Re-evaluating solar photovoltaic power

Feb 28, 2021 by

Researchers find benefits of solar photovoltaics outweigh costs | MIT News  | Massachusetts Institute of Technology

2.23.21 – Science & Technology

“Re-evaluating solar photovoltaic power”

A letter to Greta Thunberg: considering the ecological impacts we aim to reduce

By Katie Singer

Excerpts from this article:

Dear Greta,

…The illusion that we’re doing good when we’re actually causing harm is not constructive. With reality, discovering true solutions becomes possible.

…I have a hard time imagining a future without electricity, refrigerators, stoves, washing machines, phones and vehicles. I also know that producing and disposing of manufactured goods ravages the Earth.

Internationally, governments are investing in solar photovoltaics (PVs) because they promise less ecological impacts than other fuel sources…

Hazards of solar photovoltaic power

1. Manufacturing silicon wafers for solar panels depends on fossil fuels, nuclear and/or hydro power

Neither solar nor wind energy can power a smelter, because interrupted delivery of electricity can cause explosions at the factory. Solar PV panels’ silicon wafers are “one of the most highly refined artifacts ever created.” 1 Manufacturing silicon wafers starts with mining quartz; pure carbon (i.e., petroleum coke [an oil byproduct] or charcoal from burning trees without oxygen); and harvesting hard, dense wood, then transporting these substances, often internationally, to a smelter that is kept at 3000 °F (1648 °C) for years at a time. Typically, smelters are powered by electricity generated by a combination of coal, natural gas, nuclear and hydro power. The first step in refining the quartz produces metallurgical grade silicon. Manufacturing solar-grade silicon (with only one impurity per million) requires several other energy-intensive, greenhouse gas (GHG) and toxic waste-emitting steps. 2,3,4

2. Manufacturing silicon wafers generates toxic emissions

In 2016, New York State’s Department of Environmental Conservation issued Globe Metallurgical Inc. a permit to release, per year: up to 250 tons of carbon monoxide, 10 tons of formaldehyde, 10 tons of hydrogen chloride, 10 tons of lead, 75,000 tons of oxides of nitrogen, 75,000 tons of particulates, 10 tons of polycyclic aromatic hydrocarbons, 40 tons of sulfur dioxide and up to 7 tons of sulfuric acid mist. To clarify, this is the permittable amount of toxins allowed annually for one metallurgical-grade silicon smelter in New York State. 5 …

3. PV panels’ coating is toxic

PV panels are coated with fluorinated polymers, a kind of Teflon. Teflon films for PV modules contain polytetrafluoroethylene (PTFE) and fluorinated ethylene (FEP). When these chemicals get into drinking water, farming water, food packaging and other common materials, people become exposed. About 97% of Americans have per- and polyfluoroalkyl substances (PFAs) in their blood. These chemicals do not break down in the environment or in the human body, and they can accumulate over time.6,7 While the long-term health effects of exposure to PFAs are unknown, studies submitted to the EPA by DuPont (which manufactures them) from 2006 to 2013 show that they caused tumors and reproductive problems in lab animals. Perfluorinated chemicals also increase risk of testicular and kidney cancers, ulcerative colitis (Crohn’s disease), thyroid disease, pregnancy-induced hypertension (pre-eclampsia) and elevated cholesterol. How much PTFEs are used in solar panels? How much leaks during routine operation—and when hailstorms (for example) break a panels’ glass? How much PTFE leaks from panels discarded in landfills? How little PFA is needed to impact health?

4. Manufacturing solar panels generates toxic waste

In California, between 2007 and the first half of 2011, seventeen of the state’s 44 solar-cell manufacturing facilities produced 46.5 million pounds of sludge (semi-solid waste) and contaminated water. California’s hazardous waste facilities received about 97 percent of this waste; more than 1.4 million pounds were transported to facilities in nine other states, adding to solar cells’ carbon footprint.8

5. Solar PV panels can disrupt aquatic insects’ reproduction

At least 300 species of aquatic insects (i.e., mayflies, caddis flies, beetles and stoneflies) typically lay their eggs on the surface of water. Birds, frogs and fish rely on these aquatic insects for food. Aquatic insects can mistake solar panels’ shiny dark surfaces for water. When they mate on panels, the insects become vulnerable to predators. When they lay their eggs on the panels’ surface, their efforts to reproduce fail. Covering panels with stripes of white tape or similar markings significantly reduces insect attraction to panels. Such markings can reduce panels’ energy collection by about 1.8 percent. Researchers also recommend not installing solar panels near bodies of water or in the desert, where water is scarce.9

6. Unless solar PV users have battery backup (unless they’re off-grid), utilities are obliged to provide them with on-demand power at night and on cloudy days

Most of a utility’s expenses are dedicated not to fuel, but to maintaining infrastructure—substations, power lines, transformers, meters and professional engineers who monitor voltage control and who constantly balance supply of and demand for power.10 Excess power reserves will increase the frequency of alternating current. When the current’s frequency speeds up, a motor’s timing can be thrown off. Manufacturing systems and household electronics can have shortened life or fail catastrophically.

