Friday, September 26, 2008

Lights on cars in the daylight

According to the Dail Mail, crazy European legislation forcing car drivers to keep headlights on ALL day could inflate fuel costs by up to £160 a year.

What are the numbers? Well, this is one that I worked out earlier. It's in chapter 9 of Sustainable Energy - without the hot air, on page 58. Let's say the four bulbs for the running lights on a car use about 100 W. Allowing for the engine's and generator's inefficiencies, this 100 W of bulb power requires a petrol power of 730 W. For comparison, the petrol consumption of an average car running along at 50 km/h and consuming one litre per 12km is 42000 W. So having the lights on while driving requires 2% extra power.

If you drive 50km per day and fuel costs £1.20 per litre then you spend £5 per day on fuel. Putting the lights on is going to increase your costs by 2%, which is 10p per day. That's £37 pounds per year, for a typical driver. Obviously the answers come out differently if we change the vehicle to a Hummer, or if we replace the incandescent bulbs by modern LEDs.

I hope this helps!

Thursday, September 25, 2008

The book's finished!

I'm happy to announce that Sustainable Energy - without the hot air is finished.
It's got a publisher, a cover design, and a publication date of December 1st 2008.
All that remains is some frantic last minute editing and correcting; then an 8-week wait.
The book will remain free on my website.