RENEWABLE ENERGY

( File 2)

How to achieve a 60% reduction in UK CO2 emissions using renewable energy and hydrogen technology.

In the UK the programme to reduce CO2 emissions may still just meet the Government's timetable for promised CO2 reductions by 2010 and the UK's Kyoto commitments. However with fuelcells and hydrogen we could do better in years to come if we start going in the right direction from now on.

1) Hydrogen is the key for developing the full potential of the variable output from renewable energy sources such as wind power or solar PV. Hydrogen can secure for these renewable energy technologies a major share of the total energy market beyond the tyranny of the National Grid with it's need to schedule electricity supplies.

Hydrogen will enable all renewables to be used as a source of energy for manufacturing transport fuels and so give renewables access to this large higher value market for energy supplies.

Distributed generation will be important and natural gas fuelcells will take over this role followed by hydrogen fuelcells. The change to distributed generation will be driven by the improved energy utilisation of domestic combined heat and power systems based on fuelcells or other devices such as Stirling engines.

2) Hydrogen is not a source of energy, it is an energy carrier in the same way electricity is an energy carrier. Therefore hydrogen has to be manufactured and for it to be classed as a "clean fuel" not contributing to global warming the hydrogen has to be made using carbon-free sources of energy. All renewable sources of energy are carbon-free or carbon-neutral. Nuclear generated heat or electricity could also be used to make hydrogen but many people object to nuclear power and it would be necessary to quantify the fossil-fuelled activities associated with the whole nuclear cycle.

3) Hydrogen can't win the simple economic argument at present because current accounting procedures ignore external costs of carbon based fuels which are plentiful and relatively cheap. However we do need to prepare for when hydrogen is economically attractive. A carbon tax prompted by fear of global warming will help as will any rise in the cost of oil and gas. In the long term, shortages of fossil fuels will make the change to hydrogen inevitable but in the medium term it is the need to reduce CO2 emissions that will drive forward the change to hydrogen.

4) Oil, coal and gas are still by far the largest sources of energy in the World. Nuclear power is a small player supplying approximately 4% of the world's energy needs and this share is falling quickly as nearly all existing nuclear plants are old fashioned fission plants that will soon be closed.

In future the nuclear power industry will not have the advantage of a protected market share in the coming battle for energy markets and will be very dependent on Government economic support and for the Government to underwrite the insurance risk for any new building. There are no economically acceptable proven certified safe designs available at present for new nuclear plants that the private insurance industry is willing to fully insure against all risks.

5) If we continue using the existing mix of fossil fuels then World CO2 production will be more or less directly in proportion to energy use. At present the richest 1/4 of the World's population uses 3/4 of the energy consumed in the World. This means that the poor 3/4 on average use only 1/9 of the energy per person that the rich 1/4 uses per person, some of the poorest people use almost no energy at all. This imbalance is a serious problem because the World's natural systems for recycling CO2 are already overburdened by a factor of 2. If the poor 3/4 of the World's population were to use the same amount of energy with the same mix of fuels as the rich 1/4 uses then the total World energy use and CO2 emissions would increase by a factor of 3. The natural systems for recycling CO2 would then be overburdened by a factor of 6.

Obviously the World cannot go down this road and improved technology should mean that for the whole world to have a high standard of living will not require current western levels of energy use. But there is a big gap to fill, how can we provide the extra energy supplies that the World needs and lower CO2 emissions at the same time?

6) There are only three possibilities:

a) Lower expectations
b) Increase the efficiency of energy use
c) Change the fuel used.

a) Lowering expectations will be important but difficult and whose expectations are to be lowered, "theirs" or "ours"? How can the West expect any unilateral limitation on energy use by the poorer parts of the World?

We in the energy rich West could lower our expectations. For example, we could use private cars less and fly less. But I don't think we will get far down that road because people don't really want to change their lifestyle. We are much more likely to win the argument for change in energy supplies if we say what people can do rather than what they can't do.

b) Improving the efficiency of energy use is very important but it must be linked to raising the price of the energy used to avoid the release of disposable income. A good example of how things can go wrong is the continual expansion of air travel which has been facilitated by the improved energy efficiency of modern aircraft which has lowered costs. As a result aircraft are using less fuel per passenger mile but the increased volume of traffic is resulting in more fuel being used by the airline industry adding seriously to upper atmosphere release of greenhouse gases.

If, for example, we encourage people to improve home insulation and so use less gas for central heating but don't put up the price of gas by imposing a carbon tax, then these people will have more disposable income and may for example find they can now afford flying to some distant holiday destination and so burn up in a few days more energy than they have saved in a whole year on their central heating. The jet fuel used won't even be subject to VAT! So beware of energy efficiency, it can result in using more energy not less. At present energy efficiency is promoted in economic terms, how to save money, this obviously needs to change and energy prices should rise to maintain the same cost of energy use for a given activity.

c) Change the fuel This is foolproof and is obviously what this piece has been leading towards. If we change to a carbon-free or carbon-neutral energy system then we avoid creating CO2 and can use as much energy as we want to. This would avoid having to restrict people's aspirations. It would also mean we could pursue that other essential need for a sustainable world, recycling materials. At present recycling often uses more energy than making new material and so adds to CO2 emissions. If the energy used were CO2 free we could recycle everything.

