Solar vision: A rendering of a proposed solar array at the site of a coal plant near Grand Junction, CO.
Abengoa Solar
A new strategy could reduce coal plant emissions and cut the cost of solar power.
A project that will add solar power to a coal-fired power plant could reduce the amount of coal required to generate electricity and dramatically cut the cost of solar power.
The approach, announced by Abengoa Solar, based in Lakewood, CO, and Xcel Energy, Colorado's largest electrical utility, would make it easier for utilities in sunny states like California to meet impending state renewable-energy requirements.
The project will involve building an array of parabolic mirrors designed to concentrate heat from the sun, and using that heat to help make the steam that drives the coal plant's turbines and generators, making electricity. Such mirrors have been used for decades to generate electricity at stand-alone concentrated-solar power plants, also called solar-thermal plants, which are currently the cheapest source of solar power. But pairing the concentrating mirrors with a coal power plant offers a way to make this type of solar power even cheaper because a large part of the cost of a solar-thermal plant is the equipment for converting heat into electricity. The Abengoa Solar project will use existing boilers, turbines, generators, and so on, reducing this cost.
"The thing that's attractive about this is you only have to buy the solar field portion of the plant, which is 50 to 60 percent of the cost of the plant," says Hank Price, director of technology at Abengoa Solar. That could effectively make solar-thermal power about 30 to 50 percent cheaper, according to various estimates. That would equate to a range of about six to 12 cents per kilowatt-hour, which is competitive with many conventional sources of electricity. "It's potentially the most cost-effective way to get significant solar power on the grid," he says.
In the new project, because parabolic troughs don't generate sufficiently high temperatures, the heat they produce won't be fed directly into the turbines. Instead, it will be used to preheat water that will be fed into the coal plant's boilers, where coal is burned to turn the water into steam. Ordinarily, this preheating is done by siphoning off some coal-generated steam. Under the new design, more of that steam can be directed to the turbine to generate electricity. The net effect is that less coal is used to generate a given amount of electricity, and the augmented system reduces carbon dioxide emissions as much as a stand-alone solar-thermal plant with the same size array, but at a much lower cost, says Craig Turchi, a senior engineer in the concentrated-solar power program at the National Renewable Energy Lab in Golden, CO.
The hybrid plant could be the cheapest and easiest way to add renewable energy to the grid.
A pilot plant at a winery not only generates electricity, it heats the water.
Federal funds could help 15 gigawatts of solar projects move forward.
This seems to be the cheapest way to add solar power to the grid by far.
It applies, though, to all existing power generation plants that produce power with steam turning turbines: coal, natural gas, even nuclear. This is virtually all of the power we produce for the grid except for hydro.
Look at every power plant with a big enough area next to it for the mirrors, look at the expected additional solar output and the existing cost of power at that location, rank them by net profit, and start building.
Unfortunately, only a few would add incremental profit now, but if an appropriate penalty were added for the carbon produced from the existing plants, it could compete relatively soon in many locations.
The sun may shine on the whole planet, but various regions are more prone to solar energy use because of climate, elevations, latitudes, etc... While this may be great for california, not so good for Pittsburgh PA... (avg about 59 sunny days a year)
So Yes, it is a great idea for those lucky to be in a sunny area, but it doesn't scale to the rest of the country like the above post wishes...
Sorry to rain on parades (P-I..), but this doesn't solve any world crisis, just increases efficiency where it might be currently useable... We still need straight coal and clean nuclear for the rest of the country.
Oh, BTW, "appropriate penalty" = "TAX". How does that really help? Seriously, it just gets passed to the people that buy the electricty to light their homes, run their computers, TV's, CHARGE their Hybrid or Electric CARS! Etc.. etc..
(Unless you WANT everyone to be in the dark and drinking because they can't afford to watch TV?)
Yes, appropriate penalty = tax (or the equivalent value in cap-and-trade permits). It also should be revenue neutral, so that every extra dollar raised here is a dollar less taxed elsewhere (pick the tax you hate the most).
How does it help? It forces everyone to face the same cost when reducing carbon emissions.
The alternative is a mish-mash of subsidies that imply different costs for reducing carbon emissions. CAFE standards, speed limits lower than safety requires to save gasoline, cash for clunkers, renewable requirements for power generation, ad hoc requirements for approval processes for power generation plants, stimulus funds on green behavior that wouldn't have been supported without the recession, ... All imply different costs for saving a ton of carbon.
And what about the many ways to conserve with our travel, heating and cooling our homes and businesses, and industrial energy use. For most of these, there are no subsidies.
The biggest short-term change with such a tax would be conservation where subsidies are largely absent. The biggest long-term changes would be in power generation and more conservation as manufacturing processes, cooling and heating systems, autos, appliances, and buildings are remade for more energy efficiency.
