Green, ethical, energy issues in the news

zeupater

Piddles wrote: »

From that Medium article:

:rotfl: Note my caveat about vested interests against that link! I'd love to see where he got that 10% from. It seems current technology is nearer 70% according to Wikipedia with an expectation of low eighties in ten years. It seems fossil fuel derived hydrogen is still generally cheaper though, so with the other factors (including the compression overhead, the lower energy density and thick heavy steel tanks...) it doesn't yet change the balance of the argument.

Hi

Pretty much in agreement, but low pressure/high volume storage & employing lower efficiency (/low capital investment) combustion based generation in very marginal fuel cost conditions really needs due consideration as it's the combination of capital investment & operating cost that can be the important considerations as opposed to efficiency in this scenario ...

HTH
Z

silverwhistle

zeupater wrote: »

Effectively, it's not the "electricity for which there is no demand at the time of production" that becomes the issue, it's the control rooms that call for generation to be scaled back or stopped (curtailment) because there is no demand to satisfy, although there may be a requirement for compensation to be paid for not generating, so storage becomes an ideal short & medium term storage solution ...

I've just highlighted on the solar thread regarding another thread here by Zarch and the use of variable pricing which needs smart meters.

Some of the tariffs can go as low as 2p per kWh, and potentially even negative, so it would be interesting to postulate having half a million or so customers with immersions, storage heaters or BEVs all saying, "ooh, I'll have some of that" and mopping up such (potential) surpluses.

What is most interesting is that technology, computing and weather forecasting all enable the prediction of prices 24 hours in advance.


It would be fascinating for a National Grid strategic planner to come on here and enlighten us a bit. How do they see the issues of increased RE and curtailment developing in the near and longer term future?

GreatApe

zeupater wrote: »

Hi

From previous research I thought that hydrogen electrolysis ranged up to around ~80% efficient (in terms of electricity used to create hydrogen embodied energy) and that there are now a number of fuel cells based on relatively inexpensive stainless steel plate stacks which have an electrical energy to heat production efficiency of around ~50%:~50% ...

The big problem with hydrogen is the application ... if it's to produce motive power you need to lug around plenty of mass, that's not the mass of the hydrogen itself, but the high pressure vessels that it's contained in because it's essentially boiled to become a gas at our atmospheric temperatures & pressures, which effectively reduces motive efficiency on the ground and really kills the economics for gas based propulsion in commercial heavier than air aircraft.

The case can be made for short cycle hydrocarbon fuels that are stable as a liquid at pressures & temperatures that they would be required to be stored & used at as this removes the requirement for cumbersome pressure or temperature managed storage, particularly so if they could be extracted & refined directly from the atmosphere at commercial costs & volumes

The only place hydrogen might make sense is for aircraft and then in liquid form
The airplane can then be lighter and more fuel efficient or carry ~3 x the payload.
Plus it is displacing jet fuel (5.3 cents/kWh) rather than trying to displace NG (1 cent/Kwh) in this application

Hydrogen for heating or for storage makes no sense certainly not for at least another 30 years
It will cost significantly more than methane which costs 1 cent / kWh in the USA

Also the transmission cost of hydrogen will be higher than that of methane since it needs pipes which are about 3 x as thick. Most the cost of natural gas to your home is transmission and distribution not the NG itself (you pay 4p the cost of the NG is closer to 1p)




One interesting thought though, is what if you pipe both the hydrogen and the oxygen to energy users. Could you build a 100% efficient boiler this way rather than a more typical 75% efficient NG boiler? Just burn the hydrogen and oxygen inside the water itself. Interesting. But most likely we wont be ripping up streets to lay pipes for a hydrogen network let alone a hydrogen and oxygen network.

GreatApe

silverwhistle wrote: »

I've just highlighted on the solar thread regarding another thread here by Zarch and the use of variable pricing which needs smart meters.

Some of the tariffs can go as low as 2p per kWh, and potentially even negative, so it would be interesting to postulate having half a million or so customers with immersions, storage heaters or BEVs all saying, "ooh, I'll have some of that" and mopping up such (potential) surpluses.

What is most interesting is that technology, computing and weather forecasting all enable the prediction of prices 24 hours in advance.

It would be fascinating for a National Grid strategic planner to come on here and enlighten us a bit. How do they see the issues of increased RE and curtailment developing in the near and longer term future?

