The first question is whether Saudi Arabia is stable. The kingdom’s oil exports now mostly go to Asia but the volumes involved mean that any volatility will destabilise a market where speculation is rife. Crown Prince Mohammed bin Salman is apparently in control but it is a strange and fragile sort of control that requires the imprisonment of dozens of senior businessmen including members of the royal family, the concentration of power in the hands of one individual and a huge international PR campaign to persuade the world that MbS is a modernising liberal.
第一个问题是沙特阿拉伯能否保持稳定。目前，沙特王国的石油出口大多流向亚洲，但其出口量意味着任何波动都会让这个充斥着投机活动的市场变得不稳定。穆罕默德?本?萨勒曼王储(Crown Prince Mohammed bin Salman)似乎控制着局面，但这是一种古怪而脆弱的控制：它有赖于羁押包括王室成员在内的几十名大商人、将权力集中于一人之手，以及发动大规模国际宣传活动，以说服全世界穆罕默德?本?萨勒曼是一位现代化自由主义者。
That is certainly not the view held in Yemen or across the Middle East. Behind the grand plans for a new $500bn city (sorry, "urban metropolis for the world") run by robots and the radical notion of allowing Saudi women to drive for the first time is a degree of old-fashioned religious fanaticism directed against the Shia communities across the region and Iran in particular. This could produce real instability over the next few months.
The risk is that an open conflict, which Iran and Saudi have traditionally avoided despite all their differences, would spread and hit oil production and trade. It is worth remembering that the Gulf states account for a quarter of global production and over 40 per cent of all the oil traded globally. The threat to stability is all the greater given that Iran is likely to win any such clash and to treat the result as a licence to reassert its influence in the region.
The second question is how rapidly production of oil from shale rock will grow in the US — 2017 has seen an increase of 600,000 barrels a day to over 6m. The increase in global prices over the past six months has made output from almost all America's producing areas commercially viable and drilling activity is rising. A comparable increase in 2018 would offset most of the current Opec production cuts and either force another quota reduction or push prices down.
The third question concerns China. For the last three years the country has managed to deliver economic growth with only minimal increases in energy consumption. Growth was probably lower than the claimed numbers — the Chinese do not like to admit that they, too, are subject to economic cycles and recessions — but even so the achievement is considerable. The question is whether the trend can be continued. If it can, the result will limit global demand growth for oil, gas and coal.
China, which accounts for a quarter of the world’s daily energy use, is the swing consumer. If energy efficiency gains continue, CO2 emissions will remain flat or even fall. The country's economy is changing and moving away from heavy industry fuelled largely by coal to a more service-based one, with a more varied fuel mix. But the pace of that shift is uncertain and some recent data suggests that as economic growth has picked up, so has consumption of oil and coal. Beijing has high ambitions for a much cleaner energy economy, driven not least by the levels of air pollution in many of the major cities; 2018 will show how much progress they are making.
The fourth question is, if anything, the most important. How fast can renewables grow? The last few years have seen dramatic reductions in costs and strong increase in supply. The industry has had a great year, with bids from offshore wind for capacity auctions in the UK and elsewhere at record low levels.
Wind is approaching grid parity — the moment when it can compete without subsidies. Solar is also thriving: according to the International Energy Agency, costs have fallen by 70 per cent since 2010 not least because of advances in China, which now accounts for 60 per cent of total solar cell manufacturing capacity. The question is how rapidly all those gains can be translated into electric supply.
风电正接近“电网平价”(grid parity)，到了那个拐点它可以在没有补贴的情况下与其他能源竞争。太阳能也形势大好：根据国际能源署(International Energy Agency)的数据，自2010年以来，太阳能的成本已下降70%，这主要是因为中国的进展，中国目前占全球太阳能电池制造能力的60%。问题是所有这些增长能够多快转化为电力供应。
Renewables, including hydro, accounted for just 5 per cent of global daily energy supply according to the IEA's latest data. That is increasing — solar photovoltaic capacity grew by 50 per cent in 2016 — but to make a real difference the industry needs a period of expansion comparable in scale to the growth of personal computing and mobile phones in the 1990s and 2000s.
The problem is that the industry remains fragmented. Most renewable companies are small and local, and in many cases undercapitalised; some are built to collect subsidies. A radical change will be necessary to make the industry global and capable of competing on the scale necessary to displace coal and natural gas. The coming year will show us whether it is ready for that challenge.
In many ways, the energy business is at a moment of change and transition. Every reader will have their own view on each of the four questions. To me, the prospect is of supply continuing to outpace demand. If that is right, the surge in oil prices over the past two months is a temporary and unsustainable phenomenon. It would take another Middle East war to change the equation. Unfortunately, that is all too possible.