Here it is. I didn’t realize the 2012 Sankey diagram is out.
In that diagram what does “rejected energy” mean?
Energy lost to waste heat, friction, etc. e.g. an incandescent bulb loses ~98% of energy to heat; only a little goes to the intended purpose of illuminating your room.
Thanks.
That’s what I had guessed but dayum. 61% of all energy generated is lost to waste. 67% of all electricity generated. And of petroleum energy used for transportation 85% is lost to waste.
Wow.
That’s the big deal with EVs: EVs convert electricity to motive force with roughly 59 to 62% efficiency; ICEs 15% per that diagram (and maybe 17 to 21% according tofueleconomy.gov)
I’d recommend a two pronged approach. First, mandate high Solar Reflectance on new, or replacement, roofs. Not just a high R value(which is a combination of Reflectance, Emissivity, and insulation) but actual Reflectance. This raises the Albedo of the earth just slightly, and the sunlight being reflected back out of the atmosphere helps keep things from heating up as fast. This is the norm on commercial building already, but is not being used in residential neighborhoods much.
The next step is to deploy the PVs(photovoltaic panels), as they get cheap enough. There are essentially two options. Making a big farm of PVs out in the desert somewhere and losing energy to transmission costs but being able to centralize the other infrastructure. The pros of this approach is it can be upgraded more easily as better power collection and distribution tech comes available. It doesn’t force homeowners to have PV on their roof. It can be maintained by professionals year-round. The downsides are the transmission and the enormous cost of such a farm. It also doesn’t really relieve the grid, it just puts some non-fossil fuel sources of energy into it.
The second approach is more distributed. Each house gets a 1.5-2.5 KW solar install on the roof(not that big, easily fits on the average suburban roof) and it runs the daily stuff of the house. All those energy vampires, most of the time this system could keep up with refrigerators, washing machines. It’s clothes dryers and HVAC that it would have trouble with. It could even charge the typical plug-in vehicle without drawing any power from the grid. The pros of this is we generate the power where we need it. No significant loss in transmission, and a huge weight off the grid. The downsides are many though. All those installs. Batteries to charge up in each house(solar systems typically charge batteries and the house runs off batteries). Homeowner level maintenance. Odds are we wouldn’t feed that much back into the grid, but if we did we’d have hundreds of thousands of new “generation stations” we’d have to track and account for.
It’s no wonder people are beginning to look seriously at GeoEngineering, although that scares the crap out of me.
Enjoy,
Steven
Yes, ICEs have low theoretical efficiencies, and the actuals are even worse. But don’t forget generation and transmission losses for EVs. They still come out ahead, but it’s not as crazy good.
How do you account for production and transport “losses” (energy costs) on the petroleum side? I’ve read “well to wheel” comparisons (such as this one) but it seems that some of the inputs assumptions can vary widely.
Speed is not a problem on electric cars. I have driven a Chevy Volt and a Nissan Leaf (and a long time ago an EV-1). Electric has superior acceleration to gasoline by a long margin. Faster does use more batter reserves, however. Recently I was doing the 55 limit on a country road (Vasco Road) grade and was silently passed rather quickly by a Tesla S.
How about a third way: distributed but not on every house, and minimally not maintained or owned by the homeowner?
Those factory rooftops you mentioned are prime solar real estate. Those factory owners and homeowners can “lease” their rooftop real estate to utilities in return for a discount on their electricity. Maintaining the distributed array, and making a profit off of it, is the business of the utility.
Thats interesting. I heard as long as the cars are recharged at night it wouldn’t be a problem, since production capacity at night is far higher than utilization.
If you have chargers that can be turned on and off by the power company, it becomes much easier. Otherwise everyone comes home from work and plugs in. Bad times there.
Again, easily incentivized by differential pricing. My plug-in really does come with an app that allows me to time it’s charge to coincide with cheaper rates if they exist. On the board run by owners most use that app.
I looked up my notes from my last seminar. It’s not so much the drain on the total power grid - we can handle that. It’s the drain on the grid at the city and neighborhood level. That is, while we can increase capacity and do things like valley filling and load-shifting to even things out, the problem is that an amazingly large number of residential feeder and trunks could not deal with a case where 50% of people have electric vehicles. And even though people may not charge their cars on the same day, or even the same time, the system needs to be able to plan for “what if every single house in the neighborhood plugged in their EVs all at once?”
The PRB region instead of Rockies (yes, there is Rocky Mountain coal, but the PRB region is supplying close to 50% of all US coal right now, and likely will hit 75% within 20 years).
Yes, it just takes time and money…and one other thing. When our existing rail lines, pipelines, terminals, etc. were originally set up, environmental legislation was much less pervasive. The amount of environmental legal and science work required to run a new pipeline, install a new gas pumping station, or make a new LNG terminal is huge. And every single homeowner within a mile of the pipeline can file a suit, sometimes with the Sierra Club et al. taking their case.
Doable, sure. Expensive and time-consuming, yes.
That…is highly debatable. My thought is 5 years ago, yes, you could have a coal plant and be profitable. Now, no, the technology appears to cost far more than we thought, the environmental concerns regarding the sequestration portion seem much more troubling (what happens when a micro-earthquake fractures the rock and 1 B tons of CO2 come rushing out, etc.), and cheap gas is simply killing coal. I’ve lost more than 50% of my business over the last 3 years, which is one reason I’ve moved more and more into academia, and may turn my part-time University position into full-time at some point.
No, that’s not the primary source on that chart, and that loss isn’t considered on that chart anyhow. The loss in this context primarily refers to thermodynamic efficiency at Rankine and Brayton-cycle power plants. In short, what goes up the stack and out the cooling towers.
Just look at net plant heat rates in the US, convert to thermal efficiency, and the answer is there. The fleet thermal efficiency of coal is about 33-36% IIRC. The fleet thermal efficiency of GTs and CCGTs is about 45%+. I swear I worked the calculations for the entire US not too long ago, and posted it.
I thought the question was about vehicles, so I was trying to use an analogy to household devices. But you’re right that isn’t so appropriate.
Argh. Now I am more confused. How does that then translate into the “rejected energy” portion of the petroleum box? Is that waste heat of combustion? Or does it include other inefficiencies as well?
I do this for a living. Saying “we just need automated manufacturing to get better and cheaper” is like saying, “well, to cure cancer we just need to kill the cancer.”
Even gas fillups suck when the pump is slow (such as when the station has low tanks). I try to run to empty, and one of my vehicles has an about 105 liter tank. Watching the counter tick by at 10¢ per second is a frustrating experience. And being limited to $75 per transaction is salt in the wound.
In that case the situation is likely even worse … EV adoption will likely be subject to clustering, and critical mass at those local levels of clustered adoption may be hit at much lower overall adoption rates.
Of course this is, in a real world, likely to be a gradual process. Cars don’t get replaced every year. As local clusters get close to maxxing out their feeder and trunks they would get upgraded … gradually.