Maybe not, but it does involve them with their peer group. The way to solve the bullying problem is to teach kids to fight back; but adults are old and stupid and go "oh no, no, you want to cower in the corner and show people that flexing their muscles and punching people gets them power, and all they need to do is scare you into not tattling or make sure you're not known to them well enough to tattle!" Then they tell people not to beat their kids. So you have kid who gets sent home to eat peanut butter and jelly sandwiches and not study and goes "LOL STUPID SUSPENSION" and comes back and kicks your ass for telling the teacher he kicked your ass the first time.
Lots of home schooled kids commit suicide. School acts as general socialization, rather than hyper-focus socialization where you become part of an elite class of chess players and don't know how to communicate with people who lead lives doing things that actually engage the brain, like playing Go.
I am talking about the ability to actually scale power down when it dips, instead of suddenly ramping it up hard. Did you not get the memo?
The plants spin down when load reduces. Eventually. When load comes back, they come back up. If we have a 4% load spike, the plants will compensate by raging hard, mostly pumping out waste heat that's not being converted into electricity, to get the turbines up to speed more quickly. It's like how when you get on the highway your 30mpg econoshitbox is getting 4mpg coming up the merge lane with the engine roaring.
Instead, I want to spin down the pumps to very low (just idle at a speed that lets you spin the pumps back up without putting load on the starter coil or wearing down the motor life significantly--you don't want to start-stop the motors a lot, but you can declutch them or shift the CVT ratio and let them spin on no load!), and let the water towers supply water pressure. Then let the plant bring up power production gracefully to cover the demand, burning less fuel in the process (gentle acceleration). Then spin the pumps back up.
As an extension, RELY ON WIND POWER TO SUPPLY BASE LOAD POWER. We can't do that now because wind and solar can go from 100MW overproduction to 5mW depending on which direction the wind blows (literally). If we need 500GW and we have 10GW of wind and 30GW of solar and 475GW of coal, and the wind shifts and pushes the clouds in the way of the sun, you now have 490GW total production and you get a brown-out and the coal plant hauls ass.
Instead, let the wind plant 95% cover municipal water needs as baseload power. If they suddenly can't, back the waterworks down and let the water towers take over; raise the coal output gently to avoid burning excess coal.
It's a start, and it's small; but wind and solar supply are also small. This should let us handle 5% fluctuations without being so wasteful, though. Think of it like a hybrid system that uses a more efficient but more difficult to store fuel source to accelerate. Like the water towers are batteries. Accelerating a car is hard, burns a lot of gas; bolt in an electric motor and let the alternator charge up a storage cell though, and when you hit the gas hard it powers up the motor and the engine just has to idle. Electric motors are much more efficient at translating a lot of power into a lot of torque, whereas chemical fuels produce a lot of waste heat to generate high amounts of torque (this is obvious, because the chemical fuel is going to burn more fuel, then exhaust the hot gas before it's transferred its energy out as motion).
It's a lot of water to supply the power to run the pumps to pump NEW water. This water has already been pumped. A good electric motor is 70% efficient, so you need at most 0.49 times that much water (we're double-dipping here: You lose 30% in the first place to store, and then if you retrieved to convert into electricity to drive pumps you'd lose 30% again; we're bypassing that). That doesn't account for inefficiencies in the system--for the difficulty posed by pumping water long distances, incurring losses because of conversion of compressive and friction forces to heat and dissipation throughout the system (longer pipes means more loss this way) and due to the nature of trying to pump a fluid liquid in the first place.
Further, towers are extremely effective at storing water pressure--a high tower requires so much ground-level pressure to pump water up to it in the first place, and at the ground level that water will supply the same exact amount of pressure at 100% efficiency (i.e. if it takes 100PSI to get it up there, it's going to push down at ground level at 100PSI). Pumping water up against gravity, however, is inefficient: the higher you go, the slower the water moves in the whole system.
So 36,000 cubic meters of water to supply one hour of power if we're down to 10% efficiency. At the most, 180,000 cubic meters--49%. Again, smaller cities supply 24 hours of water pressure stored in towers.
The whole "Earth Day" thing is bogus because it increases emissions. Turning off the lights doesn't relieve enough demand for the coal plants to throttle back; worse, when everything comes back on, the sudden spike in demand can (and often does) result in coal plants spinning up hard if they did throttle back, so you save a pound of CO2 output and then burn a ton just to get back up to speed to match demand.
