US DOE sets new target to cut solar costs by 60%

Building on an Obama administration initia­tive, the US Department of Energy 25 March set a goal of cutting the cost of solar energy by 60% within the next 10 years through a research and development program that will provide nearly $128 million to advance new technologies, includ­ing perovskite-based thin-film modules, which are seen by researchers as one of the most promising innovations in the field.

DOE also is following Trump adminis­tration efforts to improve the economics of concentrating solar plants (CSP), which concentrate solar heat to create steam that drives power-generating turbines.

While initial utility-scale CSP plants were built through DOE cost-sharing during the Obama administration, CSP plants in recent years have been unable to keep up with cost reduc­tions in photovoltaic solar. The agency now will provide $58 million for technology improvements—including long-duration molten-salt energy storage—and a next-generation CSP plant.

DOE also will provide $20 million for its National Renewable Energy Laboratory (NREL) to set up a consortium to develop cheaper cadmium telluride thin-film solar modules, a technology that already has made First Solar the leading US solar manufac­turer due to its low cost.

The Biden administration initiative follows the path laid by the Obama administra­tion's successful SunShot program, which was launched in 2011 as a program to slash the unsubsidized levelized cost of energy (LCOE) of utility-scale solar PV by 2020. That program met its initial target of 6 cents/kWh in 2017, at which point DOE set a new LCOE target of 3 cents/kWh by 2030.

But with solar's LCOE now at about 4.6 cents/kWh, DOE said a more ambitious target was needed to meet the Biden admin­istration's ambitious goal of a 100% clean electricity grid by 2035.

"To reach that goal in the next 15 years, the country will need to add hundreds of giga­watts of solar energy to the grid at a pace as much as five times faster than current instal­lation rates," DOE said in a statement. "To that end, DOE is accelerating its utility-scale solar 2030 cost target by five years—set­ting a new goal of driving down the current cost of 4.6 cents/kWh to 3 cents/kWh by 2025 and 2 cents/kWh by 2030."

Perovskite backing

The latest DOE initiative provides $40 million for 22 projects proposed by American universities, energy laboratories, and solar companies to advance perovskite-based solar, which experts say is the most promising technol­ogy for cutting PV costs. A mineral first dis­covered in Russia and since then commonly found across the globe, perovskite is far cheaper than silicon, the primary element used in solar cells and modules.

DOE already has invested significantly in improving perovskite solar cells, which have gone from less than 4% efficiency in converting sunlight to electricity about 10 years ago to nearly 24% today, compet­ing with the highest-efficiency silicon-based cells.

Incorporating the crystalline structure of perovskites in PV cells has proven difficult to scale up to commercial manufacturing, but NREL recently hailed the success of R&D that resulted in a far more efficient and low-cost process of printing entire perovskite devices on paper-thin flexible glass.

"We have shown that perovskite-based solar cells could be produced quickly and inexpensively using techniques such as roll-to-roll manufacturing," said former NREL Director Martin Kelly in May 2019 testi­mony before the Senate Energy and Natural Resources Committee. "We are convinced … these materials would forever transform the US solar industry."

First Solar received one of the largest grants, $2.5 million, to fund the develop­ment of new cost-competitive manufacturing methods for scaling up perovskite modules. The company will use a pilot line to verify the process' feasibility, with the hopes of dem­onstrating with a module with 22% power conversion efficiency. The company will provide $650,000 as its cost share.

Additionally, the DOE is providing $14 million for a testing center to independently evaluate the performance of perovskite devices, and launching a competition to award $3 million in seed capital for new companies.

CSP's uphill battle

DOE appears to face a steeper hill to boost CSP, which has never taken off in the US due to high capital costs, poor capacity factor, and opposition from environmental­ists and conservationists who say the blind­ing light and high heat levels at solar thermal plants kill birds and endangers other sensitive desert species.

DOE is looking to provide $33 million for projects to improve CSP's reliability, per­formance, and dispatchability; develop new applications for industrial plants to replace more polluting process heat technologies; and advancements in long-duration thermal-energy storage devices that can be paired with CSP plants, some of which already are equipped with molten salt storage.

In addition, DOE's Sandia National Laboratories will get $25 million to build a facility to test a next-generation CSP plant at the National Solar Thermal Test Facility. According to DOE, the laboratory will test a multi-megawatt-thermal CSP test facility that will include a falling-particle receiver system that can operate for thousands of hours, store up to six hours of thermal energy, and heat a working fluid to more than 700 degrees Celsius.

Original reporting by Ellen Meyers, The Energy Daily.