I think if you look at future demands , electric cars and water electrolysis a HVDC network does make sense , but at the moment the engineers that can show how it will work from HVDC transmission to AC distribution arnt getting the opportunity to show why it works better. The other option of course is to dispense with the UHV transmission system completely and generate AC locally to the interconnectors , which would require very different thinking but certainly could be efficient , I wouldn't like to do the maths on losing the UHV transmission system as there are some very good arguments for having a national grid for transmission from large generation centres. Renewables have come along pretty well , way beyond what I thought was possible 10yrs ago. I think solar PV will probably lose out in all but the high regular sun places or those who want to go off grid , because distributed electricity is so cheap with the right selection of generation. Hydro will probably move towards green hydrogen by splitting water as 500mw and over are not really common and some have caused environmental problems , but wind still causes grid management problems even though £30 per MW raw price is possible, and I think wind could go to green hydrogen also , at 1/3 rd of nuclear per MW it could provide quite cheap hydrogen .

When you see the figures for Hydrogen production , just even for Ammonia production let alone the Hydrogen car, the numbers are mind boggling.

Nobody wants hydrogen cars.  The overall efficiency is too low.  You take electricity, and use it to make hydrogen.  You them pump the hydrogen into the car, where it runs a fuel cell to generate electricity again.  Instead, we use the much simpler and more efficient approach of using the electricity to charge a lithium ion battery.

Plus, you can plug in a battery car wherever there's a mains electricity supply.  There's no infrastructure to support hydrogen vehicles, and nobody is investing to build one, because nobody is buying hydrogen cars.

It maybe would be worth you reading up on how a DC- AC inverter works at these voltages- it is not at all like designing an inverter for a few hundred kVA
Line Commutated conversion explanation it is not an elegant process in terms of waveform,  and as well as needing an AC grid to synchronize to, a lot of effort is needed to clean up the sine waves.

The cases where DC wins hands down over AC, are where you are linking regions so far apart that the AC phase offset is a problem (China's transcontiental links are like this), or the frequency is different at both ends (Japan's DC links between 50Hz and 60Hz regions are like this) or the AC losses are very high (under sea links are like this)

Yeah totally agree I think fuel cell efficiency is around 60% , so if car battery gets sorted , then Hydrogen has a quite a way to go, problem is Hydrogen for chemicals , gas reforming produces CO2 around 12kg per kg of hydrogen , and if gov wants to put it in gas mains at 20% numbers get massive if from water electrolysis .

Plenty of more cost and energy efficient H2 production technologies being developed today that don't use SMR that generates CO2, that needs CCUS, and they also produce value secondary cashflow by-products that reduce their whole life costs.

Simon, you might not like/want FCEVs and HICEs, but Hydrogen scooters, cars, buses, trains and trucks are being developed because e-vehicles don't meet all current fossil fuelled transport requirements. Many countries already have national targets for 100,000s H2 vehicles in the next decade.


You make green/blue hydrogen and put it in a H2 storage vessel that has the same life as a fossil fuel tank today - the life of the vehicle. BEVs need to replace their batteries at regular intervals at cost. Analysis of the wheel-to-well GHG emissions of a H2 vehicle is less than an equivalent BEV. Recharging FCEVs is faster, simpler and more 'BAU' as vehicles today. Plus, FCEVs have no charging cables lying all over the place. BEVs expend lots of their energy moving around the heavy batteries they have on board too, whether full or empty.  


The H2 transport hydrogen refuelling infrastructure is small but rolling out in the UK (17 stns as of today I believe) and more in the pipeline.


It is the classic 'chicken (infrastructure) or egg (OLEVs)' scenario that thwarted the take up of EVs for a decade.  This is due to a complete lack of national strategy and government leadership on low carbon transport. Build the infrastructure, reduce 'refuelling' anxiety, the demand grows and the vehicles will be invested in and produced. Vehicles can also be converted to H2 relatively easily. But all stakeholders need to be working collaboratively and coherently - two big words this government does not have in its lexicon.

