Author: Tom

A Titanic feedback reversal

Ever get in a hotel shower and turn the faucet the wrong way, getting scalded or frozen as a result? It doesn’t help when the faucet is unmarked or backwards. If a new account is correct, that’s what happened to the Titanic.

(Reuters) – The Titanic hit an iceberg in 1912 because of a basic steering error, and only sank as fast as it did because an official persuaded the captain to continue sailing, an author said in an interview published on Wednesday.

…

“They could easily have avoided the iceberg if it wasn’t for the blunder,” Patten told the Daily Telegraph.

“Instead of steering Titanic safely round to the left of the iceberg, once it had been spotted dead ahead, the steersman, Robert Hitchins, had panicked and turned it the wrong way.”

Patten, who made the revelations to coincide with the publication of her new novel “Good as Gold” into which her account of events are woven, said that the conversion from sail ships to steam meant there were two different steering systems.

Crucially, one system meant turning the wheel one way and the other in completely the opposite direction.

Once the mistake had been made, Patten added, “they only had four minutes to change course and by the time (first officer William) Murdoch spotted Hitchins’ mistake and then tried to rectify it, it was too late.”

It sounds like the steering layout violates most of Norman’s design principles (summarized here):

  1. Use both knowledge in the world and knowledge in the head.
  2. Simplify the structure of tasks.
  3. Make things visible: bridge the Gulfs of Execution and Evaluation.
  4. Get the mappings right.
  5. Exploit the power of constraints, both natural and artificial.
  6. Design for error.
  7. When all else fails, standardize.

Notice that these are really all about providing appropriate feedback, mental models, and robustness.

(This is a repost from Sep. 22, 2010, for the 100 year anniversary).

What a real breakthrough might look like

It’s possible that a techno fix will stave off global limits indefinitely, in a Star Trek future scenario. I think it’s a bad idea to rely on it, because there’s no backup plan.

But it’s equally naive to think that we can return to some kind of low-tech golden age. There are too many people to feed and house, and those bygone eras look pretty ugly when you peer under the mask.

But this is a false dichotomy.

Some techno/growth enthusiasts talk about sustainability as if it consisted entirely of atavistic agrarian aspirations. But what a lot of sustainability advocates are after, myself included, is a high-tech future that operates within certain material limits (planetary boundaries, if you will) before those limits enforce themselves in nastier ways. That’s not really too hard to imagine; we already have a high tech economy that operates within limits like the laws of motion and gravity. Gravity takes care of itself, because it’s instantaneous. Stock pollutants and resources don’t, because consequences are remote in time and space from actions; hence the need for coordination. Continue reading “What a real breakthrough might look like”

The neo-cornucopians, live from planet Deepwater Horizon

On the heels of the 40th anniversary of Limits to Growth, the Breakthrough crowd is still pushing a technical miracle, just around the corner. Their latest editorial paints sustainability advocates as the bad guys:

Stop and think for a moment about the basic elements of the planetary boundaries hypothesis: apocalyptic fears of the future, a professed desire to return to an earlier state of nature, hypocrisy about wealth, appeals to higher authorities. These are the qualities of our worst religions, not our best scientific theories.

Who are these straw dog greenies, getting rich and ruling the world? Anyway, I thought the planetary boundaries were about biogeophysical systems, appealing to “higher authority” in that the laws of physics apply to civilizations too. Ted Nordhaus doesn’t believe it though:

To be sure, there are tipping points in nature, including in the climate system, but there is no way for scientists to identify fixed boundaries beyond which point human civilization becomes unsustainable for the simple reason that there are no fixed boundaries.

The Breakthrough prescription for the ills of growth is more growth: Continue reading “The neo-cornucopians, live from planet Deepwater Horizon”

Vensim + data with ODBC

I haven’t had much time to write lately – too busy writing Vensim code, working on En-ROADS, and modeling the STEM workforce.

So, in the meantime, here’s a nice tutorial on the use of ODBC database links with Vensim DSS, from Mohammad Jalali:

This can be a powerful way to ingest a lot of data from diverse sources, and to share and archive simulations.

Big data is always a double-edged sword in consulting projects. Without it, you don’t know much. But with it, your time is consumed with discovering all the flaws of the data, which remain because most likely no one else ever looked at it seriously from a strategic/dynamic perspective before. It’s typically transactionally correct, because people verify that they get their orders and paychecks. But at an aggregate level it’s often rife with categorization mismatches across organizational boundaries and other pathologies.

