In last week’s poll we asked about your preferred energy storage technologies, a question predicated on a growing renewables landscape that will need storage to cope with intermittency.
In the UK alone, the need for storage is becoming more acute, given that the cost of renewables is falling and large offshore wind farms and solar facilities are under construction.
The eventual solution is likely to involve a mixture of technologies, but some will form a major part of the storage infrastructure while others will be less important, which is why we asked you to pick the one you think will take the lead.
Of the 515 respondents, 39 per cent opted for pumped hydroelectric, which is also the subject of The Engineer’s latest cover feature.
This was followed by just under a quarter of respondents (23 per cent) who opted for hydrogen (using excess electricity to decompose water, storing hydrogen gas), and 19 per cent who chose electrochemical (defined as batteries of all types, from lithium-ion and other solid-state technologies to flow batteries).
Just eight per cent went for thermal (including cold types, with liquefaction of air and storage of the cryogenic gases; and hot, involving melting salts and storing them in that form), and the remaining 11 per cent settled on None of the above.
Energy is a subject that garners a good deal of opinion, and last week’s poll did not disappoint with 30 readers contributing to the debate so far.
SteamyTea said: “I voted for thermal. We already have it in most homes in the form of a DHW cylinder. The technology is cheap, reliable and effective. It does suffer from some limitations i.e. standing losses and is low entropy compared to electricity.”
Nick Woodward added: “Hydrogen is the answer, it’s easy to be negative to new technology, but if you actually look into it Hydrogen can be produced locally, no need to transport it around the country, the Japanese are doing it already. Hydrogen can explode, so can petrol natural gas and flour if you don’t treat it right. Please look up ITM power.”
In the electrochemical camp, Tom Foreman said: “I picked Electrochemical for storing electricity, but would suggest that Hydrogen would be better suited for replacing Natural gas to heat and cook in people’s homes.”
Speaking up for hydro, Sebastian Broady said: “Investing in hydro is essential – this is a bomb proof way of storing lots of energy. It just takes political will and backbone. We wouldn’t need lots of hydro dams either. Flow cells also seems to be a very promising technology. Unfortunately, our political leaders are not up to task.”
What do you think? Let us know using Comments below.
How about mechanical? e.g. flywheels and the like.
John – flywheels get my vote – using the ‘keep it simple stupid’ policy, I have optimised the design and proportions of a high momentum but low RPM storage system which can contain over 100MJ of energy which is enough to recharge an electric vehicle. I believe it’s a deliberately low tech, highly efficient and enduring solution which will last hundreds of years. I’d be happy to share the design freely with anyone interested in this.
Again, missed the obvious choice – all of them. If we (as engineers and as a nation) put all our eggs in one basket then, as with the IC engine, the other options fall by the wayside and these may prove to be the better option in the long run. There may also be better solutions not yet discovered, time for engineers to take over the world? Let’s hope so, energy generation and storage is too important to be left in the hands of politicians.
Investing in hydro is essential – this is a bomb proof way of storing lots of energy. It just takes political will and backbone. We wouldn’t need lots of hydro dams either. Flow cells also seems to be a very promising technology. Unfortunately our political leaders are not up to task.
In the very near future hydrogen could be produced by the surplus energy of wind farms and used to replace petrol and diesel for transport; requiring only a moderate changes to vehicles and petrol stations.
The cost of each fuel should relate to it’s total cost including environmental issues to give a level playing field on which to enable an informed choice. Regretfully high fuel cost is a regressive tax on the poorest, in exactly the same way subsidies to power generators have become.
I picked Electrochemical for storing electricity, but would suggest that Hydrogen would be better suited for replacing Natural gas to heat and cook in peoples homes.
As long as we rely on natural gas production, we can avoid storage per se by displacing some consumption of that natural gas with methane produced from renewable hydrogen. Thus energy is stored by leaving a greater proportion of natural gas in the ground. The Sabatier reaction is suitable and although of course CO2 is a product of combustion of CH4, the Sabatier reaction absorbs an identical amount of CO2.