EVs didn't really start being of interest or cost effective until 2006, and then the lack of EV charging infrastructure limited EV buying and choice - chicken (infrastructure) and egg (BEV) scenario - same for H2 vehicles. So it has taken 13 years to get to 9300 EV charging stations consisting of various electric charging technology, different connectors and cables, different BEV technology vehicles, many stations can only be accessed by membership or vehicle manufacturer, many are at home chargers not accessible to others, different payment methods, charging stations are denied to others if public chargers have cars left plugged in once fully charged, the charging slot occupied for hours by an BEV, or even occupied by a non-BEV vehicle. Range is still very limited on many BEV models, and range prediction is unreliable due to driving conditions, weather conditions, battery temperature, battery condition deterioration. BEVs are predominately focused on smaller commuter personal transport vehicles. How long would a fast charger take to recharge a large van or truck - BEVs currently not viable, or available, for most logistics and long distance uses? When charging on standard technology chargers, and for older vehicles, a full charge takes hours, etc. So, in realty, the BEV infrastructure has been a very slow burn expansion start to transition to low emission vehicles, but not yet the ubiquitous, widespread, universally accessibly, easily usable and convenient system many trumpet.
https://www.zap-map.com/charge-points/ 


Much for the H2 infrastructure rollout programme to learn from and do better, smarter, cheaper, quicker.


I don't think BEV v FCEV is the 21st Century equivalent of Betamax v VHS. We have a mixed fossil fuel transport system (petrol, diesel, LPG, hybrid) and we need a mixed LEV transport system (electric, hydrogen, hybrid) to replace it. Horses for courses as no clean energy technology is the silver bullet for all LEV transport needs - collaboration is better than competition.

OK Mapj1 I know I have to show a DC generation and transmission system , just had a bit on the for the last few years perfecting a energy environmental solution for use of wastes as fuel But you are right there is whole different area in large DC inverters which have only recently been shown to work ok. Phase interference is a big factor in losses , didn't know Japan ran 50 and 60hz systems that must be really difficult , I know USA settled on 60hz early on and it gave them a few advantages on motor power.

I don't think there is any problem in taking power from an HVDC to say a large DC battery (hoping they can get a in phase 3 phase output )and from there to invert to AC , its where you need to increase voltage in DC which is so problematic .

Apparently in early transmission experiments GE developed 12 phase transmission ? !!!

Give me 6 months and Ill see if I can design the idea/improvedl thing !! If I cant then its just seeing where we can get measurable improvement of losses with reliability.

But thanks anyhow

I agree with you Maurice , my interest in EV design was when the first reports of water table lowering as the Lithium component was taking so much water and in the recycling and life LION batteries , When they melt down the Li it can catch fire. The occasional vid of a lion battery having a chemical fire had me utterly shocked about how they could work in a crash especially given the weight, in impacts. MY thinking was in design , was when I had a trip in a little smart car and was amazed with a number of design aspects . I started thinking we have railway , so lets make that the long distance means of travel , and consider small light 150 mile range EVs .True it puts charging may be more regular and probably 6hrs at night and that could pose problems for the electrical grid , but I never saw the fast charger coming , so you could say put it on charge while shopping . No one mentioned either about battery degradation , holding 80% charge after 5 yrs and failing individual cells , and the way car designers literally build the batteries into the floor pan meant a new battery was going to be a big expense and a trip to the manufacturers garage for guarantee after fitment as OEM .So yeah the gov made a lot of engineers sort of scratch there heads with what they were thinking , because if the battery is no good or doesn't recycle or costs a fortune for a new battery then poor old customer was never going to see any purchase/ownership value , nor for that matter fleet purchases or car dealers , because the rolling chassis starts to become worthless .

EV chargers I have so far seen ,most are in funny places and I haven't seen them in use at all , but  then whilst seeing plenty of hybrids I haven't seen many purely electric vehicles.