Displaced Emissions

Also, the batteries (lead-acid?) that will have to be replaced every 5-7 years...

It takes approximately 300W to drive an average car (English) forward at an average speed, say 40mph with no mechanical losses. It must take 3000W to keep a petrol engine at operating temperature. Electric drives use re-generative braking, and don't use energy when stopped. There is no discussion to be had! Electric drives win by at least 10:1 despite transmission losses. My only question is why is this never explained to the public. It would be interesting and quite simple to work out how many amp hours the new Tesla consumes for a charge that takes it 250 miles. Then compare this to the Calories burned by a Lotus Elise doing the same mileage.

Some power plants are "baseload" -- they work 24 hours a day and their output is not easily adjusted -- and some are "peaking" -- you can turn them up or down depending on demand. The result is that there is extra baseload power in the middle of the night. Might as well use it.

My understanding is that peaking power plants only run when additional electrical power is needed, when the cost of electricity is the highest. They usually use a higher cost fuel than the normal coal fired plant, like natural gas or diesel and therefore would not be economical to run during off-peak hours.

Most power companies have surplus capacity during off-peak hours, which is why the cost during off-peak hours is normally lower (for commercial and industrial customers, residential users usually do not have the time-of-day rates available to them).

DOE figures that the average energy use to deliver a kWh to a customer from a coal fired power plant is about 10300 Btus, which is 33% efficiency (10300 Btus of coal to deliver 3412 Btus of electricity). This takes into consideration the efficiency of the boiler, the steam turbine, line losses, transformer losses, pollution control equipment etc.

I just read an article that said that a Prias charged at home at night got the "equivalent" of 100 mpg. So there is some advantage to an all electric car, assuming that the article I read is correct.

Hybrid and electric are two different things. Let's take them one at a time:

Hybrid cars use electrical energy storage to even out the load on the internal combustion engine. In an ideal system, the internal combustion engine would run all the time at the operating point that provides the average power that the vehicle needs. The electric system would provide power to satisfy peak demands and absorb energy during "valleys" and braking. The resulting system uses a smaller internal combustion engine (it doesn't need to provide peak power) that runs very efficiently because it's being operated at a fixed operating point. The result is much higher gas mileage. Note that this system does not use "grid power" at all.

Electric cars use grid power entirely and store their energy in batteries. Here the advantage accrues because the overall system is more efficient. Large electric generating plants are extremely efficient, and the electric system in the car is likewise in the 80%+ efficiency range overall (including transmission, battery efficiency, power converter, and motors). The overall system, from generating plant to wheels is in the ~50% efficiency range, contrasted with internal combustion efficiencies in the mid 20% range. Also, it's easier to control emissions from a few point sources (power plants) than from millions of distributed sources (automotive tailpipes), and some of that electric energy can be generated by alternative non-polluting sources. The only reason we're not all driving electric cars today is that there's no form of electric energy storage that comes close to matching the energy storage density of gasoline. EVs are limited to range-between-recharges of about 100 miles using today's battery technology.

Note that comparisons between EV emissions and internal combustion (IC) emissions usually compare the emissions in the entire EV system (generating plant to wheels), to the emissions of the IC CAR ONLY. The real comparision should include the emissions involved in mining, transporting, and refining the gasoline as well. Such a comparison would only make the EV look more favorable.

The next generation of hybrid vehicles, "plug-in" hybrids, will be a mix of hybrid and electric. They will have larger on board energy storage (batteries), and can be charged from the grid as well as operating as a hybrid.

References

DOE Clean Cities Web site
EV Advocates Web site. Biased, but some good information
Battery limitations

Every form of transportation has it's place. A hybrid car will have a longer commute distance then the electric car. It however would require fossil fuels until there is a reliable ethenol supply. The electric car would be fine for in city and intra city travel but would take time to recharge. The power source is a coal burning powerplant that would spue tons of CO2, etc. in the air. Or, have a small diesel powered geneator with a fuel source of biodiesel or veggie oil to recharge the electric car and add an automatic shutoff when the charging is complete. For myself, I'll stay w/ diesel power and a fuel source I can manufacture in the garage. Lots of startup kits out there already. Would someone explain to me why a diesel-hybird is viable? Diesels are heat engines. Greater efficiency at the optimal operating temperature. Not shutting down the engine when the batteries can handle the load. Makes no sense to me. I'd think an etenol powered spark-ingnition engine would be preferred. Anyway, buy staying mindful of the power source and the needs relating to the transportation mode I believe we can all say good-bye to fossil fuels. But also keep a check on the use of coal. That should be the next power source we need to reduce.

Any IC engine runs more efficiently at constant load, and that's what a hybrid system provides. Diesels in particular have higher emissions during acceleration (think of the cloud of smoke that comes out of the stack when a big truck accelerates from a stop light).

Generally speaking, the idea of replacing all fossil fuels with clean alternatives is wishful thinking. The scale is just too big. It will take a lot of energy sources and a huge boost in how efficiently we use the energy to wean us of fossil fuels.

The IC spark-ignited engine is not under constant load. To confirm this, I was reading a short testomonial by an owner. He was commenting on how quiet the operation of the car is after the engine shuts OFF. That is by design. When the battery charge is low or the drive train load increases, the engine restarts. My point is, the loading is immediate (the altenator)...on a cold engine! So I'm asking, what is the idea in the use of a diesel engine in a hybird vehicle? The comment on the diesel engine in your reply. You were witnessing either an old engine or an engine w/o the more advanced engine managment system, or lack of maintenance. Don't say another word about your 'knowledge' of diesel engines until you pickup an issue of DIESL POWER Magazine and get just a hint of what you didn't know but assumed so you could make yourself feel educated. Hey, I did the same thing. Don't be afraid of being wrong, be afraid of leading people wrongly ( lead not w/ ego but w/ common-sence). Lastly, you're right, fossil fuels will be around in some form, but in transportation we can eliminate the use. Bio-mass is the most under reported source of alternative energy. It's not wishful thinking. However it's additional research and investment (hopefully very little by the oil companies), and the resulting cost to you and I. Think positive.

