A new analysis by the Deep Decarbonization Pathways Project finds that our non-fossil energy future is economically feasible, but has widely varying costs, depending in part on the chosen technology mix.
Human civilization depends on food, food depends on weather, and weather depends on climate. Every grain and every mammal on the face of the earth – almost everything we eat – evolved under a different climate than the one we're heading toward. We are running toward a cliff, and merely walking toward that cliff isn't a viable strategy. We need to stop. Right now.
If civilization is to survive, we need to get to zero emission of fossil carbon, and we need to get there rapidly. Every ton of carbon we emit stays in the air for centuries, and will continue to warm the planet for centuries.
In this series GETTING TO ZERO we will take a very hard-headed look at current energy policy and energy strategies. We will ask hard questions: does this really get us to zero? How much would it cost? How rapidly can it be deployed? We may find some answers along the way, but don't expect them to be easy.
This diary is Part V of GETTING TO ZERO: Our non-fossil energy future.
Part I of GETTING TO ZERO: The size of the problem.
Part II of GETTING TO ZERO: Is renewable energy economically viable?
Part III of GETTING TO ZERO: Why energy efficiency will not save us.
Part IV of GETTING TO ZERO: The hidden CO2 emissions from renewables.
The Deep Decarbonization Pathways Project (DDPP) has some big names on its masthead. It was conceived by the Sustainable Development Solutions Network, a UN organization, along with the Institute for Sustainable Development and International Relations (IDDRI). The idea was to create national working groups, each of which was tasked to determine how individual nations might deeply decarbonize their respective economies -- the goal being 80% non-fossil by the year 2050. The working group for the US was led by energy consulting firm Energy & Environmental Economics (E3), the Lawrence Berkeley National Laboratory, and the Pacific Northwest National Laboratory, and they voluntarily submitted their work to outside peer-review. In other words, these guys are no slouches.
The main findings of their US report:
- The 80% reduction goal (greenhouse emissions below 1990 levels) is technically feasible.
- The overall cost could be roughly 1% of GDP, but the uncertainty range is quite wide, and depends on numerous assumptions including the price of fossil fuel and the technology mix chosen. In best-case scenarios, the cost could be zero or negative.
- The basic strategy for decarbonizing the economy involves decarbonizing the electric grid first, then switching to fossil-free electricity for numerous other applications that currently burn fossil fuel, such as cars and space heat. This will mean an increase in overall demand for electricity, even with efficiency improvements.
- If we act quickly, we can keep costs low by relying on natural turnover in the energy infrastructure, combined with a rational plan for low-carbon replacements. This requires keeping a close eye on energy investment decisions and infrastructure lifetimes.
The report considered four possible pathways to a decarbonized future: a mixed-technology case, a high-renewables case, a high-nuclear case, and a high-CCS (carbon capture and storage) case. All four pathways will get us to 80% reduction in greenhouse emissions by 2050, but they way they get there, and the costs and investments required, vary widely.
Here are the breakdowns of primary energy use among the four pathways:
Note that all four pathways are "mixed" to a certain degree.
All four pathways foresee major increases in renewable energy from current levels. Both the high-renewables and high-CCS anticipate about 3 EJ (exajoules) from nuclear power, about what we produce now. The high-CCS pathway requires less electrical generation, because CCS technology could then also be used in industrial processes, instead of switching to electricity for process heat.
Costs, however, vary widely:
Current GDP in the US is about $17 trillion, so $170 billion represents 1% of GDP. Three of the four pathways reach this level or lower at least 25% of the time, depending on assumptions. The exception is the high-renewable scenario. So of course we want to know, why are renewables so expensive? Especially when you consider that the other three scenarios are utilizing vastly expanded renewables too -- so what's the difference?
The difference arises because, in the cogent observation of Ben Heard, electricity is not just a product, it's a service. And part of that service is always-on, 24/7 reliability. Renewables are cheap right now because they are built on the top of a highly reliable and dispatchable grid that is able to step in when the Sun goes down or the wind dies, and most of that highly reliable grid burns fossil fuel. If we're not going to burn fossil fuel any more, we need something else to guarantee that reliability -- something else to back up wind and solar when the weather doesn't cooperate.
The high-renewable pathway assumes that the backup for renewables is more renewables in other locations, far enough away to have different weather than the local weather. As the saying goes, the wind is always blowing somewhere. And sure, that's feasible, as the DDPP study shows, but it's also very expensive: in the median case it's four times more expensive that the high-nuclear pathway.
That's because the only way that works is if each state or region not only builds enough capacity for its own use, but also builds enough capacity for other regions too, in case the wind dies somewhere else. But since every region has to overbuild wind (and solar) to allow for the possibility that it might be needed, that means that renewable capacity is vastly overbuilt in the nation as a whole. Therefore much of that renewable capacity will be sitting idle even when the sun is shining and the wind is blowing. This is called "curtailment", and curtailment is a big, expensive problem with high renewable penetration on the grid. That's what drives the high-renewable pathway to such high expense: we would be building a whole lot of renewable capacity that we would only need a small fraction of the time.
The high-nuclear and high-CCS pathways both add a lot of renewables, but not quite enough to reach the point of renewable curtailment, which keeps renewable costs low. The Mixed path adds more renewables, resulting in renewable curtailment some of the time, but less so than in the high-renewables pathway. The high-renewables pathway has a lot of curtailment, and therefore the highest cost. (In order to determine exactly how much curtailment occurs in each scenario, the study used hour-by-hour weather data for the nation and applied it to each model.)
The bottom line is that in the high-renewable pathway, we would need to build 2550 GW of new capacity; in high-CCS, we would need 700 GW of new capacity; but in the high-nuclear, we would need only 400 GW of new capacity, in each case to fully decarbonize the grid and reach 80% total greenhouse reductions by 2050.
The results in the DDPP report are in line with previous research, and should not be surprising to anyone who studies energy issues. For example, a widely-cited study by Budischak et al. in 2011 found that an all-renewable grid was feasible, but it would nearly triple the price of electricity if implemented, because of overbuilt capacity. Also, a recent study by the (generally left-ish) Brookings Institution found that the cost-benefit value of nuclear power as a carbon-reducer vastly outstrips that of solar or wind, even after accounting for the costs of decommissioning, waste storage, and insurance, and even after making the most favorable assumptions for renewables:
Notice that in the Brookings study, as in DDPP, the cost advantage of nuclear vs. renewables is more than three-to-one. That means that for every dollar we spend on renewables, we could be mitigating about
three or four times more carbon by spending that dollar on nuclear instead.
Finally, a shout-out for those around here who remember the deeply rational writings of NNadir: his latest thought-provoking essay on the global energy system, energy ethics, and global poverty can be found on Brave New Climate.