PITY THE POOR LUDDITES:

Unfortunately, the cutting edge of silicon panels is already at about 25 percent efficiency, and there's no way to push the material past 29 percent. And there's an immense jump in price between those and the sorts of specialized, hyper-efficient photovoltaic hardware we use in space.

Those pricey panels have three layers of photovoltaic materials, each tuned to a different wavelength of light. So to hit something in between on the cost/efficiency scale, it makes sense to develop a two-layer device. This week saw some progress in that regard, with two separate reports of two-layer perovskite/silicon solar cells with efficiencies of well above 30 percent. Right now, they don't last long enough to be useful, but they may point the way toward developing better materials.

The idea behind two-layer--called tandem--photovoltaic devices is very simple. The top layer should absorb high-energy photons and convert them to electricity while remaining transparent to other wavelengths. Then, the layer underneath it should absorb lower energy photons. Silicon, which tends to have peak absorption toward the red end of the spectrum, is a great candidate for the lower layer. That leaves the question of what might make sense to put on top of it.

Perovskites make an appealing candidate. They're an entire class of materials that are defined by the structure of the crystals they can form; they can be made from a huge variety of unrelated chemicals. That has some considerable advantages since it means you can potentially identify some very inexpensive source materials that can combine into a perovskite crystal. Many perovskites will also readily form from a solution of the raw materials, potentially allowing us to put a photovoltaic perovskite coating on a huge range of hardware.

The process of beaming solar power from space was technical, complicated, and involved many acronyms. The California Institute of Technology's (Caltech) Space Solar Power Project (SSPP) launched a device called the Space Solar Power Demonstrator (SSPD-1), which carried an instrument known as the Microwave Array for Power-transfer Low-orbit Experiment (MAPLE) into space.

It was MAPLE that was ultimately responsible for wirelessly transmitting solar energy back to Earth, where it was received by two separate receiver arrays, which then lit up a pair of LEDs (light-emitting diodes), rendering the experiment a success.

"To the best of our knowledge, no one has ever demonstrated wireless energy transfer in space, even with expensive rigid structures," co-director of the Space-Based Solar Power Project, Ali Hajimiri, said in a statement. "We are doing it with flexible, lightweight structures and with our own integrated circuits. This is a first."

Developed by the Danish energy company Ørsted A/S, Ocean Wind 1 is planned roughly 15 miles from the New Jersey shore, where it would produce enough electricity to power 380,000 homes in the Garden State.

Offshore wind is just taking off in the United States, galvanized by state and federal support. The first two large projects approved during the Biden administration are currently under construction off the coast of New England.

Elizabeth Klein, director of the Bureau of Ocean Energy Management -- the federal agency that oversees offshore wind leasing and construction -- called the project "another significant step forward for the offshore wind industry in the United States."

"The project's approval demonstrates the federal government's commitment to developing clean energy and fighting climate change and is a testament to the state of New Jersey's leadership," she said in a statement.

The project is the first proposed off the coast of New Jersey to reach federal approval and would help advance the state's goal to reach 11 gigawatts of offshore wind electricity by 2040.

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