The solution to curtailment is quite an easy one and its not the hair brained idea of hydrogen production

You regulate so boiler manufacturers have to add a 11.5 KW heating element into their boilers. This will add probably no more than £20 to the cost (seeing as you can buy an electric shower for £50 retail) and make them fully wifi linked again a tiny cost considering you can buy a smartphone for £50 which has much more than a smart boiler would need.

Give the grid and utility companies the ability to tell the boiler to use electricity rather than NG when there is excess wind or solar in the system and charge only 5p a unit for this electricity at 100% efficiency (rather than 4p for the gas at 75%)

Over time the NG boiler network would become dual fuel and as the grid gets more and more green the housing/office/retail stock would have its heating become more and more green

This also allows much more wind to be able to be added to the grid
Because as you add more wind it just gets diverted to the dual fuel boilers thus displacing natural gas

Also the good thing about offshore wind power is that its capacity while 40% year round, is closer to 50% in the winter. So more than half of winter NG heating can be provided by offshore wind powering these dual fuel boilers if you assume a correlation of 75% for a large fleet of wind farms that means 66% of the heat output of these boilers could be from wind power and the rest from NG


So what do you lot thinks makes more sense
A hydrogen industry to rival in scale and scope the current petrochemical industry
Or £20 to make gas boilers dual fuel? :T

Martyn1981

Piddles wrote: »

I guess you're saying renewable electricity for which there is no demand at the time of production. One half of the renewable energy conundrum. Isn't the environmental need that this is addressed with storage solutions (batteries) to eliminate fossil fuels rather than be wasted in an unreliable supply (and having to be topped up with non marginal generation) supporting inefficient processes?

Yes, but .......

Stage one, is I believe batteries. Actually I suppose stage one is building out too much RE generation 'at times', but let's pretend we are getting close, and I suppose we are on very windy nights.

Intra-day battery storage has been estimated at around 500GWh for the UK (I won't bore you with old links as I assume better ones will come along soon). Now, 500GWh is a terrifyingly huge number for battery storage ..... or is it?

If the UK car fleet was replaced with 50kWh BEV's, then we'd have 1,500GWh of batts almost as a side effect. I'm guessing that at any point in time one third or more will be parked up, so if plugged into a smart charger with appropriate instructions to benefit from cheap excess, or sell at peak prices, these BEV's could meet the intra-day needs.

Perhaps cars will be replaced by a smaller number of on call BEV's, but even then there would be fleets of buses, vans, trucks etc that would, at times, be sitting idle.

So, then onto stage two, as stage one doesn't allow us to get to 100% RE as we'd still need FF gas as a back up for extreme periods, perhaps 15% or so of annual generation.

It's at this stage that methane production from excess RE for gas generation, or H2 (again from excess) for thermal plant use, or fuel cell generation, makes great sense, and this can be used to aid us in hitting 100% RE.

Also, due to the higher energy density (as Z mentioned) could potentially provide for inter seasonal storage - PV for the winter, or wind for the summer, but now I'm being greedy and leapfrogging to stage four.

At this point worth a quick reminder that for all intents and purposes, UK off-shore wind potential is virtually limitless, so enough capacity, combined with enough storage (plus of course a mix of other RE generation types), and we're sorted. Simples.

Martyn1981

silverwhistle wrote: »

It would be fascinating for a National Grid strategic planner to come on here and enlighten us a bit. How do they see the issues of increased RE and curtailment developing in the near and longer term future?

Not quite what you asked, but ESO (formerly part of the National Grid) has presented a report suggesting the grid will be ready to cope with 100% RE leccy by 2025.

Note, that doesn't mean they expect 100% of all supply to be RE, or even (I assume) that it will at times be 100% RE by 2025, but that they'll be ready to cope with a 100% RE supply scenario.

Which I think is heartening news.

Zero carbon operation of Great Britain’s electricity system by 2025

GreatApe

Martyn1981 wrote: »

Yes, but .......

Stage one, is I believe batteries. Actually I suppose stage one is building out too much RE generation 'at times', but let's pretend we are getting close, and I suppose we are on very windy nights.

Intra-day battery storage has been estimated at around 500GWh for the UK (I won't bore you with old links as I assume better ones will come along soon). Now, 500GWh is a terrifyingly huge number for battery storage ..... or is it?

If the UK car fleet was replaced with 50kWh BEV's, then we'd have 1,500GWh of batts almost as a side effect. I'm guessing that at any point in time one third or more will be parked up, so if plugged into a smart charger with appropriate instructions to benefit from cheap excess, or sell at peak prices, these BEV's could meet the intra-day needs.

