Hydrogen – the green currency of the future Mark Crowther GASTEC at CRE Lt

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By 2050 it is suggested there will be three possible green energy vectors,

(excepting bio-mass, bio-oils and bio-gases).

• Low carbon hydrogen

• Low carbon electricity

• Low carbon hot water.

This paper is about the first of these three: Low carbon hydrogen.

Hydrogen – the green currency of the future

The UK gas plus electricity demand (minus gas to power stations) is strongly seasonal.

Daily gas peaks can be even twice these values.

Hydrogen – the green currency of the future

If this seasonal gas load is going to be replaced by electricity this will require a

massive increase in electrical

• Generation and
• Distribution facilities.

But the above will be used very intermittently and to a frequency

it is extremely difficult to predict.

Very approximately the cost ratio of distributing energy is as follows

(where distribution includes fees for stand-by capacity etc)

• Natural Gas    x pence/kWh
• Electricity  7x pence/kWh
• Hot water  49x pence/kWh

This can be seen in current UK fuel costs (excluding billing)

Hydrogen – the green currency of the future

Hydrogen – the green currency of the future

If a high percentage of our electricity arises from :-

• Wind  at 30% availability
• Tidal at very widely swinging values (eg Severn barrage 8.2GW to zero 4times/day)

The situation becomes even more difficult.

Thus will the peak winter loads (long lasting Siberian High) match with low wind speeds?

What happens to the thermal efficiency of gas or coal plant with CCS when operated

at steep ramp rates?

The idea of building either:-

• Coal +CCS at £3000/kW or a
• ‘surplus’ of windturbines

to only operate profitably a few days/year  is very unattractive.

Hydrogen – the green currency of the future

BUT if these plants could generate hydrogen for storage for future use

as and when required within :-

• Boilers at the point of use

Or

• In gas turbines centrally

Or (even better, and proven for 40years)

• Hydrogen fuel cells at 50% electrical performance

Then all types of low carbon energy production are on a level playing field.

This hydrogen can come from a variety of sources at a range of efficiencies

• Natural gas via reform & shift at 70-80%
• Coal gasification reform and shift at 60%
• Electrolysis at 80%.

Hydrogen – the green currency of the future

It can then be safely stored as demonstrated at:-

• Billingham
• In Germany and more recently
• By Praxair in Texas

By uncoupling supply and demand a free market can exist in both.

Hence the title of the talk. Hydrogen the green currency.

The level of this uncoupling can be subject to debate. The author suggests about

3600kWh/person ie about 95kg/person or a cube of side 850m at 80barg

for the whole of the UK.

Hydrogen – the green currency of the future

The cost of this hydrogen is difficult to accurately predict as it is dependant upon:-

• Source eg ‘surplus’ wind
• Purity
• Size of production facility.

But it often quoted as twice the price of feedstock Natural Gas ie 3 to 5p/kWh

Ie realistic AND once in production and available locally address simultaneously

decarbonisation of:-

• Static heating users
• Industry and
• Transport.

Suddenly carbon emission reduction looks tractable

Hydrogen – the green currency of the future

Distribution.

The author is NOT suggesting a national network of high pressure hydrogen lines.

This is expensive and technically challenging.

The author is suggesting the development of wide range of local low pressure (<8barg)

polyethylene (PE100) pipe gas grids using a mixture of new and existing

natural gas infrastructure.

Whilst hydrogen has a CV of only 13,000kJ/m3 compared to 39,000 kJ/m3 for natural gas,

It is still envisaged that with energy efficiency measurements and local re-enforcement,

many existing PE grids should be capable of upgrade at reasonable cost.

Each local hydrogen network would have its own storage facility.

Hydrogen – the green currency of the future

Looking at some costs let us say that Hydrogen being one third the

the CV of Nat gas costs twice the price (p/kWh) to distribute (including storage)

We now have a ‘competitive zero carbon fuel’

Hydrogen – the green currency of the future

BRISTOL as an example.

Bristol could be declared a carbon emission free city in a legislatively similar fashion

to a Smoke Control area. This would create a  demand for hydrogen.

1. A private act would be passed requiring the owner of the existing gas grid to convert

it to hydrogen by (for example) 2016. (This is no more draconian than the old Smoke Control Zones)

2) This would create a demand for hydrogen which companies could supply.

Possible sources:-

• • • • Natural gas from the NTS with reform & shift plus CCS
      • Pet.coke via a gasifier plus CCS.
      • Electricity from a local barrage.

