90 percent of Israeli households have solar water heaters 1


An information that really caught my eyes in my RSS feeds is the fact that 90 percent of Israeli houses have a solar water heater. This is a huge percentage.

It can be explained by the interest of the local government for this energy source as early as the 1950s. In 1983, up to 60 percent of households had these appliances.

Israel is thus taking profit of its most important insolation. But solar energies also work in less sunny places. It is to be hoped that more countries will follow this example.

According to MetaEfficient :

When viewed from above, the Jerusalem often glitters with the shine of the thousands of solar heaters that adorn rooftops.

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.

In 2005, Spain became the second country (after Israel) to require solar water heaters. It also became the first country to require the installation of solar cells for electricity generation in new buildings.

In many climates, a solar heating system can provide a very high percentage (50% to 75%) of domestic hot water energy.

In many northern European countries, solar power is used not only to heat water, but also to provide 15 to 25% of home heating energy.

The Foreign Ministry of Israel gives us further data on this interesting fact :

Perhaps the most common manifestation of putting the sun to work in Israel are the solar water heaters that cover roof-tops all over the country. Typical domestic units consist of a 150 liter insulated storage tank and a 2 sq.m. flat panel.

The latter collects solar radiation, heats the water and passes it to storage in a pumpless, gravity-driven loop.

These systems operate at an annual average efficiency of approximately 50%. It is therefore easy to calculate that such a unit saves its owner some 2,000 kWh per year in electricity costs, raising the temperature of a tankful of water by approximately 30oC above its starting point on an average day – i.e. heating water to a temperature of about 50oC.

This means that most days of the year there is no need to employ the electrical backup heating coil (which all storage tanks contain) in order to ensure that the water is warm enough for washing. Larger systems, usually pump- driven, are to be found on high-rise housing projects, on several kibbutzim and at a number of industrial plants around the country.

To conclude, we can note that once a government has been willing to implement a technology in a full scale way, it takes a century to do so. So, putting into application all the highly efficient technologies and renewables will take us about half a century.

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Photo taken from feministjulie on FlickR


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