A take on solar energy skepticism
So I would like to start the solar series by countering one of the arguments I often hear myself. Isn't producing a solar cells as harmful as burning fuels? Technologic advancement is exactly that, an advancement, and unless we make some wicked discovery tomorrow and become some sort of science-fictionny society like The Culture we should be focusing on progress, and not perfection.
To answer the question, I will start by looking at a rather simple concept called Net Energy. I shall compare the net energy of burning fossil fuels and producing solar cells in a different post, so we will stay away from numbers in here.
Net Energy
Almost all energy sources are not usable in their natural form. Take oil for example, before it can be delivered to our homes as electrical energy, it will have undergo an exploitation process. This exploitation process will include several stages needed to transform the source of energy to something we can use.
So let's say we would like to burn one barrel of oil, then we would have to consider the stages:
- Exploring and finding the oil.
- Extracting the oil.
- Transporting the oil.
- Refining the oil.
- Constructing the facility to burn the oil.
- Repairing environmental damage caused by all of the above (In principle, this should be included).
- Each of the stages above requires some energy to be completed. Here is where the concept of net energy comes into consideration.
Net Energy is the difference between the energy required to convert the source and the actual useful energy obtained at the end. Before exploiting non-renewable fuels, we have to prepare them, thus consuming more fuels in the preparation.
Hopefully you get the idea.
It takes more than one barrel of oil to obtain and convert the energy available in one barrel. In other words. Burning a barrel of oil has a negative net energy.
Sitting in this very simplistic point of view, you might wonder if it even makes sense to burn oil. Well the answer is yes, and it's all embedded in the word "commodity". All this preprocessing is needed so that we can store, trade and have readily available energy at our disposal, at any time.
Net energy was introduced by Odum and Odum in 1976. The idea proposed that everything has an energy content, and introduced the British thermal unit (BTU) in order to measure and compare it.
What about solar cells ?
Producing solar photovoltaic cells requires a significant amount of energy. But, over its lifetime, the solar cell will produce more energy than the energy required to create the cell itself. Using the sun as infinite resource, the cell will create enough energy to compensate its own production energy costs, its own disposal costs, and still end-up with a positive energy balance.
That was short
We should judge forms of energy by two criteria:
- Is it obtained from a renewable or non-renewable source?
- Is the net energy value positive or negative?
In conclusion, the concept of net energy is a useful tool to compare different sources. Over its lifetime (25-30 years), the solar cell will produce more energy than it took to create it, resulting in a positive net energy. Let's stop the non-sense skepticism and focus on implementing the next better thing we have, whether is solar, wind, or any other prooven sustainable technology.