[Yahya]

The demand for power has increased , and it is increasing ,think of electric cars , electric trains , electric scales,etc, almost everything has become electric, the threat of climate change made organizations , manufacturers, even politicians embrace a project of clean energy , which in fact an electric-thing project, fortunately we have unlimited sources of clean energy, unfortunately we do not have enough pots to store ocean water. 

[teragram]

QuoteThe efficiency of production of mains electricity is unlikely to exceed 80% from source to consumer.Yes, nearer 60% is more common I believe.Quote

A bit disappointing. Does this figure include the losses from using fossil fuels as the source?

[teragram]

That's true with laptops, but that's because the manufacturers want you to buy a new laptop every few years. Electric cars use almost the same type of batteries, but they do a few things differently. Number one is they recharge them more slowly- electric cars are mostly trickle charged at home. That greatly helps the battery life. Second thing is that they're mostly only charged to 80%. That roughly doubles the life of the battery. The third thing is that many cars have cooling systems for their batteries. That means that they don't get too hot during fast charges or enthusiastic driving- heat is a big enemy of Li-Ion batteries. And in hot climates they use slightly different chemistry that is more heat tolerant.

All true!

[wolfekeeper]

QuoteThe efficiency of production of mains electricity is unlikely to exceed 80% from source to consumer.Yes, nearer 60% is more common I believe.Quote

A bit disappointing. Does this figure include the losses from using fossil fuels as the source?

No, it's conversion losses all the way along the line. You lose energy in transmission from where it's generated, you lose energy converting from 240v to whatever voltage the battery uses, you lose energy in storing and discharging the physical battery, you lose energy running the inverters to power the motors, you lose energy in resistance inside the motors, you lose some energy in the gearbox. It works out in the end, when you multiply each of the relatively losses you're just over 60% efficient, depending a bit on the details of the car and the charger. It's still about twice as good as a fossil car though, and the electricity can originally have come from nuclear or wind or solar or whatever, so no CO2 pollution.

[evan_au]

A big new plant is being built in China to produce vanadium flow batteries. This will rival Tesla's US factory producing lithium-ion batteries.
The vanadium batteries use tanks of liquid, and are possibly more suited for stationary grid-style applications.
See: https://spectrum.ieee.org/green-tech/fuel-cells/its-big-and-longlived-and-it-wont-catch-fire-the-vanadium-redoxflow-battery

[Scottish Scientist]

Plan for biggest-ever Australian pumped storage hydro scheme published. 

SNOWY 2.0 – 350 GWh / 2 GW (up to 8 GW) –
  http://www.snowyhydro.com.au/our-scheme/snowy20/

"The need for large-scale storage will only increase and in the future Snowy Hydro could look to replicate Snowy 2.0 to create up to 8,000MW of pumped-hydro storage at this site."
– SNOWY 2.0 Feasibility Study Summary

[evan_au]

Snowy 2.0: Let's hope that droughts don't reduce the storage capacity of this "water battery".

[Scottish Scientist]

Snowy 2.0: Let's hope that droughts don't reduce the storage capacity of this "water battery".

Rainfall is indeed a limiting factor for Snowy Hydro.

Wikipedia - Renewable Energy in Australia - Hydro power
"The Snowy Mountains Scheme constructed between 1949 and 1974 consists of 16 major dams and 7 major power stations, and has a total generating capacity of 3,800 MW. The scheme generates on average 4,500 GWh electricity per year. Hydro Tasmania operates 30 power stations and 15 dams, with a total generating capacity of 2,600 MW, and generates an average of 9,000 GWh of electricity per year."

So the Snowy Mountains Scheme in New South Wales generates on average only half the hydroelectric energy that Hydro Tasmania generates despite Snowy having 46% more generating capacity than Tasmania.

The reason presumably is the difference in rainfall / drought - Tasmania simply gets more rainfall than New South Wales where and when the rain is needed.

As the Snowy 2.0 video points out, Snowy is located between Sydney and Melbourne and therefore the transmission costs to the consumers there and to more Australian consumers generally will be cheaper than the longer transmission distance from Tasmania, I would suppose.

I would expect that Tasmania's day for big pumped hydro will come eventually - when exactly will depend on when Australia wants to transition fully to 100% renewable energy?

