Turns out that coal-fired power plants are just not very efficient - only 35% efficiency - so they lose out to all other types of power over the vast majority of the US.
Especially the midwest.
This interactive map allows you to make your own calculations for your area, and figure out what kind of power makes sense for you and your neighbors. (And then repeat that process anywhere else on the map, too.)
Boilers are like 35% efficient. Coal is just the fuel. I know just enough to say almost but not quite the right thing. I think I'm thinking of the Carnot efficiency limit discussed on the Wikipedia Rankine cycle page. Coal plants (really pretty much any utility scale plant) will assume a 40 year life with lifespan extensions beyond that. People would happy build coal-fired plants if they thought they would remain profitable for 40 years. But the regulatory uncertainty means there's a really good chance they won't be.This gives a theoretical maximum Carnot efficiency for the steam turbine alone of about 63% compared with an actual overall thermal efficiency of up to 42% for a modern coal-fired power station.
Kentucky is converting many of its coal plants to natural gas. Turns out a pipeline from Texas is easier to maintain than a ton of rail cars from Western Kentucky and Tennessee. Also turns out that LNG is cleaner, less solid waste to deal with (translation none with gas) and coal slag/dust/ash is radioactive so you cannot even use it as landfill and fertilizer. All these coal guys in the state are not looking forward ten years to a new reality of life, for if they were they would be in full on CONDITION RED freakout mode. And with cars getting more and more efficient, I'd not be shocked at all at super high-efficiency gas/diesel burners making a comeback. My dream would be thorium nuke plants, but those are 20ish years out.
My anecdote is small, critically located coal plants are getting converted to natural gas. Small, non-critically located coal plants are getting shut down and utilities are building new combined cycle gas plants. The biggest coal plants aren't threatened yet, but their utilization is going down. They'll definitely run during pretty warm and pretty cold periods, but they might stay off for weeks in the mild periods. Meanwhile the combined cycle plants will run nonstop until they have to come down for routine maintenance.
The sun and wind are really all we need. But how can we make money off this.... Until that happens big business will only hint at work with everyone. Someday, we will all have solar and plug in our cars that drive us to work while we watch netflix. It will be a great day. Hope it's soon. The earth is needing us to do something or she will probably send out a plague or take the ground from underneath us.
Well, you don't make money off power itself, you make money off making the power available, and on maintaining the lines between privately owned properties. Same business model as cell phones. You don't charge per call, you charge for access to the network, and then how much of the network you use. The problem with power is that there is a monopoly in place currently, that controls all the wires and the sources. If you look back at the Bell Telephone System that i grew up with, it was the same thing. All phones came from one company. If you wanted a telephone in your home, you called Ma Bell, and she installed it and charged you for it. But the Federal Government broke up Bell into a bunch of different competing companies, and the prices for telephone service plummeted. Technology then came alone and untethered the phone from the wall, and boom... cell phones, t-mobile, verizon, orange, vodaphone, etc, etc, etc. There will be a confluence of factors that come together (probably due to Elon Musk grabbing the two things and dragging them near enough to each other that other companies see the opportunity and jump on it), but it is going to be a while because it involves infrastructure costs... materials, holes dug in the ground, and government permits. It'll happen. It has to.
I saw this earlier but didn't have a lot of faith in their wind power calcs... To the best of my knowledge wind tech is only incrementally better than 50 years ago yet wind farms remain rare. Wasn't sure about the disconnect; anybody know any better?
The wind tech is way better than it was even ten years ago. The expiration of GE's patent on variable speed turbine generators opened the versatile technology up to everyone. These turbines can control voltage more dynamically. Separately, the cost of power electronics have come down, so now some turbines use full converters to change the generator output to the power system frequency. These can eliminate gearboxes, too, and also control voltage. In the US, FERC has made a number of rulings that forced wind plants to improve. FERC Order 661-A (pdf) required wind turbines have low voltage ride through, forcing them to remain online during system faults. 661-A also mandated a power factor range, relating back to the GE patent and full converter turbines with their ability to control voltage. We're also able to push the power system harder than ever. Fifty years ago we still had manned substations. People would sit there and call the control center every so often to tell them what the analog meters showed. Today we scan every analog and digital point every few seconds. And every few minutes the entire system is simulated to see what would happen if a failure occurred. That lets the system accept more wind. The output is variable, of course. The system was easy when it was the same generators running all the time. The variable wind output means one day to the next could be drastically different. The tools allow us to be confident the system is still reliable. There were a couple wind output records broken in the US a week or two ago. I think MISO topped 13,000 MW. For comparison, that's about double the maximum output of Grand Coulee. To me, the issue is wind doesn't provide capacity like a gas, coal, nuclear or hydro plant does. I think MISO allows something like 16% of wind nameplate capacity to count as capacity to serve load. So you build a 100 MW wind farm, and you get 16 MW of capacity. Build a 100 MW gas combustion turbine and you get 100 MW of capacity. Load needs capacity to ensure all load can be served.
