It will take at least three decades to completely leave behind fossil fuels. But we can do it. The first step is to start with the easy stuff.
If our transition to renewable energy is successful, we will achieve savings in the ongoing energy expenditures needed for economic production. We will be rewarded with a quality of life that is acceptable — and, perhaps, preferable to our current one (even though, for most Americans, material consumption will be scaled back from its current unsustainable level). We will have a much more stable climate than would otherwise be the case. And we will see greatly reduced health and environmental impacts from energy production activities.
But the transition will entail costs — not just money and regulation, but also changes in our behavior and expectations. It will probably take at least three or four decades, and will fundamentally change the way we live.
Therefore, it makes sense to start with the low-hanging fruit and with a plan in place, then revise our plan frequently as we gain practical experience. Several organizations have already formulated plans for transitioning to 100% renewable energy. David Fridley, staff scientist of the energy analysis program at the Lawrence Berkeley National Laboratory, and I have been working for the past few months to analyze and assess those plans and have a book in the works titled Our Renewable Future.
Here's a very short summary, tailored mostly to the United States, of what we've found.
If we got a good start in all these areas, we could achieve at least a 40% reduction in carbon emissions in 10 to 20 years.
Solar and wind technologies have a drawback: They provide energy intermittently. When they become dominant in our overall energy mix, we will have to accommodate that intermittency in various ways. We'll need substantial amounts of grid-level energy storage as well as a major grid overhaul to get the electricity sector close to 100% renewables (replacing natural gas in electricity generation). We'll also need to start timing our energy usage to coincide with the availability of sunlight and wind energy. That in itself will present both technological and behavioral hurdles.
If we did all these things, while also building far, far more solar panels and wind turbines, we could achieve roughly an 80% reduction in emissions compared to our current level.
Doing away with the last 20% of our current fossil-fuel consumption is going to take still more time, research, and investment — as well as much more behavioral adaptation.
Just one example: We currently use enormous amounts of concrete for all kinds of construction. The crucial ingredient in concrete is cement. Cement-making requires high heat, which could theoretically be supplied by sunlight, electricity, or hydrogen — but that will entail a nearly complete redesign of the process.
The communications sector — which uses mining and high-heat processes for the production of phones, computers, servers, wires, photo-optic cables, cell towers, and more — presents some really knotty problems. The only good long-term solution in this sector is to make devices that are built to last a very long time and then to repair them and fully recycle and remanufacture them when absolutely needed. The Internet could be maintained via the kinds of low-tech, asynchronous networks now being pioneered in poor nations, using relatively little power. An example might be the AirJaldi networks in India, which provide Internet access to about 20,000 remote users in six states, using mostly solar power.
This plan features "levels"; the more obvious word choice would have been "stages." The latter implies a sequence — starting with stage one, ending with stage three—yet accomplishing the energy transition quickly will require accelerating research and development to address many level two and three issues at the same time we're moving rapidly forward on level one tasks. For planning purposes, it's useful to know what can be done relatively quickly and cheaply, and what will take long, expensive, sustained effort.