Fluctuation in demand is not helpful. If we scale back the coal plants when the wind plants are big (thus supplying power to the grid, thus reducing the demand on the coal plants), then we wind up burning more fuel to get back up to speed when the wind plants have no wind suddenly. Small towns store about a day's worth of water in water towers, and can run for 24 hours without pumps. That gives plenty of time to slowly, efficiently ramp up the coal plant with the water pump after the wind power to drive the water infrastructure suddenly cuts out and the pumps have to scale back and idle at 5% capacity to avoid causing a brown-out. Rather than suddenly burning shitloads of coal to rev up those turbines, we suddenly use that much less electricity and slowly, gently bring the plant back online.
Pump water can be about 4%. California uses 19% of its power to mess with water, including heating water, irrigating cropland, industrial uses, etc. 22% of that is just water transfer, distribution, and pumping, which is a little over 4% of total electrical energy usage. Baltimore City has 14 coal plants, the largest of which is 2400GW; 4% of just that plant would be almost 100GW. I am confident that the total supply of clean-air variable energy sources is not big enough to drive the waterworks of the state of California; and that the fluctuation in power drain would be significant if the waterworks could be idled quite low for 4-24 hours while the coal and oil plants gently accelerate instead of inefficiently rolling up a shitload of fuel.
Nope, not correct. The numbers at 10,000 PSI are worthless, because the density numbers I'm using for fuel ENERGY DENSITY per volume assume liquid hydrogen, which is more dense. Liquid hydrogen at 33K supplies as much energy per 1 gallon as liquid gasoline supplies per 4 gallons. Gaseous hydrogen at 10,000PSI supplies less, but I don't know how much less so I just work off the liquid hydrogen numbers which are more liberal and assume that you get more energy out of this than you really do.
It's not 17.6L/667. It's plain old 17.6L OF LIQUID HYDROGEN. Which by the way when you consider the air flow... from 10,000PSI at 5.5mL/s that would be 3.6L of hydrogen per second at atmospheric pressure using your numbers (a lot of hydrogen). Of course my numbers assume liquid hydrogen, which is more dense, so.. damn that's a lot of flow.
And if you out-gas fuel, you lose fuel. If you burn fuel to maintain temperature, you lose fuel. So you're arguing that hydrogen is superior because we can put a hole in the gas tank and constantly leak fuel to keep the tank cold so it doesn't explode? Works for NASA but really, they accept the costs too.
You continue to miss the point. I'm not talking about pumping hydro to store electricity; I'm talking about going to a big thing that consumes electricity (Water pumps) and backing off the throttle so they consume less electricity. When the wind farm can't satisfy the water pumps, scale the pumps back; the water towers WILL supply enough water for several hours of water pressure, during which time you can raise your baseline energy by burning more coal, and get the water pumps back to full capacity.
You underestimate the consumption. 4.4L/100km at 1kph for gasoline. For hydrogen it's 17.6L/100km, on the highway... christ. That's a lot. It's going to do exactly what ninja air does when you spray out your keyboard, but much colder. Think how fast those cans get cold. 5.5mL per second just about? Give it 30-45 seconds to get colder than Alton Brown's freezer (-27 degrees. Kelvin.)
If we were sitting in Huston at NASA central command, someone would probably actually tell you to squeeze the trigger on your canned air just about 1/4 of the way to get a slow, steady hiss, and watch how much longer it takes for the can to frost. Which is like, a minute.
No, but you don't need to bulk battery them. During the peak times when energy is being used and your wind farm is turning, there is no storage. You supply power. During off peak, you can supply the water to drive the water pumps. Fill the towers, then drive municipal pumping. Drain the towers as you start to lag, and spin up the municipal pumps again putting demand back on the grid.
My thinking is it's hard to sharply spin coal plants up/down to meet varying demand, and demand is not something you control. But we can control demand, can't we? We have water pumping infrastructure that supplies a constant demand baseline. We can use the excess wind energy to power the pumps, spinning down the baseline generators. When the wind power is not so great, we have big water towers that keep the pressure going, and we reduce the load from the water pumps on the grid to make up for the wind power not being big enough and thus prevent brown-outs; and while that's keeping up with the demand, we have plenty of time to steadily raise baseline power plant output to power the water pumps again.