It seems to me that all this discussion about efficiency and output levels, etc, is like a group of engineers debating what shape the electrical outlet should be; it all kinda misses the point. The real weakness is storage and transmission. We have plenty of methods for making power. What we don't have is a good way to store it for when we need it, and to transmit it from one place to another (ex: from a solar plant in Nevada to NYC in the winter). We need a good way to store vast amounts of power, and transmit it with much less loss, over much larger distances. Generating power if/when you want it, seem backwards to me. Shouldn't we take power when we can get it (solar, wind) and then store it for when we need it? I've been thinking a lot about that plan somewhere to store the energy by pushing a bunch of water up a hill into a reservoir... and then thinking of a series of dams, like a fish ladder... and we push water uphill when power is being generated... and let it flow downhill and generate hydro power when we need it... I dunno. That still means we have the power transportation problem, but if cities had hydropower generators instead of water towers, then power could be transmitted in stages, from city to city to city... and... Ok, it's a huge infrastructure project, but hey... it worked for the WPA! (Which, incidentally, would also get a whole bunch of people trained into the Trades - concrete, electrical, plumbing, etc - and provide a boost to the Trades industry with newly trained, skilled workers, and, and, and provide people with options other than going into enormous debt for a college degree... and help people in depressed areas get good-paying jobs, and...)
Having more flexible load has been talked about for years, but nobody has made much progress on it. Little load is flexible. Around a home, refrigerators have to run regularly to keep food safe. Businesses have to keep running to sell their goods. Industry needs to keep running because while they may have high energy bills, if they aren't running they can't pay for their capital needs. Storage is definitely a big deal. Today, energy is stored in piles of coal and gas pipeline pressure. Doing a little math, this link says a 500 MW coal plant burns about 1.4 million tons of coal per year. I think coal plants usually store about two weeks worth of coal, so let's say they have 50,000 tons on hand. Wolfram Alpha says coal has about 7000 kWh/ton, so that coal plant has about 350 million kWh worth of energy sitting in a big pile outside. Only about 35% of that will go out the wires; the rest will go up the stack or into the lake or river. But that's still 120 million kWh of usable energy. As far as I know, this 120 thousand kWh battery is still the largest single battery out there. It would take a thousand of these just to equal the storage capacity of a coal plant's backyard, and you still haven't produced a single watt. The problem isn't impossible, but we're still so far away from the solutions being easy.Shouldn't we take power when we can get it (solar, wind) and then store it for when we need it?
Thanks for engaging with me on this. I really think that our power grid needs to be way more like plumbing: a base level of water is always available, and then if Nevada needs to water their lawn tonight, there is additional capacity in store to draw on. A radical rethinking of where we get power, how we store it, and how we make it available to the places that need it, especially when that need spikes... It's a Big Problem, but one I can't imagine we aren't going to have to solve in the next 20 years.
It's definitely a Big Problem. The challenge with flexible load is finding load that's flexible and manipulating it to the advantage of the system. Some load can be shifted pretty simply. My refrigerator is currently running. If it had waited five more minutes to run, my food would still be cold and safe. But it will need to run eventually. Storage is the potential miracle here. Despite press to the contrary, batteries aren't economical today to store energy for any significant length of time. They've been deployed economically for extremely short duration energy shifting, seconds to maybe a minute. I think they need to come down in price by an order of magnitude to really change anything. Maybe they will; it'd be great if they did.
1) The storage is the grid. 2) The efficiency of a wind farm matters a lot less than the availability and quality of wind. 3) Yes we have "plenty of methods for making power" but if that power is only made at midnight on every fourth tuesday then you're well beyond storage problems because nothing holds megawatts for days at a time. 4) You're discussing compressed air energy storage or pumped storage hydroelectricity both of which I'm sure WanderingEng could talk a lot more knowledgeably about... as well as DC power transmission, which kinda licks the "grid" problem.
I think you and goobster are saying pretty much the same thing here. You're completely right that the grid is the storage mechanism, at least today. With demand inflexible and wind and solar inflexible, as long as the flexible parts of the grid can make up the differences, everything works. That hits goobster's point about transmitting energy over longer and longer distances. When one part of the grid becomes saturated, whether it's one neighborhood or a group of states, the grid has to be expanded to pull in more flexible resources. HVDC is awesome for that, but it's also pretty expensive. Ballpark estimates are like $150M per converter station and $2M/mile of line. Projects quickly reach billions of dollars. Any transmission line also has public opposition. They cross rivers and backyards. While some impacted don't mind and don't mind the payment that comes with, some will fight it to the bitter end. I'd say the technical aspects are pretty well understood. It wouldn't be hard to design a system around mostly wind and solar, but nobody would be willing to pay for it.
As far as I know, nobody is doing that. At this point, anyone putting up the capital for a wind plant wants to maximize output. Utility scale, horizontal axis turbines will produce more energy overall, even if it's less optimal at some wind speeds.