Like how if I have a river, I can install multiple dams in series to get more energy instead of having just one dam.
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These systems are complex and have many different stages. There are significant issues economic and engineering that come into play
a) Adding new turbines and/or upgrading existing ones involve downtime. This can be significant. Would taking a power plant off line for many months or even years be reasonable for the system as a whole?
b) At some point, a new plant is simply more reasonable. Certain aspects of a plant are going to be nearly impossible to upgrade. For a nuclear power plant, the core parts of the system cannot just be expanded. Adding turbines might not result in significant output increases while adding significant complexity, cost and safety issues. There is always a problem of diminishing marginal returns.
c) Changes in technology. A power plant built to modern standards will be more efficient, cleaner, likely safer and have less problems (downtime, etc). Upgrading old ones is simply not possible if they are fundamentally old technology – it would be like tearing down the entire existing plant and reconstructing it from scratch.
EDIT: Think of it as a car. When the car is relatively new, it makes sense to maintain it properly and maybe even upgrade components to make it “better”. But at some point, maintenance and upgrades make no sense (to a normal user) – a new car would be a better investment.
Multiple dams in a river won’t mean the water has more energy in it. More dams in sequence means the flow is slowed down, so you hit diminishing returns. Not to mention a dam is inherently not similar to other power plants because of the potential to build a reservoir behind it to increase potential energy. But that also doesn’t increase the useful volume you can get through at one time. Point being, might as well stick to one that’s made for maximum efficiency.
Likewise, adding more turbines doesn’t mean your heat generating technique becomes more effective. Hook a bicycle up to one or a hundred generators and see if you can create more power on the second setup by pedaling. 😛 Turbines are only the energy conversion method, with their own resistance that must be overcome.
Yes, you can always add more generation capacity but doing so increases the amount of fuel the plant will need. The maintenence costs will also go up, staff costs, etc.
It sounds like you’re asking why you couldn’t just have multiple turbines in series and essentially get more energy for free.
Steam turbines basically ‘use up’ the pressurized steam that goes through them. Hot pressurized steam goes in, and liquid water (plus a small amount of low pressure steam) comes out. There is no more energy left to drive another turbine downstream.
The turbines generate electricity from pressure. The input to the turbines is high pressure high temperature steam and the output is at atmospheric pressure at bearly above boiling point. Adding another turbine would not be able to extract any more energy from this. The steam you see released is the steam that is sprayed onto the condenser to get the water from the turbines condenesed back into water just bellow the boiling point so they can pump it back into the reactor.
There are a few low temperature differential generator technologies which could be used. But the efficiency of these is not that great and the amount of energy in these low temperatures is not much. So it is not yet worth it trying to install such a system.
Energy is never created, just transformed. A dam converts kinetic energy to potential energy when it stores water, then said potential energy into electricity when it releases it.
You wont be able to install infinite dams in a place.
The current turbine in a reactor is most certainly a very optimal number. If you want more, you build more reactors. A power plant usually has 4 reactors.
The steam you are heating only has a limited amount of energy in it. A river is being constantly accelerated by gravity, but once steam has left the reactor it’s gaining no more energy, which obviously means that there’s a limit to how much energy you can extract from it, and most of the usable energy is gone after passing through the first turbine.
In a river, the water level drops at every dam, and the total energy you can generate depends on the river flow rate and the height change. The river’s height change is set by its geography: you can split it up over several small dams or one big one, but it doesn’t change the total energy output.
In a thermal power plant, the temperature drops at every turbine, and the total energy you can generate depends on the heat flow rate and the temperature change. The power plant’s temperature drop is set by the materials it’s made from: you can split it up over several small turbines or one big one, but it doesn’t change the total energy output.
Nuclear engineer here.
We already do this during plant design. My nuclear plant for example has 1 high pressure turbine and 2 low pressure turbines. By the time the steam gets to the end of the LP turbines, it has virtually no pressure remaining, so it’s useless steam. Adding another turbine would actually take energy away and cause more problems. To add more turbines we would need to add another reactor.
The other thing I’ve seen, is we uprated our reactor a while ago. And in the turbine we changed to a different design that can extract more energy from the steam so that the turbine and reactor were essentially matched in output. We didn’t add more turbines, we just changed to designs which could use more steam.
You can, but why would you?
In most cases the main problem is not the amount of electricity produced, but the distribution from point of production to point of use.
Blackouts are often caused because the grid is unable to get the electricity to where it is needed as you need wires of sufficient gauge for the entire way.
That’s why distributed electricity generation, where electricity is produced locally (Ex: PV on your roof), is benefitial for the entire grid. It is not really about the amount PV panels produce, but the location.
Building large central plants will make the problem worse if the grid is not updated as well.
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