Pumped hydro is the perfect way to go with excess energy from intermittent power sources though. You could turn down the pumps (consuming electricity) and instead drive YOUR pumps drive the water system, and pump water into towers. Granted a water tower only holds oh 1800 cubic meters of water, but when the towers are full you can still do all the pumping for the city if you have that much excess electricity and demand isn't growing. Turn down the usage of those water pumps and turn up the usage of the pumps right at the turbine. Drain the towers at night and when they're low you turn the pumps back up to full output. You might be surprised.
Let out the H2 at a rate equivalent to 4 times the average gasoline use, since LIQUID H2 is 1/4 as energy-dense per volume as gasoline. For high-pressure gaseous H2 it's going to be much faster.
Assuming your H2 tank is at room temperature, it's going to be under 10,000PSI of pressure. This is a real thing. If you rupture that tank, it's going to explode. The surface area of that tank times 10,000 pounds is the amount of force it's going to explode with. That's a lot more than 60psi launching a beer can. Almost but not quite 200 times as much force.
When it's 106F outside, how do you keep your tank from reaching 106F and spiking to 30,000PSI or 50,000PSI?
The discussion was about cars, not powering your house. Cars are powered by batteries or liquid fuel. Electricity is highly transportable, which is where your original argument was; electricity storage units are more difficult, but better than hydrogen. Not as good as diesel or gasoline. As for "green" energy, why can't we supplement baseline with it anyway, and use it to pump extra water into water towers which then allow us to spin down water pumps for a time? Electric motors scale back readily enough, and we can target our grid that way... hmm.
I'm going to switch from nat-gas to a heat pump for heating. Dual stage compressor to cut back on my energy usage from gas, which is at 170 therms for January (yes that's 5,000kWh). Estimates for the heat pump to do the same job are about 250-350kWh. 70 therm for the surrounding months, so my total energy usage should drop substantially.
By the way, that's still 5MWh per month or 0.17MWh per day, not 50MWh.
No, how the heck? It would be 70kg per meter cubed (i.e. 150lb for a 265 gallon tank, or 5.5lb for a 10 gallon tank) cooled to 33K. 1kg of Hydrogen has about the same energy as 1gal of gasoline: 33.4kWh. That means your 10gal liquid hydrogen tank acts as a 2.5gal gasoline tank.
Gaseous hydrogen would be much less dense unless under extreme high pressure; that means once you raise the temperature above 33K, the pressure in the tank increases RAPIDLY and the tank explodes violently. Mind you that's 33K at the critical point with a pressure of 13.3atm or about 200PSI. The state-of-the-art for hydrogen compressed gas tanks is carbon-fiber at 5000 or 10000 PSI; while you're jabbering about how hydrogen doesn't explode because it goes up when it's released, you should realize that detonating a 60PSI tire can kill a man (stand on top a 21 inch tire you're mounting on a rim, inflate to 60psi to set the bead, and if the bead slips the tire will eject the wheel off the ground and slam your head into the ceiling 10 feet above, killing you by crushing your brain case into your brain), and people inflating bike tires to 70-90psi have gone deaf because the inner tube burst and emitted a loud bang in front of them (much less volume of gas than a car tire). If your 10,000 PSI hydrogen gas tank blows, we call that "lift-off".
On the other hand, as you draw hydrogen out and the pressure drops (due to the partial pressure of hydrogen, because even at 33K the tank's not going to be filled with vacuum), some of the hydrogen will boil, causing rapid cooling, making the tank brittle. If you're working with gaseous hydrogen this will also occur.
So in summary: You need to keep the tank fucking cold, or at extremely high pressure. In either case, you don't want the tank to warm up because pressure will increase rapidly. You also don't want the tank to self-cool as you draw off fuel, because it will freeze the material and cause the tank to become brittle, which can lead to catastrophic failure.
It's both. When you're not drawing fuel, the tank is going to need active cooling if it's exposed to a hot summer day. When you're drawing fuel, the tank might cool very fucking fast. The tank needs to retain temperature that is not hot enough to boil the hydrogen (hint: it's always hot enough to boil the hydrogen) and not cold enough to make the metal brittle such that it shatters when you hit a speed bump at 10mph. It's a pretty narrow band and everything impacts it.