It has always been clear that storage is essential to back-up unreliable sources of power. Batteries will meet rapid, short fluctuations well, but large perturbations will need more substantial storage (MWh not kWh). Gas turbines combined cycle plants are the popular solution at present, but if, say next year gas, prices were to rise, this could prove a very expensive power source. There are many other storage techniques, such as compressed air and liquefaction based processes.
What is essential is that these prices are added to the over-subsidised costs of wind and solar power to ensure a more honest picture of why the UK has the second highest electricity costs in Europe.
I am surprised that there is a country with higher electricity costs; is this done deliberately and why ? And which country is it?
EU Industrial electric prices
1. Italy
2. Germany
3. Liechtenstein
4. Malta
5. Cyprus
6. UK
EU Domestic electric prices
1. Denmark
2. Germany
3. Ireland
4. Italy
The UK is 10th.
Data from eurostats
http://ec.europa.eu/eurostat/statistics-explained/index.php/Electricity_price_statistics
Denmark leads the way in eco-lunacy and has the highest electricity prices due to the massive subsidies applied, we are catching-up. Also, Denmark has a far larger GDP per capita than us and is less dependent upon heavy industry.
There is a major problem with pumped hydro. It is excellent for short term in-fill but for any long duration requires enormous parts of the countryside to be set aside, and also has major grid implications. Of all the remainder perhaps hydrogen offers more flexibility as there is the potential for use in a transportable form. Electrochemical will require large static installations built with relatively toxic components, also with major servicing and repair issues. Storage of hydrogen makes use of relatively straightforward mechanical components, and aside from fire hazard is benign if it escapes. Hydrogen by replacing existing solid and liquid fossil fuels could also fulfill motor transport requirements.
What is the point of these surveys?
When your car breaks down, do you ask passers by to vote on what is wrong?
Yes, I am an engineer, but as such I know the limitations of my knowledge. I might offer an opinion, but I am not going to give a categorical answer that this sort of a) , b) or c) choice demands.
If you would like to hire me for some months/years, so that I can gain understanding, and gather evidence, then I will offer a judgement (hedged around with caveats, and listing assumptions made).
In the mean time; my opinion is that these surveys are pointless.
I think that you underestimate your judgement. Surveys are views towards possible consensus not proofs!
Science & engineering are fact based… not consensus based.
Not so long ago there was consensus that-
• regular ‘Bleeding’ of the sick would cure them,
• Arsenic was a cure for malaria and syphilis
(It was a kind of cure, ‘cos the Arsenic killed you before the malaria and syphilis did !!)
• Surgeons don’t need to wash or sterilize instruments between patients.
• It was a good idea to give pregnant women thalidomide.
• The world was flat & the sun revolved around the earth.
• It was impossible for man to fly.
• It was impossible for man to breathe above 45mph.
• It was impossible for man to go faster than the speed of sound.
• It was impossible for man to escape earth’s gravity.
It seems that consensus can be wrong … As demonstrated daily in politics.!!
Pumped hydro maybe suitable in Scotland and Wales, but in the South-East of England less so. Hydrogen from electrolysis can be converted into other resources such as green ammonia.
see http://www.siemens.co.uk/pool/insights/siemens-green-ammonia.pdf
The green ammonia can also be used to fuel our cars.
see https://www.theengineer.co.uk/issues/june-2014-online/hydrogen-breakthrough-paves-way-for-ammonia-fuelled-cars/
While Hydrogen might seem to be an effective way to store energy, it is impossible to contain Hydrogen for any length of time. it simply leaks out through the sides of any container. storing large quantities of Hydrogen in underground caverns would merely create a risk of an explosion from the seeping gas, and while it might be transportable it must be kept under enormous pressure if sufficient quantities are to made available for vehicle use. Hydro is not practical as pointed out above. Electrochemical can be toxic, (there is always research being conducted on safer materials). Thermal could be used, but I have no idea of the financial practicality of this form of energy storage, but ground source heat pumps and the like seem to work on a small scale. In conclusion, I think we have yet to arrive at a suitable storage technology.
I believe the medium of storage can be cheap. However, for longer term storage or domestic scale, there is a need for cheap vacuum insulation to inhibit the leakage; the Germans have done this but though their material costs are low the manufacturing time was some weeks, I believe
Jullian,
a lot of beliefs, but few facts
There aren’t enough suitable sites for pumped hydro.
