Sopogy thinks small to make megawatts of solar power

If giant solar thermal power plants spread across the desert are like a mainframe, Sopogy is making the equivalent of a personal computer.

The Hawaii-based company on Tuesday at the Intersolar 2008 conference will show off the latest version of its MicroCSP--essentially a shrunk-down version of concentrating solar power (CSP) equipment used in power plants.

The SopaNova 4.0, a "micro concentrated solar power" trough, has been redesigned to be longer and use less material.

(Credit: Sopogy)

It's a trough with a reflective coating that focuses sunlight onto a pipe that carries an oil. That heated liquid goes through an organic Rankine cycle engine to convert it into electricity.

The conventional thinking in solar these days is to think big. Proposals for concentrating solar power plants call for hundreds of rows of troughs or mirrors to make steam to drive an electricity turbine. The output of these proposed plants will be hundreds of megawatts, approaching the size of traditional power plants.

Sopogy's product, called SopaNova 4.0, is aimed at utilities as well, but for smaller-scale projects, in the range of 250 kilowatts to 25 megawatts. The latest edition is longer--between 12 feet and 18 feet long--than previous editions because of a new manufacturing process.

"On cost per watt, we're cheaper than PV (photovoltaics)," said CEO Darren Kimura. "But that's not what really matters. We can do more production. We actually get more sun energy every day."

With a higher output, the payback on an initial investment comes quicker, he argued. The troughs can be used by corporate customers as well for on-site power generation.

In terms of the efficiency of converting sunlight to electricity, the SopaNova is between 20 percent and 30 percent, he said. That's lower than its larger CSP cousins, which operate at higher temperatures, but better than most solar photovoltaic cells.

Unlike flat solar photovoltaic panels, solar thermal systems have storage today. In practice, Sopogy's trough systems can store a few hours worth of electricity, which can be used when electricity is more expensive or when there isn't light.

Sopogy is thinking relatively small when it comes to its own capital needs.

The company raised $9 million in venture funding earlier this year and got a $35 million special-purpose bond from the state of Hawaii.

Later this year, Sopogy will look to raise another round of equity, which will be more than its past round but far less than the huge deals--some topping $100 million--announced by traditional CSP companies.

"We're trying to demonstrate that you can do solar technology but still be capex (capital expenditure)-light," Kimura said.

Ultimately, the company intends to go public. "The goal in solar is to become a really big company and the market space allows for that. If you don't, you'll get acquired," Kimura said.

The company has about 20 customers now. The Natural Energy Laboratory of Hawaii recently broke ground on a project to install thousands of the troughs to ultimately make one megawatt of electricity.

The troughs can also be used to generate process heat, which can be used in a variety of applications, Kimura said.

[TonyT11]

Currently, this seems like the best design for solar energy, right? (in terms of cost + efficiency).
Any idea what the cost of their small 200kw unit would be, or will they not know until they get into mass production?

[RandyWayne]

I'm curious. We have been quoted about 60 grand for a 10kW PV system (before rebates). How does this compare and is it available for an individual home owner?

[JustinDoDrop]

Yippie, could cost effective soalr power be within reach? Awesome! (Editors' note: A link has been removed from this post.)

[daver]

Randy-

Even for PV that seems high. PV should be around $4/w, so for a 10kW system the cost should be around $40K.

This would definitely be cheaper than PV, and wouldn't need replacing in 20 years either, but it looks like their smallest system is 25kW.

[karlengblom]

Correct me if I'm wrong, but couldn't this be a fire hazard? A dry leaf that blows by too close to the focus of the mirror will ignite.
Also, why have the chain exposed to the elements? It doesn't look like it will last more than a few years, if the bicycles I've forgot outside during the winter are any example.

[masonx]

Commenters herein are hitting all the weaknesses (obvious) of this system that limit (eliminate) its commercial viability: excessively initial cost (10 times same size biodiesel electric), extremely high maintenance cost maintain light capture and absorption efficiency, short materials life span, high accident liabilities, and very limited location applicability.