And a AA lithium ion battery costs about $7-$10 but I see some on sale for $3.50 right now. I'm talking about rechargeable Li+ batteries, the same thing used in the Tesla Model S.
I'm seeing some of these at 900mAh, while my Sanyo Eneloops are 2700mAh each and somewhat cheaper (a little under $3 each). Therefor it would take, oh, a LOT of Lithium Ion and less NiMH.
What you have to remember is that electricity to power a city is best, most efficiently transported over large distances by HVDC power lines; while energy to power a car has to be portable and refuelable, and thus we have liquid fuels because batteries kind of suck for recharging since it takes hours. The Tesla Model S handles 500 recharge cycles (100,000 miles at 200 miles per charge is what Tesla suggests), whereas these NiMH batteries handle 3,000 recharge cycles. Lithium Ion batteries hold their charge pretty damn well and will charge a bit faster than NiMH, mind you; between that and the patents on NiMH for use in automobile-scale batteries, Li+ is the obvious choice for cars out of current battery tech.
By the way, my two-story house uses about 400kWh per month, or 0.013MWh per day. Turn your TV off when you go to bed.
Yeah the problem is if our bodies of water die, we have a body of stagnant dead water. This creates... problems. A lot more than just "The air smells like shit all the time," Which it will.
The only thing that's keeping the bay in tact these days is the localized diphasic timeline pairing it with a not-dead version of the bay from an alternate universe.
How so? Electricity can be stored for quite a while in lithium ion batteries. Hell I have some NiMH batteries that will retain 80% power over 3 years of shelf life and enjoy 3000 recharge cycles.
Nobody's brought up real numbers on hydrogen usage, so I question these, with hypotheticals.
Consider if you have one unit of fuel that produces 1000J of usable energy. This fuel is Hydrogen or Gasoline, for simplicity.
Now let's say it takes 2000J of energy to produce that unit of gasoline that you can burn for 1000J of usable energy, but 20,000J of energy to produce the unit of Hydrogen that you can burn for 1000J of usable energy. In these terms, gasoline is more efficient: you use less energy to get a fuel unit you can burn to produce a certain amount of output in the fueled machine.
Now let's say that 1000J unit of fuel is 1 liter of Gasoline, or 10mL of Hydrogen. Space vehicles spend most of their energy getting their own fuel off the ground in the early launch stages--really fucking heavy fuel won't work. Further, the final module is small (again to save materials weight). Since Hydrogen in this model would be 1/100 of the volume, there's a storage space savings for final module fuel (and booster size, where the booster is metal--but again, early launch cares about fuel weight). With hydrogen not being 100 times as dense as gasoline, there's also a weight savings.
So in this model, hydrogen is a TERRIBLE fuel; however it's much more viable as a fuel source than gasoline for space travel, because you would need a LOT more gasoline, your module would be a LOT bigger, your boosters would be MASSIVE, and you might break the theoretical limit where you simply can't get enough output to lift the damn thing with all that heavy fuel if you tried launching with gasoline.
NASA has different concerns that determine what's viable tech. Fuel source is tech. Is hydrogen a better fuel, or is it just a better space fuel?
Black holes draw a lot of shit toward them because gravity. Cosmic gasses are drawn in and compressed, which causes super-heating. Also objects--big space rocks--are drawn through this compressed gas, causing friction and more compression and super-heating. If you drop shit in a black hole, you get an explosion 20 times bigger than the biggest thermonuclear bombs we've built. That's why black holes glow so fucking bright even though they suck in everything up to and including light.
Holy shit that's a lot of technical problems. If the tank isn't kept ultra-cold (i.e. it's hot outside) it explodes. As you burn hydrogen, pressure drops, the hydrogen in the tank cools the metal ridiculously. And what's with this mass/volume of storage? That's good if you need transport, but not necessarily efficient to produce--gasoline could be 20 times as efficient and it would be 100% useless in space versus 2% efficient hydrogen. How do they compare?
Storing and transporting hydrogen is just too friggin' complex for econoboxes.
Polchinski is actually correct, sort of. Everything approaching a black hole is being compressed; you'd be exposed to the burning energy of a hundred thousand million thermonuclear explosions before reaching the event horizon.
