No time to waste on transition to green energy

Even if we convert totally tomorrow, it would be decades before the transition from coal-based power brings temperature benefits. We have delayed too long already and it is time to get started.

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by Kate Ravilious
Environmental Research Web, Feb 16, 2012

If the entire world adopted ‘green’ forms of energy tomorrow, how long would it take for global temperatures to stabilize? The answer is a good 50 years: even if we “pull out all of the stops” there is little we can do to diminish the impact of climate change during the first half of this century. But choosing to adopt the right technologies now should stabilize the climate by the second half of the century, according to a new study.

Nathan Myhrvold, founder of Intellectual Ventures, US, and Ken Caldeira of the Carnegie Institution for Science, US, estimated the life-cycle emissions and global warming expected to occur when adopting seven low-emission energy options: natural gas, carbon capture and storage (CCS), hydroelectric, solar thermal, nuclear, solar photovoltaic and wind.

They show that many decades pass before the transition from coal-based power to the alternative technology yields notable temperature benefits (Environmental Research Letters). There are two main reasons it takes so long.

  • First, the ocean has to release its heat. “Because of the thermal inertia of the ocean, it takes around four decades to feel the full benefit of an emission reduction,” explained Caldeira. Changing over to renewable energy systems will also take many years. During those years (while nuclear power stations are built, and wind and solar farms are erected) coal power stations will continue to emit vast amounts of greenhouse gas.
  • Second, making solar panels, constructing wind farms and building nuclear power plants all use energy and produce emissions. So, a rapid transition to low greenhouse-gas-emission technology would actually increase emissions in the short term.

Myhrvold and Caldeira calculate that solar thermal, nuclear, solar photovoltaic and wind will take around 40 years to pay back their so-called “emissions debt” and yield significant temperature benefits (assuming they replace 1 TWe of coal-based electricity, which is the current global electrical output from coal).

Meanwhile, hydropower would produce such large emissions that it could add to global warming more than coal power alone for a good 60 years or so. “Hydropower is often associated with high methane emissions [due to] the decay of organic matter in the flooded land surface,” explained Caldeira. “There may be some niche locations where additional hydropower could be environmentally desirable, but more often environmental considerations weigh in favour of removing dams, not building them.”

And natural gas will just delay the problem. “Our calculations show that with natural gas it will take a little longer to get to the same amount of cumulative emissions and warming, so it would delay a bad outcome, but not avoid it,” Caldeira told Environmental Research Web.

Carbon capture and storage (CCS) is still somewhat of an unknown – the low estimates for life-cycle emissions make CCS appear promising, but the high estimates make the technology similar to natural gas.

It is clear that the transition to ‘green’ energy is going to be difficult and, for most of us, the benefits will not be felt in our lifetime. And it won’t just be a case of switching from fossil to green fuels. “Improved conservation and efficiency is necessary and will play a role on the same scale as new technologies. It is not either/or, it is and, and, and,” said Caldeira. “This is a massive undertaking and there is no time to waste. We have delayed too long already and it is time to get started.”

 

Posted in Energy, Science

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Erik Wallenberg
4 years 7 months ago

This article draws some very unfortunate conclusions. We do NOT need to be promoting nuclear energy as an alternative to coal, especially considering the continuing radiation leaks at the Fukushima nuclear plants. This is a big problem right now. We need to connect the anti-nuclear movement with the climate justice movement. That is made difficult precisely because of articles like this (or maybe put a better way, this article is a clear example of the blind spots in the climate justice movement), which fail to look beyond the narrow focus of carbon in the atmosphere at the expense of every other environmental issue.

Read the article below from Nature. Though it ends by saying new technology in nuclear may be the solution in some distant future, the quote below tells the lie of nuclear as carbon neutral.

http://www.nature.com/climate/2008/0810/full/climate.2008.99.html

“However, nuclear emits twice as much carbon as solar photovoltaic, at 32 gCO2e/kWh, and six times as much as onshore wind farms, at 10 gCO2e/kWh….things like energy efficiency, and some of the cheaper renewables are a factor of six better. So for every dollar you spend on nuclear, you could have saved five or six times as much carbon with efficiency, or wind farms,”

4 years 7 months ago

One might wonder, then, why even struggle about lowering GHG emissions if there is not hope in turning things around.

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