Solar Novus Today readers are bright, knowledgeable professionals who are interested in keeping up with what is new and significant in the industry. By looking at the ten most-read articles in 2016, we see key trends including: batteries and energy storage, concentrated solar power, research that’s helping increase the efficiency of solar, operations & maintenance and practical and useful solar installations.
Energy storage is at a pivotal point, where a variety of home storage options are becoming available in Australia, Japan, the US and Europe. Following the announcement of Tesla Powerwall (powered by Fronius), many battery and inverter manufacturers have teamed up to offer integrated solutions.
These solutions are more than just a battery in a box, but include an inverter, a battery management system, software and power electronics—along with the ability to communicate with the local utility. Two more recent partnerships include SMA and LG Chem, and Redflow Limited and Redback Technologies.
When a fire at the Ivanpah Solar Electric Generating System in California (US) shut down a generating tower, concentrating solar power received a lot of negative publicity. The technology behind CSP goes back at least 2300 years when the ancient Greeks used mirrors to concentrate the sun’s energy. Today’s plants are more sophisticated, but are still based on the same concept. The Ivanpah complex, for example, uses more than 300,000 mirrors to focus sunlight on boilers at the top of three towers. Those boilers create steam that drives turbines, which produce electricity.
CPS is certainly not without its challenges and challengers, but today there are more than 90 CSP plants providing utility-scale energy around the world, with more under construction. (The Crescent Dunes plant is pictured at left.) Perhaps its greatest benefit is that its power is dispatchable, providing power when it is needed most.
Many solar installations are tied to the grid, and when the power goes out, the solar system is disabled. With the rise in energy storage systems, owners of solar power systems are increasingly
wanting to be both grid-tied as well as off-grid. Adding battery backup to an AC-coupled grid-tie system is easy if the installer understands the issues and challenges involved from inverter compatibility to integrating an existing generator.
While many leading companies are using lithium-based chemistries in their batteries, zinc-bromine flow batteries are another option for stationary applications such as solar energy storage. The flow battery is an “energy” battery, which delivers energy consistently, day in and day out—as opposed to a “power” battery that can provide short bursts of power when needed.
As energy storage systems for residential, commercial and utility-scale solar installations become more prolific, expect to see different battery technologies in use.
It used to be that solar panels were installed facing in a southerly direction in order to catch the most sunlight; however, a 2013 report by Pecan Street suggested that tilting them westward was more advantageous. Further analysis indicated that it is more complicated than that, and orientation depends on location.
At King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, a team of researchers have developed a solar cell that can harvest light from virtually any angle. An added bonus is that the panels are self-cleaning. The key is a hierarchical nanostructure that the team fabricates on the packaging glass. Not only does it catalyze the sunlight from multiple angels, but it repels dust and sediments from pollution.
A sodium-ion battery technology has the potential to be cheaper than current lithium-ion technology, partly due to the lower cost of the materials and also because it uses aluminum collectors rather than copper.
Researchers from the International Manufacturing Centre at the University of Warwick (UK) are working in collaboration with sodium-ion battery startup Fardion and smart energy storage specialist Moixa Technology on a home energy storage solution using sodium-ion battery technology.
String inverters offer many advantages in solar installations up to several megawatts in size; however, there are some important
implications for operations & maintenance costs that are often not taken into consideration. A few of the issues are temporary, such as central inverters being a little more reliable than string inverters, but this should change as the technology and products improve. But there are four factors to keep in mind, such as the string inverter having more points of failure, which means more repair visits to the project site. While the factors don’t preclude the use of string inverters, they serve as useful tools in calculating the overall O&M costs of a solar project.
What is called the “Sandstock” project at the Masdar Institute of Science and Technology in Abu Dhabi, researchers investigated the use of sand as raw material for boosting the efficiency of
concentrated solar power (CSP). The researchers developed a gravity-fed solar receiver and storage system, using sand as a heat collector, heat transfer and storage collector. Their breakthrough work shows that sand can withstand temperatures of up to 1000 degrees Celsius. The team is working toward commercialization using a 100 kW beam-down concentrator.
Creating hydrogen fuel from solar energy is the focus of much research around the globe. At the University of California, Berkeley; however, researchers have made a promising leap by creating a new photoanode from metal-based material for solar
water splitting cells. The key to improving charge carrier transport is that they used separate materials for light absorption and carrier transport. Before hydrogen solar fuels cells become commercially viable, the efficiency of light absorber materials must be increased—and this group is moving rapidly in that direction.
Electric vehicle owners can get a solar-powered charge at the Pike & Rose complex in North Bethesda, Maryland.The mixed-use neighborhood has residences, office space, a theatre complex and hotel, and it recently unveiled its solar canopy.
Multiple EV charging systems are available within the 7-level parking garage, with power provided by the sun.
Written by Anne Fischer, Managing Editor, Solar Novus Today