Perhaps cars will be replaced by a smaller number of on call BEV's, but even then there would be fleets of buses, vans, trucks etc that would, at times, be sitting idle.

So, then onto stage two, as stage one doesn't allow us to get to 100% RE as we'd still need FF gas as a back up for extreme periods, perhaps 15% or so of annual generation.

It's at this stage that methane production from excess RE for gas generation, or H2 (again from excess) for thermal plant use, or fuel cell generation, makes great sense, and this can be used to aid us in hitting 100% RE.

Also, due to the higher energy density (as Z mentioned) could potentially provide for inter seasonal storage - PV for the winter, or wind for the summer, but now I'm being greedy and leapfrogging to stage four.

At this point worth a quick reminder that for all intents and purposes, UK off-shore wind potential is virtually limitless, so enough capacity, combined with enough storage (plus of course a mix of other RE generation types), and we're sorted. Simples.

They dont want to charge above 80% nor discharge below 30% so only about half of the 50KWh is available

But more importantly the EV owners wont give you their juice
Who wants their 160 mile range EV (80% charge 50KWh @ 4 miles per KWh) to go down to 60 miles range (30% Charge 50KWh @ 4 miles per kWh) or rather zero miles really because they wont want to discharge to below 30% and with the risk that they can not then charge up the next day if there is no wind power? No thanks

Getting to work is more important than making a few pennies selling electricity for 5p a unit to the grid and also using up some of your finite charge/discharge cycles

Likewise fleet EV owners would rather charge customers £1 a mile (£4 per kWh) than to sell to the grid for 5p a kwh



Your ideas are silly

My idea of hybrid boilers solves the problem for at least the next 20 years
The UK could build out perhaps as much as 100 GW of offshore wind power without worrying about curtailment if we switched to dual fuel boilers

The 2030 plan is 30GW offshore wind so there is another 70 GW to go if you do dual fuel boilers

The cost of dual fuel boilers. Virtually nothing, lets say £20 a boiler

And yes EVs will help too, if they become economic which hopefully they do but these hybrid boilers are extremely cheap simple effective tech to allow much more wind power into the grid

(also it would work with nuclear too but the UK doesn't need nuclear beyond what we have, and actually offshore wind works better since winter output is about 70% higher than summer output)

1961Nick

zeupater wrote: »

Hi

The issue is that at the moment a considerable amount of renewable energy generation curtailment happens because supply exceeds demand ... you can easily see this on both on-shore & off-shore sites where only a proportion of turbines are spinning, the rest having had the brakes applied or simply turned out of the air stream ...

Effectively, it's not the "electricity for which there is no demand at the time of production" that becomes the issue, it's the control rooms that call for generation to be scaled back or stopped (curtailment) because there is no demand to satisfy, although there may be a requirement for compensation to be paid for not generating, so storage becomes an ideal short & medium term storage solution ...

Short term energy storage using hydrogen could be highly distributed and possibly linked to modular high pressure storage (5000-10000psi) supplying local PEM stacks when required, or more strategic storage in low pressure mass storage in the likes of underground caverns (salt etc) or fairly cheap overground storage based on old technology gasometers to feed either large scale fuel cells, or more likely comparatively cheap hydrogen ICE generators as the total fuel efficiency & cycle cost can only realistically be measured against lost opportunity, therefore marginal ...

This is really what's behind the arguments that those opposed to renewable energy employ when concentrating on relative efficiencies and capacity loading factors as opposed to the real issues of energy unit cost & associated impact, whether sustainable, environmental or health related ...

HTH
Z

From what I've read, converting surplus renewable energy into hydrogen makes a lot of sense. Since the cost of the energy is virtually zero, the only cost is the infrastructure required to store & distribute it. I'm sure it must be possible to build a fuel cell tanker that runs on the hydrogen it's transporting? A hydrogen filling station in every town would make a fuel cell vehicle a viable proposition & an alternative to a BEV - for those that don't relish queuing at a charger & then waiting 30 minutes for it to charge.

zeupater

Piddles wrote: »

... including the compression overhead, the lower energy density and thick heavy steel tanks... it doesn't yet change the balance of the argument.

Hi

I was going to address the 'thick heavy steel tanks' for hydrogen storage in the previous answer, but didn't get around to it, so this is what was missing ...

My post you referenced mentioned ...

The big problem with hydrogen is the application ... if it's to produce motive power you need to lug around plenty of mass, that's not the mass of the hydrogen itself, but the high pressure vessels that it's contained in because it's essentially boiled to become a gas at our atmospheric temperatures & pressures, which effectively reduces motive efficiency on the ground and really kills the economics for gas based propulsion in commercial heavier than air aircraft.