Inadequate reserves of power can result in outages. The utility’s generator provides a kind of buffer to its power supply and its demands. Rooftop solar systems do not have a buffer. In California, where grid-dependent rooftop solar has proliferated, utilities sometimes pay nearby states to take their excess power in order to prevent speeding up of their systems’ frequency.11

Rooftop solar (and wind turbine) systems have not reduced fossil-fuel-powered utilities. In France, from 2002-2019, while electricity consumption remained stable, a strong increase in solar and wind powered energy (over 100 GW) did not reduce the capacity of power plants fueled by coal, gas, nuclear and hydro. 12

Comparing GHG emissions generated by different fuel sources shows that solar PV is better than gas and coal, but much worse than nuclear and wind power. A solar PV system’s use of batteries increases total emissions dramatically. Compared to nuclear or fossil fuel plants, PV has little “energy return on energy Invested.”

7. Going off-grid requires batteries, which are toxic

Lead-acid batteries are the least expensive option; they also have a short life and lower depth of discharge (capacity) than other options. Lead is a potent neurotoxin that causes irreparable harm to children’s brains. Internationally, because of discarded lead-acid batteries, one in three children have dangerous lead levels in their blood.13 Lithium-ion batteries have a longer lifespan and capacity compared to lead acid batteries. However, lithium processing takes water from farmers and poisons waterways.14 Lithium-ion batteries are expensive and toxic when discarded. Saltwater batteries do not contain heavy metals and can be recycled easily. However, they are relatively untested and not currently manufactured.

8. Huge solar arrays require huge battery electric storage systems (BESS)

A $150 million battery storage system can provide 100 MW for, at most, one hour and eighteen minutes. This cannot replace large-scale delivery of electricity. Then, since BESS lithium-ion batteries must be kept cool in summer and warm in winter, they need large heating, ventilation, air conditioning (HVAC) systems. (If the Li-ion battery overheats, the results are catastrophic.) Further, like other batteries, they lose their storage capacity over time and must be replaced—resulting in more extraction, energy and water use, and toxic waste.15

9. Solar PV systems cannot sufficiently power energy guzzlers like data centers, access networks, smelters, factories or electric vehicle [EV] charging stations

…In 2007, Google boldly aimed to develop renewable energy that would generate electricity more cheaply than coal-fired plants can in order to “stave off catastrophic climate change.” Google shut down this initiative in 2011 when their engineers realized that “even if Google and others had led the way toward a wholesale adaptation of renewable energy, that switch would not have resulted in significant reductions of carbon dioxide emissions….

10. Solar arrays impact farming

When we cover land with solar arrays and wind turbines, we lose plants that can feed us and sequester carbon.16

11. Solar PV systems’ inverters “chop” current and cause “dirty” power

This can impact residents’ health.17

12. At the end of their usable life, PV panels are hazardous waste

The toxic chemicals in solar panels include cadmium telluride, copper indium selenide, cadmium gallium (di)selenide, copper indium gallium (di)selenide, hexafluoroethane, lead, and polyvinyl fluoride. Silicon tetrachloride, a byproduct of producing crystalline silicon, is also highly toxic. In 2016, The International Renewable Energy Agency (IRENA) estimated that the world had 250,000 metric tons of solar panel waste that year; and by 2050, the amount could reach 78 million metric tons. The Electric Power Research Institute recommends not disposing of solar panels in regular landfills: if modules break, their toxic materials could leach into soil. In short, solar panels do not biodegrade and are difficult to recycle. To make solar cells more recyclable, Belgian researchers recommend replacing silver contacts with copper ones, reducing the silicon wafers’ (and panels’) thickness, and removing lead from the panels’ electrical connections. 18

13. Solar panels warm the Earth’s atmosphere

Only 15% of sunlight absorbed by solar panels becomes electricity; 85% returns to the environment as heat. Re-emitted heat from large-scale solar farms affects regional and global temperatures. Scientists’ modeling shows that covering 20% of the Sahara with solar farms would raise local desert temperatures by 1.5 °C (2.7 °F). By covering 50% of the Sahara, the desert’s temperature would increase by 2.5 °C (4.5 °F). Global temperatures would increase as much as 0.39 °C—with polar regions warming more than the tropics, increasing loss of Arctic Sea ice.19 …

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Donna Garner

MeWe – Donna Garner

USA.Life – DonnaGarner — @DonnaTexas

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