Mon, Jun 8, 2020
Rosie provides a quick primer on aerodynamic stall then explains how it relates to wind turbines to prevent their electrical generators form burning out when wind speed get too high.
Mon, Sep 28, 2020
Rose grabs her surfboard and heads to the ocean to talk about wave energy. There are three types of motion in a wave that can be captured to generate electricity. The challenge is building a reliable mechanism that can resist corrosion by salty water to convert wave motion into the rotational motion of a turbine electric generator.
Mon, Nov 9, 2020
Wind turbines are optimized to maximize lift and minimize drag within some constraints. Lift needs to be constant along the length of the blade for maximum efficiency which is the reason for the tapering, twisting shape. But the shape is also effected by cost and manufacturability. The ideal shape also varies with wind speed but since it is not possible to vary the shape with current technology turbine support variable rotation rates.
Mon, Nov 16, 2020
Hydrogen is a wonderfully clean fuel producing only water. But to use it as a fuel it first has to be produced and most production currently uses fossil fuels. Wind and solar power can be used to produce hydrogen cleanly but it more efficient to use the electricity produced directly rather than converting it to hydrogen first.
Tue, Feb 9, 2021
Rosie consults with Florence Ungaro to understand why wave electrical generator technology remains diverse when wind turbines have settled down into just a few basic design. The difference with waves compared to wind is there are different times of energy from waves and generator design are very site specific.
Wed, Mar 17, 2021
Vertical axis wind turbines initially looks promising as a simpler alternative to the horizontal wind turbines that are cropping up everywhere. But they have two challenges; the tendency to stall at certain points in each rotation and metal fatigue due to vibrations. The vibrations can be resolved with alternative blade designs and alternative materials. But fixing that stall issue requires added complexity that eliminates its simplicity advantage.
Mon, Jul 19, 2021
Carbon capture is the extraction of carbon dioxide from fossil fuel power plant flue gases or directly from the air around us. Rosie interviews Marc Allen, a chemical engineer working in the carbon capture field who explains three technologies; chemical absorption, molecular sieves and gas membranes and how much impact they will have in reducing carbon dioxide as greenhouse gas.
Wed, Nov 3, 2021
Bioenergy is a popular idea for combating climate change. But is it still a good idea if that mean cutting down habitat, or clearing dead treats, or shipping the waste thousands of miles for processing or paying for the waste giving an incentive to generate more waste?