Comparing the Global Warming Impact from Wind, Solar Energy and Other Electricity Generating Systems through Life Cycle Assessment Methods (A Survey)

Abstract

This study compares Greenhouse Gases (GHGs) emissions as CO2 equivalent per one kilowatt-hour of two types of renewable power generation technologies (solar and wind) compared to other traditional power generation technologies through life cycle assessment methods. In addition, the study investigated the factors affecting (GHGs) emissions from different power generation technologies.Various methods are used to generate electricity, each with merits and disadvantages regarding the installation and operating cost, GHGs impact, and other considerations. Related to Global Warming Potential (GWP), the produced quantities of GHGs of each generation method vary through manufacturing, construction, utilization, and decommissioning stages with or without recycling. For wind and solar power, the release of GHGs reached between 70 and 98% during manufacturing (including raw materials) and decommissioning. The recycling stage may play a crucial role in decreasing the impact of GHGs up to 40%. Most GHGs released from traditional power plants (e.g., coal fired, oil, and gas) are from fuel combustion during the operation period. Adopting emissions calculated by the Life Cycle Approach (LCA) with electrical generation from solar and wind ways allows a fair comparison per (CO2) eq/ KWh basis and factors affecting each LCA stage. For the two studied systems, wind power emits the least amount of (CO2) eq/ KWh, with average values of 13.91 and 12.7 g CO2eq/kWh for offshore and onshore farms, respectively. While photovoltaic has the highest contribution to GHGs emissions, with a mean value of 23.39 g for CdTe, it is followed by 33.14, 39.93, 43.84,49.33, 50.76 for a-Si, m-Si, CIGs, CIS and sc-Si g (CO2) eq/ KWh, respectively. Concentrated Solar Power (CSP) occupied the medium contribution of 35.6 g for the tower and 30.94 g (CO2) eq/ KWh for the trough. Compared to fossil fuel-fired systems, the average (CO2) eq/ KWh is 936 g for coal-fired, 730 g for oil, and 502 for gas-fired power systems. Replacing one kilowatt-hour of coal or oil-generated electricity with one kilowatt-hour of wind power can save up to 923 or 716 g (CO2) eq/ kWh.