Climate Change and Renewable Energy News and Discussion

tacoburger said:

China is going all on in chemical based energy storage systems and pumped hydro. But what is China's progress on thermal energy energy storage? Seems like Europe is really investing heavily into thermal energy storage and it seems really scalable. No rare elements or complex electronics, just heat up some salt/sand/dirt. At the rate that China is installing renewables, a simple and cheap energy storage solution is needed. There's little news on thermal energy storage in China, vs the mountain of lithium ion batteries/pumped hydro news. Really the only times I see China using a thermal energy storage solution is with concentrated solar thermal power and that's only because it's baked into the design of CSP systems.

Click to expand...

Perhaps it doesn't matter if China is behind on early stage research, which is tends to be very speculative and tends to not work out?

And if a simple thermal energy storage device proves commercially viable, it should be straightforward for Chinese companies to catchup and then scale with much lower costs.

---

In addition, if you're storing energy at the thermal stage, remember that you're going to lose 70%? straightaway when turning it into electricity in a generator. That's most of the electricity being lost.

In comparison, you're looking at a ballpark loss of 10% for a lithium battery or say 30% for pumped hydro

China is testing compress air storage systems and gravity battery systems

China’s green H2 capacity higher than the rest of world combined. Will keep growing fast

18 MW offshore turbine by Dongfang Electric has successfully been installed

AndrewS said:

Perhaps it doesn't matter if China is behind on early stage research, which is tends to be very speculative and tends to not work out?

And if a simple thermal energy storage device proves commercially viable, it should be straightforward for Chinese companies to catchup and then scale with much lower costs.

---

In addition, if you're storing energy at the thermal stage, remember that you're going to lose 70%? straightaway when turning it into electricity in a generator. That's most of the electricity being lost.

In comparison, you're looking at a ballpark loss of 10% for a lithium battery or say 30% for pumped hydro

Click to expand...

Thermal energy systems are extremely simple, it's literally just heating up large amounts of raw mass. The more advanced versions are just finding ways to boost the efficiency via most efficient heat exchange systems and better materials. It's already commercially viable and in a time where the main limiting factor for renewables in China is energy storage, Chinese companies really should be building lots of them. They are becoming increasingly popular in Europe, who is also facing a renewables surplus. They don't even have to be used for electricity, they are also just used for heat, both for homes and industrial purposes.

As for efficiency

Thermal energy storage includes a number of different technologies, each one with its own specific performance, application and cost. TES systems based on sensible heat storage offer a storage capacity ranging from 10 to 50 kWh/t and storage efficiencies between 50% and 90%

Click to expand...

vincent said:

China is testing compress air storage systems and gravity battery systems

Click to expand...

Gravity battery systems are the dumbest grid scale energy storage system ever made. Compressed air systems are good, but they need complex engineering and are more expensive than TES. China has the largest renewables capacity in the world and is facing large amounts of surplus energy due to this, you would think that they would be investing heavily in basically every energy storage system, especially a major one like thermal.

tacoburger said:

As for efficiency

Please, Log in or Register to view URLs content!

Click to expand...

are you talking about using the storage system for heating or electricity generation? For heating, there are plenty of rooftop water heaters in China.
What is the efficiency of the storage systems that are used for electricity generation?

tacoburger said:

Gravity battery systems are the dumbest grid scale energy storage system ever made. Compressed air systems are good, but they need complex engineering and are more expensive than TES. China has the largest renewables capacity in the world and is facing large amounts of surplus energy due to this, you would think that they would be investing heavily in basically every energy storage system, especially a major one like thermal.

Click to expand...

Again, you have to compare apple with apples. TES for heating or TES for electricity generation?

vincent said:

are you talking about using the storage system for heating or electricity generation? For heating, there are plenty of rooftop water heaters in China.

Click to expand...

vincent said:

Again, you have to compare apple with apples. TES for heating or TES for electricity generation?

Click to expand...

