The saying “there is no free lunch” applies to clean energy also. Even clean energy has a carbon footprint. But there is a darker secret about clean power that often stays hidden: lead contamination and lead poisoning. Increasing usage of clean energy is a good trend, but conversations about its growth need honesty regarding its dirtier side.
A thoughtful assessment of all energy sources confirms that none come without a carbon footprint or a carbon cost. Hydroelectric, for example, requires a dam and turbines. The Bonneville Dam stretches across the Columbia River just east of Portland, Oregon. The dam, built in the 1930s, blocks a narrow section of the river as it passes through the Columbia River Gorge. At this location on the Washington-Oregon boundary, the river cuts across the Cascade mountain range on its way from the USA western interior to the Pacific Ocean. The dam is part of a hydroelectric grid that provides half of the Pacific Northwest’s total electricity needs.
The construction of the Bonneville dam required a million cubic yards of concrete (2 million tons). This concrete contained about 300,000 tones of Portland cement. The Portland cement, in turn, generated 370,000 tons of CO2 during its production. Hydroelectric dams, wind turbines, and solar panels all carry a carbon cost during construction and installation. However, after completion, these facilities operate with minimal carbon emissions, thus making them “clean” energy sources.
Renewable versus clean
The U.S Energy Information Administration (EIA) divides renewable energy into five categories: biomass, hydropower, geothermal, wind, and solar. These all represent energy sources that are naturally replenishing, but this does not necessarily make them clean. Wood is part of the biomass category, and burning wood releases greenhouse gases into the atmosphere. However, clean energy does not release pollutants and carbon into the atmosphere.
Hydro, wind, solar, and geothermal are a subset of renewable energy sources that classify as clean energy. However, the facilities required to harness these energy sources all produce carbon emissions. Most of these emissions occur during the construction or manufacturing stage of a project, but ongoing plant operations also incur low emission levels.
Energy on Demand
Clean energy can be directly used, as in the wind powering a sailboat, but almost all commercial applications for renewable, clean energy require conversion to electricity. However, demand for electricity cycles with peaks and troughs in its usage. Efficiently operating a power grid requires that power flows on demand. As demand rises, power output increases, thus meeting the need. The concept of ‘on-demand’ requires energy storage, so rapid conversion to electricity is possible when demand increases.
With fossil fuels like coal or oil, the energy is locked into a solid or liquid form until needed, and then it is burned releasing that energy. Hydroelectric and geothermal energy sources are also well suited to on-demand access. The water that a dam holds back is storing potential energy because that water resides above the river level downstream of the dam. When more electricity is needed, more water is released through the turbines, thus increasing the power output.
But wind and solar are not well suited for on-demand access. The wind doesn’t always blow when we want it to, and the sun only shines during the day. When electricity from these sources flows directly into the base level support for a large electric grid, no storage is needed. But when wind and solar feed micro-grids, the need arises for energy storage during peak production. The stored energy is then available to fill electric demand during energy production gaps, like nighttime for solar. The most frequently used energy storage strategy is batteries, which create the dirty side of clean energy.
Lead-acid batteries
The battery industry consumes about 80 percent of all global lead production. Also, lead-acid battery production is growing in many areas of the world due to demand from solar micro-grid installations. The leakage of lead into the environment from mining, battery manufacturing, and recycling is as high as 33% in China and 22% in India. The results are lead contamination in the environment and lead poisoning of workers and children.
Micro-grids often service rural areas where connections to national electricity grids are either unavailable or unstable. Micro-grids face on-demand issues like national grids, yet they cannot blend the output from multiple power plants and electricity sources to manage demand. Their only option is storage, and lead-acid batteries are the cheapest source for those storage needs.
Lead-acid batteries have a life cycle of two to five years. Disposal and recycling of these used batteries is a gaping hole in the friendly smile of solar power. Countries like the USA consolidate disposal to a dozen or so large facilities that can operate on a scale where safe recycling occurs at a reasonable cost. In developing countries, this is not the case, and small-scale, inefficient recycling or dumping is the alternative answer.
Without appropriate regulation, power from clean energy becomes a hollow dream that avoids carbon emissions at the expense of poisoning the environment.
ArcheanWeb:
Concrete and carbon dioxide (Source: ArcheanWeb) – https://archeanweb.com/2020/04/10/concrete-and-carbon-dioxide/ Also:
Microgrids, conservation, and energy (Source ArcheanWeb) – https://archeanweb.com/2020/01/14/microgrids-conservation-and-energy/ Also:
Coal slumps as renewable energy surges (Source: ArcheanWeb) – https://archeanweb.com/2020/06/16/coal-slumps-as-renewable-energy-surges/ Also:
Sources:
Electricity explained – Electricity in the United States (Source: U.S Energy Information Administration) – https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php Also:
Wind has surpassed hydro as most-used renewable electricity generation source in U.S. (Source: .S Energy Information Administration) – https://www.eia.gov/todayinenergy/detail.php?id=42955 Also:
Is wood a green source of energy? Scientists are divided (By Warren Cornwall; Science) – https://www.sciencemag.org/news/2017/01/wood-green-source-energy-scientists-are-divided Also:
Solar industry responsible for lead emissions in developing countries, research finds (Source: University of Tennessee at Knoxville; Science Daily) – https://www.sciencedaily.com/releases/2011/08/110831115918.htm Also:
For developing countries, more solar power — and maybe more lead? (By Anuradha Varanasi; Grist) – https://grist.org/energy/for-developing-countries-more-solar-power-and-maybe-more-lead/ Also:
Feature Image: Aikawa Solar Power Plant (Modified) – By Σ64 – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=29185912