◊ This is part of the ‘solar energy’ series of articles ◊
In this article on solar energy’s environmental impact I will reference manufacturing, geographic implications, carbon impact and end of life management.
Manufacturing solar panels
The manufacturing of PV panels requires the use of some dangerous chemicals. Many of these chemicals are commonly used in the production of electronic components and have been managed (or mismanaged) for decades. The chemical compounds include:
- hydrochloric acid
- sulfuric acid
- nitric acid
- hydrogen fluoride
- trichloroethane
- acetone
- gallium arsenide
- copper-indium-gallium-diselenide
- cadmium-telluride
Some of these compounds have valuable components that are worth recovering through recycling processes. Each country has their own protocol for managing the byproducts of PV manufacturing. The finished panels are typically made up of 90% non-hazardous materials such as glass, polymer and aluminum.
Jinko Solar Company in China spilled hydrofluoric acid into the nearby Mujiaqiao River in 2011, killing fish and livestock in the area. Environmental regulations have since been improved however it is difficult to determine how effective the changes have been. Every industry that manufactures electronic components assumes the risk of adverse environmental impact from chemical spills or improper handling of hazardous materials.
Geographic implications
Solar energy shares a similarity with wind energy in that it must occupy a significant geographic area. Unlike wind farms, there is little opportunity for solar projects to share land with agricultural uses. On the other hand there is plenty of opportunity to re-purpose rooftops in an urban environment to provide energy where it is most likely to be needed. Solar can be installed in both urban and rural spaces.
The area per megawatt capacity required for solar spans a large range depending on the scale of the development and the space needed for maintenance and auxiliary equipment. Using data from the U.S. National Renewable Energy Laboratory (NREL), a typical requirement would be approximately 5.5 acres per MW capacity. That is a significant space requirement, however it is a small fraction of the area required to accommodate wind generation. In 2017 the peak load in Ontario was 21,786 MW. In order to meet that peak it would require 485 square kilometers of space for solar farms. Providing enough solar capacity for peak load would not be nearly enough to supply the annual energy needs of Ontario. It would take almost 5 times the peak capacity rating to meet the total energy needs of the province. Now we are talking about a total area of 2,100 square km or about 3 1/2 times the size of the city of Toronto. In addition there would need to be provision for reserve capacity. This information is simply to illustrate a point and provide context for the scale of Ontario’s solar needs if we were entirely dependent on it. Solar energy alone cannot be used without some form of energy storage or alternate backup source.
Carbon impact
The life cycle of solar PV modules leave a carbon footprint. Raw material sourcing, manufacturing, maintaining and end-of-life management will require some degree of fossil fuel utilization. The National Renewable Energy Laboratory performs life cycle assessments of energy systems to determine greenhouse gas emissions. NREL estimates the emissions for solar PV to be approximately 50g of CO2/kWh of energy produced. That compares favourably to natural gas at 475g/kWh and coal at 1,000g/kWh.
PV end of life management
If you look at the proliferation pattern of solar installations globally it is apparent that the issue of recycling solar PV modules isn’t a major issue – yet.
The International Energy Agency (IEA) estimated in 2015 that 500,000 panels were installed globally every day
With an anticipated life span of 20 to 30 years we will begin to see an exponential increase in retiring panels in 2025. It represents a business opportunity as recycling volumes become too large for existing industries to manage. An estimated 85% of PV modules are recyclable through existing processes. With PV-specific recycling the amount of material retrieved should increase. The IEA estimates that global PV end-of-life management will be a $450 million industry by 2030 growing to $15 billion by 2050.
There are discussions among the solar PV manufacturers to increasingly perform their own recycling and material recovery businesses. The Solar Energy Industries Association (SEIA) has developed industry partnerships for recycling solutions in the U.S.
The environmental challenges associated with solar energy are entirely manageable with the appropriate planning and industry engagement.
Derek
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Next article… The future of solar energy
