Soliant Energy, which wants to makesolarconcentrator modules for rooftops, has appointed Marco DeMiroz as interim CEO, according to sources.

DeMiroz is a partner at Trinity Ventures and a former General Magic exec, which has invested in Soliant. Last October, Soliant raised $21 million, including $2.5 million from General Electric Energy Financial Services (see Soliant Lands $21M).

Like a lot of companies in the concentrated photovoltaic segment, Soliant is at a crossroads. On one hand, concentrators improve the overall productivity of a solar system so that more power can be produced out of a given, finite amount of roof or field space.

On the other hand, concentrators add cost. With the price of silicon and solar panels plummeting, many analysts believe that concentrators may only occupy a small sliver of the market.

GreenVolts, another company with concentrating solar PV technology, replaced its CEO this week as well.

Monrovia, Calif.-based Soliant was founded in 2005 by former NASA Jet Propulsion Laboratory scientists as Practical Instruments, and originally planned to develop a low-concentration photovoltaic system to be named Heliotube.

But the company decided last year to license that technology and shift focus to developing a high-concentration product (see Soliant Switches Focus). The company said it would rather focus on developing technology that uses lenses to magnify the sunlight more intensely than can be done with the low-concentration technology. A high-concentration solar system also is more expensive to build than a low-concentration system.