37

When a reactor is shut down the core produces much less heat, but they do still produce heat through a mechanism known as decay heat. The fact that the core is producing less heat means that the coolant temperature is going to drop, but how far that temperature drops depends on the decay heat generation rate. This in turn is based on operating history, or ...


15

There are no silver bullets when it comes to decarbonising the grid. That's good news: it means you can stop looking for one, and accept that every form of generation has its pros and cons. Concentrated solar power [CSP] relies on direct sunlight. Not just ambient daylight, but lots and lots of direct sunlight all year round. Whereas ordinary photovoltaics [...


13

Xenon is a result of the nuclear reaction and a neutron poison. If you don't wait for the xenon to decay, it eats up too many neutrons and you can't go critical. They always say "there are not enough rods to pull." If you have a nice new reactive core, you can get started sooner. If the core is old, you will have to wait a long time before enough xenon (...


10

Everything we do as humans has consequences of some sort. Although not a huge downside (in my opinion), critics have often cited the plant's supposed adverse effects on wildlife: Wikipedia Article: It has been noted that insects can be attracted to the bright light caused by concentrated solar technology, and as a result birds that hunt them can be ...


9

In the UK, the sun does not shine every day. We also need the most power in winter when the sun shines the least. Therefore every solar power station must be backed up by anther power station that can work when the sun is not shining. Concentrated solar power allows short term storage of the steam, so at least copes with 5 minutes of cloud cover, it ...


7

The answer really boils down to two factors: safety and testing. I'm going to give a generic summary of these two things below, but the real answer is quite complicated. The crux of nuclear plant operation revolves around nuclear safety. I'm not talking about personal safety, which is the purview of the Occupational Safety and Health Administration (OSHA),...


6

So, this battery costs US$70, weighs 406 grams, and holds around 200,000 Joules of energy. To get the same energy from that weight as a "gravity battery" you'd have to pick it up over 49 kilometers into the air. There are applications where picking stuff up and powering things as it falls is useful -- the gravity-powered lighting for 3rd-world countries is ...


5

Because they're both live Just because you see multiple wires doesn't mean they are carrying different things. They are frequently paralleled for more ampacity. It's perfectly common in HVDC lines to use earth as the return path. For instance, the Pacific Intertie does just that, with absolutely massive grounding electrodes at each end. The grounding ...


5

There are a few possible reasons. Elimination of electrolysis problems with ground connections. Elimination of variations in ground resistance. Grounding one of the conductors on the HVDC line might save money on isolators, ... Using a ±½VDC on each wire is common. If transmitting, say, 500 kV DC then one wire is +250 kV DC and the other is -250 kV DC. ...


4

In the US, Nuclear is used to base load the grid. As implemented in the USA, Nuclear energy has very high fixed costs and relatively low variable cost. So it is in the utility's interest to run their nuclear capacity as close to 100% as they can. This may be different in places (France?) with a more significant investment in nuclear or other electrical ...


4

Consider 1 kWh = 1000 W * 3600 seconds = 3,600,000 J. 1 kg lifted 1 m = ~10J. Let's use 1 metric tonne. 1000Kg. So we get 10,000 J per meter of elevation. 3,600,000 / 10,000 = 360 meters. Around a thousand feet. Ok. Getting a 15 cm diameter well dug and cased is on the order of \$20/foot. So \$20,000 buys you a 1000 foot deep hole. Use whatever ...


4

Your four drawbacks are very good reasons for not laying cables on the ground and just covering them with soil or "stuff". Erosion will be a major issue. Exposed cables would be a safety hazard to humans and wildlife. It would also increase the risk of cable degradation and failures. Countering the affects of erosion, but covering the cable, will also add ...


3

Concentrated solar power plants are best located in isolated areas that receive a lot of sunshine all year round, which basically means arid or semi-arid regions. Most of these regions don't have large populations so long power transmission lines will be needed. To increase performance and efficiency, each CSP plant will need to be uniquely designed and ...


3

Here are some pylons in Norilsk, Northern Siberia, where temperatures get down towards -50°C (source) It's all a question of design and engineering: pylon spacing, the range of max and min ambient temperatures, and the range of currents carried on the cables - there will be whole design manuals that cover this, so a full answer would be way too long ...


2

I do not know the laws in your country, but the key is "risk assessment". And the risk we are talking about is the risk of killing someone, not the risk of the cable being damaged. Irrespective of laws, it is likely the project will be signed off by a professional engineer and protected by your companies malpractice insurance. If someone dies as a result of ...


2

With the high voltage AC power lines, there are trade offs between losses due to resistance in the wires, where the higher voltages are better and losses due to capacitance to the air, etc. where lower voltages are better. That is why many big, high voltage power transmission is done with DC these days. For example, the 500 kVDC line from the Intermountain ...


2

Since I lack the reputation to write comments: The electricity cost of mining is way higher than the earnings. Small scale mining is not profitable anymore for a long time already, mining farms have 20000 graphics cards or something in that range. Beyond that: a 750 Watt PSU will (at its limit) consume 0.75kWh per hour and thus 126 kWh per week, roughly ...


2

A 1% shift in grid frequency will shift the running speed of every AC induction motor connected to it by 1%. Factory machinery and AC-powered clocks would all slow down, with potentially disastrous effects in those factories and big upsets would occur in any setting where event timing relied on AC synchronous motor-driven clocks. As to the condition of the ...


2

Are there some shortcomings that I am missing here? Yes there are a couple of things you have missed. Firstly I will deviate slightly from your question but I believe this is relevant. The need for localised storage has only relatively recently become desirable. With the increase of large scale Solar and in particular wind farm projects the need for ...


1

Re: load following, from Wikipedia Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope. Nuclear power plants in France and in Germany operate in load-following mode and so participate in the primary and secondary frequency control. Some units follow a variable load program ...


1

The listing in the provided link is a summary of generally accepted sources of power for EV charging systems. Your question appears to be what is allowed by those sources, which really is not related to EV charging. Modes 1 and 2 indicate the use of a domestic socket. The power allowed is limited by the wiring, circuit breakers and for Mode 2, additional ...


1

On a 230 V system 16 A would be the circuit breaker rating for one circuit with a couple of sockets on it. A typical cooker would be 35 A. In Ireland the traditional connection is single-phase 63 A. A quick web check says that the Nissan Leaf has a 40 kWh battery. Charging at your < 4 kW rating would mean an 11 hour charge, allowing for some losses. I don'...


1

Generally, no. Transmission lines can act like antennas, but they operate at around 50 Hz. The wavelength of a 50 Hz EM-wave is $6\times 10^6$ m. In order to effectively couple that energy, you'd have to have a receive antenna of $3\times 10^6 $ m length. That's not feasible. Not only this, but of course the gain of the antenna scales with frequency and ...


1

When we had to run HV lines to a building, we put them in steel pipes 6 ft deep, covered the pipes with 2 feet of sand, then laid a foot of concrete on that and painted it red, and filled the trench with earth. People dig, maps get lost.


1

They are many reasons for the time it takes to startup or return to full power operation in commercial nuclear power plants. In the US there are two main types of plants, Boiling Water Reactors(BWRs) and Pressurized Water Reactors (PWRs). Answers will differ according to the type of reactor and even which version of the type. A common explanation that I did ...


1

Some of these answers already touched on the environmental impact of CSP, I would like to add this article as a source. It reiterates on the points made by others who answered the OP's question and pointed out the issues with biodiversity (specifically bird species) being affected. However, nobody pointed out the water use required for the cooling system ...


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