Answering that question requires wading through a host of big uncertainties, and it really calls for a scenario approach, rather than straight-line reasoning. That's more than I can take on in one day's posting, but I feel safe suggesting that we will need a much more aggressive energy plan than the one implicit in the current forecasts from the Energy Information Agency of the Department of Energy. Their 2005-25 reference case would have us using 1/3 more oil by 2025, while importing 60% more of it. At the same time, they don't see the energy contribution of renewables growing by enough even to cover what will be lost in the decline of domestic oil production, or to prevent renewable energy falling as a share of total consumption by 2025. This is not a slam on the DOE, because that's probably a reasonable status quo forecast. However, it doesn't constitute an acceptable national plan for energy. I'd also argue that it's out of synch with worldwide trends driven by climate change and two globalizing "billionaires."
If the DOE's view represents a floor for alternative energy, where is the ceiling? While there might not be any laws of physics preventing wind and solar power from ultimately providing most of our energy, several issues will limit their contribution over the next 20 years. The cost of energy storage is a big factor in this calculation, and we must assess how long it would take a breakthrough in this area to go from laboratory to low-cost, mass production. I'm not an expert on technology development cycles, but 10-15 years doesn't sound too long. If that's the case, then even with a continuation of the steady cost reduction trends for both wind and solar, their intermittent nature will impede their penetratation of the power market. Nor does that address our need for non-oil transportation fuels, which by 2025 might include a modest component of hydrogen. Despite this "pessimism", I expect both wind and solar to grow dramatically in the next decade, with results that should be noticeable at the scale of our national energy statistics.
The divergence betweeen the status quo future and what's realistically possible highlights an important distinction between the Energy Policy Act of 2005 and a true national energy plan. Plans include goals, as well as the means for achieving them. What we need are explicit, quantified national goals, and these would have to include things like the following:
- To reduce our use of oil as a fraction of the total energy we consume, e.g. from 40% down to 35% by 2025.
- To increase the contribution of non-hydroelectric renewable energy from less than 1% today to 5% by 2015 and 15% by 2025.
- To shift our energy imports from being 85% oil-based to 50% gas-based, including LNG and synthetic liquid fuels produced from gas.