A single TES system can be used for both depending on the setup. And of course I'm talking about large industrial scale GWH scale storage systems, not rooftop water heaters.

vincent said:

What is the efficiency of the storage systems that are used for electricity generation?

Click to expand...

It highly depends on the system in question of course. TES is such a wide range of various different systems that you might as ask the effectiveness of chemical batteries: which can range anywhere from Li-ion, lead acid or salt water batteries. I already gave you the source of 50-90%, that purely for electrical conversion, if it's just for heat generation, it's something like 80-95% round trip efficiency, again depending on the system.

Of course the TES can have much greater efficiency since they don't always require electricity to store heat, they can be used in conjuration with industrial process that already generate waste heat and have to get rid of large amounts of waste heat and thus act as a heat sink and get free heat in the process.

Heat pumps are 300% efficient because of this, they are just moving heat around, not generating it directly. If you want to be technical, TES can be >100% efficient because they don't need to use anything to generate their heat, they can just be used as a heat sink for a some industrial process that generates a lot of waste heat, and without said TES the industrial process would have used some other method of cooling that didn't generate any power at all. In fact, most of this cooling methods involves using electricity

And again, for industrial process that need heat, a TES basically saves you electricity/fossil fuels since they can generate heat directly, while a battery system has to use the electricity to generate heat, which generates some power loss in the process, which is never factored into the efficiency process.

If you want to focus on efficiency so much I guess green hydrogen- efficiency 30-40%, pumped hydro- efficiency 70-85%, compressed air- 60-70%, flow batteries-60-85% are all useless and we should use lithium ion for every grid scale energy storage solution. Let us ignore costs, material viability, energy density, max discharge cycles, other uses than producing electricity.

If China is producing a ridiculous amount of excess renewable energy as will be often the case, even a energy storage system with efficiency of 10% is worth it, if the cost of making and setting up the system is cheap enough, as well as the other factors like max discharge cycles, energy density etc etc.

tacoburger said:

A single TES system can be used for both depending on the setup. And of course I'm talking about large industrial scale GWH scale storage systems, not rooftop water heaters.

It highly depends on the system in question of course. TES is such a wide range of various different systems that you might as ask the effectiveness of chemical batteries: which can range anywhere from Li-ion, lead acid or salt water batteries. I already gave you the source of 50-90%, that purely for electrical conversion, if it's just for heat generation, it's something like 80-95% round trip efficiency, again depending on the system.

Of course the TES can have much greater efficiency since they don't always require electricity to store heat, they can be used in conjuration with industrial process that already generate waste heat and have to get rid of large amounts of waste heat and thus act as a heat sink and get free heat in the process.

Heat pumps are 300% efficient because of this, they are just moving heat around, not generating it directly. If you want to be technical, TES can be >100% efficient because they don't need to use anything to generate their heat, they can just be used as a heat sink for a some industrial process that generates a lot of waste heat, and without said TES the industrial process would have used some other method of cooling that didn't generate any power at all. In fact, most of this cooling methods involves using electricity

And again, for industrial process that need heat, a TES basically saves you electricity/fossil fuels since they can generate heat directly, while a battery system has to use the electricity to generate heat, which generates some power loss in the process, which is never factored into the efficiency process.

If you want to focus on efficiency so much I guess green hydrogen- efficiency 30-40%, pumped hydro- efficiency 70-85%, compressed air- 60-70%, flow batteries-60-85% are all useless and we should use lithium ion for every grid scale energy storage solution. Let us ignore costs, material viability, energy density, max discharge cycles, other uses than producing electricity.

If China is producing a ridiculous amount of excess renewable energy as will be often the case, even a energy storage system with efficiency of 10% is worth it, if the cost of making and setting up the system is cheap enough, as well as the other factors like max discharge cycles, energy density etc etc.

Click to expand...

China is building coal-fire power plants that can reduce their outputs to 20%. They act as the base load for the renewable grid.

vincent said:

China is building coal-fire power plants that can reduce their outputs to 20%. They act as the base load for the renewable grid.

