDC

Spain and Italy extended lockdown deadlines on Monday, as Italy became the second country in the world to surpass 100,000 confirmed coronavirus cases.

The big picture: COVID-19 cases surged past 755,000 and the death toll topped 36,000 by Monday, per Johns Hopkins data. Italy reported more than 11,500 total deaths.

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  2. U.S.: Leads the world in confirmed cases. Total confirmed cases as of 1 p.m. ET: 143,672 — Total deaths: 2,575 — Total recoveries: 4,865.
  3. Federal government latest: The White House will extend its social distancing guidelines until April 30 — Hospital ship the USNS Comfort arrives in Manhattan.
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U.S. coronavirus updates: Majority of governors order residents to stay home

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Andrew Witherspoon/Axios

At least 29 state governors have ordered their residents to stay home to promote social distancing and limit community spread from the coronavirus pandemic as the U.S. copes with more than 144,000 positive cases — more than any other country in the world, per Johns Hopkins data.

The big picture: COVID-19 killed over 2,500 people in the U.S. by Monday. That's far fewer than in Italy, where over 10,700 people have died — accounting for a third of the global death toll. The number of people who've recovered from the virus in the U.S. exceeded 4,800.

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