The International Energy Agency (IEA) this month forecast primary energy demand would increase by a third between 2010 and 2035, with 90 per cent of that growth from non-Organisation for Economic Co-operation and Development countries.
By 2035, China would consume more than 70 per cent more energy than the United States, the IEA said in its widely-followed 2011 World Energy Outlook report.
This trend has important implications for long-term investors. Projected growth in energy demand is both an opportunity and threat, if it leads to sharply higher energy prices.
The IEA forecasts oil demand will rise from 87 million barrels per day in 2010 to 99 million in 2035, with all the net growth coming from the transport sector in emerging economies. The global passenger vehicle fleet is projected to double to almost 1.7 billion in 2035.
The agency's report would have pleased long-term energy bulls.
It also projects coal use will rise 65 per cent by 2035. Coal met almost half the increase in energy demand in the past decade.
The IEA was less confident on the future of nuclear power and much more confident on natural gas.
It is unsurprising energy projects dominate a multi-billion-dollar pipeline of local minerals projects.
The big unknown is how much more supply of these commodities there will be as new projects come on stream, and the effect on prices.
But there is an argument long-term portfolio investors need to increase exposure to commodities.
Already, some financial advisers are telling clients to hold as much as 5 per cent of their portfolio in gold bullion.
Gaining exposure to commodities is becoming easier as more exchange-traded funds (ETF) list on the Australian Securities Exchange.
This week saw the launch of Australia's first oil ETF from BetaShares.
The complex product tracks the performance of West Texas Intermediate (WTI) crude oil futures traded on the New York Mercantile Exchange, via the S&P GSCI Crude Oil Index.
Technically a 'synthetic' ETF, the product is fully backed by cash rather than the physical asset (which is not possible in oil), which means counter-party risk is limited although not entirely absent.
Investors seeking exposure to energy stocks could use Australian Index Investment's Energy ETF, which is based on an index comprising 20 stocks.
Much depends on Woodside Petroleum, which makes up almost 30 per cent of the index. For gold bullion exposure, investors can use BetaShares' currency-hedged Gold Bullion ETF, or ETF Securities' Physical Gold ETC, which is not hedged for currency movements.
Interestingly, the relationship between the US-dollar oil and gold prices has broken down this year.
With everyone talking about gold, it may be that oil surprises in 2012 on supply constraints.
WTI crude has rallied more than 6 per cent in November, building on gains in October.
A higher oil price is the last thing the global economy needs, but the IEA forecasts easing pressures on oil markets because of the global economic slowdown and the return of Libyan oil supply.
The wildcard is investment in Middle East and North African (MENA) energy industries.
The IEA said: "If between 2011 and 2015 investment in the MENA runs one-third lower than the US$100 billion per year required, consumers could face a near-term rise in the oil price to US$150 a barrel."
If that happens, the short and long-term case for more energy exposure, and more commodity exposure generally, in portfolios looks stronger.
