US could replace coal power with existing gas-fired plants

[bananas]

Without building anything new at all, we could significantly reduce co2 emissions literally overnight.

http://blogs.ft.com/energy-source/2010/04/20/us-could-replace-coal-power-with-existing-gas-fired-plants/

US could replace coal power with existing gas-fired plants
April 20, 2010 10:51am
by Sheila McNulty

The shift from coal-fired generation to gas- fired generation sounds like something that would be lengthy and difficult to accomplish. But a new report by PFC Energy, the consultancy, indicates it is anything but. The report says US gas fired power plants average about 25 per cent utilisation, compared with 70-75 per cent for coal.

So operating existing plants at 72 per cent utilisation would theoretically increase gas demand by 30bn cubic feet per day - a rise of about 50 per cent - and displace almost all coal fired capacity. In doing so, carbon dioxide from the power sector would be cut 50 per cent, according to PFC.

This is something that Colorado has adopted enthusiastically.

On Monday, Colorado Governor Bill Ritter signed into law the Clean Air-Clean Jobs Act, which will retire or retrofit older coal-fired power plants to take on gas and other cleaner fuels.

From the governor’s statement:

“This law is a template for tomorrow that allows us to transform our energy portfolio, our economy and our environment by working strategically and collaboratively. By shifting our oldest and least efficient coal plants to cleaner, Colorado-produced natural gas, we send a strong message to the rest of the country that we absolutely can cut air pollution and protect public health while also creating jobs and protecting ratepayers”.

The Colorado legislation requires Xcel Energy, a key provider in that state, to cut nitrous oxide emissions by up to 80 per cent from several coal plants by the end of 2017. To that end, it is to submit a plan to regulators detailing how it will retire or retrofit 900 megawatts of coal-fired capacity by August 15.

Xcel is to replace that generation with natural gas, renewables, greater efficiencies or other cleaner energy sources.

The governor said the law sets a national example by bringing economic, energy and environmental benefits together in one package. Given PFC’s report on the ready availability of capacity to make this transition across the country, how might the Colorado example be considered by Congress?

Via comment #9 at http://climateprogress.org/2010/04/27/one-myth-about-the-washington-post-it-still-practices-serious-journalism/#comment-272326

9. wag says:
April 27, 2010 at 11:33 pm

The right peddles all sorts of contrarian myths about clean energy. Another myth is that transitioning away from coal would take a long time. In fact, a new study from PFC Energy actually shows we could switch nearly 100% of our coal plants to natural gas almost overnight:

http://akwag.blogspot.com/2010/04/ending-use-of-coal-overnight-new-study.html

[Statistical]

1. A major reason we MUST have a cost attached to carbon.

Problem with switching from coal to natural gas is coal operating costs is about 2 cents per kWh while natural gas is about 5 cents per kWh.

You are talking a rise of roughly 3 cents per kWh. When you figure average retail electricity in US is 10 cents thats 30%. No utility is going to raise costs & thus rates 30% unless forced.

A carbon tax alters that differential. At $25 per ton coal incurs about a 2.5 cents per kwh "tax" while natural gas incurs about 1 cent. Now that is on average. There are many older coal plants with lower efficiency so overnight they would become more expensive than natural gas. At around $50 per ton virtually all coal plants become more expensive than natural gas.

A carbon tax especially a slowly rising carbon tax would cause the switch to happen without even forcing utilities to stop burning coal.

Utilities do what is in their best interest = lowest $$$ per kwh.
The planet needs what is in it's best interest = lowest CO2 per kwh.
A carbon tax simply aligns those goals. What is in the best interest of utilities becomes in the best interest of the planet.


* A carbon tax isn't a silver bullet. As coal is burned less and natural gas more the prices fall and rise respectively offseting some of the effects of the carbon tax however it will help.

On edit: ignore this. the numbers I had were way out of date.

[kristopher]

2. Mmmmm...

Accepting for the sake of discussion as true, you wrote

switching from coal to natural gas is coal operating costs is about 2 cents per kWh while natural gas is about 5 cents per kWh.
You are talking a rise of roughly 3 cents per kWh. When you figure average retail electricity in US is 10 cents thats 30%. No utility is going to raise costs & thus rates 30% unless forced.

Only if coal is 100 of the retail price. Taking the average mix of coal as 50% of generation, that means a 3cent/kwh increase on 50% of the portion of the retail price that is from generation.

