At the beginning of the week, I came across the second law of thermodynamics and it had me wondering if it contradicts the concept of renewable energy, can energy be 100% eco-friendly???
The second law of thermodynamics states that "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state." and in the process of energy transfer, some energy will dissipate as heat. This implies that all forms of renewable energy including solar energy, hydropower will presumably leak some level of heat into the biosphere which can lead to global warming.
Now, that leads me to question the efficiency of renewable energy in mitigating the global warming problem.
The second law of thermodynamics in this context can be analyzed using the first and third laws to conclude. The first law of thermodynamics states that energy can not be created or destroyed while the third law states that any process cannot reach absolute zero temperature in a finite number of steps and within a finite time. Entropy is a measure of how much energy is not available to do work. Although all forms of energy are interconvertible, and all can be used to do work, it is not always possible, even in principle, to convert the entire available energy into work. That unavailable energy is of interest in thermodynamics because the field of thermodynamics arose from efforts to convert heat to work.
In the words of a friend I discussed this with:
If you take into account the third law, the biggest issue with renewable energy is in its resilience of these systems to conserve the matter - the solar or wind only are efficient to some extent as these systems try to conserve energy they lose to the environment mostly as heat.
In the case of solar energy, It's not so much about trapping the incoming solar energy so much as trapping the outgoing infrared energy. That energy emitted into space is why the temperature of the Earth isn't continually increased by incoming solar energy until it's white-hot. Greenhouse gases absorb that outgoing energy and bounce some of it back towards the surface or in other directions.
With further research, I learned the second law of thermodynamics is only applicable to closed systems. The earth is an open system. We receive energy from the sun, which can be put towards useful work / decreasing entropy. The Earth achieves an equilibrium temperature with various forces affecting it. Energy comes in mainly from the Sun, and energy goes out mainly from thermal radiation to space. Burning fossils tempers with the energy equilibrium in one direction, renewable energy avoid this channel.
The point is, that the heating effect of the CO2 far exceeds the heat generated by burning the coal. When I start my coal grill with 3kg of coal, it will heat my garden a bit. But the 9kg of CO2 that I generate in the process will keep on heating the climate for hundreds of years to come. The gases are the problem that we need to address if we want to leave an habitable world to future generations