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Maybe not, but it does involve them with their peer group. The way to solve the bullying problem is to teach kids to fight back; but adults are old and stupid and go "oh no, no, you want to cower in the corner and show people that flexing their muscles and punching people gets them power, and all they need to do is scare you into not tattling or make sure you're not known to them well enough to tattle!" Then they tell people not to beat their kids. So you have kid who gets sent home to eat peanut butter and jelly sandwiches and not study and goes "LOL STUPID SUSPENSION" and comes back and kicks your ass for telling the teacher he kicked your ass the first time.
Fell down some stairs, sir.
Catholic school is superior to regular school. Love those slightly slutty 18 year olds in college.
Lots of home schooled kids commit suicide. School acts as general socialization, rather than hyper-focus socialization where you become part of an elite class of chess players and don't know how to communicate with people who lead lives doing things that actually engage the brain, like playing Go.
I am talking about the ability to actually scale power down when it dips, instead of suddenly ramping it up hard. Did you not get the memo?
The plants spin down when load reduces. Eventually. When load comes back, they come back up. If we have a 4% load spike, the plants will compensate by raging hard, mostly pumping out waste heat that's not being converted into electricity, to get the turbines up to speed more quickly. It's like how when you get on the highway your 30mpg econoshitbox is getting 4mpg coming up the merge lane with the engine roaring.
Instead, I want to spin down the pumps to very low (just idle at a speed that lets you spin the pumps back up without putting load on the starter coil or wearing down the motor life significantly--you don't want to start-stop the motors a lot, but you can declutch them or shift the CVT ratio and let them spin on no load!), and let the water towers supply water pressure. Then let the plant bring up power production gracefully to cover the demand, burning less fuel in the process (gentle acceleration). Then spin the pumps back up.
As an extension, RELY ON WIND POWER TO SUPPLY BASE LOAD POWER. We can't do that now because wind and solar can go from 100MW overproduction to 5mW depending on which direction the wind blows (literally). If we need 500GW and we have 10GW of wind and 30GW of solar and 475GW of coal, and the wind shifts and pushes the clouds in the way of the sun, you now have 490GW total production and you get a brown-out and the coal plant hauls ass. Instead, let the wind plant 95% cover municipal water needs as baseload power. If they suddenly can't, back the waterworks down and let the water towers take over; raise the coal output gently to avoid burning excess coal.
It's a start, and it's small; but wind and solar supply are also small. This should let us handle 5% fluctuations without being so wasteful, though. Think of it like a hybrid system that uses a more efficient but more difficult to store fuel source to accelerate. Like the water towers are batteries. Accelerating a car is hard, burns a lot of gas; bolt in an electric motor and let the alternator charge up a storage cell though, and when you hit the gas hard it powers up the motor and the engine just has to idle. Electric motors are much more efficient at translating a lot of power into a lot of torque, whereas chemical fuels produce a lot of waste heat to generate high amounts of torque (this is obvious, because the chemical fuel is going to burn more fuel, then exhaust the hot gas before it's transferred its energy out as motion).
It's a lot of water to supply the power to run the pumps to pump NEW water. This water has already been pumped. A good electric motor is 70% efficient, so you need at most 0.49 times that much water (we're double-dipping here: You lose 30% in the first place to store, and then if you retrieved to convert into electricity to drive pumps you'd lose 30% again; we're bypassing that). That doesn't account for inefficiencies in the system--for the difficulty posed by pumping water long distances, incurring losses because of conversion of compressive and friction forces to heat and dissipation throughout the system (longer pipes means more loss this way) and due to the nature of trying to pump a fluid liquid in the first place.
Further, towers are extremely effective at storing water pressure--a high tower requires so much ground-level pressure to pump water up to it in the first place, and at the ground level that water will supply the same exact amount of pressure at 100% efficiency (i.e. if it takes 100PSI to get it up there, it's going to push down at ground level at 100PSI). Pumping water up against gravity, however, is inefficient: the higher you go, the slower the water moves in the whole system.
So 36,000 cubic meters of water to supply one hour of power if we're down to 10% efficiency. At the most, 180,000 cubic meters--49%. Again, smaller cities supply 24 hours of water pressure stored in towers.
The whole "Earth Day" thing is bogus because it increases emissions. Turning off the lights doesn't relieve enough demand for the coal plants to throttle back; worse, when everything comes back on, the sudden spike in demand can (and often does) result in coal plants spinning up hard if they did throttle back, so you save a pound of CO2 output and then burn a ton just to get back up to speed to match demand.