Shocking stats from the WSJ

The WSJ has an article on the Chinese electric power sector that’s anecdotally interesting. It notes that increasing electricity prices would spur investment, creating a win-win for energy intensity and system reliability. Maybe so, but the supporting graph is an interesting example of statistics that are uninformative because they fail to account for bathtub dynamics. Here it is:

It seems plausible to compare investment and consumption, until you look at the system structure:

This indicates four problems with drawing conclusions from the plot:

  • Investment is not necessarily the same thing as installation of capacity, unless you assume constant price.
  • Consumption is essentially a direct function of stocks of consuming equipment and generating capacity, while investment is a flow. While there’s reason to expect growth rates of stocks and flows to match along a steady state growth path, this only applies in the very long term; in the short run, noise and disequilibrium will destroy any correspondence.
  • The thing we do care about is the match between generating capacity and consuming equipment, but that depends on outflows (retirements of capacity) as well as inflows, so again the stock-flow comparison tells us nothing.
  • There’s an additional level of indirection because we don’t see investment and consumption directly; the graph shows year-on-year changes. But that means that we’re seeing the slopes of investment and consumption, which tell us nothing about their absolute levels. So, it’s possible that investment growth is falling because it was much too high, and that consumption is growing because there’s excess generating capacity.

The best you can say about this graph is that it doesn’t contradict the article; otherwise it’s almost completely uninformative about the true state of the Chinese power system. It would be far better to have a direct comparison of generating and consuming capacity, or perhaps the growth rate of consumption (which is the net flow of consuming equipment) vs. investment in absolute terms.

Gas – a bridge to nowhere?

NPR has a nice piece on the US natural gas boom.

Henry Jacoby, an economist at the Center for Energy and Environmental Policy Research at MIT, says cheap energy will help pump up the economy.

“Overall, this is a great boon to the United States,” he says. “It’s not a bad thing to have this new and available domestic resource.” He says cheap energy can boost the economy, and he notes that natural gas is half as polluting as coal when it’s burned for electricity.

“But we have to keep our eye on the ball long-term,” Jacoby says. He’s concerned about how cheap gas will affect much cleaner sources of energy. Wind and solar power are more expensive than natural gas, and though those prices have been coming down, they’re chasing a moving target that has fallen fast: natural gas.

“It makes the prospects for large-scale expansion of those technologies more chancy,” Jacoby says.

From an environmental perspective, natural gas could help transition our economy from fossil fuels to clean energy. It’s often portrayed as a bridge fuel to help us through the transition, because it’s so much cleaner than coal and it’s abundant. But Jacoby says that bridge could be in trouble if cheap gas kills the incentive to develop renewable industry.

“You’d better be thinking about a landing of the bridge at the other end. If there’s no landing at the other end, it’s just a bridge to nowhere,” he says.

(For those who don’t know, Jake Jacoby is not a warm-fuzzy greenie; he’s a hard line economist who leads a big general equilibrium modeling project, but also takes climate science seriously).

For me, the key takeaways are:

  • Gas beats coal, and may have other useful roles to play. For example, gas backup might be a low-capital-cost complement to variable renewables, with minor emissions consequences.
  • It’s better to have more resources than less.
  • Whether the opportunity of greater resources translates into a benefit depends on whether the price of gas accounts for full costs.

The last item is a problem. In the US, the price of greenhouse emissions from gas (or anything else) is approximately zero. The effective prices of other environmental consequences – air quality, pollution from fracking, etc. – are also low. Depletion rents for gas are probably also too low, because the abundance of gas is overhyped, and public resources were suboptimally over-allocated decades ago. Low depletion rents encourage a painful boom/bust of gas supply.

Not only physical assets are mispriced. Another part of the story is learning-by-doing, deliberate R&D, and economies of scale – positive feedbacks that grow the market for low-emissions technologies. Firms producing new tech like PV or wind turbines are only able to appropriate part of the profits of their innovations. The rest spills over to benefit society more generally. Too-cheap gas undercuts these reinforcing mechanisms, so gas substitutes aren’t available when scarcity inevitably returns, hence the “bridge to nowhere” dynamic.

Long-term renewable deployment in the U.S. is going to depend primarily on policy. Is there enough concern about environmental consequences to put in place incentives for renewable energy?

– Trevor Houser, energy analyst, Rhodium Group

They key is, what kind of policy? Currently, we rely primarily on performance standards and subsidies. These aren’t getting the job done, for structural reasons. For example, subsidies are self-extinguishing, because they get too expensive to sustain when the target gets too big (think solar feed-in-tariffs in Europe). They’re also politically vulnerable to apparently-cheap alternatives:

“If those prices hang around for another three or four years, then I think you’ll definitely see reduced political will for renewable energy deployment, ” Houser says

The basic problem is that the mindset of subsidizing or requiring “good” technologies makes them feel like luxuries for rich altruists, even though the apparently-cheap alternatives may be merely penny-wise and pound-foolish. The essential alternative is to price the bads, with the logic that people who want to use technologies that harm others ought to at least pay for the privilege. If we can’t manage to do that, I don’t think there’s much hope of getting gas or climate policy right.