Hydrogen works only with a land based distribution system but may be the long term solution when the gas runs out.
Thermal will always be lossy.
Only short term solution is electrochemical as battery technology advances at startling pace.
None of the above.
We need more Nuclear, it’s that simple !
Nuclear is a storage technology?
Hydrogen is the answer, its easy to be negative to new technology, but if you actually look into it Hydrogen can be produced locally, no need to transport it around the country, the Japanese are doing it already, Hydrogen can explode, so can petrol natural gas and flour if you don’t treat it right, please look up ITM power.
All the Green Hydrogen we can produce will be required to de-carbonise the heating of millions of homes currently using ‘natural gas’. Otherwise their de-carbonisation pathway is likely to be steam re-forming of natural gas to make H2, with the waste CO2 buried using CCS. I think CCS at that scale is implausible, and high cost. So – hydrogen should not be used as a storage vector for electricity: doing so would make heat de-carbonisation less feasible and more expensive.
‘Thermal’ using hot and cold seems to me to be the most adaptable technology. It can be distributed and located near to centres of generation and demand, and it can be built in various sizes without massive civil engineering work like pumped hydro.
Hydro should be in the mix as well though.
I voted for thermal. We already have it in most homes in the form of a DHW cylinder. The technology is cheap, reliable and effective.
It does suffer from some limitations i.e. standing losses and is low entropy compared to electricity.
or to re-phrase the question: which shovel would engineers choose to clean the Augean stables, after politicians fouled-up by promoting technologies which produce lots of electricity when demand is low and little or none when demand is high?
Great analogy, I was not aware of this one of the labours of Hercules, so thanks fort his. Classics has a place but it is a pity that our politicians are only knowledge about these!
The solution is all of the above and more, including nuclear generation. There will be a hierarchy of capacities and time constants that determines the best fit in each case. I won’t have pumped hydro at home. Equally, if I had a spare 1GW of wind power I’d not put it in a battery.
Ideally I’d convert dense, renewable energy sources into LPG – wind to butane. This provides as near as possible “business as usual” for the vast majority of end-users of energy and a well-understood distribution network.
Bring back the gas holder (gasometer). They used to be a common sight in our towns and cities. They could be used to store hydrogen and oxygen (separately of course) from electolysis using the surplus electricity.
I had been wondering what uses there would be for the oxygen.
The answer is Allam Cycle Technology. https://www.netpower.com/technology/
Instead of using an Air Separation Unit (ASU) to separate oxygen out of ambient air, the ‘waste’ oxygen from electrolysis could be used. The process produces electricity from Natural Gas and carbon-capture-ready CO2 without the need for expensive add-on equipment.
It would be better if there was more information in the call and some indication of the amount of energy.
And there are other indicators – such as the purpose or the localisation of storage – as well as the abstraction rate (or time).
I do think, and have indicated in previous posts , that thermal energy storage is a bit of a Cinderella, in the research stakes; the main limitation being the associated volume/MJ and, for the smaller ones, there is the need for cheap high performance (& temperature) insulation. And, in comparison with geothermal it would be designed to have a non-diffusive throughflow.
The source for such storage could be thermal (eg nuclear or solar) or electric (such as wind) – and the application process heat or electricity.
The old-fashioned ice-house worked for seasonal storage and there were even steam locomotives with accumulators; a technology worth revisiting – with a modern eye to manufacturing.
Better thermal design in buildings can save a lot of expensive heating and cooling.
http://www.icax.co.uk/Tesco_Greenfield_Supermarket.html
Thermal storage of energy for heating and/or electricity can be done on medium to large scales by a number of commercially available methods. If the thermal store is under or surrounded by a building which need heating for nine months of the year then the leaking energy becomes useful energy.
Molten salt storage (for electricity “storage”) appears to be affordable and well proven.
If one reduces the heat loss then your (size) constraint is removed – and one can move to smaller scale too.
And why not molten metal ? – easier to pump – and could, so, be a transport medium from the store itself (better heat transfer and conductivity)
Yes… as is… Coal, bio-mass & oil; the energy is stored & released on demand.