Surplus power on the grid results in increased frequency, while too little power results in decreased frequency.
OK; that confirms the obvious: to feed power into the grid, your generator has to run with the phase slightly advanced, and to draw power from the grid, your “motor” has to run with its rotation slightly retarded.
In the former case the phase difference may be only a fraction of degree. I am sure the answer is on google, but it will be directly related to the source impedance of the generator.
In the latter case it can be a lot; a small motor may be running with a 10-30 degree lag, and the lag is proportional to the torque. That is how motors work: there is a lag between the armature angle and the rotating field angle and this lag is according to the torque.
The UK has very few hydro storage plants and they are used for extra capacity when needed. The pumps are either uphill or downhill, not at the same time.
Does anyone know anything about those solar panels which form a joined-up roof, which I mentioned above?
One thing I came across recently was the question asked, why use inverters at all for stuff which doesn’t need it? As inverters do loose some energy in the process, going 12 V directly (which most solar panels produce and which most batteries are rated) can that do some significant saving?
As a backup to our lights, I got a set of 4 LED light bulbs which are connected to a solar panel with a small battery inside. The whole set costs less than $20. So I put the panel on the balcony and feed the cables so, that the 4 lamps are distributed in such a way that they light up in my case 3 upper rooms. Clearly, it is not very bright light, but it is more than sufficient and way better than candels or whatever. I have yet to test how long they would light up, but from out patio lights, which have been solar since 3 years, I would estimate a good couple of hours.
So why not use 12 V LED’s for the inside lighting altogether, rather than converting power to 220V and then back to 12 V for the LED lights we use today? And furthermore put 12 V and USB outlets wherever you got a 220V one, so you can plug whatever runs on 12 V (particularly lights) directly.
Also most phones, laptops e.t.c. can run on 12 V or USB.
As I also know some cabins and smaller homes which run entirely on 12 V, I wonder what this could do for backup or even daily life solutions. Would it really save energy? In theory, a simply car battery (size wise) should be quite enough to cover a lot of light and appliances during the dark hours and if I am not mistaken, LEDs are 12 V by default?
Lots more losses in cabling at 12V.
Inverters can be made 90% efficient; more if you spend more money.
LEDs are 1.5-2.5V and they need to be driven with a controlled current so this has to be synthesised electronically in all cases. With just some little indicator LED, drawing say 5mA, you use a resistor but for illumination LEDs you have to have a proper circuit – a “switch mode power supply”. It is true that these are much more reliable at 12V than at 230V (I’ve designed loads of them) but this is visible only on chinese crap electronics (ok; that’s almost everything we use).
And you would need dual cabling around the house. Only lights would benefit from 12V. Admittedly better house wiring does separate lights from power so this could be arranged even in many existing houses.
This may also help a bit, min. 7.37
Peter wrote:
How did the grid work in the days of only coal or oil fired power stations? Or nuclear plus coal? No magic back then but it worked just fine
There was a TV programme on a few years ago (a series) about the Ferrybridge coal fired station. Grid synchronization when bringing up the power station was done manually – there was some kind of large box with a dial indicator on it that spun around, and the operator had to do something manually to make another pointer line up and run at the same speed before connecting to the grid. Once they were connected things stayed in sync.
Synchronizing a Canadian nuke plant – also manual:
Avweb article today:
There are plenty who are fed up with startup aviation businesses that, despite clearly impractical ideas, seem to raise a lot of investment capital. A recent article in Forbes might bring a breath of fresh air. Veteran aviation consultant Brian Foley projects that the times may be a changin’ for marginal ideas sucking up investment cash that could be going to more worthwhile projects. The title of his article sums it up: “For Many Early-Stage Aviation Companies, The Jig Is Up.”Italic
I hope this means more money will flow to investments in promising renewable energy ideas.
When the CEGB was privatised the National Grid managers were very concerned about who would pay for the reactive load. The power generators can produce it but the way the market was originally set up the grid controllers would “buy” electricity on the spot market and then “sell” it to the electricity suppliers who in turn would supply their customers ie buy 50Gw and sell 50 Gw. The problem was that the government lawyers had not taken into account the load that the grid would have to purchase to balance the grid. They had only taken into account a transportation fee.
Regarding one of the other questions..IIRC it was in 1987 that a quasi hurricane hit the South East of England unannounced by the weather bureau. Well I believe Michael Fish said that " a lot of people are concerned that a hurricane is coming, there isn’t ". Did he ever live it down?
Anyway S.E. England became separated from the grid, and the area was blacked out.
Grid controllers now had to avoid turbine runaway of the turbines that were being used when the area became separated. If you imagine that you are hammering along on your bicycle and you start going down a steep hill and you have no brakes, catastrophic damage vould ensue. Electricity generating sets work much like the bicycle. As load is applied when people turn on electricity appliances, more fuel had yo be put into the boiler, just as we need to work harder to ride our bike uphill. If all demand is suddenly stopped its like going downhill with a sudden brake failure.
All this required reactive load in order to stop a chain reaction affecting the rest of the grid.
When control had been realised the controllers then had to restart the much needed turbines, it was winter after all.
To restart the turbines required high tech🙂 IIRC it was a 24 volt battery which in turn was used to start a diesel standby generator which was then used to start the turbines all the way down the line. And the grid was brought back together.
All this can be seen in a CEGB video called “Riding the Hurricane”.
Wind turbines, solar power, interconnectors, nuclear power, battery storage, pumped storage anf all types of thermal power are integrated into what is a very well planned system.
The original idea of grid systems was to have a diversified electricity supply. Renewables are just one tool but the economics of them once built allows for less reliance on overseas fuel suppliers holding a country to ransom. The trouble is that most politicians do not think long term, neither do.most corporations. And they certainly don’t do joined up thinking, especially energy ministers, most of whom would need assistance, to change a fuse, and that would be after comissioning a review.
@LeSving you are totally wrong about a European grid system. We already are pretty much there, although it could be strengthened. Europe also has a gas grid system joining many countries.
Although Egypt is neutral in this war as it has strong ties with both Ukraine and Russia it has already agreed to sell Egyptian gas to Europe and is looking at building a huge solar power site in the desert to supply Europe with electricity via an interconnector.
Egypt has enough solar and hydro electric power to meet its needs already.
Even without this war due to climate change the increase in renewable energy, technological innovation and insulation measures to reduce energy demand, will have a huge impact on Europe’s overall requirement for oil and gas.
The way to maintain a reliable, efficient and economical supply of electricity for the majority of people in the UK can only be through a very efficient and stable grid system covering the whole of the EU or better still the Continent of Europe.
gallois wrote:
Did he ever live it down?
No, he didn’t. But he was right – it wasn’t a hurricane, even if it might have felt like one if you were in it!
