Solar energy is supposed to be the savior of our generation. The pace at which we are consuming our natural resources is not sustainable and the day is not far when we would be left which none of the natural resources known to mankind. Based on current resources and consumption levels we have probably 60 years worth of oil to burn. That is at the point where a large number of people in developing countries have still not been connected to the grid. The number of people who are going to get connected to the grid is going to increase from here on and so will their consumption of resources. This image here shows the current consumption of electricity, in the coming years the image is going to get brighter but do we have enough resources to fuel these light bulbs? I don’t think so. And this is where Solar Energy comes in.
The total solar power generation capacity in the world is around 65 GW and this is going to expand considerably in the next few years. Especially in countries like India and China, which are constantly looking to break the records for the biggest solar power plants in the world. This should be great news for the future of this planet. The solar power skeptics will tell you why we should stick with coal and natural gas and how solar power is not reliable. All of it is unfortunately true to some extent. It all depends on how you look at it. The biggest issue with solar power, or any power production facility in general is that power cannot be stored for a long period. You might argue that it can be stored in photovoltaic batteries but unfortunately the world we live in economics matters more than the future of the planet and therefore a lot of electricity goes to waste without being stored in batteries. All these issues though are changing and power generation utilities in Arizona and California are changing them. This New York Times report here talks about it.
The issue I want to explore in this blog though is storing the energy produced, which was till now theoretically possible and is finally being implemented. You can store as much energy in a coffee thermos as in a laptop battery, which costs 10 times as much. That’s essentially what the thermos is doing, storing the heat of that coffee. And heat generates electricity in a solar-thermal power plant, so storing heat is a way to pause the process: Let the sun heat something up, keep that thing hot until the sun goes down, and then use that heat to generate the steam that turns the turbine. Of course, as relatively easy as it is to store heat, you’ve got to find the right substance for a solar-power application. To store the extreme heat that runs a solar-thermal power plant, the substance has to remain stable at high temperatures — in the area of 750 degrees F, otherwise you’d run into problems with vaporizing and pressure changes. It’s also helpful is the substance is cheap and readily available. Enter that white, crystalline stuff in your cupboard that you probably put on your scrambled eggs, your margarita glass and your edamame: salt. Salt melts at only very high temperatures, vaporizes at very, very high temperatures and it’s available in virtually unlimited, low-cost supply. Plus, it only loses about 7 percent of the energy put into it. Actually, the first salt-storage-equipped solar power plant isn’t using table salt. It’s using a different salt mixture often applied as fertilizer, a combination of sodium and potassium nitrate. This makes storage of solar power a possibility and solves one of the biggest questions in the energy security of this planet. More on this can be found here .