,
19 tweets,
12 min read
Read on Twitter
@aria606 @MichaelEMann Storage has been part of the US grid since 1929, with over 25.2 GW installed as of 2018, with more being added all the time. CA has almost 1.2 GW in progress
It is possible to have a grid w/o storage, even with wind/solar, with enough geographic diversity, but it won't be robust
It is possible to have a grid w/o storage, even with wind/solar, with enough geographic diversity, but it won't be robust
@aria606 @MichaelEMann So storage is and always has been critical. (It's not just robustness you sacrifice, but also economics; you have to overbuild).
It is critical that you never over-power the grid. That always means, taking some power out of the grid. You can't easily operate a nuke at low power
It is critical that you never over-power the grid. That always means, taking some power out of the grid. You can't easily operate a nuke at low power
@aria606 @MichaelEMann And gas turbines (and hydro) can't operate below a minimum power. You have to turn them off. And even the less-efficient ones used as "peakers" take about 10 minutes to turn on again and are inefficient in the meantime.
@aria606 @MichaelEMann Solar and wind can be turned on and off in much smaller increments. Currently, China curtails about 15% of their wind power this way. CA curtails some solar, and other times pay other states to take the surplus.
@aria606 @MichaelEMann China has built the world's largest single battery, 200 MW/800 MWh, in Dalian and the factory that built that is building more. South Australia began rapidly adding storage after a huge storm-caused outage.
@aria606 @MichaelEMann California added storage to replace gas plants offlined because of the Aliso Canyon gas leak. The last two were done in months. (Dalian required the factory be built first).
Batteries are good at quickly both adding and removing power from the grid.
Batteries are good at quickly both adding and removing power from the grid.
@aria606 @MichaelEMann So rather than having to shut down an efficient gas plant and run a peaker gas plant harder, you can rely more on the efficient plant. This same principle applies to wind/solar. It lets you use your efficient sources fully and rely less on inefficient ones.
@aria606 @MichaelEMann So while you a no-storage wind/solar grid, storage means you need less over-capacity, less sources offlined for lack of load. And it means you're less vulnerable to damage to the grid.
And baseline sources like hydro or geothermal help as well.
And baseline sources like hydro or geothermal help as well.
@aria606 @MichaelEMann But baseload is not absolutely essential. Anyone who tells you it is, is giving you a snow job. If they talk instead about how baseload contributes, by reducing the amount of power that has to be time-shifted, then you're getting the real story.
@aria606 @MichaelEMann So yes, we should not focus on just one thing. Diversity itself is important to the grid. Wind+solar+hydro+geo+[some nukes]+storage+load-shifting+conservation.
We should not sequence these, but work in parallel on each.
We should not sequence these, but work in parallel on each.
@aria606 @MichaelEMann The US is berhind much of the world on storage. In Europe, storage first appeared in the 1890s, and today, about 10% of power is stored before delivery, and 15% in Japan. In the US, it is only 2.5%
This will need to change. But diversity from our large geographic area has helped
This will need to change. But diversity from our large geographic area has helped
@aria606 @MichaelEMann So sunny Los Angeles draws power from Celilo, Oregon, 836 mi (1362 km) to the north, up to 3.1 GW in the summer when LA power use is greatest, less in the winter when it's used for heat in the north.
@aria606 @MichaelEMann (Edit: Celilo is the name of the power station; The Dalles is the geographic location)
This link is not new. It was approved by JFK, and went into operation in May 1970, and has been upgraded several times since.
This is an HVDC link, more efficient over long distances.
This link is not new. It was approved by JFK, and went into operation in May 1970, and has been upgraded several times since.
This is an HVDC link, more efficient over long distances.
@aria606 @MichaelEMann But the US is not in the lead here. China is the world's largest generator of wind, solar, hydro, and nuclear power in the world (as well as coal), and they have been deploying ultra-high-voltage links to take advantage of the diversity to bring distant power to where it's needed
@aria606 @MichaelEMann I forgot to talk about hat kind of storage is in use. The two traditional ones are pumped hydro and flywheels. The dates I gave (1890's in Europe, 1919 US)( were for pumped hydro. Flywheels may have been added earlier, and to a degree are part of any rotating generator.
@aria606 @MichaelEMann Pumped hydro stores large amounts of energy for long periods, while flywheels act quickly, to remove or add power to react to sudden change.
Today, we have more options. Batteries and Compressed Air are both in use. Other techs are in development, like stored hydrogen.
Today, we have more options. Batteries and Compressed Air are both in use. Other techs are in development, like stored hydrogen.
@aria606 @MichaelEMann Batteries can respond as quickly as flywheels, but the amount of energy they can store is unlimited except by cost. A typical value is 4 hours at rated peak power. which is about enough to take a day's solar and give it out overnight, roughly.
@aria606 @MichaelEMann BTW, you mention that France gets 90% GHG-free power.
Vermont is 99.6%. In Canada
QB 99.9
MB 99
NB 98
YT 95
BC 95
NL 93
ON 90 (58 nuclear)
Most of this is hydro, but the share of wind and solar is growing.
Canada exports about 10% of its power to the US.
Vermont is 99.6%. In Canada
QB 99.9
MB 99
NB 98
YT 95
BC 95
NL 93
ON 90 (58 nuclear)
Most of this is hydro, but the share of wind and solar is growing.
Canada exports about 10% of its power to the US.
