New Hampshire, USA — SunPower says it has sold 70 MW of concentrated solar PV (CPV) “cell packages” to its joint venture in China’s Inner Mongolia region for the first phase of two projects using the company’s C7 low-concentration CPV (LCPV) technology: a 20-MW (dc) project in Saihan and a 100-MW (dc) project in Wuchuan, both scheduled for completion in 2015.
The JV, Huaxia Concentrated Photovoltaic Power — involving SunPower and Tianjin Zhonghuan Semiconductor, with regional independent power grid company Inner Mongolia Power and state-owned Hohhot Jinqiao City Development Company — was formed in December 2012 and officially registered last November to establish a foothold in China for SunPower’s C7 Tracker technology, which combines a horizontal single-axis tracking with parabolic mirrors to focus sunlight at 7× concentration onto the company’s third-generation Maxeon solar cells, which boast conversion efficiencies exceeding 24 percent. These specific Inner Mongolia operations, like other arid regions, have to deal with cold weather and soiling, so the company also plans to use its recently acquired Greenbotics robotic solar panel cleaning technology which uses far less water than traditional panel washing, noted Matt Campbell, SunPower’s senior director of power plant products.
LCPV is a good fit for regions that have good solar irradiance, but it doesn’t need the especially high-DNI areas required to make high-concentration CPV (HCPV) economically feasible. Those high-DNI regions also tend to be remote, so LCPV can work in areas that are nearer to load centers. Other areas suitable for CPV are the Middle East, South Africa, Chile, North Africa — and the Southwest U.S. Campbell highlighted a 20-MW installation at Apple’s Nevada data center is scheduled to begin construction later this year.
Average annual direct normal irradiance in kWh/m2. Credit: SolarGIS, via GlobalData
CPV is talked about in terms of overall systems costs, or levelized cost of energy (LCOE), rather than the metric of $/Wp on which conventional solar PV is focused. In some regions LCOE savings can reach 20 percent, according to Campbell. Those savings gets achieved in a number of ways. Concentrating the sunlight on these cells means fewer are needed for the same output; the company says a 400-MW plant with C7 technology requires fewer than 70 MW of PV cells. Helping to lower costs even more is a “significant localization” of manufacturing and supply chain not easily achieved with conventional silicon solar PV. “A polysilicon-ingot-wafer-cell cluster requires a scale of at least 1 GW to be cost-effective and requires very large capital expenditure,” whereas SunPower’s C7 CPV technology can be localized at a smaller scale and capex, Campbell said. For example, these CPV cell packages now being shipped to China incorporate a laminate of solar cells that’s converted to a receiver in the JV’s receiver manufacturing facility in the region, and almost all the components for these two CPV projects in Inner Mongolia will made in China, he said.
Soitec’s CPV Milestone in South Africa
Meanwhile, in South Africa, Soitec says its medium-concentration CPV project, the 44 MWp Touwsrivier, has achieved “full commissioning” on 50 percent of its total capacity, indicating performance to contractual specs and validating the entire project’s power purchase agreement. This also triggers the project’s refinancing through proceeds of bonds issued on the Johannesburg stock exchange last spring. “Reaching this point shall entitle Soitec to have access to the restricted cash and significantly increase its cash resources,” the company said in a related statement. More than 60 percent of the plant has been installed, and the company pledges to complete the entire thing “in the coming months.” Earlier this month the South African Department of Energy approved a shuffled financing structure by which Soitec would offload majority ownership of the project to an unidentified investor.
In the U.S., Soitec just sold its 7-MWp (5-MWac) Desert Green project in Borrego Springs, CA (north of San Diego) to Invenergy Solar Development. It’s the first of five Soitec projects with PPAs hand from San Diego Gas & Electric, which collectively total 155 MW and were the stimulus for the company’s $150 million CPV module factory in San Diego, which opened last winter. Last fall the company said that new site would be its new central manufacturing operations, as it closes its older and smaller CPV facility in Freiberg, Germany.
CPV Still Finding Its Way
Overall CPV is still a technology seeking to break through into mainstream use. In the past several years a number of the early developers have consolidated or driven out of the market, unable to compete with the plunging prices of conventional solar PV. Those remaining include Suncore, Soitec, Solaria, SunPower, and Magpower which now account for more than 80 percent of the CPV market, IHS calculates, with French firm Heliotrop and U.S.-based Semprius also in the mix. GlobalData says there’s just shy of 154 MW cumulatively installed CPV across the globe, but it sees this more than doubling to 358 MW in 2014 and topping 1 GW cumulatively by 2020.
There’s enough promise in CPV, with continued technology improvements and targeting the right locations and applications, that keep analysts bullish. Unlike solar PV where the emphasis has shifted from manufacturing improvements to streamlining soft costs, in CPV (and especially HCPV) efficiency remains the key to greatly lowering total systems costs. And there’s still a lot of headroom to go, especially in HCPV which eschews the familiar silicon-based PV material with its known efficiency limitations for combinations of more exotic materials. IHS sees high-concentration CPV cell efficiencies boosted from 40-42 percent now to more than 45 percent in the next three years, leading to entire system efficiencies exceeding 40 percent vs. today’s 35 percent. GlobalData projects the LCOE for a HCPV system with ~960× concentration and 39 percent cell efficiency falling from $2.05/W in 2013 to $1.77/W by 2016.