Vulnerabilities UK - Overview

Electricity generation and cooling water use

In the UK 90% of electricity generation comes from thermoelectric power stations. Cooling of thermoelectric plants is often achieved by water abstractions from the natural environment. In England and Wales, the electricity sector is responsible for approximately half of all water abstractions and 40% of non-tidal surface water abstractions (17).

Four types of cooling systems are being used: (1) once through (open loop), where heat is removed through transfer to a running water source, (2) closed (re-circulatory), where heat is removed to the air by re-circulating water cooled in ponds or under cooling towers, (3) air-cooled, where heat is removed by air circulation via fans and radiators (a setup that can operate without water), and (4) hybrid, where cooling towers can operate both with and without cooling water. Water is being abstracted from three types of water systems: freshwater, tidal water, and coastal/ sea water. All of the UK’s freshwater cooled thermoelectric generation is in England and Wales whilst for tidal water the proportion is 91% (16). The current levels of tidal and sea water abstraction in the UK are 40–50 times higher than freshwater abstraction, although consumptive proportions (the part of the abstracted water that does not flow back into the water system) are only 2% and 1% respectively, due to the use of once through cooling (16).

Over the years all inland coal plants in the UK have switched from open to closed loop cooling, whilst gas plants are a mixture of both. Closed loop reduces environmental impacts as thermal discharge is to the air (instead of to water) and abstraction volumes are small, although consumptive losses are higher. Coastal power stations almost always use open loop cooling, but the effects of thermal pollution and fish entrainment and impingement on local ecology can be substantial (18).

When sufficient cooling functions are not possible, power station operators are required to ‘ramp down’ the generation output in order to reduce cooling demand, whether this is to maintain safe and efficient operation or to protect the aquatic environment according to legislative constraints on abstraction volumes and discharge temperatures (16).

A reduction of CO2 emissions by 80% by 2050, a legally binding target of the UK Climate Change Act 2008, may be reached through several pathways of different mixtures of energy sources (16). These pathways have impacts on the water resources. Pathways with high levels of nuclear and carbon capture and storage, for instance, show an increase of abstraction and consumption levels that far exceed current use. Carbon capture and storage technology, especially, significantly increases the intensity of freshwater consumption.  Significant reductions in freshwater consumption are possible through wide scale use of hybrid cooling, which would increase the level of freshwater resources available, for either the electricity sector or other uses. Hybrid cooling would however marginally increase cost and emissions, but also security of supply, by enabling the use of air-cooling during low flows when abstractions may be prohibited (16).

With high levels of nuclear, abstractions of tidal and seawater can be expected to increase substantially. The greater the need to protect inland water resources for agriculture and public water supply, whilst maintaining levels of environmental quality, the greater the pressure will be to shift thermoelectric generation towards the coast. In this case, careful management of the effects of fish entrainment and thermal pollution in marine and estuarine environments will be required (16).

Demand

West and Gawith (1) report on the energy sector in England. While there will be a reduction in the need for winter heating, the demand for summer cooling will increase. It has been estimated that the percentage change in cooling energy for air conditioned commercial buildings are over 10% by the 2050s and around 20% in the 2080s (2).

Increased temperature could change the demand for energy, with a reduction in demand for winter space heating and an increase in the demand for cooling in the summer. Reduction in winter space heating demand could help to reduce incidences of fuel poverty (3), although this will depend on future energy costs and housing conditions. Use of natural ventilation, shading, and green spaces for cooling may be able to meet any increased demand for cooling but these measures will need to be incorporated into building design.

Electricity network

Potential impacts of climate change on the UK’s electricity network have been assessed (13):

• Future projections of wind and gale faults indicate that they may remain the same, increase, or decrease in the future, due to uncertainty in wind gust projections;
• Lightning faults are projected to increase in the future as a consequence of a greater number of days projected with stronger convection;
• In the future snow, sleet and blizzard (SSB) faults are projected to decrease due to a reduction of snow days, but when snow does fall the intensity of the event may remain the same or increase;
• The incidence of solar heat faults is projected to increase throughout the UK, due to projected increases in maximum temperatures. However, due to the network’s resilience to high temperatures, these faults are likely to remain relatively rare;
• The occurrence of rainfall amounts that have caused significant flooding events in the past may increase in the future, but a decrease cannot be ruled out. However, this assessment has not explicitly considered important terrestrial processes.