The retail price, however also includes taxes, fees, transmission, and distribution costs. So the generation portion is actually only about 60% or so of the final retail price.

Therefore your price increase would be applied to roughly 30% (1/2 of 60%) of the input to the final bill.

To get to the final amount of change in the bill we'd need to know the average costs of the entire non-coal 50% of the generation mix, not just the natural gas portion.

[Statistical]

3. On edit.... scrap what I wrote.

Looks like my operating costs for coal & natural gas were way out of date.

Looking up some new numbers now.

[joshcryer]

7. I suspect that the costs would nideed be pretty huge, though.

And your basic thesis was correct that if carbon had costs (ie a tax) then this would be more viable.

[happyslug]

4. Most Coal plants are base load plants, most gas plants are peak load

Electrical generation can be seen as two types, base load, what is used all the time every day and peak load, what is used over and above base load during times of high electric usage (Generally hot weather and Air Conditioning but also cold weather and heating).

Nuclear and Coal fired plants tend to be "base load" i.e. what is used day to day. You can increase this somewhat over a brief period but if the demand increase to much you have to put another plant in line. Nuclear and coal produce the lowest cost electricity, but have the highest fixed costs and the least flexibility. They produce power, it is almost constant but Nuclear plants and Coal plants tend NOT be be plants you can turn off when you do NOT need them and then turn on when you do.

The best peak load power is hydro-electric. It is also the lowest cost electrical source. Hydro dams can keep water behind the dam till power is needed and then just turn on the juice by simply releasing the water. The chief problem with hydro is location are limited and most areas where we can install such a hydro-electric dam has a dam and power station. In fact outside DC the electrical company uses excess base load electrical power to pump water ABOVE a dam to fill the dam when electrical demand is low, so that when peak demand occurs all it has to do is open up the dams for the additional power. Pumping water with excess power is the cheapest way to store that power for later use.

Side note: In my home area of Pittsburgh there has been a proposal to operate electric power plants via the lock and dams on the rivers. Almost all such locks and dams do NOT have such capacity at present and would provide a good source of electrical power, but unlike Hydro-electric dams such lock and dams could NOT turn off power when not needed and turn it on when needed do to the need to move barges up and down the locks AND such locks and dams on on river to maintain a pool of water for shipping, some water could be contained behind such locks and dams, but overall the electric power will be more of a base load nature do to the flow of the river and the lack of excessive holding area for the water. Similarly the proposal to install giant hydro system in the Mississippi River below St Louis to provide power (Based on new technology that uses the flow of water as current to produce electrical power) is similar i.e. good for base load but NOT peak load do to a lack of an ability to store water. Just a comment that when it comes to Hydro power as a peak load source we are looking at the large power dams NOT the smaller locks and dams or the proposed use of water current itself as an electrical power source. Wind and Solar power has similar problems, can be part of the base load but NOT an additional source of power when peak power is needed (i.e. Solar and Wind can provide the power, but in a base load matter NOT as some sort of way to hold onto the power till needed).

Once you look at the other sources of electrical generation you come to accept the best source of new (as opposed to existing) peak load production is Natural Gas (Given Oil use for electrical generation has been disfavored since the 1970s). A Natural Gas plant is NOT as easy to turn on and off as a Hydro electric dam, but it is easier to turn on and off compared to a Coal or Nuclear plant. Thus Natural Gas plants are kept to provide peak power when needed. They operate at about 25% (or less) of capacity (One plant in Pittsburgh is never operated EXCEPT during period of peak demand). Such plants are used just enough to keep them ready when peak demand is needed, thus the low usage rates, but do to their higher cost of operation used only when Hydro power is used up OR incapable of providing the power needed.

Just a comment on why Natural Gas plants usage is so much lower then Coal and Nuclear plants AND why they are kept. Natural Gas plants are kept for peak usage period, other period they are shut down for compared to coal and nuclear plants they are the cheapest plant to turn off and on based in demand for electricity.

[Statistical]

5. There is no reason that natural gas plant couldn't be used for basload....

except cost. There is no technical limitation that would prevent it.
Carbon tax helps to equalize the cost.

The other issue them becomes spare capacity. I did the math and to go 0 kwh from coal would require average utilization (capacity factor) for existing natural gas plants of 82%. I don't think that is achievable. Nothing short of nuclear has that little downtime.

Second issue is that even if we COULD do that natural gas is used for quick spin up and down (at least some of it) so there would be no reserve capacity to handle emergencies, unexpected demand, plants going offline or even routine things like fueling outage at nuclear plant.

