In Part I of this series provoked by the documentary Planet of the Humans, we examined the validity of the claims made by the film regarding un-sustainability of Green Technology. Part I provided a quick and dirty analysis of completely switching off of Fossil fuels to Solar and Battery technology. The analysis concluded that it was not possible even with modern equipment to completely disengage from Fossil fuels, thus concurring with the claims of the film.
Thank you to all the readers that provided feedback and raised some good questions. A few readers have questioned if I have biased the outcome by specific equipment choices, whereas others have questioned why I have ignored many factors that would make the outcome worse for the panels. So I will attempt to address these questions in this part hoping to provide additional insight and food for thought.
Why do you include a battery in your analysis?
Most residential Solar installations today do not include a battery and they simply return excess energy back into the grid without any local energy storage. So why is it necessary to include the battery in the analysis?
Answer: It is true that returning excess energy back into the grid is the most common mechanism employed today. For sustainability the grid must devote some of that energy to mitigate harm and create replacement panels, but that entire lifecycle would be rather complex to analyze. So to keep the analysis simple I introduced the battery as a stand-in for what the grid must accomplish. We can quibble over how good a stand-in the battery is, but as I will show further down in this article it does not really matter, if we take into account all the factors, the answer comes out the same.
Aren’t you double counting Emanuf?
You have used the 1373 kWh of energy spent during manufacture of the Solar panel twice when calculating the Esustain energy required to be generated to pay off the sustainability debt. Why?
Answer: In calculating Esustain I considered two components: the harm inflicted on the environment and the energy needed for replacement of the Solar panel after its eventual degradation. It is difficult to assess exactly the amount of harm that can be reasonably mitigated, even though the total amount of input energy maybe significantly larger than the Emanuf, some of the wasted energy and resources during the manufacturing process may simply be things such as escaped heat or water that may not be considered as environmental harm to be mitigated, so for simplicity’s sake I simply used an estimate equal to the manufacturing energy as the amount to be spent on mitigation of harm. Therefore the Emanuf term of 1373 kWh appears twice in the calculation of Esustain.
In reality I actually ignored the recycling cost of the degraded Solar panel (and also neglected the fact that the panel output itself drops off after 10 years) as well as potentially degrading the battery within the 33 year span and needing a replacement battery. If we take into account these factors and add the corresponding energy budget to Esustain then debt payoff time would significantly exceed 33 years. In fact, we may never catchup and could be stuck in a perpetual replacement cycle.
Won’t a smaller battery reduce the time to debt payoff?
A smaller battery, for example a 2kWh battery (vs the 14.5kWh battery used in Part I) reduces the impact of Ebatt in the Esustain equation and can hence reduce the debt payment time below the life of the panel.
Answer: As explained earlier, the use of the battery is a contrivance to simplify the analysis and constrain it to single panel system. If we completely ignore the Harm2 of the battery and only considered Eharm = Epanel, and Erepl = Epanel then yes the debt payoff time reduces. If you set the 797kWh in the calculation to zero then Esustain = 2 x 4160 = 8320kWh and 2kWh battery at 50% panel output would generate about 339kWh per year. Hence, debt payoff years would go down from 33 years to 8320/339 = 24.5 years. But there are a few problems with this. One, the total charge/discharge cycles per year go up significantly, making the battery failure and replacement a near certainty well before 24.5 years. Secondly, as mentioned above, to be realistic about sustainability we must include recycling cost of the panel as well.
Even if we ignore the battery replacement and recycling and only considered three factors for the Solar panel, Eharm, Erepl and Erecycle and used the same 1373kWh value for all three we get Esustain = 3 x 4160kWh = 12480kWh. The debt repayment years for this value would 12480/339 = 36.8 years. So no matter whether you consider a capable battery or consider only the panel with all sustainability factors the answer exceeds the lifetime of the panel.
Why do you assume 300W power for all 6 hours of the day?
The rating of 300W for the Solar panel may be its peak power when the Sun is not directly overhead, it must be less than 300W all other times. Therefore you may be overestimating the energy generated over 6 hours.
Answer: It doesn’t really matter for the purposes of this analysis to be precise on the daily panel output, because even if the precise value comes out somewhat lower than 300Wh per day, Solar panel efficiency may go up next year and we may get a new panel that does have a 300Wh daily output.
33 year debt pay off time vs 30 year panel life is pretty close won’t we surely overcome it with improved technology?
Don’t you think technology will eventually solve this?
Answer: First of all as the earlier answers showed the actual debt payment may be impossible if we consider all the harm factors. Second, this question probably deserves a whole series by itself, but for the purposes of this series, let us analyze what we mean by technology and what type of technology this analysis applies to. I will coin the terms net-negative-technology and neutral-technology and assert that this analysis applies to net-negative-technologies.
A net-negative-technology produces net harm to the eco-sphere in its total life-cycle. What have been variously termed as externalities. All the Green technologies we have been talking about Solar, Wind etc, as well as Fossil fuels are all net-negative-technologies and hence we can never overcome the harm in their lifecycles.
A neutral-technology creates no net harm to the eco-sphere, because Earth’s biological processes are well equipped to reverse any harms incurred in the lifecycle of these technologies. Perhaps wooden windmills and waterwheels of yesteryear qualified to be in this category, as also animal power.
Is it possible that we can invent some neutral-technology that manages to supply our current energy needs? I would put that in the highly unlikely category.
There is no hiding from the inconvenient truth that what we are trying to sustain is our profligate way of life and not really the planet’s eco-sphere and net-negative-technologies will never sustain the eco-sphere.
Aren’t we better off running on Solar even if it is only part of the time?
Answer: As we’ve seen here, attempting to replace all fossil fuel use with Solar, Wind and other net-negative-technologies is pointless if we care about sustainability. We are really deluding ourselves into believing we are doing good when in fact we are not doing anything better, in fact the net additional harm of large Solar and Wind farms is high, not just from manufacturing and replacement, but also the landscape damage as evinced in the film.
This is not to say that these technologies don’t have some pleasant applications. They do. There is no question if I lived in a wilderness area, I would rather use Solar to power my cabin than a fossil fuel powered generator. But, if we are to preserve any wilderness at all for posterity we need to think hard about how to reduce demand. That discussion inevitably leads to the other controversy in the Planet of the Humans, Human population. May be we can discuss that in the next part of the series.