Before we begin with the renewables, we should ask ourselves a question: Seeing as we have to rebuild our energy infrastructure almost whole, what should our criteria for new energy sources be?
I think a fair list of criteria would have to include the following:
1) The proposed energy source should be abundant. It doesn't do us any good if we invest trillions in new infrastructure costs, only to have a limited supply run out on us. “Abundant” should mean that a new source of energy can both meet current demand, and allow for substantial growth among developing nations, without expiring.
2) It should be as clean as possible. As a baseline, as clean or cleaner than oil should be our minimum standard. Our current energy mix is already killing thousands of people a year in pollution. It doesn't make any sense to go backwards.
3) It should be as safe as possible. Safe and Clean do not always mean the same thing. Modern coal plants (and the more advanced coal mines) are extremely safe in the immediate sense, but contribute massively to pollution. Nuclear is clean, but poses a non-trivial security problem.
4) It should be affordable. We could mine oil shale from the asteroids if we wanted – it wouldn't exactly make sense to.
A final criteria that isn't a deal-breaker, but is desirable is this:
5) If possible, a new source of energy should be well-distributed around the world. We've seen what geographic concentrations of energy resources has done to the world – the US is essentially playing gas station manager to the world by protecting some rather unsavory oil regimes, Saudi Arabia being first among them. It should be said that the world benefits from the US playing this role, so we shouldn't wag our fingers too much. If possible, it would be best if new energy sources were available to all countries, not concentrated in the hands of a select few.
If you have problems with these criteria, I'd like to hear criticisms. I don't want to be accused of stacking the deck, after all.
But looking at these criteria, we can see that all fossil fuels are essentially out of consideration. With oil and natural gas already running low, we can make up some of our demand with coal – but coal simply cannot meet the needs of a growing global economy.
Now, nuclear is another story. Properly used, nuclear could conceivably provide all of our energy for us for millenia. So check on abundance. Similarly, it's one of the cleanest sources of electricity we have using current technology. So check on clean, too. But safety, affordability, and distribution are serious problems. Nuclear waste and proliferation are essentially insoluble problems, no matter how good your plants are. As for affordability, a proper nuclear plant is always going to be a major expense – they are large, complicated buildings that require constant attention, if not supervision. Finally, distribution of Uranium around the world is almost as uneven as distribution of oil and coal. Does it make sense to give up one simple form of imported energy for a more expensive, complicated form of imported energy? Not really.
Meanwhile, when we look at the renewable options on the table, things suddenly look brighter. Solar and Wind energy are abundant – the US could run it's entire economy off of either of these options, much less both. Sunlight in particular is a simply staggering supply of energy – something like 6,000 times our daily energy consumption reaches the Earth's surface every day. So there's plenty of room for growth. More importantly, some of the sunniest places on Earth are also still very poor. Solar energy gives Africa and South America a chance for real development.
Wind power is currently the cheapest of renewable energies, and continues to expand by leaps and bounds. Spain installed more than 2 gigawatts of wind capacity last year alone- a 30% increase in one year! Germany still leads the way in overall capacity, with Denmark leading in % of total consumption. There's plenty of wind, too – something like 5 times current world energy demand. Just about enough to meet the needs of 9 billion well-off consumers by 2050.
Now it's not all rosy. The biggest problem with wind and solar is their intermittency – that is, what happens when the sun doesn't shine and the wind doesn't blow. Given the generally poor shape of the electric grid in North America, it could cause serious problems to have a high percentage of our electrical production constantly turning off and on all the time.
There's some additional concerns about wind, namely a) that it kills birds, and b) that it's well, ugly. The bird concern, while real, is vastly overstated, especially compared to other aspects of modern life that are avian-hostile. At the absolute worst, wind power would kill a small fraction of the fowl that our pet cats do, or our glass buildings.
The ugliness problem is somehow the bigger problem in getting major new wind farms approved in the US. The most famous case is that of Cape Wind, the effort to build a wind farm off of Cape Cod. I was saddened to see RFK Jr. leading the opposition to this recently, proclaiming that “some views are too good to ruin”. Frankly, I find wind turbines very appealing, so this whole issue is a bit confusing to me. Certainly, the implications of a wind turbine are less nasty than a coal plant.
But the problem of volume still applies – we need lots of energy, fast, if we're going to avert a major calamity. Can we build wind and solar power quickly enough to meet demand? Despite my general optimism, I don't think so. The amounts needed are simply too large. Renewables are growing incredibly fast – solar grew more than 60% in 2004! - but they still make such a small overall percentage. And solar and wind still don't directly address the problem of liquid fuels, which is after all the critical problem of peak oil.
The only way we're going to escape this problem is by thinking different about how we use energy.