Green, ethical, energy issues in the news

Martyn1981 wrote: »

Assuming you own the batts, then the financial impact of P2G does need to be considered. So would the import savings be enough, if the car is charged on E7 ... perhaps, perhaps not.

If EV owners can sell leccy at market rates during demand peaks and price peaks it may be worth it.

My understanding is that the large EV batts, designed to deliver very large amounts of power (I think the Leaf has an 80kW motor), would see little to no impact on life expectancy from delivering just a couple of kW's for a couple of hours, as they'd barely be ticking over compared to what they can do.

But, I'm mostly guessing, and basing thoughts on comments form off-gridders with huge battery banks who don't consider lots of small charge/discharge cycles as 'proper' cycles when considering life expectancies.

If car batts were to suffer from P2G use, then the economics do shift.

The concensus on speakev forum is that it is using the extremes of the battery storage, full and empty, that leads to degredation. So setting a maximum max charge 5 or 10kwh below the max and only discharging to say 50% required for day to day driving would have negligible impact on longevity.

lstar337 wrote: »

Of course if we invested in Thorium molten salt reactor development we wouldn't have that issue. It will increase/decrease its output to follow the load automatically. Plus we could burn up our current stock of waste material from our PWR's and AGR's in the process. We could even charge other countries to burn up their waste too, making extra money from generating.

Thorium reactors would be the perfect accompaniment to RE.

As far as I was aware, the issue with nuclear isn't that it can't modulate to follow the load, but that doing so makes the electricity more expensive as almost all the costs are fixed such as building and decommissioning the plant, maintaining it etc. Unlike a fossil fuel power station in which if you don't generate electricity, you save money on the fuel you don't burn.

So if you've spent a huge amount of money building your nuclear power plant, the last thing you want to do is have it idling away. You have to maximise its output and sell all the electricity you can.

By all means carry on research into thorium reactors, but i don't think we can afford to hold our breath waiting for them, given the decades of promises of something great just round the corner!

ed110220 wrote: »

As far as I was aware, the issue with nuclear isn't that it can't modulate to follow the load, but that doing so makes the electricity more expensive as almost all the costs are fixed such as building and decommissioning the plant, maintaining it etc. Unlike a fossil fuel power station in which if you don't generate electricity, you save money on the fuel you don't burn.

PWR's and AGR's do not modulate that well due to possible damage to fuel assembly modules. They can swing up to about 30% @ roughly 1%/s, but it isn't really done because fuel assemblies are easily damaged and costly to replace. It is therefore much more cost effective to run at as near a constant output as possible. Running at a near constant output for most of the time also reduces the chance of anything going wrong.

No issue with fuel assemblies in a molten salt reactor design, you just chuck the fuel into the molten salt like coal into a furnace (ok, not quite :rotfl:), but you get the idea.

Decommissioning costs are *assumed to be far lower as there is no huge pressure chamber to get rid of. In fact it is likely that molten salt reactors would be built underground, and simply covered over once the remaining fuel has been pumped out after shutdown.

ed110220 wrote: »

So if you've spent a huge amount of money building your nuclear power plant, the last thing you want to do is have it idling away. You have to maximise its output and sell all the electricity you can.

Certainly initial cost would be high (for a new design etc.), but we could just wait for the Indians/Chinese to do all the hard work for us. :rotfl: Running costs will be considerably lower due to the low pressure design and inherent safety features, and lets not forget the additional revenue from burning up the spent fuel from other countries. That will be big business. I can foresee us paying either India or China to burn up our waste tbh, we have quite a bit of it!

ed110220 wrote: »

By all means carry on research into thorium reactors

I think I have already done more research than anybody who is not building one should have ever done. :rotfl:

ed110220 wrote: »

but i don't think we can afford to hold our breath waiting for them, given the decades of promises of something great just round the corner!

Decades of inaction! You can extol the advantages of a technology til the cows come home, but if nobody builds it, it isn't the technologies fault. Blame the companies creating uranium fuel pellets and assemblies (also the ones building the same old reactors :think:), as they will be the ones suddenly put out of business!

Thorium MSR's show a lot more promise than Fusion reactors, yet there is a lot of time/money going in to them at present. IMHO, by the time they have a sustainable fusion reactor, they will be irrelevant as RE and storage will have solved the worlds energy hunger crisis.

*I say assumed as nobody has decommissioned one yet.

By fixed, i meant that they are fixed no matter how much or little the plant is used, so you might as well use it as much as you can, as not using doesn't save you anything significant. Halve the output and have to sell the electricity for twice the price and it's not difficult to see why that would make no sense, unless the plant was unfeasibly cheap.

Think about it - even if there are technical limits to how much a reactor can load follow, it's not difficult to imagine how one achieve the same end simply by dumping the heat it produced as waste rather than using it to make electricity or even just wasting the electricity it did.