I've had a quick casual scope of Tasmania for suitable pumped hydro sites - (Blakers has done a systematic survey, identifying 22,000 potential sites all across Australia) and  Lake St Clair caught my attention as a reservoir that should be very useful for pumped hydro schemes to use.

Actually, New South Wales is still heavily dependent on coal and doesn't have anything like the wind power that Scotland generates now. It is South Australia which really needs energy storage but because they've not planned ahead to have pumped storage ready for when it is needed, South Australia has been resorting to batteries and peaking gas generation to back up their significant wind power.

This is why Snowy 2.0 is described as a "national" project, not merely for New South Wales alone.

Snowy 2.0 looks to be a very promising project. Quite exciting really for pumped-storage hydro nerd like me! 

What would be great is if Scotland's or the UK's official pumped hydro plans were as big and as well advanced as Snowy 2.0. Oh we have smaller advanced plans - but for example, the SSE's plan for Coire Glas only plans a 30GWh scheme - less than 9% the energy storage capacity of Snowy 2.0.

We also have bigger unofficial plans a plenty - like mine for Strathdearn - a mighty 6,800GWh - nearly 20 times bigger than Snowy 2.0 but I am nowhere near getting the sort of official feasibility study that Snowy 2.0 is - and neither has anyone else with a big Scottish, Welsh, British pumped hydro scheme plan, to my knowledge.

Hopefully the UK will take a look at Snowy 2.0 and raise our game to what's needed for energy storage for the British Isles.

Using Norway's hydroelectricity is not the way to go for Britain in my opinion - the Norwegians will have many customers bidding up the price they can charge for energy storage. Britain needs our own energy storage.

[wolfekeeper]

Scottish scientists results are interesting. I think that significant amounts of electricity are going to be coming from solar though, and it has somewhat different properties to wind. Notably, it's less variable, and is somewhat anti-correlated with wind.

Realistically, the UK grid is going to have both on it, and that means that they're going to statistically cancel. Somebody modeled that here:

http://www.wind-power-program.com/intermittency2.htm

[Scottish Scientist]

Scottish scientists results are interesting.

Thanks.

I think that significant amounts of electricity are going to be coming from solar though, and it has somewhat different properties to wind. Notably, it's less variable, and is somewhat anti-correlated with wind.

Realistically, the UK grid is going to have both on it,

Agreed.

Solar is not the strong year-round performer at UK latitudes that it is closer to the equator.
Nevertheless, in summer (even between equinoxes - 20 March to 23 September) solar is a very useful supplement to wind.

[evan_au]

cheaper than the longer transmission distance from Tasmania, I would suppose.

Tasmania is fairly close to Melbourne - but Tasmania is an island, and underwater electrical lines are much more expensive to install, and harder to repair than overland routes. Recently the Tasmania-Victoria link was out of action for 6 months after an electrical fault - and because it also has an optical fiber, internet capacity to Tasmania was greatly reduced for the same period.

I've had a quick casual scope of Tasmania for suitable pumped hydro sites

Tasmania values its forest areas. A number of years ago, the Tasmanian hydro authority's campaign to dam every river was blocked on environmental concerns over the Franklin River. I think they will proceed more carefully now.

They are more likely to succeed with wind power - but it will involve building transmission lines from the windy west to the populated east side, which won't be popular, either.

And hydro-generator engineers will need to get their brains around the concept that air is also a fluid.

See: https://en.wikipedia.org/wiki/2016_Tasmanian_energy_crisis#Basslink_outage

[Scottish Scientist]

cheaper than the longer transmission distance from Tasmania, I would suppose.

Tasmania is fairly close to Melbourne - but Tasmania is an island, and underwater electrical lines are much more expensive to install, and harder to repair than overland routes. Recently the Tasmania-Victoria link was out of action for 6 months after an electrical fault - and because it also has an optical fiber, internet capacity to Tasmania was greatly reduced for the same period.

See: https://en.wikipedia.org/wiki/2016_Tasmanian_energy_crisis#Basslink_outage

I suggest an alternative approach for Australia's grid interconnectors between Tasmania and Victoria.

Basslink Island Hop Routes

Map adapted from Basslink map here.

My concept is to use 2 interconnectors carrying half the current each, instead of one, and to use the islands to break the underwater lengths into shorter segments, by hopping between islands as shown in the map.

