Green, ethical, energy issues in the news

JKenH

Thanks mmmmikey. That’s what I understood was happening with generators even paying customers to take load but what I am hoping someone can tell me is if is technically possible to dump power to earth in an extreme situation?

Using the car engine analogy if the throttle is stuck open and there is no load on the engine the revs will rise until the engine explodes (- of course modern engines have rev limiters and ecus to prevent this.) Presumably that could happen with a wind turbine in a storm if there was no load to take the power.

Edit - for instance if there is a serious failure on the transmission side of the grid, so the customers are suddenly disconnected, where would the power being generated go. I know it shouldn’t happen but things do. I can imagine all sorts of other things happening at the same time if the voltage suddenly shot up but leaving those aside, if the generation can’t be switched off instantly where does the power go?

GreatApe

markin wrote: »

How cheap storage would have to get for renewables to get to 100 percent, Out of an MIT lab run by researcher Jessika Trancik.


https://www.vox.com/energy-and-environment/2019/8/9/20767886/renewable-energy-storage-cost-electricity

Full paper
https://www.cell.com/joule/fulltext/S2542-4351(19)30300-9

Seasonal storage won't because by definition you only charge and discharge once per year
If it has a 20 year life and cost $20/KWh that is still a $1 per kWh cost some 25 X USA wholesale prices

What's more this storage has maintenance labor land taxes interest to add on top and at some point in the future it will end up in the electronics waste stream so some poor Africans will have to shift through actually harmful chemicals to try and partially recycle these electronics. Nuclear on the other hand internalised all its waste rather than landfills them.

The USA has by far the most successful nuclear industry
If they build just 40 nuclear power stations, that's less than one per state, they would have an electricity grid which is 75% nuclear with 7% from hydropower 7% wind 3% solar and about 10% NG

Of course there is a world of existing infrastructure that would be against that outcome
Coal would be against it
Gas would be against it
Oil would be against it (as it destroys a huge amount of demand for NG an important byproduct of oil drilling)
Train infrastructure would be against it
Pipeline infrastructure would be against it
And all the services that provide to these industries would be against it

Instead of nuclear actually achieving a rapid deep decarb the indutesy is oro solar and wind because it's slow and because it can't achieve as deep a decarb. What's more intermittent supply means the existing coal and gas infrastructure operates less efficiently so wind and solar does not displace as much coal and has as first imagined.

This is because a CCGT operating at baseload can get 62% efficiency while a CCGT ramping up and down will be closer to 50% efficient. Imagine your cars milage on the motorway doing a steady 65mph Vs the same car doing city driving

GreatApe

Martyn1981 wrote: »

Thanks, that's an excellent article. I think they set out the issues well, and the challenge of reaching 100% from clean energy only. No idea if $20/kWh (down from $200) is correct (well out of my comfort zone), but all my concerns were quickly answered:

What about bio-energy, this is after the US?

Are there alternatives to localised storage?

Why does RE generation have to match consumption, aren't we assuming(?) some overcapacity as a cheap 'storage' option?

Why 100%?

So for now, a softer future target of 95%, at a 'too stringent $150/kWh', looks doable at todays storage costs and options. Excellent news.

Note - I thought those storage costs per kWh seemed too high as domestic options are already well below that, but the article explains that they are talking about the cost of buying and installing a kWh of storage, not the cost of using a kWh.

For instance one flow battery supplier is contracting $95/KWh for 2022 delivery on massive batts, which would, fairly I assume, come in at around $200/kWh delivered, installed and all other costs, but at 5,000+ cycles, would work out at a cost of ~4c/kWh.

Good news, there are loads of generation + storage contracts being issued in the US at very, very low prices. I've posted some, and on one occasion the price was so, so cheap, that I 'naturally' misread it as 10x higher till Z pointed out my mistake.

Most of the contracts require storage of about 4hrs, since obviousluy, the majority of the generation/supply doesn't need any storage, so storage costs only add to the small proportion that needs, well, storage, and those cost are diluted across the far larger volume of energy supplied.

All looking good. Nice start to the week.

Storage has a bright future in large PV farms because it can allow a PV farm to oversize it's panels 3 X while keeping its grid connection and converter stations the same size

Something like the following in a sunny USA state

15 GW PV panels
50 GWh batteries
5 GW grid link
5 GW DC to AC converter

This allows a level of load following and an annual CF for the grid link and converter station of some 75%

50GWh battery at $200/KWh would cost $10 billion if the rest could be done for $30 billion you have a capable high CF system for $30 billion producing about 32 TWh annually (and by comparison HPC will produce 26.3TWh and cost $25.5 billion so more or less the same cost. However the bike will probably last 3 X the projected 25 year life of the PV farm and the nukes have a better output profile for the UK grid (more in winter less on the summer which correlates better to UK demand))

Both prices are too expensive but there would be rapid cost reductions in nuclear with learning curves allowing build times to tend down towards 4 years. There will also be reduction in PV farm costs when AI starts to do production and construction

GreatApe

JKenH wrote: »

Thanks mmmmikey. That’s what I understood was happening with generators even paying customers to take load but what I am hoping someone can tell me is if is technically possible to dump power to earth in an extreme situation?

