Group items tagged

Feb 7 2009. Join the Group Read. Chapters 5 and 6. Flight and Solar Will solar energy technologies allow us to sustainably take those long-haul flights to get our winter dose of sunshine? On the way, we discover that flying intecontinentally once per year has an energy cost slightly bigger than leaving a 1 kW electric fire on, non-stop, 24 hours a day, all year, despite the fact that modern planes are twice as fuel-efficient as a single-occupancy car. It may be no surprise, therefore, that Airline businessman Michael O’Leary, CEO of Ryanair, has developed a Swiftian the solution to the problem: " The best thing we can do with environmentalists is shoot them."

Second, to supplement solar-thermal heating, we electrify most heating of air and water in buildings using heat pumps, which are four times more efficient than ordinary electrical heaters. This electrification of heating further increases the amount of green electricity required. Third, we get all the green electricity from a mix of four sources: from our own renewables; perhaps from “clean coal;” perhaps from nuclear; and finally, and with great politeness, from other countries’ renewables. Among other countries’ renewables, solar power in deserts is the most plentiful option. As long as we can build peaceful international collabor- ations, solar power in other people’s deserts certainly has the technical potential to provide us, them, and everyone with 125 kWh per day per person.

paving 5% of the UK with solar panels seems beyond the bounds of plausibility in so many way

It doesn’t require high-cost hardware, in contrast to solar photovoltaic power.

Chapter 18 was depressing --- the diffuse nature of renewables in the crowded UK basically means that a realistic view of their usage makes it clear we won't make it on local wind, tide, sun, geothermal, wood etc. Assume: a) we can't change energy per capita too much; b) we can't change the capita (ie no creepy population control) and we still want sustainability ... The basic solution is:  1. electrify transport 2.  electrify space heating 3. produce electricity with whatever local renewables we can, augmented by clean coal, nuclear and imported solar from desert regions. Sounds simple, no?

March 30th 2009. Join the Group Read. Chapter 18. A first balance (Instructions on how to join are at the bottom of the original post) This is the first chapter attempting to balance-up consumption and production. While the story told so far of the raw energy potential from renewable sources shows an ecouragingly close race to maintain our rich lifestyles with sustainable energy sources, a little digging provides much disappointment. Between the potential and the realisation lies a factor of over 100! From a production potential of 180 kWh per day per person, we get to an actual production figure of just 1 kwh/d/p and a "realisable" estimate of 18 kwh/d/p---a full ten times less than our consumption. Looking at the heart of the physics problem, David MacKay points to the geographically diffuse nature of renewables: each person needs a huge amount of land, tidal exposure, wind per person to make the sums add up. The sustainable potentials, as David emphasises, need "country-sized solutions". "To get a big contribu- tion from wind, we used wind farms with the area of Wales. To get a big contribution from solar photovoltaics, we required half the area of Wales. To get a big contribution from waves, we imagined wave farms covering 500 km of coastline. To make energy crops with a big contribution, we took 75% of the whole country." Yet protection of species, habitats, nature, beauty etc. all move the same people who want to reduce fossil fuel dependency to limit the installations. Something will need to give to balance our energy ...