Also, don't read more into a message than is there. Currently, this much reduced incremental cost is not now competitive in many places. Without the renewable power requirements in CA, it might not even be competitive there. With the appropriate tax, it would be competitive in some places. Thermal solar power attached to existing thermal power plants is not a magic bullet to solve global warming, but a useful component to our energy portfolio.
I think it's not a very useful component of our energy portolio, more like a useful strategy to bring down the cost of the solar field and get more operating experience (good for attracting investors)...
Think of it as a 'stepping stone' to standalone solar power plants with thermal storage, just like natural gas - solar hybrids are a stepping stone to standalone solar power plants with thermal storage. As natural gas gets more expensive over the years, add more storage to reduce gas usage per kWh. Gets gradual experience with thermal storage to reduce risk.
What would be more simple is gasoline tax first then general energy tax. Those can afford 2000sf home or 15mpg car will pay more tax and penalty.
Yes, appropriate penalty = tax (or the equivalent value in cap-and-trade permits). It also should be revenue neutral, so that every extra dollar raised here is a dollar less taxed elsewhere (pick the tax you hate the most).
How does it help? It forces everyone to face the same cost when reducing carbon emissions.
The alternative is a mish-mash of subsidies that imply different costs for reducing carbon emissions. CAFE standards, speed limits lower than safety requires to save gasoline, cash for clunkers, renewable requirements for power generation, ad hoc requirements for approval processes for power generation plants, stimulus funds on green behavior that wouldn't have been supported without the recession, ... All imply different costs for saving a ton of carbon.
And what about the many ways to conserve with our travel, heating and cooling our homes and businesses, and industrial energy use. For most of these, there are no subsidies.
The biggest short-term change with such a tax would be conservation where subsidies are largely absent. The biggest long-term changes would be in power generation and more conservation as manufacturing processes, cooling and heating systems, autos, appliances, and buildings are remade for more energy efficiency.
Also, don't read more into a message than is there. Currently, this much reduced incremental cost is not now competitive in many places. Without the renewable power requirements in CA, it might not even be competitive there. With the appropriate tax, it would be competitive in some places. Thermal solar power attached to existing thermal power plants is not a magic bullet to solve global warming, but a useful component to our energy portfolio. Free-standing large solar power plants of other types are not likely to be useful for decades, at least.
Every time you say "global warming", half the population turns off. Just say "it is not good to burn tons of crap in the air we breath". Even Boss Hog (from Captain Planet) can believe that.
I prefer the term "global climate change" since I think it's more accurate and probably more true.
It is too bad that we have to scare people with the threat of global meltdown before the greater population starts getting passionate about what is pumped into the atmosphere. The burning of fossil fuels has always released some nasty chemicals into the air. Carbon, when you ignore the effect it has on earth's temperature, is in itself quite harmless. This is why it is not included in the EPA's list of Hazardous Air Pollutants.
So instead of putting all this focus on reducing carbon emissions due to its potential to accelerate climate change, why can't we just limit stack emissions for the purpose of protecting human and environmental health? Really you would be killing two birds with one stone in that case, and there would be no disagreements between scientists regarding the benefits of doing so.
but a tax focused on carbon is unnecessary, counterproductive, and based on non-science. taxes may make sense to attempt to change behaviour in some cases, but in the case of carbon, it makes no sense at all.
Please! Please! No more Taxes.
Our Government, the drunken saliors will play the shell game and line their own pockets. In Pa gambling was to benefit seniors.
Guess what? When municapalities realized that senior folks had that subsidy which was less than 5% they raised taxes and the benefit to seniors evaporated. Another government Tax scam is to tell people they will reduce police and fireman unless they raise taxes. They know this is an issue close to peoples hearts, and that folks will be suceptable to their demands. Government needs to learn to live within it's means. We have so many hidden taxes now, we don't need another.
Citizens are supose to be their boss, not the other way around. More taxes never solves anything. It's only a bandage to a potential real solution.
Keep it simple. "That Government is best that governs least"
We already pay enought taxes.
I don't want Tax Free Day to be October 31st.
It is an unhappy truth that any new investment made by a coal plant is going to result in consumers paying higher tax on the energy they purchase. Although I too do not like the thought of my wallet being strained more than it already is, I am an advocate of taking a good look at the true cost of industry. From an environmentalists point of view, we as consumers do not pay the 'true' cost for anything. Since our current topic references coal, I'd like to point out that the amount we pay for electricity takes zero consideration for the massive amount of environmental destruction we are causing when we mine for coal. The cost of pollution and loss of biodiversity is in no way calculated into the price we pay per kilowatt hour. This is why the state of the Appalachian mountains and the community that lives there is as poor as it is today.
