Technology Diffusion Curves

Earlier this week, we wrote about embodied energy of buildings, and the concerns it poses when we think about legislating building efficiency measures. Today we take a broader view, examining economic limitations of any technology replacement effort, from rebuilding houses to replacing lightbulbs.

Suppose that high-efficiency washing machines are a necessary part of a low-carbon economy (as we believe they must be). Government tax write-offs are an effective way to encourage consumers to spend the extra money on these energy-saving machines. If the U.S. started an incentive program so effective that every consumer chose a high-efficiency machine over a conventional one, however, it would still take quite some time to replace all the energy-hogging washers in the country. Because they are such a large purchase, the vast majority of consumers replace their washing machine only when forced to do so by problems with the old machine’s operation. If you […]

Embodied Energy in Buildings

It’s been a while since you’ve heard anything from us at Energy Literacy, but rest assured, our minds are still on energy issues. Lately, we’ve been spending a lot of time thinking about methodologies for doing reasonably accurate whole-picture energy audits using limited data (Think Saul’s energy project, but for any scale). Working with something as complex as the total set of energy flows through the city of San Francisco, for example, we’re bound to rack up all kinds of uncertainty in our estimates. We’re convinced, however, that these calculations are still helpful, even if only to determine the relative orders of magnitude of sources of energy consumption. Just these ballpark estimates can have a remarkable effect on policy conversations, directing focus towards the lowest-hanging fruit and dispelling arguments that have little long-term relevancy.

In that vein, today we talk about the embodied energy of buildings, a topic which is […]

The Short List of Effective Actions

Part of The Short List of Effective ACtions

This list of action items for individual energy savings is the most focused and quantitative I’ve seen. It comes from an October 2008 article in Environment Magazine by Gerald Gardner, professor emeritus of psychology at the University of Michigan-Dearborn, and Paul Stern from the National Research Council.

The actions in the list are grouped by whether they’re for transportation or inside the home, immediate or longer-term, and no-cost/low-cost or higher-cost. Each item also includes an estimated percentage savings of total energy use. Here’s an example of an immediate, no-cost action for everyone:

Space conditioning:

Heat: Turn down thermostat from 72°F to 68°F during the day and to 65°F at night

A/C: Turn up thermostat from 73°F to 78°F

Energy saved: 3.4 percent

Compare that to the language from the Department of Energy’s “Tips to Save Energy Today: Easy low-cost and no-cost ways to save energy,” from their Energy Saver’s […]

Spaghetti diagrams, part 2 — “Spaghetti box”


In earlier years of Lawrence Livermore National Laboratory’s spaghetti diagrams, such as the above example from 1976, the ends of the swaths were more like the simpler energy flow diagrams. On the above diagram it’s easier to see that the height of the lines on one side would end up around the height of the lines on the other side than it is on some of the newer versions with oversized boxes that serve as labels. But the boxes are a useful tool, and can let us think about embedding another diagram form — box diagrams — into the spaghetti diagram.

Box diagrams are used for teaching electricity, and were developed by Peter Cheng and David Shipstone in the UK. The picture below is from part 1 (Word doc) of their introductory paper (here’s the Word doc part 2). Since power is the voltage across a bulb multiplied by […]

Spaghetti diagrams, part 1


This “spaghetti diagram” (aka Sankey diagram, or Energy Flow Chart officially) is the 2008 version. Lawrence Livermore National Lab (LLNL) has been making these things since the 1970s. It’s more detailed than a simpler national energy flow diagram because it includes “rejected energy.” It’s also more complex — it actually includes within itself the electricity flow diagram. It’s a pretty cool visualization.

The main thing I dislike is that it doesn’t split up transportation or electricity generation “rejected energy” by sector. Since these are really the two biggest sources of “rejected energy,” you can’t see which group is the biggest “rejector.”

Below, in an undated but funkier design, they’ve not only split up transportation into light duty vehicles, freight/other, and aircraft, they’ve also added domestic and net imports to petroleum and natural gas. They still haven’t split up “Electricity Generation, Transmission & Distribution Losses,” so we don’t know who […]

Energy losses in electrical systems

Reprinted with permission from "What you need to know about energy," 2008, by the National Academy of Sciences, Courtesy of the National Academies Press, Washington, D.C.

