Good afternoon， ladies and gentlemen. It’s a privilege and an honor to participate in the second season of conversations hosted by the prestigious Harvard University Center for the Environment， and to share my thoughts on the subject of the“Future of Energy.”Let me begin this afternoon by thanking Harvard University for its kind invitation， and the Center staff for their warm hospitality during my visit to Cambridge.
This afternoon， I want to share with you my views on our energy future， to examine some of the most critical factors and trends we need to consider whenaddressing energy issues.
The decisions about energy taken here in the US， back in Saudi Arabia， and indeed across the globe are important， because energy touches every aspect of modern civilization and pervades our daily lives. Access to an economic and reliable supply of energy is essential to achieving greater prosperity and eradicating poverty， to raising living standards in our communities， and to fueling economic and social development at home and abroad. At the same time， we have a responsibility to both our current and future generations when it comes to the protection and preservation of precious natural ecosystems， meaning that decisions about energy， economic expansion and the environment must go hand-in-hand. That is both our challenge， and our opportunity.
Let me begin with a brief look at today‘s energy picture， and the factors that those of us in the energy industry grapple with every day， that influence our mental models about energy’s future， and provide the basis for our strategies.
The world currently consumes around 210 million barrels per day of oil equivalent， with most of that supplied by a fairly limited number of sources； a reality that applies equally to the United States. Oil meets nearly 40 percent of the world‘s total energy needs， coal and natural gas each account for just under a quarter of total demand， hydropower and other alternatives for 8 percent， and nuclear energy for 6 percent of total energy supplies. In fact， for all of the attention garnered by renewables and alternative energy sources， fossil fuels like coal， oil and gas still account for a whopping 85 percent of total global energy supplies. In addition， because the number of currently viable energy sources out there is so limited， we have to recognize that the options that are realistically available to policymakers， producers and consumers are also relatively limited. Of course， the flexibility the world may have in termsof choices is also a function of the time horizon under consideration， and in future these may indeed be more options on the table.
We must also remember that each sector of energy use has its own source dynamics.
Turning to the future， we find a variety of scenarios about where energy use is heading. These scenarios are shaped by multiple drivers， ranging from global economic conditions and their impact on energy demand， growth in energy supplies， policy considerations， the state of alternatives and their associated technologies， the comparative economics of different energy sources， and assumptions about environmental policies. The supply and demand projections which these scenarios produce vary widely-a fact which makes my job considerably more difficult when it comes to business planning and investment decisions！ However， the one thing all these estimates agree upon is that the next quarter-century will witness tremendous growth in demand for energy. The Energy Information Administration of the Department of Energy， for example， predicts that over the next 25 years， global energy use will increase an average of 2 percent annually-meaning that total energy consumption in 2030 will be roughly 70 percent greater than today’s level.
In other words， over the next several decades my industry colleagues and I must substantially increase the amount of energy available to consumers around the world.
Can we do it？ Yes， without a doubt， as there is more than enough oil remaining to meet the world‘s needs for many decades to come. Why am I so confident？ Because our industry has devoted tremendous efforts and resources to understand the earth’s petroleum resource base， and based on there efforts， we know that the world‘s remaining petroleum resources are vast. Currently proven conventional oil reserves are approximately 1.2 trillion barrels， while recoverable non-conventional reserves-heavy oils and tar sands-are at least1.5trillion barrels. Upstream experts believe that with on-going advances in technology， we will find an additional 2 trillion barrels from yet-to-be- discovered fields and through increased recovery rates in existing fields. Added together， we are looking at more than 4.5 trillion barrels of potentially recoverable oil， and that translates into more than 140 years of supply at today’s current rate of consumption. To put it another way， to date the world has only consumed about 18 percent of its conventional and non-conventional producible potential.