The astonishing thing about social media is some high school dropout in East Tanjikastan can sit in his mother’s basement and crank out posts designed to spread fear, uncertainty, and doubt about electric cars, solar panels, wind turbines, or energy storage batteries and people who ordinarily question everything read that tripe and immediately assume it is true because it is on the internet. Most CleanTechnica readers are exempt from this tendency, fortunately.
The latest schmutz about solar panels and batteries circulating online is that both are “dirty” — that is, they have unacceptably high carbon emissions and environmental impacts. It’s better to stick with good old reliable coal, oil, and methane gas than take a risk on new technologies is the message. Of course, it should be intuitively obvious to the most casual observer that fossil fuel interests are paying that pimply teenager to post such bilge water in the first place, but somehow when we see something on social media, we instantly lose our ability to question its authenticity. It’s some kind of flaw in the human psyche.
Solar Panels And Embedded Carbon
Energy Matters is an Australian clean energy website. Recently, it has noticed an increasing number of otherwise normal people are nattering online about how solar panels and energy storage batteries have such high carbon emissions during production that they can never be offset during their lifetime. If that is so, then of course there is no earthly reason to waste good money on such playthings of the devil is there?
Solaris Renewables attempts to answer these questions about solar panels. It begins by explaining that there are two sources of carbon emissions. The first occurs during manufacturing. The second occurs during operation. Manufacturing solar panels requires energy, just like any other manufacturing process. The source of that energy plays a big part in determining how much carbon is embedded during manufacture.
Factories that rely on renewable electricity have lower embedded carbon emissions than factories that use electricity from thermal generation. China currently has the lowest priced solar panels in the world but they are manufactured almost exclusively in factories that use electricity from burning coal. That means Chinese made solar panels have far higher embedded carbon that panels made in other countries.
By the third year in operation, most solar panels become carbon neutral, Solaris says. From that point on, they are about 20 times less carbon intensive than coal powered electricity sources. If you take into consideration the number of greenhouse gases coal mining produces versus the amount for solar panels, it is clear that solar panels are a much cleaner alternative to coal. Here is the data for greenhouse gas emissions from the most common energy sources during their operational phase:
- Solar panels produce 0 grams per kWh
- Natural gas burns 0.91 lbs of CO2 per kWh
- Petroleum burning produces 2.13 lbs of CO2 per kWh
- Burning coal produces 2.23 lbs of CO2 per kWh
The result is that the life cycle GHG of solar panels is far lower than other energy sources. Even with solar panel manufacturing accounted for, the entire process puts solar among the cleanest sources of energy available.
Batteries And Carbon Emissions
At the beginning of the solar power revolution, homeowners put solar panels on their roof. They used the electricity generated to power their homes and sold the excess back to the local utility company. In effect, the grid became a battery homeowners could tap when needed.
Over time, more people have come to realize the electricity generated by those rooftop solar panels could be stored in a residential battery, making them less dependent on the grid. While batteries add to the cost of a system, they can pay for themselves over time because the electricity they provide costs virtually nothing.
Batteries also rely on lithium and other materials that have to be mined or extracted from the Earth. Opponents point to that and say “Ah HAH! See? Batteries are dirty cuz they mining is dirty.” As with every lie, there is a kernel of truth at its core.
Yes, mining is dirty business, one that releases carbon dioxide and other nasty stuff into the environment. But those same naysayers don’t mind a bit when iron ore is mined for steel, or bauxite is mined for aluminum, or when cement production sends clouds of carbon dioxide into the atmosphere. They only object when the mining is done to make batteries, which is the very definition of hypocrisy.
The Center For Alternative Technologies in the UK delves into embedded carbon in residential storage batteries. It says the carbon footprint of current lithium ion batteries is around 100 kg of carbon dioxide per KWH of battery capacity when manufactured in factories that use fossil fuels. When renewable energy is used for the manufacturing, this is reduced to about 60 kg of CO2 per kWh.
Replacing 1kWh of electricity from burning methane gas will avoid emitting about 0.35 to 0.4 kg of CO2. Using an average of 80 kg of CO2 per kWh for manufacturing a lithium ion battery, that means the embedded carbon in a battery is about 200 times as much as for thermal generation that uses methane gas. Therefore, for the carbon savings to outweigh the manufacturing impact, the battery needs to be charged from zero carbon energy and discharged to replace methane powered stations about 200 times — or less than one year of use.
The benefit of using batteries, says Solaris, is that they are “like having a super-powered piggy bank for sunshine. You save up the good stuff during the day and tap into it when the sun dips low without using fossil fuel crutches.”
The Takeaway
The other component to this discussion is recycling. The critical components of both solar panels and storage batteries can be recovered when they reach the end of their useful life and used to make new items. This will greatly reduce the need to extract raw materials, which means the new product will have a much lower amount of embedded carbon in the first place.
And of course the real key to all this embedded carbon scary talk is that is assumes every electron of electricity is generated by burning coal. It may be true that coal is still a major source of electricity in some parts of the world but renewables are putting pressure on coal and methane gas generation, not because they are cleaner but because they are so much cheaper. Once the cost of construction are paid, the cost of fuel is free. It’s very, very hard to compete with free, which means for every year that passes, the carbon footprint of electricity will be lower and lower.
Ignore the internet trolls. That’s the best way to support the renewable energy transition.
