Lovely solar mapping project at NREL.

They are seeking more data on PV solar installations for this map. It’s fascinating to see the progression over time of installations, and I was startled at just how active California is compared to the rest of the nation.

578.5 MW to date ! only another 500GW to do !

State Installed Capacity (MW) CA 422.828 NJ 62.43 CO 17.363 CT 14.904 AZ 8.252 MA 7.502 MD 1.229 NM 0.753 HI 0.324 MN 0.274 MO 0.003

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 […]

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 […]

Land Use and Renewable Energy.


Before embarking on some enormous exercise like converting America’s energy use to 100% renewable energy, you might like to get a 20000 foot view of the impact on other things like land area use. Here are some charts to put that in perspective:

1. Land Area of the US by state, (does not include water area in those states) – note the country has been reduced to a square where each stripe is the proportional area of that state, starting with the biggest (Alaska) to the smallest.

2. Land area by use category for the US:

3. Land area required for 1000GW (1TW) each of Solar, Wind, Biofuels, and Hydroelectric. These are “all in” estimates that include capacity factor and the whole hog. Think of it as a year-round average.

4. And now we overlay them all on each-other to get a sense of just how big […]

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:

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