During the floods of 2007 tens of thousands of people lost power. The ‘near-misses’ at Walham substation (serving 500,000 people in Gloucestershire and south Wales) and a number of electricity substations around Sheffield (servicing 750,000 people) that brought home the vulnerabilities of infrastructure assets. The failure of supply on that scale in either region would have caused chaos and, almost certainly, loss of life (15).

Hydropower

The primary vulnerabilities of the energy sector are associated with sea level rise, storm damage and intense precipitation events (4). This latter impact will, for example, lead to increased water levels and overflow volumes in reservoirs built to a design specification of a 1 in 10,000-year flood event. Rectifying this would require extensive improvement works on all reservoirs. Earlier snowmelt would also reduce the effectiveness of hydropower into late spring and early summer. Large-scale infrastructure will require a long lead-time to adapt to climate impacts. Customers will ultimately pay for the additional cost of climate impacts borne by industry.

Infrastructure

Analysis and experience has shown that energy infrastructure may be vulnerable to certain aspects of climate change; however the infrastructure has a significant degree of resilience to change, and therefore adaptation. In addition, technically it will be feasible to deal with adaptation issues over short, medium and long-term periods (11).

Oil platforms are designed to withstand 1:1000 year waves, which are of the order of 30 metres high. Wave heights close to this specification have occurred west of Shetland. Expert respondents suggested that by the 2050s the evolution of the industry is likely to mean platforms will be floating rather than attached to the sea floor. Such structures are less susceptible to wave damage. The general opinion received was that the physical impacts of climate change are not the major issue for the offshore industry (4).

Mining

In 1997 nuclear predominated with a 42% share of generation, followed by coal (~29%). Scottish mines are 'wet', in terms of the volume of water pumped per tonne of coal produced, and continuous pumping is required to extract coal. It is not known whether climate change, for example more intense rainfall events, will affect operations. The pollution control of abandoned mine water is of great importance, since the 1995 River Survey suggests it can have a devastating effect on surrounding receiving waters (4).

Vulnerabilities UK - Regional differences

West and Gawith (1) present an overview of expected climate change impacts on several activities for different regions of the United Kingdom, based on several regional scoping studies. The results for energy are listed below.

A blank cell indicates that no specific issues were identified for the region besides those noted in the first row. Each region identified and discussed issues differently, so this table might not provide comprehensive coverage of all issues.

Region Positive impact on energy Negative impact on energy Uncertain impact on energy Majority of regions Opportunities for biofuels and renewables Higher risk of damage to infrastructure Changes in seasonal demand South East       London       East of England       East Midlands       West Midlands Less fuel poverty. Reduced damage to infrastructure from freezing weather and ice Power stations constrained by water availability   Wales   Reduced performance of hydroelectric plants   North West   Distribution affected   North East   Disruption to supply through weather events. Additional cooling may be needed in industrial processes   Scotland       Northern Ireland Greater development of renewables. Efficiency gains  

Benefits of climate change in the UK

The major benefit is the increased potential of renewable sources, such as wind and wave power schemes, as mean wind speeds increase. Hydro may benefit from further rainfall, but this will depend on the seasonality of the changes (4).

Significant market opportunities exist for many business sectors to develop climate-proof products and services which reduce climate impacts and increase adaptability (2,6):

• The development and increased use of renewable energy products within this sector and others will result in increased demand for technologies such as solar power, heat exchange technologies and tidal power installations.
• The use of on-site renewable energy will also reduce dependency upon vulnerable energy distribution infrastructure, and reduce energy costs related to fossil fuel combustion.
• Groundwater heat pumps could utilise the cooler underground waters for cooling of buildings, whilst heat exchangers extending into the river Thames would moderate temperatures in summer, also providing some warmth in the winter.

In the United Kingdom 2°C warming by 2050 is estimated to decrease fossil fuel demand for winter space heating by 5 to 10 % and electricity demand by 1 to 3 % (7). On the other hand, in London the typical air conditioned office building is estimated to increase energy used for cooling by 10% by the 2050s, and around 20 % by the 2080s (8).

