Impact of solar PV on national grid

SallyKing

This was posted on another thread:

"We are going to need to move into a world with wall to wall solar, wind, wave and nuclear power and develop storage technologies to suit. We need to roll out appliances that have intelligent load shedding (freezers that drop to lower temperatures when in surplus and shut down at peak periods) and tariffs that do the same, immersion heaters that come on automatically when there is surplus power to store energy."

I think this is an excellent idea, especially the fridge feezers being smart, this would be an excellent way to soak up some of the solar electricity, especially as freezers are going to be working harder and using more in the summer months. Smart appliances sounds like the way forward to me.

SallyKing

energysavingexp wrote: »

because 1 house using about 1kwh will not make the power company
cut down on production as this will be covered in the over production

it would need more than one house to make a difference

if you read the original post, the question was if I ( not every one else) use less during the day will the power station that is using coal etc burn less fuel

they dont say mrs B has put the kettle on so better put another log/coal on to the fire

the fossil fuel generators take a long time to get going to produce enough steam to turn the turbines
short demand for supply is made up from turning on quick start generators like hydro where they can open a valve letting water turn the turbine in matter of seconds

As the original poster, I should clarify a little. I used the term I, but I did also want to know the impact of many people having solar. I think both scenarios have been covered in the discussion. I probably should have been clearer in the original post.

grahamc2003

energysavingexp wrote: »

because 1 house using about 1kwh will not make the power company
cut down on production as this will be covered in the over production

it would need more than one house to make a difference

if you read the original post, the question was if I ( not every one else) use less during the day will the power station that is using coal etc burn less fuel

they dont say mrs B has put the kettle on so better put another log/coal on to the fire

This is where the term 'noise' comes from. The effect of one person saving 1kwh won't be noticed because it is dwarfed by other natural variations in the supply.

But that doesn't alter the fact that less fuel will be burnt. I'm sure you'd accept that if a million people saved 1kwh each day, then less fuel would be burnt (I hope!), so, obvioulsy, on average 1 person saving 1kwh would save one millionth of what a million people would, which is a finite positive number. And to negate your point, even 1 person saving 1kwh per day for 1 million days would, on average save the same, even though undetectable in the noise.

the fossil fuel generators take a long time to get going to produce enough steam to turn the turbines
short demand for supply is made up from turning on quick start generators like hydro where they can open a valve letting water turn the turbine in matter of seconds

No, I'm sorry it's not as simple as that.

There are several timescales involved with ensuring we have a reliable elecrticity supply. The key point is that the generated electricity must match the (varying) demand all the time within a very tiny margin, which comes about from the rotational inertia of the gensets (i.e. miniscule mismatches of generation and demand result in changes of mains frequency).

The instantaneous control is, as stated before, automatic, and is primary reserve. (In fact, primary reserve is the expensive commodity which needs to be increased when unreliable generation (like wind and solar) is connected to the grid, and necessarily involves burning more fuel to supply it).

Between 5 and 180 seconds away from realtime, there is secondary reserve, which is instructed by a grid operator, for stations which cannot meet the realtime primary response. In the balancing mechanisms, this may be a logical reserve and amalgamated in the terminology. (This is the respnose I think you are describing). Since Dinorwig was built, this will be the station instructed if it still has availablilty

5 minutes away from realtime there's 5 minute reserve (again, may have different terminology in the balancinh mechanism) - A grid operator rings up a station supplying 5 minute reserve and tells them to increase or decrease their output, which they must do within 5 minutes.

Something like an hour to 24 hours before realtime, the grid engineers monitor the frequence and the frequncy integral, and may decide to bring a station online a period earlier or later than planned, to target an average 50Hz frequency.

In the days before realtime, predicitions are made for the half hourly demand, and are refined (with things like changes to tv schedules, weather prediction changes), and a refined balancing schedule of generation is made to balance that demand.

grahamc2003

SallyKing wrote: »

This was posted on another thread:

"We are going to need to move into a world with wall to wall solar, wind, wave and nuclear power and develop storage technologies to suit. We need to roll out appliances that have intelligent load shedding (freezers that drop to lower temperatures when in surplus and shut down at peak periods) and tariffs that do the same, immersion heaters that come on automatically when there is surplus power to store energy."