If the power plant is coal burning, then it's somewhat better to use Electric Cars at this momment in time. If your power comes from Hydropower (Niagara Fall etc.), then an Electric car would be much better. If we all started driving Electric cars, the range and efficiency would improve a lot as Automakers fought to improve their product, but if nobodies buying, what's their motivation? To answer your question, yes, driving electric cars would help the environment (The batteries could be recycled).

That said, it's not gonna happen, however Hybrids are the future. Right now the automakers are using hybrid engines to improve power more often than gas mileage, but with gasoline prices going up all the time, there will be more of a push for improved mpgs in the future. The good news is that there is a lot of overlapping technology between hybrids and electric cars and years from now I think you'll see Hybrids go from being mostly gas and some electric to mostly electric and some gas. I hear people saying electric cars are impractical, actually it's much more practical than our gasoline cars.

In 1979 I worked on a unique hydro electric plant in California it was called pumped storage .The principal was a natural lake would be dumped down a tube and hit a turbine at peak demand and then on off peak the water would be pumped back up .I believe it took more energy than it produced but it became an availible "battery" for peak demand .It was outside of Fresno Called granite Ball Grove,as I remember , in the sequoia national forest .I wonder if it worked out and how it might be an effective way to power cars in the future .

I don't know about California but Niagara Falls produces 2.4 Million kilowatts Peak Power. Here's the link:

http://www.nypa.gov/facilities/niagara.htm

We have a pumped storage facility near us in upstate New York called the Blenheim-Gilboa Pumped Storage Project. It uses a 5 billion gallon man-made lake on top of a 2000 foot mountain, and a reservoir on the Schoharie creek at the bottom. Water is pumped up to the lake when power is available, and the pumps are run backward as turbines to generate power when needed.

When fully charged, the facility can generate 1 Gigawatt for 12 hours. Also, unlike ANY other type of power plant, the facility can be brought online to full power from a standstill in 2 minutes. I once had the privelege of standing on one of the turbines while they opened the valve and started it. The entire (concrete) building shook. It gives you new respect for the power of water.

Wikipedia has a good article about how pumped storage works. Pumped storage facilities are a great way to store energy, except that there aren't that many good locations for them. In fact there are so few of them that the Wikipedia article above has a complete list of the world's pumped storage facilities.

Incidentally, the operators of B-G told me that they have tagged fish in the upper reservoir and caught them in the lower reservoir. What a ride that must be!

I did some research it turns out the project I worked on was called the Helms pumped storage powerhouse outside of Fresno .It has some distinction for the highest head or hieght of drop to the turbines .The company was Granite Ball Grove now called Granite construction. I would like to go back some day there is camping and maybe I could get a tour. Imagine me working at 20 yrs old to think 27 yrs later something I worked on still running as designed .Maybe a trip to your NY facility would be worthwhile as long as they turn the valve for me ,that must have been a thrill . There are limitations to new pumped storage construction due to the need for hieght otherwise they are a great concept . I'm a little proud to be a part of something innovative .

I worked at this plant just after there was a failure in the Helms Creek Crossing Penstock. The plant is working fine and generates electricity for only a few hours a day. It pumps the water up to the upper reservoir for the rest of the time. Both reservoirs do not have the water capacity for the turbines to generate more power. The failure at Helms Creek was very interesting. PG&E did not oversee the contractor very well. Much of the material that was supplied was inferior. Heat treating of the metal was not done. It would have only added $5.00 per ton to the final cost. Many of the welds contain defects that exceed code limits. The piping was overdesigned so these defects will not cause another failure. I was at the opening ceremony of the plant.

I worked with the team that determined the cause of the failure and oversaw the repairs. What you said is correct. I was also at the dedication ceremony along with my wife. The job was a massive undertaking. Auditing or third party review could save companies alot of money and grief. My company learned its lesson at a high price. This is the same company that caused the film "Erin Brocovich" to be made. I used to temporarily work at the plant that caused all those people to contract cancer. I noted that the heat exchangers were in poor condition and there was a white dust lying on everything. I used to get nose bleeds, but since I retired, I do not. Nose bleeds are a symptom of Hexavalent Chromium exposure. My job was very interesting, but I am glad that I am now retired.

Yeah I worked there too. I remember the first test in the powerhouse when we did a three unit "full load rejection".... three units at full load, and you trip the 52T breaker open.... and as the three units spun up into overspeed.... I swear I saw two sets of shoes left on the ground after two young engineers scrambled out of there.

It was pretty noisy, and with a lot of vibration....but we few knew... if something happened...there would be, no place to run.

If something big let loose, there would be no way out of the powerhouse, which was a cavern excavated under a thousand feet of granite....

In safety training, on site, they would tell you that if anything bigger than a 4 inch pipe broke...at 800+ psi, that cavern would fill up and spit your body, your equipment and your truck, up and out the access tunnel and into oblivion in about 10 seconds....nice!

Seen the pictures of that Russian Hydro disaster??? And that was only one third the head of the Helms Project.....

J Brand

One other strong point in the emissions discussion, is that it is more efficient to control the emissions of one power plant than 100,000 cars