Company that moves with the sun nabs $8 million

Practical Instruments, which makes a device that lets solar panels follow the sun, has announced it has raised $8 million dollars in a series A round of funding.

Practical, which grew out of Cal Tech, has designed the Heliotube, a tube that contains solar panels. The trick is that the tube rotates with the sun, so that the panels can generate more electricity. Commercially available silicon solar panels at best can convert about 22 to 20 percent of the light that strikes them into electricity. The theoretical maximum is 29 percent. Different elements can be added to solar panels to boost that number, but that adds expense.

Practical and other so-called concentrator companies say they can increase energy output at lower costs. Practical's system, for instance, works with existing solar panels. The Heliotube, however, is currently only a prototype.

RockPort Capital Partner, Nth Power and Trinity Ventures all invested in the company.

In solar these days, everyone is getting money. Fat Spaniel, which makes technology for monitoring solar panel output, announced officially today that it has raised $7 million to date. And earlier this year, Nanosolar announced one of the biggest venture deals of 2006: $100 million of funding to build a CIGS (copper indium gallium selenide) solar panel plant.

More news will come out no doubt at Solar Power 2006 taking place this week in San Jose.