I think this is an excellent idea, especially the fridge feezers being smart, this would be an excellent way to soak up some of the solar electricity, especially as freezers are going to be working harder and using more in the summer months. Smart appliances sounds like the way forward to me.

It's fine having a wish list of requirement you would like, but a totally different matter to bring them into fruition. It's easy saying 'let's have a world with no wars', but it appears to be pretty impossible to implement that.

There's nothing new in what is now termed 'the smart grid'. The requirement is sound, but the implemetation takes time and expense.

Wall to wall solar the way forward in the UK? Really?

A lot of people write a lot of things on boards such as this. As you stated very early on in this thread, it's very difficult for a layperson to disentangle those who live in a dreamworld, and those who know a little of the physics and implications of what many BB posters think is a great idea.

SallyKing

grahamc2003 wrote: »

It's fine having a wish list of requirement you would like, but a totally different matter to bring them into fruition. It's easy saying 'let's have a world with no wars', but it appears to be pretty impossible to implement that.

There's nothing new in what is now termed 'the smart grid'. The requirement is sound, but the implemetation takes time and expense.

Wall to wall solar the way forward in the UK? Really?

A lot of people write a lot of things on boards such as this. As you stated very early on in this thread, it's very difficult for a layperson to disentangle those who live in a dreamworld, and those who know a little of the physics and implications of what many BB posters think is a great idea.

When I said an excellent idea I was referring to the smart appliances/grid. I think regardless of where our power comes from this has to be a good idea for the future. Its very interesting to read how the grid is balanced, thanks for another informative reply. A smart grid would surely make it more efficient if appliances can be controlled rather than having to fire up more expensive generation (as happens today)?

Cardew

SallyKing wrote: »

When I said an excellent idea I was referring to the smart appliances/grid. I think regardless of where our power comes from this has to be a good idea for the future. Its very interesting to read how the grid is balanced, thanks for another informative reply. A smart grid would surely make it more efficient if appliances can be controlled rather than having to fire up more expensive generation (as happens today)?

As posted in the other thread:

It is already in the USA.

In my place there I get a discount for allowing the major appliances to be switched off at the power companies discretion.

http://www.fpl.com/residential/energ...s/oncall.shtml

Apparently saved them building 3 power stations.

My electricity meter is read remotely(was built in during construction - some 9 years ago)) so half the technology was in place.

rogerblack

Cardew wrote: »

As posted in the other thread:



Apparently saved them building 3 power stations.

My electricity meter is read remotely(was built in during construction - some 9 years ago)) so half the technology was in place.

No, underinvestment caused them not to build power stations, and this is a tiny, tiny sticking plaster.
http://www.istockanalyst.com/article/viewiStockNews/articleid/3771212
"Jan. 11--Florida Power & Light Co. is implementing rolling blackouts for some customers on Florida's east coast as Orlando and the rest of the state continues to shiver through some of the coldest temperatures in years. "

Cardew

rogerblack wrote: »

No, underinvestment caused them not to build power stations, and this is a tiny, tiny sticking plaster.
http://www.istockanalyst.com/article/viewiStockNews/articleid/3771212
"Jan. 11--Florida Power & Light Co. is implementing rolling blackouts for some customers on Florida's east coast as Orlando and the rest of the state continues to shiver through some of the coldest temperatures in years. "

I was quoting from their website:

The energy saved by On Call® customers has helped the environment by deferring three medium sized power plants from being built since the program's inception.
More than 780,000 customers have said "yes" to savings and protecting the environment by enrolling in the On Call® Savings Program.

The question asked was about load shedding, and to be able to 'instantly' reduce consumption by several kW each for many thousands of customers is a useful tool for those managing the Grid.

The obvious answer to cope with those sort of temperatures( -8C in central Florida!) would be a few solar panels;)

SallyKing

Having just re read this thread, I thought it would be worthwhile summarising. So the consenus is that Solar PV reduces the amount of fuel burnt at the power station, but does not help with overall generating capacity.

Cardew

SallyKing wrote: »

Having just re read this thread, I thought it would be worthwhile summarising. So the consenus is that Solar PV reduces the amount of fuel burnt at the power station, but does not help with overall generating capacity.

Correct - also wind!