Still I think the goal in a less black or white manner would be useful.
Currently our coal plants have about 70% capacity factor and natural gas turbines are about 30%.
Moving some of those turbines over to baseload (at 70%+ capacity factor) and shutting down 1/5th of the dirtiest/oldest/least efficient coal plants would make sense.

[kristopher]

6. That is precisely what wind causes to happen.

When the more profitable spot market in an area starts to become saturated with wind generation bidding at zero, it forces natural gas to seek an alternate profit stream.

[One_Life_To_Give]

9. Depends upon design

When designing something to run 25% of the time and be idle 75% of the time. You don't invest money into things that help keep a plant up near 100% of the time or design them to last longer than x years at 25% usage. You make similar tradeoffs when buying a car. If you are buying it to use like a taxi then investing in beefier parts makes sense.

[kristopher]

8. From the last link in the OP

Monday, April 26, 2010
Ending the use of coal overnight: new study shows it's possible

One of the common arguments against climate legislation is that clean energy technology just isn't ready yet. Most often, it's made to defend coal, and usually goes something like this: "Sure, maybe eventually we can replace coal, but right now that would be too expensive. For the next 50 years, we'll need to continue using coal at the same time we're developing cleaner alternative fuels."

This argument has always been illogical. Just because alternatives to coal are expensive now does not mean they always will be, and a major national push would soon bring down costs through economies of scale. But a new study goes even further, showing the "technology not there" argument to be not just illogical, but factually incorrect. In fact, the United States could replace nearly 100% of its coal-fired power generation--and do so almost overnight. How? With natural gas (which emits 50% less CO2 than coal). The Financial Times reports:

The shift from coal-fired generation to gas- fired generation sounds like something that would be lengthy and difficult to accomplish. But a new report by PFC Energy, the consultancy, indicates it is anything but. The report says US gas fired power plants average about 25 per cent utilisation, compared with 70-75 per cent for coal.

So operating existing plants at 72 per cent utilisation would theoretically increase gas demand by 30bn cubic feet per day - a rise of about 50 per cent - and displace almost all coal fired capacity. In doing so, carbon dioxide from the power sector would be cut 50 per cent, according to PFC....


Note that this is referring to existing power plants. In other words, we could completely eliminate the use of coal in this country without building hundreds of new power plants.

Also note that this is a recent development. Just three years ago, the idea of abundant natural gas replacing coal actually was ludicrous, and coal's defenders at least had a point. But that's no longer true. The difference is new technology that has unlocked previously out-of-reach shale gas formations such as the Marcellus Shale in Appalachia.

Providentially, much of the nation's most promising gas potential is in the very states where coal is currently strongest politically: West Virginia, Pennsylvania, and Ohio....

http://akwag.blogspot.com/2010/04/ending-use-of-coal-overnight-new-study.html

[NickB79]

10. Does the US have enough nat. gas to run all of those plants at full capacity?

And if we did, wouldn't the greatly increased demand for natural gas drive the cost of the fuel much, much higher in very short order?

[ConcernedCanuk]

11. NO

.
.
.

BUT

they have for decades been getting much of their Natural Gas from Canada

yeah

If we try to keep it for ourselves

we will be the next Iraq . . .

Our government sold us out decades ago

[kristopher]

12. That is the initial weakness of just using natural gas.

We've ramped up production but a massive, all-at-once switch would not be possible because of limited supply.

The route envisioned, however, is that we continue to build out wind and solar with natural gas being used to load follow. That dramatically reduces the reliance we'd have on natgas.

ETA: I suggest that this thread also be reviewed for a good idea of what the generating profile of large pools of renewable generation looks like; that defines the challenge we are trying to meet. this link only discusses wind, but it's worth the look: http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x243131

Here are some references that taken together give an example to make the point.