The static reserve life index rears its ugly head in the State of the Union

The President said, in the State of the Union Address,

We have a supply of natural gas that can last America nearly one hundred years, and my Administration will take every possible action to safely develop this energy.

The 100 year figure presumably comes straight from EIA:

According to the EIA Annual Energy Outlook 2011, the United States possesses 2,543 trillion cubic feet (Tcf) of potential natural gas resources. Natural gas from shale resources, considered uneconomical just a few years ago, accounts for 862 Tcf of this resource estimate. At the 2010 rate of U.S. consumption (about 24.1 Tcf per year), 2,543 Tcf of natural gas is enough to supply over 100 years of use.

100 years is the static reserve life index (SRLI). It’s well known that the SRLI is a misleading metric (this figured prominently in Limits to Growth, for example). Exponential growth in consumption violates the basic assumption of the SRLI, which is that consumption remains constant. Even a small amount of growth greatly erodes the actual lifetime of a resource:

Growth at 3% per year reduces the SRLI of gas from 100 years to a realized lifetime of 45 years, which is not nearly so comfortable. This ought to be intuitive even if you can’t integrate exponentials in your head, because gas consumption would have to roughly double to replace coal (and that doubling would have to happen quickly to meet job claims), so clearly “100 years at current rates” isn’t going to happen.

Update: EIA just lowered shale gas resource estimates by nearly half, taking another big bite out of the SRLI:

In the AEO2012 Reference case, the estimated unproved technically recoverable resource (TRR) of shale gas for the United States is 482 trillion cubic feet, substantially below the estimate of 827 trillion cubic feet in AEO2011.

Disinfographics

I cringed when I saw the awful infographics in a recent GreenBiz report, highlighted in a Climate Progress post. A site that (rightly) criticizes the scientific illiteracy of the GOP field shouldn’t be gushing over chartjunk that would make USA Today blush. Climate Progress dumped my mildly critical comment into eternal moderation queue purgatory, so I have to rant about this a bit.

Here’s one of the graphics, with my overlay of the data plotted correctly (in green):

“What We Found: The energy consumed per dollar of gross domestic product grew slightly in 2010, the first increase after steady declines for more than half a century.”

Notice that:

  • No, there really wasn’t a great cosmic coincidence that caused energy intensity to progress at a uniform rate from 1950-1970 and 1980-2009, despite the impression given by the arrangements of points on the wire.
  • The baseline of the original was apparently some arbitrary nonzero value.
  • The original graphic vastly overstates the importance of the last two data points by using a nonuniform time axis.

The issues are not merely aesthetic; the bad graphics contribute to distorted interpretations of reality, as the caption above indicates. From another graphic (note the short horizon and nonzero baseline), CP extracts the headline, “US carbon intensity is flat lining.”

From any reasonably long sample of the data it should be clear that the 2009-2011 “flat lining” is just a blip, having little to do with the long term emission trends we need to modify to achieve deep emissions reductions.

The other graphics in the article are each equally horrific in their own special way.

My advice to analysts is simple. If you want to communicate information, find someone numerate who’s read Tufte to make your plots. If you must have a pretty picture for eye candy, use it as a light background to an accurate plot. If you want pretty pictures to persuade people without informing them, skip the data and use a picture of a puppy. Here, you can even use my puppy:

Why learn calculus?

A young friend asked, why bother learning calculus, other than to get into college?

The answer is that calculus holds the keys to the secrets of the universe. If you don’t at least have an intuition for calculus, you’ll have a harder time building things that work (be they machines or organizations), and you’ll be prey to all kinds of crank theories. Of course, there are lots of other ways to go wrong in life too. Be grumpy. Don’t brush your teeth. Hang out in casinos. Wear white shoes after Labor Day. So, all is not lost if you don’t learn calculus. However, the world is less mystifying if you do.

The amazing thing is, calculus works. A couple of years ago, I found my kids busily engaged in a challenge, using a sheet of tinfoil of some fixed size to make a boat that would float as many marbles as possible. They’d managed to get 20 or 30 afloat so far. I surreptitiously went off and wrote down the equation for the volume of a rectangular prism, subject to the constraint that its area not exceed the size of the foil, and used calculus to maximize. They were flabbergasted when I managed to float over a hundred marbles on my first try.

The secrets of the universe come in two flavors. Mathematically, those are integration and differentiation, which are inverses of one another.

Continue reading “Why learn calculus?”