FACTBOX: Culture, energy unite Turkey and Azerbaijan

(Reuters) - Turkey and Armenia have agreed on a framework to normalize ties after nearly a century of hostility, a move that could stabilize the volatile, oil-rich Caucasus but may affect European energy security plans.

Oil-producing Azerbaijan said the deal, likely to include the opening of the Turkey-Armenia border, risked raising tensions in the region if it goes ahead before a dispute over an Armenian-backed enclave inside Azerbaijan is solved.

Following are the key facts on what unites Turkey and Azerbaijan, and what might be changing:

CULTURE, WAR

* Azerbaijan and Turkey have been close allies since the collapse of the Soviet Union, when Turkey found in Baku an enthusiastic partner in the growth of the Turkic idea. The two countries are both overwhelmingly Muslim and Turkic-speaking.

* The alliance took concrete form after the collapse of the Soviet Union when fighting intensified in Nagorno-Karabakh, a mountain enclave in Azerbaijan where Christian ethnic Armenian separatist forces battled to throw off Baku's rule. Hundreds of thousands of Turks protested in the streets demanding intervention on behalf of Azerbaijan. In protest, Ankara broke off talks with Armenia on establishing diplomatic ties and closed their frontier. Turks have long felt beholden to help their smaller ally of 8.3 million people in recovering the enclave.

* Given their cultural, religious, and linguistic ties, Turkey sees Azerbaijan as a bridge to the Turkic republics of Central Asia, where Russia and Iran are also competing for political and economic influence.

PIPELINES

* Azerbaijan and Turkey are strong trading partners, but the key to their economic alliance is energy. Major gas and oil pipelines run from Azeri deposits in the Caspian Sea to Turkey, by-passing Armenia and instead running via Georgia.

* The BP-led Baku-Tbilisi-Ceyhan (BTC) oil pipeline ships 850,000 barrels per day (bpd) of high quality Azeri crude to the Mediterranean. The Baku-Tbilisi-Erzurum (BTE) gas pipeline, opened in 2007, will eventually be able to carry 20 billion cubic meters (bcm) of offshore Azeri gas per year.

* Phase 2 of Azerbaijan's Shah Deniz field is due to come online by 2014, and Europe is hoping it will supply the proposed 3,300-km Nabucco pipeline that would would run through Turkey, Bulgaria, Romania and Hungary to an Austrian distribution hub. Azerbaijan has said it is happy to provide the gas providing it sees the political and financial will from the stakeholders. But it has also begun talks on selling gas to Russian export monopoly Gazprom from 2010 for re-export to Europe.

* Azerbaijan is already frustrated by Turkish demands for 15 percent of the throughput of the pipeline for domestic use or re-export rather than a simple transit fee.

Analysts and diplomats warn Baku might turn to Russia for future gas sales in retaliation for Turkey's rapprochement with Armenia.

NEW CIRCUMSTANCES

* Turkish foreign policy has evolved dramatically since the turn of the century, with a policy of "zero problems with neighbors" that has helped cement Turkey's position as a key player on the international stage. Turkey has seen very little return for the closure of its frontier with Armenia, and no sign of progress on Nagorno-Karabakh. A growing body of opinion questions the validity of keeping the border closed, which has cost Turkey in terms of lost trade. Turkey also knows that normalizing ties with Azerbaijan would boost its bid for membership of the European Union.

* Last year's war between Russia and Georgia, which affected the supply of oil and gas to Europe, cast new doubt on Georgia's reliability as a transit route and compelled the search for alternatives, potentially via Armenia.

* Some in the Turkish leadership continue to insist diplomatic ties with Armenia will only follow progress on Nagorno-Karabakh. It remains to be seen how long it will take for the roadmap announced late on Wednesday to be put into action, and whether Armenia will be forced into concessions on the breakaway enclave.

(Writing by Matt Robinson; Editing by Louise Ireland)