How to ensure energy supplies underground can be tapped in the future

6 June 2013

Known hydrocarbon resources are sufficient to sustain economic growth for the foreseeable future, but developing those resources – and bringing them to market – is ever more technically challenging.

The new IEA book Resources to Reserves 2013 investigates whether oil and gas resources can be produced at a reasonable cost and in a timely manner, surveying the cutting-edge technologies needed to find, produce and bring them to the market while protecting environmentally sensitive areas. It also analyses the challenges of greenhouse gas emissions associated with fossil fuel production. And it considers technological advances for coal, especially as a potential source of liquid and gaseous fuels, as well as the demands on coal production, where the most attractive reserves may already have been exploited.

Fossil fuels currently meet 80% of global energy demand. Even if countries made good on all current policy commitments to tackle climate change and other energy-related challenges, global energy demand in 2035 is projected to rise by 40% – with fossil fuels still contributing 75%. Building on the findings in the 2005 edition of Resources to Reserves, the new book updates the known hydrocarbon reserves and resources to demonstrate the world’s potential supply, boosted since 2005 by a seven-fold increase in shale gas production in the United States and an even more startling rise in light tight oil – both largely due to advances in technology:

  • Worldwide proven reserves of conventional oil are estimated to be around 1.3 trillion barrels, with remaining recoverable resources representing about 2.7 trillion barrels. Globally, proven reserves have increased modestly since 1990, despite growth in consumption. The global reserves-to-production ratio, based on current consumption levels, is in the range of 40 to 45 years but will grow as resources are successfully converted into reserves.
  • Aided by the boom in shale gas and light tight oil in North America, global proven reserves of unconventional oil are around 400 billion barrels, with estimated recoverable resources of 3.2 trillion barrels.
  • Proven reserves of conventional gas are estimated at around 200 trillion cubic metres (tcm) – or approximately 1.3 trillion barrels of oil equivalent (boe) – with remaining recoverable resources of 440 tcm. Based on current consumption levels, the global reserves-to-production ratio of conventional gas is in the range of 55 to 60 years.
  • Proven reserves of unconventional gas, because of rock formations’ heterogeneity, are very difficult to assess. Remaining recoverable resources (excluding methane hydrates) are estimated at 240 tcm.
  • Reserves of coal are high, with proven reserves of hard coal estimated at 730 gigatonnes (Gt), or approximately 3.6 trillion boe, for a global reserves-to-production ratio in the range 110 to 120 years at current consumption levels. Proven reserves of lignite are estimated at 280 Gt, or approximately 700 billion boe. Remaining recoverable resources of hard coal and lignite are estimated at around 18,000 and 4,000 Gt, respectively.

With adequate resources of fossil fuels to meet the increasing energy demand, Resources to Reserves 2013 shows that the emphasis now is on the technology, prices and policies that can ensure resources are developed into proven reserves in financially viable and environmentally sustainable ways.

To read the Executive Summary of Resources to Reserves 2013, please click here.

To download a webinar presentation about Resources to Reserves 2013, please click here .

To view the Table of Contents (detailed in the webinar presentation), please click here.

Resources to Reserves 2013 is on sale at the IEA bookshop. Accredited journalists who would like more information or who wish to receive a complimentary copy should contact