Pages

March 29, 2012

No quick fixes on energy generation and temperature

1. WSJ - Vinod Khosla is a major investor in renewable and alternative energy and Daniel Yergin is an expert on fossil fuels. They were asked - How many years do you think it will be before half of our global energy production comes from non-fossil fuels?

MR. YERGIN: World energy probably is going to grow by 25% or as much as 35% over the next 20 years. I think the shift in the composition won't be too significant until after 2030, so maybe by 2050.

MR. KHOSLA: I guess 25 years. I'm definitely more optimistic.

MS. STRASSEL: Can you scale up to the levels necessary to make a big dent in fossil-fuel use?

MR. KHOSLA: You can absolutely scale up technologies off feedstocks—things like wood chips. The simplest way to think about is if there are a thousand paper mills in the country that have gone out of business, you can replace each of those and their feed basins for the wood chips with a fuel facility that would produce competitive fuels.




MS. STRASSEL: Vinod, in the past, you've talked about black-swan technologies—the idea of some innovative idea coming out and turning everything on its head.

MR. KHOSLA: Shale gas was a black swan. And my point is black-swan technologies will show up again. Shale gas was some combination of fracking, which we already knew how to do, and horizontal drilling that changed the assumptions around natural gas from "we need to import $100 billion worth" to "we can export it." The same thing will happen if an oil equivalent can be produced in country at $60 to $70 a barrel.

As soon as liquid-fuel technologies from things like wood chips, which are scalable, start to reach that level, our assumptions will change.



2. Environmental Research Letters - Greenhouse gases, climate change and the transition from coal to low-carbon electricity by N P Myhrvold and K Caldeira (9 pages)

A transition from the global system of coal-based electricity generation to low-greenhouse-gas-emission energy technologies is required to mitigate climate change in the long term. The use of current infrastructure to build this new low-emission system necessitates additional emissions of greenhouse gases, and the coal-based infrastructure will continue to emit substantial amounts of greenhouse gases as it is phased out. Furthermore, ocean thermal inertia delays the climate benefits of emissions reductions. By constructing a quantitative model of energy system transitions that includes life-cycle emissions and the central physics of greenhouse warming, we estimate the global warming expected to occur as a result of build-outs of new energy technologies ranging from 100 GWe to 10 TWe in size and 1–100 yr in duration. We show that rapid deployment of low-emission energy systems can do little to diminish the climate impacts in the first half of this century. Conservation, wind, solar, nuclear power, and possibly carbon capture and storage appear to be able to achieve substantial climate benefits in the second half of this century; however, natural gas cannot.
The time evolution of atmospheric CO2(eq) concentrations resulting from the construction and operation of a 1 GWe electric power plant varies widely depending on the type of plant. (A), (B) Atmospheric CO2(eq) concentrations from single power plants of different types based on high (A) and low (B) estimates of life-cycle power plant emissions. Renewable technologies have higher emissions in the construction phase (thin lines prior to year zero); conventional fossil technologies have higher emissions while operating (thick lines); emitted gases persist in the atmosphere even after cessation of operation (thin lines after year zero). The operating life of plants varies by plant type. (C), (D) Atmospheric CO2(eq) concentrations from the construction of series of power plants built to maintain 1 GWe output. For high estimates of life-cycle emissions, periodic replacement of aging plants produces pulses of emissions resulting in substantial, step-like change in atmospheric concentrations. However, in all cases except hydroelectric, continued electricity production results in increasing trends of atmospheric CO2(eq) concentrations.

Many decades may pass before a transition from coal-based electricity to alternative generation technologies yields substantial temperature benefits. Panels above show the temperature increases predicted to occur during a 40 yr transition of 1 TWe of generating capacity. Warming resulting from continued coal use with no alternative technology sets an upper bound (solid black lines), and the temperature increase predicted to occur even if coal were replaced by idealized conservation with zero CO2 emissions (dashed lines) represents a lower bound. The colored bands represent the range of warming outcomes spanned by high and low life-cycle estimates for the energy technologies illustrated: (A) natural gas, (B) coal with carbon capture and storage, (C) hydroelectric, (D) solar thermal, (E) nuclear, (F) solar photovoltaic and (G) wind.



Transitions of 1 TWe of coal-based electricity generation to lower-emitting energy technologies produces modest reductions in the amount of global warming from GHG emissions; if the transition takes 40 yr to complete, only the lowest-emission technologies can offset more than half of the coal-induced warming in less than a century. (A) Increases in global mean surface temperature attributable to the 1 TWe energy system 100 yr after the start of a 40 yr transition to the alternative technology. Even if the coal-based system were phased out without being replaced by new power plants of any kind, GHGs released by the existing coal-fired plants during the phaseout would continue to add to global warming (rightmost column). Split columns reflect temperature changes calculated using both high and low emissions estimates from a range of life-cycle analyses, as described in the text and SOM text SN2 (available at stacks.iop.org/ERL/7/014019/mmedia). (B) Time required from the start of power generation by an alternative technology to achieve break-even, warming equal to what would have occurred without the transition from coal (lightest shading); a 25% reduction in warming (medium shading); and a reduction by half (darkest shading) as a result of the transition. The bars span the range between results derived using the lowest and highest LCA estimates of emissions.
It appears that there is no quick fix; energy system transitions are intrinsically slow. During a transition, energy is used both to create new infrastructure and to satisfy other energy demands, resulting in additional emissions. These emissions have a long legacy due to the long lifetime of CO2 in the atmosphere and the thermal inertia of the oceans. Despite the lengthy time lags involved, delaying rollouts of low-carbon-emission energy technologies risks even greater environmental harm in the second half of this century and beyond. This underscores the urgency in developing realistic plans for the rapid deployment of the lowest-GHG-emission electricity generation technologies. Achieving substantial reductions in temperatures relative to
the coal-based system will take the better part of a century, and will depend on rapid and massive deployment of some mix of conservation, wind, solar, and nuclear, and possibly carbon capture and storage.

Previous UN study suggests that biggest nearterm climate benefit is from action against soot and methane


Acting against CO2 only helps slow the increase for about 30-50 years and has small temperature effect up to 100 years.

If you liked this article, please give it a quick review on ycombinator or StumbleUpon. Thanks
blog comments powered by Disqus