Shale Gas - Energy and Climate Change Contents


Memorandum submitted by Martin Quick

SUMMARY

S1 This submission proposes that if shale gas turns out to be a large scale environmentally acceptable energy source, it should be used to provide the funding and energy for the development of a sustainable long term energy system. Assuming such a system incorporates a high proportion of intermittent renewables, as well as methods of demand management and demand time shifting and possible means of energy storage, sufficient gas should be reserved for power generation in the relatively small number of hours in a typical year when there is a shortage of generation relative to demand.

S2 Leakage of shale gas to the atmosphere in other than very small quantities would offset any climate change benefits this gas could have

S3 The UK should investigate its shale gas potential, but (assuming environmental factors are acceptable) we should delay exploitation until global energy prices become very high.

1. IMPLICATIONS OF GLOBAL EXPLOITATION OF SHALE GAS ON CLIMATE CHANGE MITIGATION

1.1 The exploitation of shale gas in a number of countries, particularly the USA, is likely to extend the availability of gas at reasonable prices for a number of years, but for how long is uncertain. While this must ease issues of energy security, its impact on climate change mitigation efforts is less clear. In principle, if uncontrolled leakage is minimal (see 1.3 below), if this gas were to be used in power stations to substitute directly for electricity generation in coal burning power stations, the immediate effect in the shorter to medium term would be beneficial. This is because of the lower amount of carbon per unit of energy in gas compared with coal, and the generally greater efficiency of gas fired power stations. However, if the exploitation of shale gas were to reduce the drive to develop low carbon energy sources as fears of an energy crisis in the near term are lessened, this could have an adverse effect on longer term climate change mitigation efforts.

1.3 If the exploitation of shale gas gives rise to any significant leakage of gas to the atmosphere, any climate change mitigation potential from shale gas could be negated. The fact that shale gas (methane) has penetrated the water supplies in some sites in the USA suggests that the escape paths for the gas are not very well controlled. As the global warming potential of methane is ~20 times that of CO2, if, for example, 5% of the gas were to escape the climate change impact of gas from this source would be about twice that of gas produced more locally under tighter control. This would make the climate change impact of energy from shale gas greater than that from coal. If power stations were operating with CCS, the climate change impact of such escaping gas would be many times that from the fuel actually producing energy.

2. IMPLICATIONS FOR THE UK OF SHALE GAS EXPLOITATION

2.1 If it turns out that the UK has significant reserves of shale gas, these should not be exploited as soon and as fast as possible, as in effect happened to the UK North Sea hydrocarbon resources. We continued to extract oil and gas from the North Sea at a high rate even when prices were very low, for example in the 1990s when oil was priced at about $10 per barrel. Now, when prices are much higher our reserves are very much depleted, we have become net importers of oil and gas. While global gas costs remain tolerable, any UK shale gas should be conserved until global gas supplies become very expensive.

3. ROLE OF SHALE GAS IN UK AND EUROPEAN ENERGY SYSTEMS

3.1 The government's target for reduction of CO2 emissions is 80% reduction by 2050. Many climate change scientists believe that to achieve an acceptably low risk if dangerous climate change and an equable distribution of greenhouse gas emission allowances between countries, even more stringent reductions may be needed1. Some studies for the UK 2 3 and Europe 4 have proposed energy systems based totally or largely on renewables. However, to achieve the last few percentage points of energy from renewables may be disproportionately expensive, and in the case of a Europe wide system, there could be political delays. To achieve very major reductions in greenhouse gas emissions, in the longer term, the electricity system will need to be almost totally decarbonised. Some sectors currently largely dependent on fossil fuels such as heating and transport will need to switch largely to low carbon electricity. Nearly all fossil fired generating plant would require carbon capture and storage (CCS) to meet very low greenhouse gas emissions targets, but it must be recognised that CCS still is not fully proven and has its own problems.

3.2 In an energy system with a high proportion of intermittent renewables (in the UK, mainly wind power), demand side management will have an important role to play. Some electricity demands can be shut down, possibly by a signal from the utility, for varying lengths of time without adverse consequences. Heating provided by heat pumps on a community or district scale could incorporate heat storage in large hot water stores for a few days supply. Electric vehicles and plug-in hybrids can be charged mainly at night or at other periods of low demand. There are also different forms of energy storage. Today, these are applicable only in some geographical locations (eg pumped storage), or are at the development stage (eg flow batteries) and may remain expensive. If there is a Trans European electricity grid, possibly with connections to North Africa, as being promoted by a number of organisations 4 with generation from a variety of renewable sources, the likelihood of large scale loss of power generation would be reduced.

3.3 However, it is likely there will be some periods when wind and other renewables cannot meet demand, and there may be insufficient "dispatchable" power (ie power that can be turned on at will) from renewable sources such as biomass or hydro power. It is for such conditions that generation by gas should be reserved. Gas fired power stations, including those with Carbon Capture and Storage are more suitable for catering for intermittent use and load changes than comparable coal fired stations, and their lower capital cost makes them more suitable for low load factor operations.

4. OPTIMUM USE OF SHALE GAS

4.1 The supply of easily accessible hydrocarbons is likely to fall short of potential demand within a few years. Even the International Energy Agency, for many years in denial over this, now accepts this is likely. Coal, the most plentiful fossil fuel, may become expensive as China becomes a significant purchaser of coal on the world market, as is predicted by some analysts 5. If significant shale gas is produced globally, this would postpone the energy crunch when the supply of relatively low cost fossil fuels falls short of potential demand. Any such postponement should not be used as a "get out of jail free" card, but should be used to ensure a sustainable energy system is developed while funds and energy are less constrained. The main costs and energy input for most renewable energy systems (eg wind, solar, tidal) and for efficient transport and energy efficient buildings are in the construction stage. While the energy for manufacture of wind turbines (mainly for producing steel and cement) is relatively low in relation to the lifetime energy generation, this energy is required up front. Building a super-grid for linking varied sources of renewable energy to centres of consumption will require large amounts of copper and aluminium and energy is required to produce these. Any period of easing of energy supplies should be used for constructing the infrastructure for a long term sustainable energy system.

5. RISKS AND HAZARDS OF DRILLING.

5.1 From the experience in the USA it is clear that there are significant risks of pollution of water sources and of methane getting into water supplies. Given the higher population density in the UK, such risks may be more significant.

6. RECOMMENDATIONS

6.1 The potential for leakage of gas from shale gas exploitation should be fully investigated, and means of monitoring leakage developed. If there are circumstances where it is not possible to guarantee leakage remains very low, exploitation should be discouraged. The global warming potential of any leaking gas should be included in assessing allocations of greenhouse gas emissions between countries in any global agreement.

6.2 If significant shale gas able to be tapped in an environmentally acceptable way is found in the UK, it should not be rapidly exploited, but reserved until global energy prices reach very high levels.

6.3 Any postponement of the global energy crunch anticipated by many analysts provided by shale gas exploitation should be used to build a long term sustainable energy system with minimal greenhouse gas emissions.

REFERENCES

1 James Hansen "Climate target is not radical enough" Guardian 7 April.2010

2 Zero carbon Britain2030. Centre for alternative technology www.zerocarbonbritain.com

3 The offshore valuation www.offshorevaluation.org

4 The European roadmap www.roadmap2050.eu

5 China set to become largest importer of thermal coal. Financial Times 23 June 2010

Martin Quick is a Chartered Mechanical Engineer, having graduated from Cambridge University and done practical training with Rolls Royce Motors and GEC. Most of his professional career was in the electricity supply industry, and he has also carried out consultancy on building energy efficiency

January 2011


 
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Prepared 23 May 2011