3)The grid could be modified and users required to convert to:-

• • • • Hydrogen boiler (already available)
      • Hydrogen fuel cell (already proven unlike their natural gas equivalents)
      • Petrol filling stations could install additional hydrogen pumps.

4) Hydrogen storage would be built.

Allocation of Costs

Possible costs are divided into three parts, as required by the:-

• Householder
• Network operator
• Fuel vector generator

• Some of these are better known than others; thus typically householder cost can be quantified, as can generation. Distribution costs are far less well chararterised.

Ref for gasification:-Gasification Plant Cost and Performance Optimization Contract No. DE-AC26-99FT40342

Ref for storage:- NREL/TP-570-25106

Householder Costs

Householders would be required to change their appliances but commercial hydrogen boilers already exist. Ideally householders would install hydrogen fuel cells that given their simplicity compared to natural gas units produce attractive pay-backs.

It is unlikely to be cost effective to modify existing condensing boilers and wholesale installation of condensing hydrogen boilers would be necessary. These are anticipated as not significantly more expensive than an existing natural gas boiler ie about £600 wholesale. The cost installed is anticipated to be about £2500. There would be no need to change the heating system. This would be £375m for the 150,000houses in Bristol.

Using electric heat pumps (4kWe) is likely to require lowering of the design temperature of the heating system and/or a slinky and/or a bore hole to obtain good COP’s. Costs are thought unlikely to be less than £10,000 rising to £20,000 in larger houses where complex additional insulation is required.

Commercial User Costs

Households only consume about half of  non power station gas use. The rest is used in commercial buildings and industry. It is unproven how heat pumps can be used in many of these situations due to the use of high temperature j hot water as a heat transfer medium and /or the process requires temperatures above about 60C.

Hydrogen would be an obvious solution to the current emissions of CO2 from this sector.

Network Operator Costs

The gas network operator would be required to modify their system to handle hydrogen. This an area of unknown cost but should be similar to the distribution of Towns gas still carried out in Germany. This is 50%v/v H2.

For Bristol an upgrade cost of about £60,000/km of pipe equates to £1000/house.  This would total £150m The cost of storage is currently very open for discussion but it is widely practiced and for 3600kwh/person is estimated at £175m. The total of transmission & storage would £0.016p/kWh

The comparative costs to upgrade the Bristol electrical infrastructure to handle the additional electrical infrastructure is unknown. The previous slide assumed 4kWe electric heat pumps ie about 10kW thermal. This is much smaller than nearly all existing boilers. This implies continuous heating and about 20% more annual energy consumption. The numbers need greater study as Bristol itself would require long distance re-enforcement, or local generation For this exercise it is assumed to be £350m.

Fuel Production Costs

This can be estimated relatively accurately for hydrogen but is critically dependent upon the price of carbon sequestration. The base price without CCS could be as low as £0.02/kWh, CCS could double  this but identical issues occur with electricity. It depends whether the price of the CCS is offset against a trading scheme, however the process still has to be paid for. It is taken as £0.035/kWh, giving a retail price of £0.062/kWh

The comparative price of generation of the electricity is even more difficult to predict as this depends upon the price  of marginal/peak load plant and the required level of CCS. It is projected to rise to 20% greater than the typical current EU price of £0.20/kWh ie to rise to £0.24/kWh

Hydrogen – the green currency of the future

Possible costs:-

Ref for gasification:-Gasification Plant Cost and Performance Optimization Contract No. DE-AC26-99FT40342

Ref for storage:- NREL/TP-570-25106

Hydrogen – the green currency of the future

BRISTOL as an example contd:

Advantages are lots of CERTAINTY in an uncertain world.

• Hydrogen providers have market certainty 6000hrs/yr.
• Consumers have certainty of supply of a low carbon fuel 8760hrs/yr from competitive hydrogen generators.
• Certainty of technology from Town’s Gas (50%v/v hydrogen) and the hydrogen industry
• Bristol City has certainty of its carbon emission reduction figure.

And Certainty reduces costs and enables sensible investment decisions.

Hydrogen – the green currency of the future

Where from here:-

Gather certainty in the above projections by carrying out a study of the comparative costs for Bristol of :-

• Ultra-high levels of energy efficiency (including solid wall insulation etc)
• Conventional levels of insulation but plus electric heat pumps and battery powered cars
• The above hydrogen route.

Lets put some certainty into the carbon debate and thus create a stable currency for the future.