To see where Thailand's future interests and alignments lie, follow the power lines, some already strung, most still on power planners' maps which run into Indochina and China's web of influence and interests.

A decade ago Thailand, its own gas fields slowly dwindling, made a deal to buy gas from Burma over three decades. In 1999, a pipeline was completed from Burma's offshore Yadana gas field to a huge power station in Thailand serving Bangkok. Burma accounts for about a fifth of the gas Thailand uses to generate electricity. In 2004, gas began flowing along a pipeline from Malaysia to southern Thailand.

Now Thailand's attention has turned to importing electricity which will come mostly from dozens of hydro-electric dams being built along the Mekong valley in Cambodia and Laos and the Salween valley in Burma.

Last July engineers from the Electricity Generating Authority of Thailand, or EGAT, resumed surveying a site for a dam on the Salween river inside Burma not far from the Thai border.

In November, EGAT officials sealed an understanding to buy power from a dam being built on the Ou river in northern Laos by Sinohydro, a Chinese state-owned dam-builder. Another six dams, or levels to use Sinohydro's euphemism, are planned for the Ou, their electricity destined for China or Thailand. That's on top of 34 sites for dams across Laos now drawing interest from developers.

EGAT already has deals to buy power from Laos, where Thai corporations are along with the Chinese are among the biggest investors in the power sector. Thailand is the biggest customer for what will be the largest dam in Laos when finished next year, the Nam Theun II.

Ital-Thai, one of Thailand's largest construction firms, in January announced it was building a $4-billion dollar coal-fired power station in Koh Kong, Cambodia, to generate electricity for Thailand.

More deals are on the cards. EGAT's power development plan forecasts up to a fifth of Thailand's electricity needs will be met by imports from Burma, Cambodia and Laos by 2020.

Thailand is caught in a tight spot. Not much thought was given in the past to using less energy. Renewables like solar and wind never figured highly with policymakers. Nor did reducing pollution from coal-burning power stations. Consumers are now hooked on cheap power. Influential corporations and political patrons favour big power station projects. But pollution has poisoned fields and made people sick provoking stiff resistance to new coal power stations.

Gas, which pollutes less, has been Thailand's fuel of choice. However Thailand's fields are dwindling. Instead of lining up more contracts with big gas producers like Australia, Indonesia and Qatar, Thailand is turning to Burma, Cambodia and Laos. They are keen to fill their coffers feeding Thailand's hunger for electricity, which is generating a dam-building boom of epic proportions.

Thailand's moves towards depending on neighbours with whom relations are fragile might seem a strategic folly. Europe's eastern fringe holds a salutory lesson. Russia cut gas supplies holding Ukraine hostage a year ago in the middle of winter.

More so when the three states in question are clients, if not vassals, of China, which is coming to dominate the Mekong and Salween valleys through aid, investment, trade and diplomacy. Last year, for example, Beijing made rare use of its security council veto to defeat a resolution aimed at Burma.

Were this to alarm Bangkok it would surely be going for harder choices such as reducing electricity demand, investing heavily in renewable energy, and making more deals with gas kings like Australia, Indonesia and Qatar.

Instead Bangkok's moves suggest it sees China's rise as peaceful rather than the threat seen by many policymakers in New Delhi, Tokyo and Washington. Indeed Bangkok's deepening ties with Beijing might be what makes it feel comfortable in turning to depend on Burma, Cambodia and Laos, which in turn may increase Beijing's prospects for luring Bangkok away from close defence ties with Washington.

Bangkok's enduring friendship with Washington is doubtless a concern for Beijing, which in seeking to secure its southern flank and dominance of the South China Sea needs a neutral Thailand. Patterns of energy, investment and trade suggest matters may be moving in Beijing's favour. That in turn raises the prospect Bangkok may in a crisis keep its ports and airbases closed to American forces.

Thailand's enthusiasm for plugging into the Mekong and Salween also comes in the face of rising competition. Vietnam is looking to take power from the Mekong. Bangladesh and India may yet emerge as customers for Salween electricity. While China looks like importing electricity from both valleys, China Southern Power Grid plans to connect with the Burmese and Laotian power grids within a decade.

This complex, subtle dynamic reshaping power and interests in Indochina is clearly moving in Bejing's favour. Yet another sign, if any were needed, portending the return of continental Southeast Asia, after an absence of a few hundred years, to the sphere of China.