Click to expand...

China is building hundreds of gigawatts of renewables a year. A handful of new coal power plants that can scale down their output isn't going to cut it. Eventually renewables capacity will outstrip all coal capacity within a decade at the rate of new installations. Stable baseload won't be that much of an issue, the main issue will be that China will be producing so much excess power on sunny and windy days that it will have to curtail much of it's renewables or risk shorting out the grid.

Coal can provide good baseload but does nothing to store extra power. You're gonna need terawatt hour scale energy storage systems to store all that energy, or it all gets wasted. Anyway, the entire point is to eventually phase out coal eventually not having hundreds of coal plants just idling for most of the year and only running at full power during a handful of days a year. Which in itself is wasteful anyway, have you seen the prices of gas peaker power plants? if you have enough enery storage and renewables, it can act as a baseload anyway, with nuclear and maybe a handful of coal/gas peaker power plants acting as a final backup. Of course, that does mean that you need a insane amount of energy storage systems and the excess renewables to charge it up

Anyway, as I have already said, TES offers a lot of utility other then electrical generation. It can act as a heat sink to capture and store waste heat. It can directly supply heat for industrial processes instead of using electricity to heat up a resistor or firing up a gas boiler. You would think that the country with the largest heavy industrial sector would be investing more into thermal energy storage for this reasons.

tacoburger said:

China is building hundreds of gigawatts of renewables a year. A handful of new coal power plants that can scale down their output isn't going to cut it. Eventually renewables capacity will outstrip all coal capacity within a decade at the rate of new installations. Stable baseload won't be that much of an issue, the main issue will be that China will be producing so much excess power on sunny and windy days that it will have to curtail much of it's renewables or risk shorting out the grid.

Click to expand...

Theoretically, once you have a completely electric vehicle fleet, you only need about 20% of that existing paid-for battery capacity for an entire day's electricity usage.

And each car battery would need another 20% for average daily usage.

That leaves you 60% slack on average.

And with the latest LFP batteries, these will last the lifetime of the car, even if they are used for grid load balancing in addition to daily driving usage.

---

So during periods of low renewable production, you only need a few coal plants running 24/7 to generate enough electricity for a day. In China, I would expect to see coal backup plants running for weeks at a time in the winter.

tacoburger said:

Coal can provide good baseload but does nothing to store extra power. You're gonna need terawatt hour scale energy storage systems to store all that energy, or it all gets wasted. Anyway, the entire point is to eventually phase out coal eventually not having hundreds of coal plants just idling for most of the year and only running at full power during a handful of days a year. Which in itself is wasteful anyway, have you seen the prices of gas peaker power plants? if you have enough enery storage and renewables, it can act as a baseload anyway, with nuclear and maybe a handful of coal/gas peaker power plants acting as a final backup. Of course, that does mean that you need a insane amount of energy storage systems and the excess renewables to charge it up

Anyway, as I have already said, TES offers a lot of utility other then electrical generation. It can act as a heat sink to capture and store waste heat. It can directly supply heat for industrial processes instead of using electricity to heat up a resistor or firing up a gas boiler. You would think that the country with the largest heavy industrial sector would be investing more into thermal energy storage for this reasons.

Click to expand...

Solar electricity costs are already just 2 cents per kWh in many places. That is 3-4x cheaper than coal.

So it's better to overbuild solar generation capacity by say 3x. That means you still end up with electricity which is cheaper than coal at all times.

During the summers and afternoons, there is a huge amount of cheap, almost free electricity.
During the winters and the mornings/evenings, you end up with solar electricity costs somewhat lower than coal.

Tony Seba's group did a study, and ended up with the optimal scenario being roughly:
1. overbuild renewables by 3x
2. require about 4hours of electricity storage. But note there will be terawatt-hours of spare battery capacity in cars anyway.

---
Heat is a low-quality form of energy. There's like waste heat from all sorts of places.
But it has to compete with low-cost renewables which generate electricity.