Emissions and Energy Efficiency Assessment of Baseload Wind Energy Systems

P A U L D E N H O L M *
1500 Engineering Drive, University of WisconsinsMadison,
Madison, Wisconsin 53706

G E R A L D L . K U L C I N S K I
439 Engineering Research Building, 1500 Engineering Drive,
University of WisconsinsMadison, Madison, Wisconsin 53706

T R A C E Y H O L L O W A Y
Center for Sustainability and the Global Environment (SAGE),
1710 University Avenue, University of WisconsinsMadison,
Madison, Wisconsin 53726

Abstract
The combination of wind energy generation and energy storage can produce a source of electricity that is functionally equivalent to a baseload coal or nuclear power plant. A model was developed to assess the technical and environmental performance of baseload wind energy systems using compressed air energy storage. The analysis examined several systems that could be operated in the midwestern United States under a variety of operating conditions. The systems can produce substantially more energy than is required from fossil or other primary sources to construct and operate them. By operation at a capacity factor of 80%, each evaluated system achieves an effective primary energy efficiency of at least five times greater than the most efficient fossil combustion technology, with greenhouse gas emission rates less than 20% of the least emitting fossil technology currently available. Life-cycle emission rates of NOX and SO2 are also significantly lower than fossil-based systems.

Environ. Sci. Technol. 2005, 39, 1903-1911

The role described here for natural gas is a step down the road from that proposed in the OP, and it produces significantly fewer carbon emissions than coal or natural gas. That carbon reduction of 80% over a regular natgas system is achieved because you are using natgas to augment energy stored from a renewable resource.

You can even go a step further and fire it with methane derived from biomass for near complete carbon neutrality.

Improving the technical, environmental and social performance of wind energy systems using biomass-based energy storage

Paul Denholm*

A completely renewable baseload electricity generation system is proposed by combining wind energy, compressed air energy storage, and biomass gasification. This system can eliminate problems associated with wind intermittency and provide a source of electrical energy functionally equivalent to a large fossil or nuclear power plant. Compressed air energy storage (CAES) can be economically deployed in the Midwestern US, an area with significant low-cost wind resources.

CAES systems require a combustible fuel, typically natural gas, which results in fuel price risk and greenhouse gas emissions. Replacing natural gas with synfuel derived from biomass gasification eliminates the use of fossil fuels, virtually eliminating net CO2 emissions from the system. In addition, by deriving energy completely from farm sources, this type of system may reduce some opposition to long distance transmission lines in rural areas, which may be an obstacle to large-scale wind deployment.

Natural gas is stored energy in a form that is very responsive, as in we can turn it on and off quickly; and that is compatible with renewables. While there are several different approaches besides Compresssed Air Energy Storage to do this with, the picture is the same as far as their performance goes. The big advantage offered by natural gas is that the plants are largely already sitting their under-utilized.

The key is charging for carbon in some way. If we can link energy prices to carbon everything else will follow.

So a practical path to the OP's plan would be to push building wind and solar. The lack of a fuel cost for wind and solar will competitively move the natural gas generation to compete with coal which has been made more expensive than natural gas by the cost of carbon (natgas emits less than half as much carbon per unit of energy as coal).

We keep tightening up the noose and as carbon costs keep rising the opportunities for other storage technologies like CAES, pumped hydro, and batteries become cost competitive with natural gas.

The last to go would probably be the existing nuclear fleet. If we roll out wind and solar on the scale needed to do the job, there is little doubt that solar energy technologies and storage will become just like any other commodity where their costs follow predictable patterns of reduction as manufacturing capacity increases.

So we need to do two concrete things to make this path a reality: 1) deploy existing renewable technologies as rapidly as possible. We don't need to wait for storage; and 2) start charging for the cost of carbon.

[FBI_Un_Sub]

14. Does That Include Fischer-Tropsch Artificial Methane

Forgive Me - my dissertation adviser was kind of obsessive-compulsive about Fischer-Tropsch; he was really a fine old gentleman

If you "play with" the feed stream to a Fischer-Tropsch convertor you get a clean fuel.

[kristopher]

15. Synfuels aren't really on the radar as far as I've seen, although I wouldn't rule them out.

The focus for the next generation liquid fuels is on a variety of biofuel options such as bugs that excrete ethanol or algae that can be harvested for their lipids. All of these are expected to deliver a positive energy balance that is better than 3:1.

While the production of synthetic fuels isn't an area I've looked at in detail, from what I know I think the only place it may find much applicability is in waste incineration where we are already using energy to address the problem of accumulating garbage. It burns much cleaner than traditional incineration and it is a good means of recycling the constituent elements of the input. I also have a vague memory that it also has a problem with consistent performance, and that frequent failures of the process leads to undesirable emissions. IIRC that (and the relatively low cost of gasoline) is the reason they aren't used more.

I think that generally they will not be able to compete with the alternatives, even in the area of waste incineration, but I could be wrong.

Feel free to correct me if I'm off base on any of this or add anything you think relevant, as I said, I haven't looked at this much.

[kristopher]

13. Kick