So before I turn this into an environmental debate, I just want to say that we need to look at the big picture when it comes to the price we are paying for any product on the market. If the consumer wants their televisions, i-Pods, and NetBooks, be prepared to pay the environmental and social costs associated with them.
Nuclear cost the same per kw at this moment $4500/KW (after subsidy) for nuclear, $4490/Kw (before subsidy) for Solar Thermal... and that doesn't count legacy costs of nuclear storage, decomissioning costs of $1 billion, and catastrophic failure associated with nuclear, as well as immune suppression lost work hours world wide from radiation related immune problems amounting in the trillions! Solar Wind and Hydro win hands down.
is that steam turbine delivery is also a big bottleneck for standalone plants, it takes a long time from turbine order to first kWh generated. This approach avoids that delay. Maybe they can build some plants quickly.
The coal steam plant piggybacking thing allows for economies of scale in manufacturing and installation and improved operating performance to reduce the cost of the solar field. After all that's the biggest cost component of a concentrating solar thermal electric powerplant!
Ausra's CLFR design tried this coal hybrid strategy though they found their technology a bit limited due to the even lower field temperatures. What really killed them in Australia was a negative policy environment, causing them to flee from Australia to the US. Now they're still in trouble because of the macro economic situation...
Maybe the hotter run troughs can do better and get more MW from a given coal plant, though it is doubtful that such troughs are cheaper than the CLFR design.
This idea shows how the money tends to follow the investments that are already made. The owners of the coal rich land push what ever keeps their investments going. I understand and would do the same. It is the same for the oil producers, with all their ships, pipelines and armies. However, a lot of small nuclear plants diversified with solar, wind and/or geothermal (what ever is best in that geographic area) would be better for the country, environment and freedom. Fossil fuel should be used for making plastics and chemicals, not burning in the air. I suppose it is how it must be. If the government tries to force a different path they just make it worse because of corruption and stupidity. I wish the singularity would hurry up and get here to save us from this crap.
No you are wrong, see my comment above! Nuclear has tremendous costs, and is not so cheap, without subsidy it would not even be worthwhile, and carries tremendous costs long term which are not often accounted for in calculations. Solar thermal stand alone plants are much more cost effective.
Supplementing Coal or Nuclear plants with solar electricity is a vital way to push development in solar forward. Investment cost is everything, all of a sudden, the existing Coal plants (which may people dislike) have a competitive advantage at entering the solar business, simply amazing!
I am surprised this idea did not come out to TechReview sooner.
Dr. Brian Glassman
Ph.D in Innovation Management from Purdue Univesity
What I don't get is why are they using solar thermal to pre-heat the water? Every coal power station I've seen has massive cooling towers to try and cool the water down - why not just use some of that instead. Surely that's a lot cheaper than installing a load of parabolic troughs etc?
Those cooling towers cool the liquid which is being recycled. The cooling towers turn the steam back into liquid, and yes the heat from them should be recycled.
Basically, conversion of liquid into gas causes wind. That's how nuclear/coal/solar steam engine work. Natural gas function two way into similar wind(ie function similar to car engine, plus use the heat for steam).
Cooling is unnecessary, except to recycle energy and H2O so one don't discharge it and start from room temperature water.
to use coal to maintain the baseload power levels (at night when the sun doesn't shine), and supplement with solar during the day for peak loads. In this case, the solar heat and the coal feed their energy through the same generating system of boilers, etc.
I have not seen this idea yet: if we electrolyse water to make hydrogen, oxygen is a byproduct. If we burn dirty coal with the oxygen, we then have pure pollutants (mostly CO2), which can be pumped directly underground (or otherwise dealt with)--the savings is that one does not have to use concentration & filtration systems to separate the pollutants from atmospheric nitrogen and oxygen. Another layer of efficiency is from running the plant at full capacity, so that off peak electricity is used for electrolysis, and yet another is to use wind & solar for electrolysis as available. Also, hydrogen could be burned with the oxygen to meet peak electricity demand as well. So the H2 & O2 is also used as energy storage. (much the same way as gas turbines sometimes compress air into a resevoir during low demand times, to be used in the turbine later during high demand times)
Maybe I don't read enough.....
See dotyenergy.com regarding your ideas. You are on target, but you are not alone in having your ideas. The problem is the capital costs in building equipment that will capture energy (solar, wind) that is intermittent, i.e. not always available
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jmaximus9
86 Comments
Great Idea
This is an awesome idea and business concept. Once the initial expense for the solar collectors are paid for the rest is nearly pure profit. The utility will run the coal plant and all you have to do is make sure the collectors are cleaned once in a while.
In Michigan I think Geothermal would work better and would provide continuous power 24/7 unlike the solar thermal collectors. BP recently announced a well that is in 10,000 ft of water and then goes 10 km down, so the technology is there today for Geothermal. 10 km down is deep enough to power a geothermal plant in every state in the country.
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