Wind power in the UK

Wind share of total electricity consumption in The United Kingdom was 3.2% by the end of 2010. Overall in the EU, in a normal wind year, installed wind capacity at the end of 2010 meets 5.3% of the EU’s electricity needs (9).

Model studies based on two GCM’s and three IPCC scenario’s (A2, B1 and A1B) suggest a strengthening of the seasonal pattern of wind speeds in the UK at the end of the 21st century (14). The results for all scenarios appear to show that the typical pattern of UK wind speeds, which tend to be high in winter and lower in summer, could be emphasised further under the influence of climate change. The overall effect on the annual production is likely to be small, however. The degree of uncertainty, on the other hand, is high, both within the modelling process, the selection of scenarios and the empirical relationship between geostrophic wind and wind energy. Besides, the study did not analyse temporal variability in detail, and neither does it address the possibility of changes in extreme wind conditions; these factors are important for the wind industry and may obligate adaptation in the future (14).

Climate change impacts on electricity markets in Western Europe

The expected climate changes in the 21st century are likely to have a small impact on electricity prices and production for the energy markets of Western Europe. This has been estimated by modelling three climatic effects (12):

• changes in demand for electricity due to changes in the need for heating and cooling,
• changes in supply of hydropower due to changes in precipitation and temperature, and
• changes in thermal power supply due to warmer cooling water and therefore lower plant efficiency.

According to the model results each of these three partial effects changes the average electricity producer price by less than 2%, while the net effect is an increase in the average producer price of only 1%. Similarly, the partial effects on total electricity production are small, and the net effect is a decrease of 4%.

The greatest effects of climate change are found for those Nordic countries with a large market share for reservoir hydro. In these countries total annual production increases by 8%, reflecting an expected increase in inflow of water. A substantial part of the increase in Nordic production is exported; climate change doubles net exports of electricity from the Nordic countries, while the optimal reservoir capacity is radically reduced (12).

Adaptation strategy

Measures that can be taken to adapt energy consumption to global warming are (2,5):

• expand conservation, energy efficiency and demand side management strategies to reduce demand on hydropower systems dependent on snowpack or vulnerable to drought, and to reduce peak loads during heat waves that make transmission systems vulnerable to blackouts;
• increase street tree planning and maintenance, green roofs and high-albedo surfaces to reduce urban heat and unsustainable energy demand for air conditioning;
• amend building codes to decrease energy needs for cooling (more natural ventilation);
• implement weatherization programs to reduce building loads, especially for low-income people; invest in distributed energy systems such as cogeneration, and local renewable energy systems to reduce vulnerability to transmission interruptions from storms and high winds;
• invest in increased power generation to meet peak demands;
• reduce the H/W ratio, where H is building height and W is spacing (width) between buildings;
• reduce anthropogenic gains, by having low energy buildings and less traffic;
• build fountains and open water.

Electricity production

Decreases in water withdrawal for electricity production are likely. Many older power stations rely on once-through cooling systems, and newer plants are expected to replace many of these over the next thirty years. The newer plants usually operate with tower cooling systems, which should result in substantial reductions, of 50% or more, in water withdrawal, despite an expected near doubling of thermal electricity production in Europe between 1990 and 2030 (10).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for the United Kingdom.

1. West and Gawith (2005)
2. London Climate Change Partnership (2002)
3. Anderson et al. (2003)
4. Kerr et al. (1999)
5. Clean Air Partnership (2007)
6. C-CLIF and GEMRU (2003)
7. Kirkinen et al. (2005), in: Alcamo et al. (2007)
8. LCCP (2002), Alcamo et al. (2007)
9. European Wind Energy Association (2011)
10. EEA (2005), in: European Commission (DG Environment) (2007)
11. National Grid Electricity Transmission plc (2010)
12. Golombek et al. (2012)
13. McColl et al. (2012)
14. Cradden et al. (2012)
15. Pitt Review Team (2008)
16. Byers et al. (2014)
17. EA (2008a,b), in: Byers et al. (2014)
18. EA (2010), in: Byers et al. (2014)