Fluctuation in demand is not helpful. If we scale back the coal plants when the wind plants are big (thus supplying power to the grid, thus reducing the demand on the coal plants), then we wind up burning more fuel to get back up to speed when the wind plants have no wind suddenly. Small towns store about a day's worth of water in water towers, and can run for 24 hours without pumps. That gives plenty of time to slowly, efficiently ramp up the coal plant with the water pump after the wind power to drive the water infrastructure suddenly cuts out and the pumps have to scale back and idle at 5% capacity to avoid causing a brown-out. Rather than suddenly burning shitloads of coal to rev up those turbines, we suddenly use that much less electricity and slowly, gently bring the plant back online.
Pump water can be about 4%. California uses 19% of its power to mess with water, including heating water, irrigating cropland, industrial uses, etc. 22% of that is just water transfer, distribution, and pumping, which is a little over 4% of total electrical energy usage. Baltimore City has 14 coal plants, the largest of which is 2400GW; 4% of just that plant would be almost 100GW. I am confident that the total supply of clean-air variable energy sources is not big enough to drive the waterworks of the state of California; and that the fluctuation in power drain would be significant if the waterworks could be idled quite low for 4-24 hours while the coal and oil plants gently accelerate instead of inefficiently rolling up a shitload of fuel.
Nope, not correct. The numbers at 10,000 PSI are worthless, because the density numbers I'm using for fuel ENERGY DENSITY per volume assume liquid hydrogen, which is more dense. Liquid hydrogen at 33K supplies as much energy per 1 gallon as liquid gasoline supplies per 4 gallons. Gaseous hydrogen at 10,000PSI supplies less, but I don't know how much less so I just work off the liquid hydrogen numbers which are more liberal and assume that you get more energy out of this than you really do.
It's not 17.6L/667. It's plain old 17.6L OF LIQUID HYDROGEN. Which by the way when you consider the air flow... from 10,000PSI at 5.5mL/s that would be 3.6L of hydrogen per second at atmospheric pressure using your numbers (a lot of hydrogen). Of course my numbers assume liquid hydrogen, which is more dense, so.. damn that's a lot of flow.
And if you out-gas fuel, you lose fuel. If you burn fuel to maintain temperature, you lose fuel. So you're arguing that hydrogen is superior because we can put a hole in the gas tank and constantly leak fuel to keep the tank cold so it doesn't explode? Works for NASA but really, they accept the costs too.
You continue to miss the point. I'm not talking about pumping hydro to store electricity; I'm talking about going to a big thing that consumes electricity (Water pumps) and backing off the throttle so they consume less electricity. When the wind farm can't satisfy the water pumps, scale the pumps back; the water towers WILL supply enough water for several hours of water pressure, during which time you can raise your baseline energy by burning more coal, and get the water pumps back to full capacity.
What do you imagine water towers are for?
True, but wax is also a lot cheaper.
You underestimate the consumption. 4.4L/100km at 1kph for gasoline. For hydrogen it's 17.6L/100km, on the highway... christ. That's a lot. It's going to do exactly what ninja air does when you spray out your keyboard, but much colder. Think how fast those cans get cold. 5.5mL per second just about? Give it 30-45 seconds to get colder than Alton Brown's freezer (-27 degrees. Kelvin.)
If we were sitting in Huston at NASA central command, someone would probably actually tell you to squeeze the trigger on your canned air just about 1/4 of the way to get a slow, steady hiss, and watch how much longer it takes for the can to frost. Which is like, a minute.
No, but you don't need to bulk battery them. During the peak times when energy is being used and your wind farm is turning, there is no storage. You supply power. During off peak, you can supply the water to drive the water pumps. Fill the towers, then drive municipal pumping. Drain the towers as you start to lag, and spin up the municipal pumps again putting demand back on the grid.
My thinking is it's hard to sharply spin coal plants up/down to meet varying demand, and demand is not something you control. But we can control demand, can't we? We have water pumping infrastructure that supplies a constant demand baseline. We can use the excess wind energy to power the pumps, spinning down the baseline generators. When the wind power is not so great, we have big water towers that keep the pressure going, and we reduce the load from the water pumps on the grid to make up for the wind power not being big enough and thus prevent brown-outs; and while that's keeping up with the demand, we have plenty of time to steadily raise baseline power plant output to power the water pumps again.
