May 21 2018

Solar and Wind Power and Energy Balance

My latest post sparked a bit of conversation, which is typically the case when the topic has a politically controversial angle. The question, an important one that we are currently facing as a society, is how to chart the best path forward in terms of our energy infrastructure. There is legitimate debate among experts on this question because of the various trade-offs and the uncertainty of projecting technology even a little bit into the future. There are many complex variables, and how you account for all of those variables can affect the bottom line.

As is also often the case, the more political a topic the more propaganda and nonsense seeps into the conversation. In such cases not only do we have to contend with a lack of information, but there is actual misinformation to address first. And that misinformation is not random or due to error – it is manufactured with a purpose, motivated misinformation, if you will.

Usually I (and others) will address such issues in the comments themselves, but occasionally correcting important misinformation requires a blog-length response. One comment in particular was a string of error representing common propaganda, that I thought worth addressing at length:

“We can never achieve 100% wind and solar power because the wind and solar industries consume more energy in their operations than their hideous wind turbines and solar panels can ever produce. That’s why they always lose money, unless they are given subsidies and set-asides. Along with being energy and economic parasites, the wind and solar industries are environmental disasters. From the fouling of ground water at their rare earth element mines in China, to child slavery at their cobalt mines in Africa, to the slaughter of migratory birds and bats, to the health problems from infrasound, the wind and solar power industries wreak environmental havoc across the globe. No other power sources are allowed to pollute the environment to the extent that wind and solar power do.”

Energy Balance

The question of how much an alleged energy source consumes vs provides is called “energy balance.” This is a topic of detailed scientific analysis, because obviously it is a critical question. It is often also raised as a propaganda point against an energy source one doesn’t like. I actually read someone claim that fossil fuels require more energy to extract, refine, and transport than they provide. This is transparently absurd if you think about it for even a moment – for then where is our civilization getting its energy from, if our main source of energy is a net negative?

The question is not as obvious for newer energy sources, such as wind and solar. These industries could be riding on top of our existing energy infrastructure, if you have to burn coal or gas in order to manufacture solar panels, for example. In order to answer this question you have to analyze how much energy does it take to manufacture and install solar panels, how much energy do they produce, how much maintenance do they require, how long do they last, and how are they disposed/recycled? You can apply the same approach to their carbon balance as well as energy balance.

A review published in 2013 found that the photovoltaic industry was a net energy consumer up until 2010, when they became a net energy producer. Further, the industry will pay back their entire energy deficit by 2020, after which the industry will be a net energy producer over its entire lifetime.

A 2016 study also found that as solar production increases, the net energy and carbon advantages improve, due to greater production efficiency.

So at best the claim that solar is a net energy loser is outdated. Further, solar technology is steadily improving, using cheaper materials and an easier manufacturing process. Also as the efficiency of the panels increases, they produce more energy per unit. The lines have already crossed, and they will only get better going into the future.

Wind turbines also have a net positive energy balance:

The energy balance is an assessment of the relation between the energy consumption of the product and the energy production throughout the lifetime. The energy balance analysis in Vestas V90 3.0 MW shows that, for an offshore wind turbine 0.57 years (6.8 months) of expected average energy production are necessary to recover all the energy consumed for manufacturing, operation, transport, dismantling and disposal.

As far as an onshore wind turbine is concerned, the energy balance is similar but shorter than the offshore one, with only 0.55 years (6.6 months) needed to recover the energy spent in all the phases of entire lifecycle. This difference is due to a larger grid transmission and larger steel consumption for the foundations in an offshore scheme.

And they too are getting better and better as the technology improves. It is often the case that a new technology is not much better, and may be worse in some ways, than an older but maturer technology. The first jets weren’t really better than the best planes at the time. Switching is often a lateral move at best. But the newer technology puts us on a new trajectory of improvement, because it has more potential.

We have already invested in the early phase of wind and solar, and now we are reaping the potential benefits. These technologies are also a long way away from maturing (especially solar). They are cost, energy, and carbon efficient right now, and will only get better.

Environmental Impacts

What about the net environmental impacts of these technologies, as claimed? Let me address the latter two first, since I have already written about them. Do wind turbines present a significant risk to birds and bats?

As I wrote recently:

A recent review of the literature on bird deaths from wind turbines concludes that the annual death of birds in the US from wind turbines is between 140,000 and 328,000. If we extrapolate this out, then if the US increases its wind energy production to 20% of total energy, that would result in 1.4 million bird deaths per year.

This may seem like a lot, but it is insignificant compared to other technologies – cell towers kill 6.8 million, high tension lines 200 million, windows between 365-988 million, and domestic cats over 1 billion birds annually.

Having said that, we should strive to minimize bird and bat loss from wind turbines, and there are efforts to do so. The newer designs are safer, and we are making an effort not to put turbines in high-traffic areas for birds and bats.

But seriously – windows kill 1000 times more birds that wind turbines currently.

Infrasound is also a non-issue. The amount of noise generated by wind turbines drops off quickly with distance:

The closest that a wind turbine is typically placed to a home is 300 meters or more. At that distance, a turbine will have a sound pressure level of 43 decibels. To put that in context, the average air conditioner can reach 50 decibels of noise, and most refrigerators run at around 40 decibels.

At 500 meters (0.3 miles) away, that sound pressure level drops to 38 decibels. In most places, according to Keith Longtin of GE Renewable Energy, background noise ranges from 40 to 45 decibels, meaning that a turbine’s noise would be lost amongst it. For the stillest, most rural areas, Longtin says the background noise is 30 decibels. At that level, a turbine located about a mile away wouldn’t be heard.

And this is getting better with newer designs also. So what we have here is a clear case of taking minor and easily solvable issues and exaggerating them beyond reason for propaganda purposes.

What about the rare earths and mining issues? These are real concerns, but they are not unique to wind and solar. These issues exist for the entire electronics industry. Your new TV also has rare earths in them.

This is part of the larger problem of where we source our raw material, workers rights and environmental protections in the developing world. To pin these on renewable energy is absurd. Also, as I stated above, as the technology improves solar and wind will become less dependent on these materials.

For example, a recent study shows that organic solar cells have reached commercially viable efficiencies (around 15%). Organic cells use carbon – no silicon or rare earths. These would be truly inexpensive solar cells, not dependent on any limited resource. And again – that’s just today. This industry is progressing very rapidly in many different directions.

Conclusion

The questions surrounding our energy infrastructure are complex and require knowledge of the current technology, which is a moving target. Don’t accept any factual claims about energy production without checking first with reliable objective sources. Otherwise you are likely to fall into an echochamber of misinformation.

Published studies clearly show that wind and solar energy have a positive energy balance and a favorable carbon balance and cost to fossil fuels. Further, while fossil fuel burning is a rather mature industry, solar and wind power are burgeoning industries on the steep part of the curve in terms of technological progress.

Wind and solar can and should play a significant role in the future of our energy infrastructure.

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