Wow, you want-to-know readers never let me off easy!
Your questions about yesterday's solar water heaters need a whole new post.
1. OK, so today I telephoned the company that installs the dood shemesh pictured above.
The basic dood unit costs 2300 shekels = $614 =446 Euros.
Not bad, right?
Big savings on your electric bill when you let the sun heat your water for free.
2. The black collector panels connected to the water tank are NOT the same as solar panels.
The water inside the black coils heats up quickly (because that is what black does).
Solar panels, on the other hand, collect heat and turn it into useable electricity.
3. The high percentage (90%) of Israeli families that have a dood shemesh is because we WANT them and believe in them, not because it is now mandatory.
I found the following historical information in a good blog called MetaEfficient, The Guide to Highly Efficient Things:
"These heaters were first installed when the country experienced a fuel supply crisis in the early 1950s. The government responded by severely restricting the times when water could be heated. Israelis in turn responded by purchasing huge quantities of solar water heaters. By 1983, 60% of the population heated their water with the sun. A law was eventually passed requiring the installation of solar water heaters."
4. We are poor in natural resources but rich with sunshine.
Israeli companies are the forerunners in alternative energy sources.
Hawaiian bloggers like Cloudia even tell me that our ORMAT company is harvesting power from their Big Island's volcano!
I think it is something like digging a well to capture geothermal fluid (steam?) and turn it into electricity.
But better you ask the Hawaiians about that. :)