.. and this is what you refer to as being 'thick heavy steel tanks', however it's likely that the high pressure (~10kpsi) storage solutions used for efficient motive solutions would be constructed from multi layer polymer which is reinforced by carbon fibre to reduce the vessel weight considerably below that of the steel 'bottles' we're all familiar with ... this lightweight solution likely reduces the contents:container ratio to somewhere between 10:1 & 20:1, so lets assume a midpoint of 15:1, where a fuel load of 5kg of hydrogen (approx 160kWh) would require around 75kg of 10000psi storage plus a fuel cell stack weighing somewhere around 2kg/kW of deliverable power to convert the hydrogen into usable electricity ... so a typical ~130HP (~100kW) vehicle would require a combined 275kg storage & generation solution providing approx 65-80kWh of usable energy, which is in line with storage capacity of a long range Tesla Model 3 (75kWh) where the battery pack is capable of delivering around 2.5x the power (258kW) ... yes the fuel cell system could be upscaled to deliver similar power levels, but at considerable cost and an additional ~300kg to the vehicle weight, although it's far more likely that a hybrid solution of hydrogen fuel cell for driving with a battery pack for additional power delivery when required would form a better solution ....

This is exactly the quandary that the automotive sector has been mulling over on employing hydrogen power efficiently for decades - it's embodied power density can be high on a kWh/kg basis, but the energy storage & delivery requirements are really heavy when compared to liquid fuel storage tanks or even an equivalent specification storage & delivery solutions based on rechargeable batteries ... but what does this mean for the 'heavier than air aircraft' mentioned ? ...

Well, as has been described for vehicles, the cost of efficient hydrogen conversion to useable electricity is heavily related to mass, the more power intensive the demand, the more mass intensive the solution and there's one constant about running commercial heavier than air aircraft, they're power hungry, so much so that fuel cells, at anywhere near current efficiencies, fall far short of what's required purely on weight grounds, so some form of combustion process is a more likely solution, however that still doesn't address the storage to content weight ratio for the fuel ....

In aeronautics the proportion of the take off weight for any aircraft is referred to as the fuel fraction, which for long range commercial aircraft is typically around 40% .... take this and apply between 10x and 20x the fuel weight as lightweight storage and the range is either severely impacted or the plane weighs around ~4.5x & 8x more, carries no commercial payload and the undercarriage likely collapses as it starts to taxi ....

So what are the options? ... cooled liquid hydrogen with all of the environmental stability & safety issues that implies?, or processing hydrogen into a liquid hydrocarbon form using any one of a number of processes, all of which have process cost implications, but solve the storage:contents weight ratio as they effectively use current liquid fuel no/low pressure storage ....

Yes, aviation high pressure hydrogen, fuel cell and LH2 solutions have been researched & trialled on a small scale basis, but that's a completely different prospect from the commercial conclusions, which when looked at in detail, are pretty stark ... the alternative of some form of biomass based or recovered synthetic fuel looks far more promising for the aviation sector where weight and commercial viability form far more critical concerns than where the force of gravity is easily countered by solid ground ...

HTH
Z

Martyn1981

zeupater wrote: »

Hi

Yes, aviation high pressure hydrogen, fuel cell and LH2 solutions have been researched & trialled on a small scale basis, but that's a completely different prospect from the commercial conclusions, which when looked at in detail, are pretty stark ... the alternative of some form of biomass based or recovered synthetic fuel looks far more promising for the aviation sector where weight and commercial viability form far more critical concerns than where the force of gravity is easily countered by solid ground ...

HTH
Z

Very early days, but electric or hybrid aircraft may prove viable for short haul trips, and allow airports to go 24/7 with near silent night flights.

Regarding your last para, here's a recent article on producing hydrocarbon fuels, only a demonstrator at 0.1 litres per day, but a start.

Carbon-neutral fuel made from sunlight and air

Carbon-neutral fuels are crucial for making aviation and maritime transport sustainable. ETH researchers have developed a solar plant to produce synthetic liquid fuels that release as much CO2 during their combustion as previously extracted from the air for their production. CO2 and water are extracted directly from ambient air and split using solar energy. This process yields syngas, a mixture of hydrogen and carbon monoxide, which is subsequently processed into kerosene, methanol or other hydrocarbons. These drop-in fuels are ready for use in the existing global transport infrastructure.