7) So lets now look at energy supply in the UK starting with the electricity sector. The base year for measuring CO2 reductions is 1990. At this time 1/3 of the CO2 produced in the UK was created by the electricity generating industry from coal and oil fired generation.

8) Assuming every possible favourable factor, the UK electricity generating industry should achieve a 30% reduction on 1990 CO2 output by 2020. ( see A pragmatic review of the likely reductions on 1990 CO2 emissions that the UK electricity generating industry may be able to achieve by 2020 / 2030 ) But this is only 30% of 33% of the total 1990 UK CO2 output, i.e. a reduction of approximately 10%.

9) The Royal Commission on Climate Change has recommended that the UK needs to reduce it's CO2 output by 60% of the 1990 level. This figure should be about 80% because, as we saw earlier, we are exceeding our sustainable output of CO2 by a factor of 5 to 6 in the UK, not a factor of 2.5 that 60% corresponds to.

So, onerous as the Royal Commission's target may appear, it is still a compromise in favour of the developed world.

There is only one way to achieve these sort of CO2 reductions and that is to use hydrogen made from water using renewable energy or possibly nuclear power. There is no alternative if we want to sustain our modern energy intensive world and reduce CO2.

Let us now consider the transport sector.

10) The transport sector represents 25% of the total 1990 CO2 and could be completely changed over to hydrogen or bio-fuels. We now have the technology for hydrogen-powered zero-emission fuelcell engine vehicles and for internal combustion engines running on bio-fuels. It will take time but we are already on this road.

(Therefore the transport and electricity generating sectors together have the potential to) (reduce 1990 CO2 by 35%) The two segments of 10% and 25% representing the reductions from the electricity and transport sectors have been put adjacent to each other because there is an important possibility at the boundary where these two sectors could in effect overlap.

In the UK it will be most likely that hydrogen-fuel for transport will be made using electricity from offshore wind farms. The UK has a huge potential offshore wind capacity and the capacity required for making hydrogen for transport fuels could be of the order of 40GW which is the same as the current total average UK demand for electricity. It is anticipated that 8GW ( 20 % ) of the required electricity generating capacity will come from wind power by 2020 and so the total market for offshore wind power could be approximately 40 + 8 = 48 GW. If this capacity is eventually built, then at peak times the wind farm operators will have the capacity to guarantee supplies to the National Grid during periods of low availability of wind.

As soon as we start building wind-powered generation for hydrogen production the supply of wind-generated electricity to the National Grid becomes more secure because there will be progressively more capacity to supply a fixed demand.

To provide an average generation of 1GW the amount of installed wind generating capacity will be between 2.5 and 3 GW and so the average generation of 48 GW ( for vehicle fuel and national grid ) would correspond to an installed capacity of at least 120 GW. and so the required guaranteed out put from wind generation for the National Grid of 8 to 10 GW is only 7 to 8% of the 120 GW capacity that would be available so 8 and 10 GW should be available when required. In this way wind-powered electricity generation will achieve security of supply with less reliance on coal fired backup plant in future years. This will reduce the amount of CO2 produced by the proposed coal fired backup plant and it may be possible to avoid the need for coal fired plant altogether.

( see: Maintaining the capacity to meet the peak demand for electricity from an integrated energy system incorporating significant variable renewable energy sources, while at the same time reducing average annual CO2 emissions )

So it can be seen that the transport and electricity generating sectors together have the potential to reduce 1990 CO2 by 35%.

Therefore to achieve a 60% reduction in 1990 CO2 will require a further 25% reduction in the 1990 CO2 to come from the heat sector. To achieve this we have to approximately half the energy consumption of the heat sector.

11) Because we are starting with the 1990 base it has not been possible to have a "dash for gas" in the heat sector. North Sea gas was introduced in 1968 onwards and so by 1990 most of the domestic ( central heating ) commercial and industrial heat market had already gone over to natural gas. The cheapness and convenience of natural gas displaced firstly coal and then oil. Until 1990 North Sea gas was not allowed to be burned in power stations. As soon as it was, we had the "dash for gas", it was the only way to make privatisation of the old CEGB work.

To reduce CO2 from the heat sector we need the following policies.

1) Most of the heat is used in domestic buildings and commercial premises. Therefore we need to provide better buildings insulation so we use less natural gas for heating.

2) And we need to change over to distributed generation of electricity using domestic and local combined heat and power running on natural gas and in due course change over to hydrogen imported from abroad.

We need to install Combined Heat and Power decentralised generating systems in homes and commercial premises.

Improved insulation gives the best return on investment for saving energy and so reducing CO2.