The advantage is that when you get a break in an underwater cable then you still have 50% current capacity and the repair is quicker because it is more affordable to completely replace the broken segment with a temporary replacement cable. Then you've got all the time you need to make a permanent repair.

For interconnectors over stretches of ocean where there are not enough natural islands to serve as segmenting points, then artificial (floating) islands could be constructed or decommissioned oil and gas rigs reused for the purpose.

Simple. 

[wolfekeeper]

One interesting thing I worked out; the UK has about 30 million cars. If you replaced them all with electric cars with (only) 30kWh batteries, that's a storage capacity of 900 GWh. The UK daily usage is roughly 1000 GWh; so it's comparable.

Cars are stationary about 95% of the time so potentially you could use the cars as pretty much the only storage on the grid, but you could certainly add more as well.

One other thing I read was that cars used as grid storage their batteries are predicted to last longer than cars that aren't. The reason wasn't specified, you'd think it would wear them more quickly, but my guess is that the average state of charge can be maintained closer to 30% which gives the batteries the best longevity.

[alancalverd]

So we use your car for storing electricity when nobody else is using it. Presumably that means we can take electricity from your car when we need it, which is OK unless you happen to want to drive your car when your neighbour has "siphoned off the gas" to heat his house....Or will you only drive at night or on windy days?

I find it interesting that my car and my house run on pretty much the same fuel, and almost the same quantity. 25,000 miles per year at 10 miles per liter of diesel, and heating the house takes 2500 liters of oil a year. I use far less electrical energy  - maybe a quarter of the heating oil energy content. So if I went "all electric" the grid would have to supply me with 9 times as much as at present. That's a huge infrastructure investment in generating capacity alone, to be added to the cost of uprating the distribution network and finding some way of storing 3 - 5 days' worth of the stuff. Hence my enthusiasm for using the existing and entirely adequate gas and liquid fuel storage and distribution infrastructure and end-use machinery, and using all that free electricity to synthesise carbon fuels.

[wolfekeeper]

So we use your car for storing electricity when nobody else is using it. Presumably that means we can take electricity from your car when we need it, which is OK unless you happen to want to drive your car when your neighbour has "siphoned off the gas" to heat his house....Or will you only drive at night or on windy days?

No. The user would configure their car to sell electricity back, if and when and only to the extent that they want to do that; but don't forget they would be selling it back at a significant premium. Also, don't forget that the average mileage is only 30 per day, which is only 10 kWh per day. Most electric cars now have ~30 kWh batteries so there's spare capacity that's not being used.

If you're commuting at the full range of your car, then you need a bigger battery in your car anyway. The new Tesla model 3 for example has a 50-75kWh battery which can do over 200 miles on a single charge.

[puppypower]

I like the idea of 24 hour moon power, via the tides. The moon's gravity moves oceans of water back and forth, with a lot of dynamic and potential energy, just waiting to be tapped.

For example, picture if high tide brought water into a large cove, that is then dammed, just before the tide goes out. We have a huge daily reservoir of water power. Or you run underwater turbines  to capture the energy of the tidal water flow, in both directions. The tides are very reliable and have energy in both directions.

[wolfekeeper]

Tidal power looks like it's quite expensive though, and it's not 24 hours, the tide has to turn around.

[alancalverd]

Tidal power, like rocket flight,  is one of those scientifically obvious solutions that spawn massively imponderable engineering problems. As a result, after a hundred years of R&D, there are still only a handful of tidal generating stations around the world. Part of the problem is the ecological and economic impact of a tidal dam. Many life forms, including coastal communities of homo sapiens, depend on the tidal range, and even the variation of tidal range, for their life and living. And of course the antifracking treehuggers will complain that extracting energy from the moon's orbit will upset Selene and bring her crashing to earth.

[Scottish Scientist]

Tidal power looks like it's quite expensive though, and it's not 24 hours, the tide has to turn around.

The superior double lagoon design ...

(see The Naked Scientist topic - How can tidal lagoons generate electrical power on demand? )

.. produces power for 24 hours a day, if not uniformly for 7 days a week, 52 weeks a year because of the variation between high energy spring tides and low energy neap tides.

[sophiewilson0191]

It defend on the power storage and the use.
Energy can be harvested enough for a day.