Using the car engine analogy if the throttle is stuck open and there is no load on the engine the revs will rise until the engine explodes (- of course modern engines have rev limiters and excuse to prevent this.) Presumably that could happen with a wind turbine in a storm if there was no load to take the power.

Edit - for instance if there is a serious failure on the transmission side of the grid, so the customers are suddenly disconnected, where would the power being generated go. I know it shouldn’t happen but things do. I can imagine all sorts of other things happening at the same time if the voltage suddenly shot up but leaving those aside, if the generation can’t be switched off instantly where does the power go?

You wouldn't really want to 'ground it' but you can create a very simple cheap resistor bank that can respond in milliseconds. If you imagine an electric bar fire or a kettle that is basically a 'resistor bank'

However there is already some inbuilt flexibility so if a load drops like a town the frequency will jump a little bit. If a generator drops the frequency will fall a little bit. This is ok for about 500MW load drops/gains beyond that you need a generator to kick in or out

pile-o-stone

Would it be possible to rename this thread to "General Energy Discussion" (or something and to create a new "Green & Ethical Energy in the News" thread?

I miss the old days where I used to come to this thread and see Green & Ethical News Stories that would keep me up to date with the latest developments in Green Energy tech.

(I guess this is aimed at Mart as he created this thread and can therefore update the title)

zeupater

mmmmikey wrote: »

... With wind it's a bit more complicated - you have to regulate the power by slowing down the turbine some way or using a "dump load" to soak up any excess ...

Hi

Turning the swept area of the blades out of the airstream, feathering the blades & applying the brakes seems to work quite well in most situations ... it's not unusual to see a high proportion of turbines in a wind farm not spinning whilst others are happily generating ...

Looking at inter-field load to capacity variances in offshore generation in the Irish Sea (Crown Estate asset-map) would provide a general idea of the number (/percentage) of turbines which should currently be spinning in airflow which would be around 50%-60% of nameplate capacity .... nice easy (;):whistle:!) calculation for engineers to assess if anyone has the time to look into each field, but in the meantime a proportion of the population may decide to put the kettle on, resulting in some keys being pressed in Wokingham! ...

HTH
Z

zeupater

Hi

Whilst on the subject of wind, some news ...

Last week #wind produced 27.3% of British electricity, more than gas 27.1%, nuclear 20.7%, imports 9.1%, biomass 6.4%, solar 6.0%, hydro 1.4%, coal 1.0%, storage 0.6%, other 0.4%, national demand 4.7 TWh *excl. non-renewable distributed generation
9:12 am · 12 Aug 2019

https://twitter.com/NGControlRoom/status/1160826470039719936

HTH
Z

zeupater

markin wrote: »

How cheap storage would have to get for renewables to get to 100 percent, Out of an MIT lab run by researcher Jessika Trancik ...

Hi

Interesting, however the capital cost of storage ($20/kWh) would be highly questionable as it's value is directly related to cost plus cycles as opposed to cost alone ....

Think about it as being kinetic energy recovery to storage (battery/capacitor) in an electric or hybrid vehicle ... the additional capital cost of the storage solution may be high, but in terms of additional cost per cycle would be heavily diluted by the number of potential cycles per journey ... at the other end of the scale we may have a pumped hydro system for which a full cycle may be represented in days or even weeks (think Dinorwig etc!) ...

HTH
Z

GreatApe

zeupater wrote: »

Hi

Whilst on the subject of wind, some news ...

https://twitter.com/NGControlRoom/status/1160826470039719936

HTH
Z

Great news it means we don't have to buld much more wind or Solar farms!! Coal and gas only generated 28.1%

With the huge amount of infrastructure already under construction (especially the 6.2 GW of links to Norway and France) we will soon be 100% non fossil on the grid and more mass deployment of solar or wind will be unnecessary and will lead to curtailment of domestic or foreign non fossil fuels.

Martyn1981

pile-o-stone wrote: »

Would it be possible to rename this thread to "General Energy Discussion" (or something and to create a new "Green & Ethical Energy in the News" thread?

I miss the old days where I used to come to this thread and see Green & Ethical News Stories that would keep me up to date with the latest developments in Green Energy tech.

(I guess this is aimed at Mart as he created this thread and can therefore update the title)

Don't worry it'll all blow over soon (pun intended). With an offence based on 'respect the opinions I don't agree with and even mock openly', it's only a matter of time before 'they' give up.

The recent attempt to pretend that I don't think people have a right to an opinion, as opposed to my refusal to respect some stated opinions, means we are getting near to the 'desperation' stage that typically preempts the end.

As I've posted many times, 'Everyone is entitled to their own opinions, but not to their own facts.'