Not so green after all?

[binky]

OH Binky I do love a statistic!!!

so do I, it's my engineering background.

 

[binky]

Something I have been looking into! I Travel around numerous places for work and see so many unused rooftops and now even find myself counting how many panels could fit! (sad times ay!). Developers, unfortunately, do not care about eco, 12500 new homes are being built near one of my places of work, and around 1% are said to be having solar (but we all know the developers will claim to have hit cash flow problems and will not install them).

I have had my council (Bracknell Forest) leafletting regarding group buying in the area to tender the workout and the best price wins the contract, not sure how successful these schemes are, and feel they also then dictate what you are having for your money.

Developers have CO2 targets to meet, but that doesn't have to include solar. Considering how cheap the gear is now, and how energy prices have shot up, you would think it would be a great selling point..

group buying - not sure why busy companies would want to do the work for 'lowest price wins' contracts other than sheer bulk of work?

 

[ish]

Developers have CO2 targets to meet, but that doesn't have to include solar. Considering how cheap the gear is now, and how energy prices have shot up, you would think it would be a great selling point..

group buying - not sure why busy companies would want to do the work for 'lowest price wins' contracts other than sheer bulk of work?

My thoughts exactly, after seeing the quotes roll in I was thinking who in their right mind is going to think "Let me rip the arse out of the quote just because a few people have got together". Don't see it having legs to be fair plus I know if I contact them they will want me to install some type of hybrid inverter for my 3 elevations of roof space, which I can't see as being the most efficient for me

 

[michael8554]

"Ideally you would site solar farms somewhere like the Sahara and transmit the energy back to Europe,"

There is a proposed scheme to supply the UK with solar from Morocco.

Octopus is one of the investors.

It's not clear from my searches whether it is going to happen or not.

https://xlinks.co/morocco-uk-power-project/

 

[binky]

"Ideally you would site solar farms somewhere like the Sahara and transmit the energy back to Europe,"

There is a proposed scheme to supply the UK with solar from Morocco.

Octopus is one of the investors.

It's not clear from my searches whether it is going to happen or not.

https://xlinks.co/morocco-uk-power-project/

Interesting video, it has Plymouth in it, so hopefully a few jobs will be created in my hme city too.

According to someone I was having a debate with many months ago, high voltage DC transmission makes it viable to locate generation deep into Africa. I've been meaning to check it out and have a read. Personally I think it's a good thing that a poor country will be able to earn some good money, but I'm still not so convinced about the political stability of such countries.

This link shows areas of the Sahara that would need to be covered to power the world. I have read articles that are concerned it will affect the climate by changing the desert climate to something greener and wetter, so not necessarily all good, although I'm sure the locals may like more rain. Parts of modern day Libya used to be wetter, so much so the Romans descirbed it as the 'bread basket' of Rome as they grew all their wheat there.

https://futureu.europa.eu/en/proces... of the,realize the production of freshwater.

 

[ish]

"Ideally you would site solar farms somewhere like the Sahara and transmit the energy back to Europe,"

There is a proposed scheme to supply the UK with solar from Morocco.

Octopus is one of the investors.

It's not clear from my searches whether it is going to happen or not.

https://xlinks.co/morocco-uk-power-project/

Interesting if it goes ahead

Still not a fan of relying on other countries to supply resources that we need for everyday living - just look what has happened with so many relying on Russia's supply.

I agree with @binky in part regarding political stability but I don’t think this is just specific countries, it’s more all countries for me

 

[arwooldridge]

With the DNOs it's down to the fact their infrastructure is old and knackered ( no excuse on new build estates). They don't like their transformers being backfed more than 30% of their capacity. They also get problems with voltages floating too high if say a whole estate has solar fitted, like a social housing estate. So I understand their problems, it's another issue from lack of investment in the UK.

I don't get the voltages floating too high argument. Most if not all inverters now will progressively reduce output if voltage rises beyond a threshold. Also don't get the 30% back feed argument either, All transformers can work equally well forwards or backwards it makes no difference to them. It's a bit like saying a copper wire can only feed current one way. Transformers are a little more complicated with magnetics but the bidirectionally is the same.

 

[binky]

I don't get the voltages floating too high argument. Most if not all inverters now will progressively reduce output if voltage rises beyond a threshold. Also don't get the 30% back feed argument either, All transformers can work equally well forwards or backwards it makes no difference to them.

Whether you get it or not, it's still the case. I've had many chats with DNO engineering staff over the years.

 

[johnb2713]

Whether you get it or not, it's still the case. I've had many chats with DNO engineering staff over the years.

Just done a bit of searching and the issue appears to be the ancillary equipment rather than the transformer itself.

"Reverse power flow in and of itself is not necessarily a problem for the transformer, as it is basically a lump of iron with copper windings, and the copper itself doesn’t mind which direction the power goes, as long as it’s not too high.

But there are other bits of kit and other network parameters that reverse power flow can cause a problem with. The following list describes some of the main issues.

• The rating of the transformers is the first thing to look at (for example the 90MVA rating in the examples above). If the reverse power flow is greater than the rating of one transformer (as the network companies will assume one is switched out when making their assessment), then the generator can’t connect, or needs to be smaller, or the network needs to be upgraded.
• The tap changers on the transformers don’t always have the same rating in the reverse direction as in the forward direction. This is particularly true for older models. So for example, instead of having a rating of 90MVA in the reverse direction, it could potentially have a rating of only 45MVA.
• Automatic Voltage Control (AVC) relays measure the voltage on the low voltage side of the substation and trigger the tap changers to go up or down to maintain a steady voltage. These were historically designed to control the voltage in the forward direction and some of them don’t work in the reverse direction. These can usually be changed without changing the transformers, and customers would be charged for their replacement.
• Directional Overcurrent (often abbreviated as DOC) protection relays are often included in substations to look at power flowing in the reverse direction through a transformer, to detect faults on the high voltage side of the transformer and to trip off the circuit breaker. However, these relays often can’t differentiate between normal level load current and fault current, and so could spuriously trip if there was too much reverse power flow. As such, these relays often need to be changed when a generator causes reverse power flow.
• Reverse power flow through a transformer results in the voltage on the high voltage side of the transformer increasing. Sometimes this can increase to levels that are too high for the network equipment to cope with, or go over the statutory voltage for other customers. In this instance, the network company would need to work out a network reinforcement scheme to help keep the voltage down to acceptable levels."