Chip maker promises to bolster energy from shaded solar panels

For many companies looking to install solar panels, an inconveniently placed tree or rooftop facing in the wrong direction can soon put paid to their green ambitions by casting a shadow over the best spot for their solar array.

But now US-based electronics component manufacturer National Semiconductor is hoping to address the problem with the launch of a new product that promises to reduce the effect of shade on photovoltaic solar panels.

The device, called SolarMagic, will be attached to solar cells to optimise the output of each different cell in a string.

Direct current-based solar cells in a string must all operate in series. If shade reduces the power output of one cell in a string, it lowers the output of all the cells.

SolarMagic will enable other cells to operate independently when an individual cell’s output drops, explained Ralf Muenster, director of strategy and business development at the company.

The device, which will ship next spring, is an optimiser rather than a microinverter, and a separate inverter is still required. Designed to make cells independent of each other, it will initially ship to installers, Muenster said, adding that it will make it easier to configure solar arrays.

"They may just be contractors and don't want to calculate and match string lengths and sizes," he said. "With SolarMagic you enable installers to mix panels and module types. You can allow them to have shorter and longer strings, and panels on east and west facing roofs."

SolarMagic will typically save between 10 per cent and 30 per cent of an array's power in shaded conditions, although it could save more, according to Muenster.

Pricing has not yet been decided for the devices, but Muenster argued that they can be placed just on panels that are subject to shading by projecting roof parts and trees, meaning that overall costs for an installation could be kept down.

The devices will also be useful in the nascent building-integrated PV (BIPV) market, said Muenster, arguing that thin film is very susceptible to power mismatch issues and that low-profile BIPV systems are innately prone to shade problems.