Thanks to Gooch for alerting me to this ... have known of the gas reserves in sea-bed off shores of Gaza for a few years now, but wasn't aware of Egypt's pumping gas to Israel, at all... so, most illuminating.
I amended the title soon after posting, since when I started to collect background links to flesh this post out, I realised this has implications all over the wider topic - not least Egypt's Islamic Brotherhood and political Islam, and the unfolding situation in Syria, with western military intervention there all but certain very soon. And what about major players in the energy business, such as Russia's Gazprom? Various links in replies. Readers are encouraged to click through for a better overview.
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The Arish–Ashkelon pipeline is a 100 kilometres (62 mi) submarine gas pipeline connecting the Arab Gas Pipeline with Israel. Although it is not officially a part of the Arab Gas Pipeline project, it branches off from the same pipeline in Egypt. The pipeline is built and operated by the East Mediterranean Gas Company (EMG), a joint company of Mediterranean Gas Pipeline Ltd (28%), the Israeli company Merhav (25%), PTT (25%), EMI-EGI LP (12%), and Egyptian General Petroleum Corporation (10%).[10] The pipeline became operational in February 2008, at a cost of $180 million – $550 million (the exact figure is disputed).[11] Initially Egypt and Israel had agreed to supply through this pipeline 1.7 billion cubic metres (60 billion cubic feet) of natural gas per year for use by the Israel Electric Corporation.[12] This has since been raised to 2.1 billion cubic metres (74 billion cubic feet) per year to be delivered through the year 2028. In addition, by late 2009, EMG had signed contracts to supply through the pipeline additional 2 billion cubic metres (71 billion cubic feet) per year to private electricity generators and various industrial concerns in Israel and negotiations with other potential buyers were ongoing. In 2010, the pipeline is supplying approximately half of the natural gas consumed in Israel, with the other half being supplied from domestic resources. The total physical capacity of the pipeline is 9 billion cubic metres (320 billion cubic feet) per year and agreements between the two nations provide a framework for the purchase of up to 7.5 billion cubic metres (260 billion cubic feet) per year of Egyptian gas by Israeli entities, making Israel one of Egypt's most important natural gas export markets. In 2010 some Egyptian activists appealed for a legal provision against governmental authorities to stop gas flow to Israel according to the obscure contract and very low price compared to the global rates, however the provision was denied by Mubarak regime for unknown reasons. In 2011, after the 25 January Revolution against Mubarak regime, many Egyptians called for stopping the gas project with Israel due to low prices.[citation needed] After a fifth bombing of the pipeline, flow had to be stopped for repair.[13][14]
http://en.wikipedia.org/wiki/Arab_Gas_Pipeline#Arish.E2.80.93Ashkelon_pipeline
(note: according to this image, Tripoli is in Lebanon? I'm assuming that's just a city with the same name as the Libyan one...)