The Skeptics Guide #829 - May 29 2021 (Ad Free)

It is well worth pointing out that energy used to heat things in industrial processes (for example cement) could come directly from the sun using mirrors. There is a claim that we can totally replace fossil fuels by 2035. Is this true? Solar capacity for electricity has almost tripled in recent years, from 19,000 MW in 2015 to 48,000 MW in 2018. More than 54,000 utility-scale wind turbines are installed in the U.S., with a cumulative capacity of 89.4 GW. U.S. wind capacity increased by 431% between 2007 and 2017, a 18% average annual increase. https://www.windpowerengineering.com/business-news-projects/reaching-100-renewables-with-the-green-new-deal/ That's an APR of 36.2% for solar and 18% for wind. At this growth rate, this is what percentage of current U.S. total generating capacity (786 GW) we would get each year: solar-30% capacity, wind-60% capacity year solar wind total 2019 2.48 8.05 10.5 2020 3.40 9.50 12.9 2021 4.62 11.2 15.8 2022 6.30 13.2 19.5 2023 8.59 15.6 24.2 2024 11.7 18.4 30.1 2025 15.9 21.7 37.6 2026 21.7 25.6 47.3 2027 29.5 30.2 59.7 2028 40.2 35.7 75.9 2029 54.8 42.1 96.9 2030 74.7 49.7 124.4 What about storage? No problem! In 2017 Blakers and colleagues used satellite imagery and algorithms they described in an Applied Energy (https://www.sciencedirect.com/science/article/pii/S0306261918305270) paper to identify 22,000 Australian sites with the right topography. Now they have expanded this to the world, releasing maps of the locations they have identified. Each site is suited to storing at least 2 gigawatt hours, enough to last a small city through a windless night. This world-scale map of potential pumped hydro sites shows that heavily populated areas have more than enough sites very nearby, although northern Europe may depend on storage to the south. Matthew Stokes and ANU Colleagues AREMI Collectively, these sites could store 22 million gigawatt hours. “Only a small fraction of the 530,000 potential sites we’ve identified would be needed to support a 100 percent renewable global electricity system,” first author Dr Matthew Stocks (http://www.anu.edu.au/news/for-journalists/dr-matthew-stocks) said in a statement (http://www.anu.edu.au/news/all-news/anu-finds-530000-potential-pumped-hydro-sites-worldwide). Urban areas and national parks have been excluded. Blakers dismisses the idea many sites lack sufficient water, noting the water is recycled endlessly. He added floats that suppress evaporation can ensure even desert sites will refill with rain quicker than the water escapes. 500,000 Possible Pumped Hydro Sites Show We Can Easily Store Renewable Energy (https://www.iflscience.com/technology/500000-possible-pumped-hydro-sites-show-we-can-easily-store-renewable-energy/) Pumped hydro can’t respond fast enough to match power grid fluctuations? Batteries (which can be calcium ion instead of lithium ion in the case of grid storage) can respond instantly and keep going until the power from hydro is up to speed. For fossil fuels that do not generate electricity, it is harder. Electric trains could replace overland air travel, but they could take a long time to build, and you would still have overseas air travel. Electric cars can replace gas burning ones. I traveled from Tampa Bay to Tallahassee and back on one - it worked great, only needed one charge each way, and it only took a half hour to fully charge. However, I am not sure if we can build enough of them fast enough for gas powered cars to be gone by 2035.

Ted Apelt