What are some common misconceptions that people have about clean energy?
I will make an attempt to discuss some misconceptions, but I am sure I will miss many misconceptions that people might have. Misconceptions mainly happen because people may not understand the clean energy resource and the science behind its applications. One of the biggest misconceptions of solar energy is that the resource is not large enough to provide for all of our energy needs or we will have to cover the whole earth with solar panels if we wanted to produce all of our needed energy from solar. This is because solar energy is very diffuse. Nature made it diffuse to keep us safe when we are exposed to it. What people don’t understand is that we can concentrate that solar radiation to whatever concentration we want.
When I teach a solar energy course to college students, who are mostly seniors and graduate students in sciences or engineering, I ask them a question in the first class and ask them to write down the answer on a piece of paper. The question is how much area of the earth we will need to cover with solar panels if we were to use them to produce all of the electrical power capacity of the USA (approximately 1000 GW) 24 hours a day. At first they thought that we would need to cover the whole country with solar panels to produce that much power. However, when we just go through simple back of the envelope type of calculations, based on 1 KW/m2 solar radiation, 8 hours of sunlight availability per day and 40% of that being cloudy and 25% conversion efficiency and keeping enough distance between the rows of collectors to prevent shading, we find out that a 100 mile x 100 mile area is more than sufficient to provide all of the power needed in USA. The point is that the amount of sunlight available on the earth is a lot more than what we need to fulfill our energy needs. However, sunlight is available only during the day and even during the day when it is not cloudy. Therefore, we need to collect enough energy when it is available and store it for later use. Some people don’t realize how much energy storage is needed in order take care of all our needs. At the same time, you don’t need to depend on just direct solar radiation for your energy needs.
Clean energy, which is mostly renewable energy, includes direct solar radiation, wind, biomass, ocean energy and geothermal. We can combine many of these resources to reduce the need for storage.
Some people also consider nuclear power as clean energy. They are right to some extent since nuclear power does not contribute to the global climate change, which in my view is one of the biggest threats to the planet. However, nuclear power also produces radiological waste which has a very long half-life, so it must be stored somewhere away from people for a very long time.