As global adoption of solar energy continues to accelerate, researchers and engineers face a fundamental spatial challenge: how do you generate more electricity without consuming more land?

Cosimo Borrello and Ferdinando Gioia – co-founders of the Italian photovoltaic technology startup A.M.P.S. – together with a team of researchers from the “Mediterranea” University of Reggio Calabria developed and field-tested a dynamic double-layer photovoltaic prototype designed to maximize solar power output per square meter of ground area. 

The challenge: overcoming land constraints

Conventional single-layer solar farms require significant spacing between rows to avoid mutual shading during solar tracking. While tracking raises energy yields per module, the extra space reduces overall energy production per unit of land. 

To solve this, the innovators at A.M.P.S. and the university stacked two vertically aligned layers of bifacial solar mini-modules within the exact same ground footprint as a single-layer setup. Rather than accepting the inevitable shadows cast by the top layer onto the bottom layer, the team implemented independent solar tracking for the stacked panels. By dynamically controlling panel rotation, the system is built to actively manages mutual shading while harvesting direct, diffuse, and reflected sunlight across both active surfaces. 

The brain behind the setup: GIGA R1 WiFi

At the core of the experimental testbed in Reggio Calabria, Italy, is a GIGA R1 WiFi. Installed on a custom-designed control PCB, it acts as the central embedded manager for the entire installation: 

• Automated motion control: It is structured to coordinate twelve Nema23 stepper motors via dedicated DM542T drivers to independently adjust the rotation angles of twelve bifacial mini-modules across both layers. 
• Independent current sensing: It is engineered to acquire real-time current measurements from twelve INA260 sensors attached to each module to track energy performance. 
• Remote data logging: It is constructed to process the synchronized current sweeps and uploads the experimental data directly to a remote server for analysis. 

“We chose the GIGA R1 WiFi because it brings together everything a prototype like ours needs, with lots of I/O, a fast dual-core microcontroller and built-in Wi-Fi on a single board,” Cosimo told us. “We had to drive twelve stepper motors independently, read twelve limit switches and twelve current sensors, and send the data to a remote server, and very few boards can handle all of that on their own. Having used an Arduino Mega board in many past projects, GIGA R1 was the natural next step, with the same familiar format and far more power and connectivity. It gave us a reliable control platform quickly, so we could focus on the photovoltaic research rather than on the electronics.”

Real-world results and future applications

In field testing under clear-sky conditions, with the top layer tracking the sun and the bottom layer fixed, the researchers reported the following increases in short-circuit current, a test measurement that is not the same as total energy production, compared with a fixed single-layer installation occupying the same ground area:

• About +42% relative to a monofacial single-layer installation.
• About +27% relative to a bifacial single-layer installation.
• About +39% and +25% respectively with a simplified open-loop tracking model based on a five-parameter sigmoid function, which the researchers reported were close to the results obtained using closed-loop control.

The researchers identify potential applications ranging from compact rooftop modules for space-constrained urban environments to utility-scale plants and agrivoltaics. In agricultural settings, the dynamic rotation of both layers may also allow operators to adjust the amount of natural sunlight reaching crops, although these applications were not evaluated in the reported field test.

By serving as a reliable control platform, GIGA R1 WiFi helped enable the team to move rapidly from concept to field validation – demonstrating how accessible open-source hardware can support advanced research in clean energy and land-use efficiency. 

Want to explore the mathematical models, control algorithms, and complete test data? Read the coverage on PV Magazine or dive into the full published paper in Renewable Energy.

Arduino, Arduino Mega, GIGA R1 are trademarks or registered trademarks of Arduino S.r.l.

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Tesla has launched a feature called "Charge on Solar" that allows owners to fill up their electric vehicles' batteries using only excess solar energy. As TechCrunch notes, the automaker started testing the capability in May, but now it's more widely available to Tesla customers in the US and in Canada. The number of people who can access the feature, however, likely remains pretty limited. To start with, it will only be accessible to those who have newer Teslas — 2021 and later — who also have a Powerwall. That's the company's battery system that stores solar energy harnessed by solar panels. 

Tesla

To enable Charge on Solar, users will need to fire up their Tesla app, choose the feature and then set it up. They'll then see a slider with a sun icon within the feature's settings that they can drag left or right to set the charge limit. The vehicle will charge itself from solar and the grid like usual before it reaches the sun slider, ensuring users have enough power to get where they need to. But after reaching the sun slider, the vehicle will only charge itself using excess solar energy. 

The Powerwall will still prioritize storing backup energy or charging other appliances when it's in Storm Watch mode before allocating any excess solar power for vehicle charging. Charge on Solar will truly only charge EVs using excess energy, which is also why owners worried about not having enough juice can set a time limit for it. Of course, they can also adjust their charge limit, or switch off Charge on Solar entirely if they want to be absolutely sure that their batteries will get fully charged. 

Japan and JAXA, the country’s space administration, have spent decades trying to make it possible to beam solar energy from space. In 2015, the nation made a breakthrough when JAXA scientists successfully beamed 1.8 kilowatts of power, enough energy to power an electric kettle, more than 50 meters to a wireless receiver. Now, Japan is poised to bring the technology one step closer to reality.

Nikkei reports a Japanese public-private partnership will attempt to beam solar energy from space as early as 2025. The project, led by Naoki Shinohara, a Kyoto University professor who has been working on space-based solar energy since 2009, will attempt to deploy a series of small satellites in orbit. Those will then try to beam the solar energy the arrays collect to ground-based receiving stations hundreds of miles away.