Here’s a picture from What You Need to Know about Energy by the National Academy of Sciences. It shows 100 energy units of coal being used by an incandescent bulb to produce light that has only 2 energy units:

Reprinted with permission from "What you need to know about energy," 2008, by the National Academy of Sciences, Courtesy of the National Academies Press, Washington, D.C.

Incandescent bulbs get hot because only 2/36 (about 5%) of the energy coming into the house to power the bulb comes out as light — the rest of the energy produces heat. If you trace the energy back to the power plant, it turns out a mere 2% of the energy from the coal is doing the desired lighting job! The power plant itself loses 62% of the coal’s energy! Compact fluorescents use about 5% of the coal’s energy — better, but not […]

Solar roadways – a good or a bad idea?

Solar Roadway

At first blush, this looks like a fabulous idea:

Turn roadways into an enormous solar cell and get lots of other advantages like better new infrastructure. A long while ago, I looked at making solar roadways (and parking lots and driveways and footpaths and….) under contract when I was at Squid-Labs :

The very difficult thing about making a road is making it structurally sound enough to carry vehicles. That means it has to take very high loads, and be very durable for up to 50 years.

So putting a solar cell there is completely possible, but then you’ll need to put some protective material on top that has some texture (so the roads are not slippery) and enough resilience to last a long time. The problem is that that protective material uses A LOT of energy to produce. Perhaps the company pitching this idea has some […]

Historical US electricity production, by generation source, and consumption by sector.

US electricity production, historically, by source, (GW)

Production data by primary energy source:

And the PDF:

US electricity production, historically, by source, (GW)

Consumption data, by source:

And the pdf:

historical electricity consumption, by sector, (GW)

Source data for both:

Electricity Grid, Generation by source, Consumption by Sector

Electricity Grid, Generation Source, Consumption Sector, 2008

This I find to be a fascinating breakdown of the production and consumption of electricity for the US grid. I was a little surprised at just how high the losses are, especially as the primary energy measured in for nuclear is considered 100% effective, as is the primary energy coming in from Solar, PV, Wind, Hydro and Geothermal. What that means is the fossil fuels are even less efficient than they appear here. I’ll try to break that out in a new graph soon. I’ll also try to tease out the contribution of combined heat and power. There is an awful lot of heat going on here to be combined…

Electricity Grid, Generation Source, Consumption Sector, (GW), 2008



Electricity Generation and USE, 2008


I was a little surprised the generation losses were quite this high….

And some nice PDF’s for your delectation:

US Electricity Generation and Use Flow Diagram 2008 (GW)

US Electricity Generation and use Flow Diagram 2008 (QUAD BTUS)

And here’s the data in spreadsheet at google:

US energy use by state, 2006


This is the per capita energy consumption. Go NYC!

Here’s the PDF, all nice and vectored. US per capita energy consumption, by State, 2006

And this pdf:

energy use by state total (GW) 2006

All the data comes from the EIA report.

You can find it here in a google spreadsheet:

Green Buildings, a question from Graham Hill.

This request came from my friend Graham Hill at Treehugger:

I am wondering if we are not quite looking at the right metrics when it comes to buildings being green. And i’d be interested in your thoughts. and ideas about who would really know a lot about the lifecycle/energy considerations of buildings.

Here’s what I think we should be looking at from a carbon perspective: I think we want a measurement of CO2 Emitted per person hour. Here’s how you might figure it out:

(Total Building CO2) = (CO2 of Embodied energy of materials used) + (CO2 of Energy used in construction) + (CO2 of Energy used throughout building’s life) + (CO2 of Energy used to disassemble bldg at end of life) – (CO2 of Embodied Energy of materials reclaimed at end of building’s life)

(Total Building Person Hours) = (Number Building “Users” (density)) x (Hours Used Per Person)

Figure […]

Energy is everywhere.

This passage is to accompany the print edition of the book and illustrates the difficulty of measuring all of the ways that energy is consumed. This essay was inspired by the essay “I pencil” which outlines the complexity of modern society and modern supply chains. This is an approximate view of the actual energy used in making a book and some liberty has been taken with the details. In fact we started, but couldn’t complete, a full energy audit for the manufacture and delivery of the book, for the reasons you will see below. This is meant to be qualitative, not quantitative.

Anatomy of this book about energy.

The book is about energy, climate change, finite resources, and our future. Unfortunately, this book is implicated in the very climate change and energy challenges we wish to avoid. You chose to read this book, which means you chose to use some […]

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