A visitor to Israel will unavoidably notice the urban landscape bursting with solar collectors and hot water storage tanks covering the roofs of buildings. Almost all residences in Israel are equipped with solar water heaters. The most common are the thermosyphonic system, a completely passive, standalone unit consisting of one or two flat plate solar collectors and an insulated storage tank. Large multistory apartment buildings often use a central system with a collector array on the roof and a storage tank in the basement, employing a pump controlled by a differential thermostat. Other arrangements are also available. In most of the country, the solar system will supply the full demand for hot water during 9-10 months per year, with an electric resistance backup employed the rest of the time. Freeze protection is never required, except in some isolated locations. The economics: the installed cost of a typical single-family system comprising a 150 l storage tank and 2-3 m2 flat plate collectors is about $700; an equivalent electric-powered system costs about $300. The difference of $400 is recovered by the owner in about 4 years (on a simple-payback basis); these systems carry a manufacturer's warrantee for 6-8 years, and if properly maintained can last over 12 years. Several decades of nation-wide experience have generated consumer confidence and acceptance to the point that a domestic solar water heater is perceived as a common, reliable household appliance.
There is no single legislation concerning solar energy utilization in Israel. The above-mentioned Article 9 of the Law for Planning and Building (1970)  is probably the most important solar legislation, and has been the government's predominant contribution to Israel's success in the solar area. The law requires the builder (not the homeowner!), since 1980, to install a solar water heating system in every new building. Other laws and regulations describe in detail the size of the installation required for the various types of buildings, set minimum standards for the quality of the solar equipment and installation, and provide the regulations for retrofit installation of solar water heaters in existing multi-apartment buildings. Based on government data  an average single-family domestic solar water heater saves 1250 kWh electric power per year; the total contribution to the country is about 1.6 billion kWh per year, 21% of the electricity for the domestic sector or 5.2% of the national electricity consumption, providing for 3% savings on the primary energy consumption. This amounts to about 270 kWh per year per capita—the highest in the world.
Israel's example in domestic solar water heating provides an impressive demonstration of what can be achieved (in countries with similar or even more favorable climates), if the government makes a commitment to clean and environment-friendly technologies . However, while solar for residential use has become an everyday reality in Israel, the much larger industrial/commercial sector uses very little solar energy, despite the fact that the industrial user is much better suited to do so than a homeowner. Some key considerations are: industry works mostly during the day, requiring little storage relative to a residence; the economy of scale provides a significant capital advantage to large industrial installations; industry generally has plenty of roof area in single-story buildings located in areas where architectural considerations do not hinder the installation of solar collectors; the industrial user is used to perform small maintenance jobs, thus eliminating the need for a fool-proof system and reducing first cost. While some industries require high-temperature process heat, there are many who need the same temperature range as the domestic user; these include textile, food, pharmaceutical, chemical, and many more. The same applies, of course, to the commercial sector. It is estimated that widespread solar energy utilization in industry for process heat and the like, and in commercial applications, could increase the country's utilization by a factor of five, if not more.
Unfortunately, present tax considerations create a negative incentive for businesses to use solar energy. An industry burning polluting fuel can write the cost off as a business expense, thus reducing its tax liability, whereas an investment in a solar heating system can only be amortized over 12-15 years, making it considerably less attractive economically. Moreover, the law presently exempts industrial plants, shops, hospitals, and high-rise buildings (height over 27 m) from the requirement to install a solar water heating system in new buildings . The government could play an important role in changing this situation, by introducing appropriate measures, closing tax loopholes, and creating positive incentives for renewable energy. This can be achieved within a short time—there is no need for long-term investments and development of new technologies. Solar energy is a reality here and now, as already demonstrated by the country's residential sector.
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.