It's a lot of coordination though.
Pumped hydro is the perfect way to go with excess energy from intermittent power sources though. You could turn down the pumps (consuming electricity) and instead drive YOUR pumps drive the water system, and pump water into towers. Granted a water tower only holds oh 1800 cubic meters of water, but when the towers are full you can still do all the pumping for the city if you have that much excess electricity and demand isn't growing. Turn down the usage of those water pumps and turn up the usage of the pumps right at the turbine. Drain the towers at night and when they're low you turn the pumps back up to full output. You might be surprised.
50kWh is more reasonable.
Let out the H2 at a rate equivalent to 4 times the average gasoline use, since LIQUID H2 is 1/4 as energy-dense per volume as gasoline. For high-pressure gaseous H2 it's going to be much faster.
Assuming your H2 tank is at room temperature, it's going to be under 10,000PSI of pressure. This is a real thing. If you rupture that tank, it's going to explode. The surface area of that tank times 10,000 pounds is the amount of force it's going to explode with. That's a lot more than 60psi launching a beer can. Almost but not quite 200 times as much force.
When it's 106F outside, how do you keep your tank from reaching 106F and spiking to 30,000PSI or 50,000PSI?
The discussion was about cars, not powering your house. Cars are powered by batteries or liquid fuel. Electricity is highly transportable, which is where your original argument was; electricity storage units are more difficult, but better than hydrogen. Not as good as diesel or gasoline. As for "green" energy, why can't we supplement baseline with it anyway, and use it to pump extra water into water towers which then allow us to spin down water pumps for a time? Electric motors scale back readily enough, and we can target our grid that way... hmm.
I'm going to switch from nat-gas to a heat pump for heating. Dual stage compressor to cut back on my energy usage from gas, which is at 170 therms for January (yes that's 5,000kWh). Estimates for the heat pump to do the same job are about 250-350kWh. 70 therm for the surrounding months, so my total energy usage should drop substantially.
By the way, that's still 5MWh per month or 0.17MWh per day, not 50MWh.
No, how the heck? It would be 70kg per meter cubed (i.e. 150lb for a 265 gallon tank, or 5.5lb for a 10 gallon tank) cooled to 33K. 1kg of Hydrogen has about the same energy as 1gal of gasoline: 33.4kWh. That means your 10gal liquid hydrogen tank acts as a 2.5gal gasoline tank.
Gaseous hydrogen would be much less dense unless under extreme high pressure; that means once you raise the temperature above 33K, the pressure in the tank increases RAPIDLY and the tank explodes violently. Mind you that's 33K at the critical point with a pressure of 13.3atm or about 200PSI. The state-of-the-art for hydrogen compressed gas tanks is carbon-fiber at 5000 or 10000 PSI; while you're jabbering about how hydrogen doesn't explode because it goes up when it's released, you should realize that detonating a 60PSI tire can kill a man (stand on top a 21 inch tire you're mounting on a rim, inflate to 60psi to set the bead, and if the bead slips the tire will eject the wheel off the ground and slam your head into the ceiling 10 feet above, killing you by crushing your brain case into your brain), and people inflating bike tires to 70-90psi have gone deaf because the inner tube burst and emitted a loud bang in front of them (much less volume of gas than a car tire). If your 10,000 PSI hydrogen gas tank blows, we call that "lift-off".
On the other hand, as you draw hydrogen out and the pressure drops (due to the partial pressure of hydrogen, because even at 33K the tank's not going to be filled with vacuum), some of the hydrogen will boil, causing rapid cooling, making the tank brittle. If you're working with gaseous hydrogen this will also occur.
So in summary: You need to keep the tank fucking cold, or at extremely high pressure. In either case, you don't want the tank to warm up because pressure will increase rapidly. You also don't want the tank to self-cool as you draw off fuel, because it will freeze the material and cause the tank to become brittle, which can lead to catastrophic failure.
It's both. When you're not drawing fuel, the tank is going to need active cooling if it's exposed to a hot summer day. When you're drawing fuel, the tank might cool very fucking fast. The tank needs to retain temperature that is not hot enough to boil the hydrogen (hint: it's always hot enough to boil the hydrogen) and not cold enough to make the metal brittle such that it shatters when you hit a speed bump at 10mph. It's a pretty narrow band and everything impacts it.
