For years now, incredible advances in the field of #solar power have been made. However, convincing the mass population of the ability of solar power to replace or even compete with fossil fuels as a primary source of #energy has been a challenge given the limited time of the sun to create energy, and the cost to collect and store that energy in the event that solar generation falls too low.
Now, the price of photovoltaics has dropped significantly in the past few years and that is quite a solution to this issue. But, as always, economic challenges remain a battle that splits the nation. With plenty of other international locations moving forward at least with the first steps in taking on solar, there must be something that can be done to bring solar power into market competition with fossil fuels. And researchers at Purdue University and Georgia Institute of Technology have been working to uncover a new key factor.
Given the fact that photovoltaics may only provide occasional storage capabilities, the new possibility is transferring solar energy to heat. That heat would then be used to power turbines rather than the wind we usually have to wait for. In addition to this process, storage of that solar-produced heat would introduce another method for round-the-clock energy originally created by the sun. This could hopefully reduce the otherwise unchanged cost of concentrated solar, providing some overall savings on top of what has been seen from photovoltaics in recent years.
How the Process Works
Similar to the process that solar panels on rooftops and on farms, these new concentrated power plants would run on heat energy. The sunlight heats up a fluid at the focus of the mirror, then transfers the heat to a turbine, usually a steam turbine. Heat energy would be generated using mirrors or lenses to focus a large amount of sunlight onto a small area. On this area, the heat would be created and transferred to a molten salt.
Similar to what has been mentioned in the past about solar heat, the creation of higher temperatures produces more energy in the long run, providing more long-term work. Extreme temperatures are needed to replace the steam in the turbine with a supercritical carbon dioxide, that expands to better run the turbine, thus adding further efficiency to the process. Unfortunately, the fact that most metals would melt under this heat, the process is hard to perfect as of yet. Other factors like chemical resistance and durability add in as well.
So, one question remains: what material will best be suited for the long-term management of this process? Most scientists have estimated the possibility of certain composite materials like tungsten and zinc carbonide. With melting points nearing 4,000K, the potential of heat conduction and halted expansion in the process may stop it altogether.
How Were these Materials Determined?
The initial answer to this is, “by chance.” Researchers went through an incredible process when trying to find the materials that could withstand the process of using solar heat for power. First, there was tungsten carbide, which is a ceramic that can be made into a porous material by pouring it into a mold as a powder and heating. The ceramic is machined to produce a final shape, where it is then placed in a hot, fluid mixture of copper and zirconium. The mixture then filled the pores of the ceramic to replace the tungsten. Finally, the copper formed a thin film on the surface of the resulting solid material.
After all of this, the tungsten was able to maintain the same shape and size despite the temperature and chemical changes that occurred during the process. Additionally, zircon carbide provides the material with a stiffness that also remains at high temperatures while the tungsten id flexible enough to keep the entire thing from becoming brittle. The materials together conducted high levels of heat better than the materials that were already in use.
Although many questions have been answered there are issues still in question. The conditions of solar thermal plants are one. The copper on the final material would react with the carbon dioxide, forming copper oxide and releasing carbon monoxide. However, researchers have presented a preventive solution to this is adding a small amount of carbon monoxide to the supercritical carbon dioxide that could suppress this reaction, though experiments still need to be done.
Economic analyses have also been performed on how this new process would benefit consumers. Estimates have shown that the upscale manufacturing process of these heat exchanges could be produced at a comparable or lower rate than existing stainless steel or nickel alloy-based processes.
Because solar power only accounts for two percent of American electricity currently, there is much room for growth and development in the solar industry. Also, since fossil fuels are more than 60% of our national power source, predictions within research give solar the room for growth to over half of America’s electricity if costs are reduced enough to impact consumer receipt of the product.