Changing to distributed electricity generation at a domestic scale will require the development of fuelcells or other small scale devices like Stirling engines running on natural gas. As distributed generation develops it will reduce the demand for central generation and so natural gas can be diverted from power stations to domestic CHP systems. This will result in the waste heat from the electricity generation being available at a location where it can be used, i.e. in the home rather than at the power station.

The limitation on CHP is that the generation of electricity and a demand for the heat has to be in balance. The demand for central generation will reduce by the same amount that distributed generation from CHP increases. To make economic sense the domestic CHP device will have to run 24 hours per day and so will be limited to the base load electric demand of the home which on average is of the order of 0.5 kW. Assuming 20 million homes in the UK the demand for electricity from CHP would be 10 GW assuming the heat produced can be absorbed in the home for heating and hot water.

To convert this 10GW of gas fired generation into a reduction in 1990 CO2 we need to visit the table in ( file 3 ) from which it can be seen that 10GW of gas generation corresponds to 10 units of CO2 out of the 48 units of CO2 produced in 1990. Therefore if we treat this gas as a "free bonus" as a result of adopting distributed generation using gas-fired domestic CHP it gives a saving of 10 / 48 x 33% = 7 % on 1990 CO2. This 7% reduction will be recorded in the electricity sector on the following pie chart.

In the future when we have fuelcell-powered cars and a hydrogen gas grid, CHP and distributed generation will expand beyond domestic base load provision. The energy used in a well insulated home will be dependent to some extent on the number of people at home. Now when people are at home their car will be at home and so the fuelcell in the car can be "plugged in" to the home and so add the extra power needed. The car could also be recharged with hydrogen during this time from the hydrogen gas supply to the house. Cars travelling 12,000 miles per year are on average only in use about 4% of the time, they stand idle most of their lives. By plugging the car's fuelcell into the home their usefulness can be greatly increased and the capital cost of the car's fuelcell spread over more use thus reducing average costs.

Therefore, while natural gas is still readily available, the diversion of natural gas from power stations to domestic CHP will produce significant CO2 savings, but we need to plan ahead for a change over to CHP running on hydrogen for when natural gas runs out.

If the proposed domestic combined heat and power systems use fuelcells running on natural gas or reformed natural gas this will not increase dependence on natural gas for electricity generation above the 50% limit assumed in the projections for electricity generation. By diverting gas from gas-fired power stations as they wear out after 2010 to domestic CHP using fuelcells the increased efficiency of total energy conversion achieved will result in the amount of gas used being less than the total gas consumption that would have been the case if the heat and power were generated separately. In due course as hydrogen replaces the natural gas used by the fuelcells the dependence on natural gas will decrease.

12) To move to a hydrogen based system we need to develop fuelcells running on natural gas or hydrogen produced from locally reformed natural gas for domestic and local combined heat and power. The natural gas, and later the hydrogen, can be delivered by the existing gas grid.

What we could do is divide the gas grid up into small districts and then slowly district by district convert the grid to imported hydrogen. Slowly the whole grid could be converted to hydrogen and expanded as natural gas supplies run out and become more expensive.

This would be an economic transition utilising the existing gas grid and the same fuelcells could be used before and after the transition if they were designed to run on hydrogen made from reformed natural gas. Alternatively natural-gas fuelcells could be used initially and then moved onto the next area for conversion as the gas grid was changed over to hydrogen.

The initial natural-gas fuelcells could be publicly owned and loaned free of charge as an encouragement for people to change. When the local gas grid was changed over to hydrogen then the publicly owned natural-gas fuelcells would be moved on to the next district for conversion and people would buy their own hydrogen fuelcells for ongoing use. In this way we could change over from imported gas and oil to imported hydrogen. ( For details of these options see Hydrogen section )

It would not make sense to use UK produced hydrogen for the heat sector because the hydrogen would be made using renewable electricity so the electricity could be used directly.

13) The importance of introducing hydrogen to the heat sector is not solely to reduce CO2. If we look ahead to when natural gas and oil is no longer available and assuming fusion power still doesn't work, then the UK and Europe will need a way of importing vast quantities of energy and hydrogen will be the only feasible energy carrier. By this time we will need to have a distributed electricity generating system based on fuelcells to use hydrogen to provide combined heat and power ( electricity ). For this we will need to have developed a national hydrogen gas grid and this is what the ideas described here are to lead towards.

14) So you can see hydrogen is the key but we have to move in the right direction now that leads us to a hydrogen-powered world.

We must encourage the use of hydrogen for fuelcells and bio-fuels for transport and fuelcells running on hydrogen from reformed natural gas, or other devices like Stirling engines that can run on natural gas or hydrogen, for domestic and local combined heat and power, and we must improve the insulation of buildings.

We should make sure our actions now fit into a master plan that gets us through the looming crisis of global warming, provides more energy supplies for today's overcrowded world, particularly the great cities, and brings us towards a sustainable integrated energy system. Oil and gas and coal will last for hundreds of years because what is running out is the capacity of the atmosphere to absorb CO2, we cannot use all the oil, coal and gas at the current rate, we must start substituting carbon free or carbon neutral fuels.

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