And a AA lithium ion battery costs about $7-$10 but I see some on sale for $3.50 right now. I'm talking about rechargeable Li+ batteries, the same thing used in the Tesla Model S.
I'm seeing some of these at 900mAh, while my Sanyo Eneloops are 2700mAh each and somewhat cheaper (a little under $3 each). Therefor it would take, oh, a LOT of Lithium Ion and less NiMH.
What you have to remember is that electricity to power a city is best, most efficiently transported over large distances by HVDC power lines; while energy to power a car has to be portable and refuelable, and thus we have liquid fuels because batteries kind of suck for recharging since it takes hours. The Tesla Model S handles 500 recharge cycles (100,000 miles at 200 miles per charge is what Tesla suggests), whereas these NiMH batteries handle 3,000 recharge cycles. Lithium Ion batteries hold their charge pretty damn well and will charge a bit faster than NiMH, mind you; between that and the patents on NiMH for use in automobile-scale batteries, Li+ is the obvious choice for cars out of current battery tech.
By the way, my two-story house uses about 400kWh per month, or 0.013MWh per day. Turn your TV off when you go to bed.
Yeah the problem is if our bodies of water die, we have a body of stagnant dead water. This creates. .. problems. A lot more than just "The air smells like shit all the time," Which it will.
The only thing that's keeping the bay in tact these days is the localized diphasic timeline pairing it with a not-dead version of the bay from an alternate universe.
How so? Electricity can be stored for quite a while in lithium ion batteries. Hell I have some NiMH batteries that will retain 80% power over 3 years of shelf life and enjoy 3000 recharge cycles.
I don't need to cool my gas tank. Burning gasoline doesn't freeze the tank and cause it to become brittle.
Nobody's brought up real numbers on hydrogen usage, so I question these, with hypotheticals.
Consider if you have one unit of fuel that produces 1000J of usable energy. This fuel is Hydrogen or Gasoline, for simplicity.
Now let's say it takes 2000J of energy to produce that unit of gasoline that you can burn for 1000J of usable energy, but 20,000J of energy to produce the unit of Hydrogen that you can burn for 1000J of usable energy. In these terms, gasoline is more efficient: you use less energy to get a fuel unit you can burn to produce a certain amount of output in the fueled machine.
Now let's say that 1000J unit of fuel is 1 liter of Gasoline, or 10mL of Hydrogen. Space vehicles spend most of their energy getting their own fuel off the ground in the early launch stages--really fucking heavy fuel won't work. Further, the final module is small (again to save materials weight). Since Hydrogen in this model would be 1/100 of the volume, there's a storage space savings for final module fuel (and booster size, where the booster is metal--but again, early launch cares about fuel weight). With hydrogen not being 100 times as dense as gasoline, there's also a weight savings.
So in this model, hydrogen is a TERRIBLE fuel; however it's much more viable as a fuel source than gasoline for space travel, because you would need a LOT more gasoline, your module would be a LOT bigger, your boosters would be MASSIVE, and you might break the theoretical limit where you simply can't get enough output to lift the damn thing with all that heavy fuel if you tried launching with gasoline.
NASA has different concerns that determine what's viable tech. Fuel source is tech. Is hydrogen a better fuel, or is it just a better space fuel?
Black holes draw a lot of shit toward them because gravity. Cosmic gasses are drawn in and compressed, which causes super-heating. Also objects--big space rocks--are drawn through this compressed gas, causing friction and more compression and super-heating. If you drop shit in a black hole, you get an explosion 20 times bigger than the biggest thermonuclear bombs we've built. That's why black holes glow so fucking bright even though they suck in everything up to and including light.
Holy shit that's a lot of technical problems. If the tank isn't kept ultra-cold (i.e. it's hot outside) it explodes. As you burn hydrogen, pressure drops, the hydrogen in the tank cools the metal ridiculously. And what's with this mass/volume of storage? That's good if you need transport, but not necessarily efficient to produce--gasoline could be 20 times as efficient and it would be 100% useless in space versus 2% efficient hydrogen. How do they compare?
Storing and transporting hydrogen is just too friggin' complex for econoboxes.
What about the fill/extraction ports?
Polchinski is actually correct, sort of. Everything approaching a black hole is being compressed; you'd be exposed to the burning energy of a hundred thousand million thermonuclear explosions before reaching the event horizon.