In a sunny corner of Italy that produces roses and olive oil, an American startup will get to demonstrate its technology to harvest both electricity and heat. Solergy, which is in the process of raising a B round of funding, plans to install a hybrid solar electric and thermal system on top of a greenhouse for the farm Azienda Agricola Ciccolella in the Puglia region, and intends to team up with Ciccolella to market Solergy’s systems to growers in the area, said Yoav Banin, Solergy’s CEO.
The project, which Banin hopes to complete by the end of the year, will be an important showcase and data-gathering site for Solergy, which announced its product launch last November. Founded in 2007, Solergy has developed a system that uses lenses to concentrate the sunlight 500 times and direct it to solar cells to produce electricity. Aside from this solar electric system, the company also offers a different design that can capture heat from the electricity production and use it to heat water for a variety of applications, such as running air conditioning systems or food processing operations.
Harnessing Solar Heat & Power
The main selling point of hybrid solar technologies is their ability to harvest heat that would otherwise be unused and dissipated into air. Most of the sunlight that hits solar cells become heat rather than electricity because the solar cells that are sold today aren’t very efficient. Silicon solar cells in conventional solar panels on rooftops can convert at most around 23 percent. More expensive but efficient solar cells that use other types of semiconductors can reach around 40 percent efficiency (this is achieved by concentrating sunlight several hundred times).
Heat can be very useful for businesses that, for example, use a lot of hot water or heat for running cooling/heating and factory equipment. Cogenra installed a demonstration project last year at a California winery that needs hot water for washing barrels and tanks.
But in a hybrid system, there is a tradeoff between electricity and heat production. Solar cells’ performance falters steadily with higher temperatures, so adjusting a hybrid system to increase heat production means you will get a lower electricity productio and vice versa.
“Concentrating solar photovoltaics, conceptually, is so easy – it’s the magnifying glass we all know as kids. But to engineer a low cost product is not trivial at all,” Banin said.
Solergy’s emergence comes at a time when concentrating PV technology is starting to attract more customers who traditionally have wanted only electricity generation, such as utilities. The company also is among a crop of tech developers building designs that can harvest electricity and heat for industrial and commercial customers, including Cogenra Solar, EchoFirst (formerly PVT Solar), Cool Energy and Chromasun. Many of these companies have only launched their first commercial products and have just started to line up customers over the past year and half.
Solergy’s core technology lies on its use of glass for the optics to concentrate the sunlight, Banin said. Other concentrating PV technology companies choose acrylic or a combination of acrylic and glass because acrylic is lightweight, durable and inexpensive. He contends that glass is even more durable, and the trick is to design a way to produce large sheets of glass cheaply and engineer them to become good optics for aiming the sunlight precisely onto the solar cells, Banin said.
A Solergy panel is made up of rows of cone-shaped modules, where the glass covers the wider opening and concentrates the sunlight onto a cell that sits at the other, narrow end of the cone. A fluid-containing tube that runs under the narrow end of the cone absorbs the heat from the solar cells and transfers that heated fluid to a storage tank. The heated fluid can then be used to produce hot water or other industrial uses. The company doesn’t use silicon solar cells but those that from the III-V group of semiconductors; companies that make those cells include Spectrolab and Emcore.
A Solergy system is made up of several panels that are mounted on each tracker, which makes sure the panels follow the sun’s movement throughout the day. Each 620-watt panel achieves an average efficiency of 28 percent, Banin said. The goal is to hit 30 percent by the end of the year.
Concentrating technology works best with direct light, so it’s crucial to align the panels as precisely as possible to capture the sunlight using trackers. While other CPV systems use one tracker to move several panels uniformly, Solergy has designed sensors and actuators to better adjust the position of each panel, Banin said.
Solergy also has designed its system to be able to fit onto the top of a structure rather than only on the ground. The project at the Ciccolella farm will demonstrate how well Solergy’s technology works in the field. The solar company has signed a memorandum of understanding with Ciccolella and still needs to finalize a contract and the project design for mounting the CPV systems on a greenhouse, Banin said. The preliminary design calls for a system with 70KW of electricity generation and 105KW of heat production, he added. The company also recently signed a contract with the Italian Civil Aviation Authority to build a 250 KW system at the Pantelleria Airport in Sicily.
Banin declined to disclose the price of Solergy systems. He said the company needs to sell them in volumes in order to drive down the cost, and hopes to get to $2 per watt for the cost of equipment and installation “in a few years.” The company is setting up a pilot production line of its modules and panels in Italy and expects to get it running by the end of the year, Banin said.
Located in Piedmont, a town across the bay from San Francisco, Solergy raised an undisclosed A round from investors Videocon and Lazio Green Energy. Banin said he’s raising a second round now and expects to close that round it in about a month. Solergy’s research and development center is near Rome, Italy, however, because its co-founder and technology guru, Giovanni Lanzara, is based there.
Photo courtesy of Solergy