Sunday, August 30, 2015

Some SEWTHA updates (video, html, and hype)

Three pieces of news...

1: Updated SEWTHA video

There is a new release of my 2010 "Sustainable Energy - without the hot air" lecture at Caltech which includes close-captioning. Thank you, CMU, for providing the cc!
Original version: Sustainable Energy - without the hot air - David MacKay lectures at Caltech, April 2010
NEW: on YOUTUBE with close-captioning kindly provided by CMU's Equal Opportunity Services
Caltech DJCM

2: Improving the HTML for viewing on small devices

I have made a New Contents Page for Sustainable Energy - without the hot air - which is intended for viewing on thin, small displays. This contents page enables quick navigation to any page in the book. I recommend bookmarking it as the best quick way into the HTML book, especially on a smart-phone.
More enhancements to the HTML version of the book may be on the way soon.
For twitter users, I've added a "tweet" button to the top of every HTML page.

3: Solar and Batteries

Lots of people have asked me whether recent hype and hoopla about solar panels and batteries overthrows what I wrote in my book in 2008. I am preparing a detailed update. Watch this space! The theme of my update will be the existence of a phenomenon called winter, which many of the solar-hyponauts seem to ignore. Here is a teaser trailer showing the winter and summer 3-month-average insolation in 50 US states.
winter and summer 3-month-average insolation in 50 US states


John Russell (@JohnRussell40) said...

Anyone who lives in the temperate zones and has solar panels on their roof should know that peak summer month generation will total approximately five times that of the lowest winter month. In the UK I can generate ~25kWh on the sunniest June day and ~5kWh on a sunny December day (when I need power most!).

Obviously this multiple will become larger the nearer the poles you are.

David MacKay FRS said...

- John Russell, I think my numbers agree with what you said, bearing in mind that "a sunny December day" is not the same as an average December day. In the UK the ratio between an average June day and average December day is ~ 22.5 kWh/d : ~ 2.5 kWh/d DATA HERE i.e. about 9:1. There tend to be much more dull days in December than June. This nine-to-1 ratio is the main problem with the wishful thinking about solar power making a "huge" contribution in northerly locations. I'll write more in due course as promised.

Anonymous said...

How much could this ratio be changed, if the inclination of solar installations was optimized for greatest wintertime production, rather than greatest overall production?

Also, would this make hotter climates a more sustainable place to live? Solar panels produce more energy closer to the equator, the difference between summer and winter production is smaller, and due to the warmer climate the energy demand is actually greater during the summer. Such places tend to be rather dry, which represented a barrier to populating them before because people need water more than they need warmth, but with sufficiently cheap energy desalination of sea water could become a feasible source of drinking water.

Mauri said...

Dear Professor MacKay, have you already written a comment on the new report by Greenpeace called "Energy [R]evolution"?

I'm sorry if I'm asking something already answered elsewhere.