Using orbital solar panels and microwaves to send energy to Earth was first proposed in 1968. Since then, a few countries, including China and the US, have spent time and money pursuing the idea. The technology is appealing because orbital solar arrays represent a potentially unlimited renewable energy supply. In space, solar panels can collect energy no matter the time of day, and by using microwaves to beam the power they produce, clouds aren’t a concern either. However, even if Japan successfully deploys a set of orbital solar arrays, the tech would still be closer to science fiction than fact. That’s because producing an array that can generate 1 gigawatt of power – or about the output of one nuclear reactor – would cost about $7 billion with currently available technologies.

Good news out of Mars from the little lunchbox that could — in the seven times that MOXIE has run since it arrived in February 2021, it has reached its target production of six grams of oxygen per hour, which is in line with the output of a modest tree here on Earth. The research team which includes MOXIE engineers report that although the solid oxide electrolysis machine has shown it can produce oxygen at almost any time or day of the Martian scale, they have not shown what MOXIE can do at dawn or dusk, when the temperature changes are substantial, but they say they have ‘an ace up (their) sleeve’ that will let them do that. We can’t wait to see what they mean.

In other, somewhat funnier space news — early last Sunday morning, the ESA’s Solar Orbiter was cruising by Venus as part of a gravity-assist maneuver to get the Orbiter closer to the Sun. Two days before the Orbiter was to reach its closest point to the spacious star, it spat a coronal mass ejection in the general direction of both Venus and the Orbiter (dibs on that band name), as if to say ‘boo’. Fortunately, the spacecraft is designed to withstand such slights, but the same cannot be said for Venus — these events have their way with Venus’ atmosphere, depleting it of gasses.

Is this not the most Hackaday-esque thing you’ve ever heard of? A solar-powered, Arduino-driven cockroach. Not a robot, an actual cockroach with a backpack. Why? Cyborg insects for urban search and rescue missions, obviously. We’d make some quip like ‘all it needs is a Nixie tube’, but in all seriousness, that would just weigh them down needlessly.

So anyway, here’s (an ‘Arduino guitar device’ playing) Wonderwall.

With the US back in the Paris climate accord, President Joe Biden has the lofty goal of decarbonizing the US power grid by 2035. As part of that plan, the Department of Energy (DoE) has announced that it's rolling out a new tool that will make it much easier and faster to get a permit for a rooftop solar installation. 

The cost of solar has plunged 90 percent over past decade, but permit-related costs can take up to a third of the price of a rooftop installation. On top of that, with solar permitting varying widely around the US, some customers must wait months to get approval, the DoE wrote. 

The Solar Automated Permit Processing (SolarAPP+) platform will supposedly solve those issues, becoming the standard portal for local governments to process permit applications. It automatically checks codes to ensure safety while generating a standardized inspection checklist that installers and inspectors can use to verify compliance in the field. 

We have 3 million households today that have solar on their roofs, but the potential is so much greater.

The government piloted the SolarAPP+ program in four communities around Arizona and California: Tucson and Pima County in Arizona, and Menifee and Pleasant Valley in the California. "In Tucson, for example, SolarAPP+ reduced permitting reviews from approximately 20 business days to zero," according to the DoE. 

"We have 3 million households today that have solar on their roofs, but the potential is so much greater," DoE's solar energy director told Reuters. "Having streamlined processes and an automated permitting platform that can make it faster, easier and cheaper for homeowners to go solar promises to really help expand the residential solar sector."

Local governments and installers can now sign up to get started with the app, or attend webinars listed on the DoE's blog. All of that is part of the DoE's Summer of Solar campaign which includes research by the agency aimed at lowering soft costs (design, siting, permitting, installation, etc.) associated with rooftop solar power. 

Every scrap of power is precious when it comes to power harvesting, and working with such designs usually means getting cozy with a microcontroller’s low-power tricks and sleep modes. But in the case of the Ultra Low Power Energy Harvester design by [bobricius], the attached microcontroller doesn’t need to worry about managing power at all — as long as it can finish its job fast enough.

The idea is to use solar energy to fill a capacitor, then turn on the microcontroller and let it run normally until the power runs out. As a result, a microcontroller may only have a runtime in the range of dozens of microseconds, but that’s just fine if it’s enough time to, for example, read a sensor and transmit a packet. In early tests, [bobricius] was able to reliably transmit a 16-bit value wirelessly every 30 minutes using a small array of photodiodes as the power supply. That’s the other interesting thing; [bobricius] uses an array of BPW34 photodiodes to gather solar power. The datasheet describes them as silicon photodiodes, but they can be effectively used as tiny plastic-enclosed solar cells. They are readily available and can be arranged in a variety of configurations, while also being fairly durable.

Charging a capacitor then running a load for a short amount of time is one of the simplest ways to manage solar energy, and it requires no unusual components or fancy charge controllers. As long as the load doesn’t mind a short runtime, it can be an effective way to turn even indoor light into a figuratively free power source.

ArdaSol is the name of a project for a solar energy monitoring system based on Arduino Mega and UNO, made by Heinz Pieren. It’s a system built to monitor energy production and consumption of a domestic photovoltaic plant:

The ArdaSol Energy Monitoring System has 3 devices:

- ArdaSol Display based on a Arduino Mega Board
The master of the system, it collects the data from the two other ArdaSol devices, shows the data on the display, stores it on a SD card and sends it to a server in the internet.

- ArdaSol Energy Monitor based on a Arduino Uno
Measures the consumption of the energy, shows energy values on local display and delivers it on request to the ArdaSol Display.

- ArdaSol Remote PVI Interface based on a Arduino Uno
The photovoltaic inverter (PVI) has a RS485 interface, this is connected to ArdaSol Remote, which interacts as a gateway to ArdaSol Display. It converts the requests, coming with a radio signal to the PVI and vice versa.