Climate related risks for the electricity sector

which means that a drought period might result in a significant drop in hydropower production. As hydroelectricity accounts for almost a third of the electricity supply, a drop in hydropower production, particularly in the regions of Cuyo and Comahue, can cause major shortages. So far, a decrease in hydropower generation has been in general balanced by other generating sources, particularly thermal power.

Large amounts of water are also required for thermal power generation whether conventional or nuclear. The availability of water is therefore an important factor in the decision about the location of power plants. The Argentinean nuclear power plants are strategically located near ample natural water sources; thus, climate change does not seem to jeopardize their water supply. Nevertheless, decreases in the efficiency of thermal electricity generation can occur under extended periods of high temperature. Likewise, transmission and distribution losses might increase in times of overload owing to the higher temperature of the lines and can further increase if the ambient temperature is high.

According to the DesInventar database [130], the EWEs that most affect the electricity system of Argentina are storms (48%), followed by floods (25%), wind storms (17%), heatwaves (5%), snowfall (3%), hailstorms (1%) and other events (<1%). On the basis of the information compiled in the disaster information management system DesInventar [130], of the about 20 000 EWEs that have had disastrous consequences in Argentina, more than 3000 affected the energy sector, out of which 1764 events affected various components of the electricity system. The vast majority (1194) of these events caused power outages. This was followed by 453 events affecting different components of the distribution system:

damage or breakage of poles (272), damage or fall of cables and lines (158) and breakdown of substations at processing centres (23). The transmission system was affected 105 times by either the breakage of power towers (73 times) or the

cutting or falling of high voltage lines (32 times). Power plants were affected only by 11 events (see Fig. 17).

Under flood conditions, a few problems in supplying fossil fuel to conventional thermal plants have been registered. The adaptation measure may envisage increasing the storage capacity of fuels at power plants located in flood prone areas. The current vulnerability of electricity generation from biofuels as a result of floods affecting plantations is negligible because most of the biofuel production is destined for transport fuel and only a minor amount is used for electricity generation. This situation might change in the long term if the nationwide support for biofuels in electricity generation continues. However, the shortage of biofuel produced electricity, if any, might also be compensated by conventional thermal plants. In the case of nuclear power, the methods of site selection in Argentina consider possible flooding, including the surrounding water sources used for reactor cooling. In addition, safety measures for normal operation include systems that address this type of climate contingency.

Strong winds and tornadoes have caused damage to power lines and breakage of towers and poles of the transmission and distribution systems, leading to power outage at demand centres. The continuing expansion of the electricity transmission network in recent years has strengthened the security of supply by multiplying the connecting lines between nodes, resulting in a mesh configuration. Furthermore, strong winds and tornadoes can affect wind generation and cause the collapse or partial destruction of wind turbines. For safety reasons, the rotation of the blades is stopped when wind speed exceeds 25 km/h. In addition to these findings, the most relevant risks to the Argentinean electricity system and the related adaptation options are summarized in Table 10.

FIG. 17. Impacts of extreme weather events on the electricity system in Argentina [130].

TABLE 10. CLIMATE CHANGE VULNERABILITY OF THE ELECTRICITY SYSTEM RiskVulnerability before adaptationAdaptation strategy and options Hydropower

Decreases in mean rainfall and dischar ges in certain rivers in the Andean region,

north-western Patagonia and the Comahue region Decreasing river stream flows, which cause less hydropower generation. However

, in the last 20

years, records do not show a decrease in the load factor of the Comahue reservoir hydropower plants under regular hydraulic conditions. Potential water crisis in the Andean foothill oases (Cuyo and Comahue).

Win–win/technical — diversification of power generation

Compensate decreasing hydropower generation with conventional thermal power Incorporate ener

gy planning sources independent of

reduced rainfall in the mountains (such as renewable and nuclear power) Incorporate future climatic conditions into the design of new power plants and ancillary structures

Increase in the mean annual precipitation, except in the areas mentioned above, especially in the north-eastern and central regions Increased flows in the three main rivers of the La Plata basin (Paraná, Paraguay and Uruguay). Despite their high interannual variability

,

increasing average flows have been observed since 1970. Electricity output of run-of-river plants has not increased.

An increase in stream

flows may result in increased hydropower generation if plants are able to handle higher levels of stream flows.

Low regret/informational — risk assessment for siting Add more turbines in the case of sustained increase in river flows

TABLE 10. CLIMATE CHANGE VULNERABILITY OF THE ELECTRICITY SYSTEM (cont.) RiskVulnerability before adaptationAdaptation strategy and options Steady rise of the 0°C isotherm in the Andean area, reaching 120–200 m by midcentury Continuing retreat of glaciers. Snow accumulation and the regulation capacity of glaciers are affected. Glacier melting influences river stream

flows, and spring flooding would not be dammed by hydropower plants. The retreat of glaciers can also lead to a minor and transient increase in mean stream flows of rivers feeding hydropower plants and a corresponding increase in power generation. By contrast, higher temperatures increase evaporation and decrease mean stream flow

, consequently reducing generation by the reservoirs’ hydropower plants.

Win–win/technical — higher and more robust dams and/

or small upstream dams, diversified power generation Improve regulating capacity of hydropower plants Build taller and more robust dams depending on the level of the ef

fect

Diversify power generation when the retreat of glaciers commences

Hydropower: electricity demand Increasing temperatures, which affect the entire country,

especially the northern and Andes region Increased water stress throughout the northern and western parts of the country due to warming. The central and Litoral regions located in the affected area concentrate 60% of the electricity demand.

Low regret or win–win/technical — diversified power generation Build riverine defences Review the design of hydropower plants located near mountain ranges

TABLE 10. CLIMATE CHANGE VULNERABILITY OF THE ELECTRICITY SYSTEM (cont.) RiskVulnerability before adaptationAdaptation strategy and options Hydro and thermal power plants

Rise of sea level and water level in Rio de La Plata Uncertainty in the availability of water resources in the La Plata basin. Impact on some parts of the sea coastline and on the banks of the La Plata River

.

Low regret/informational — risk assessment for siting Monitor progress of water level in the La Plata River and changes in wave conditions Use records to update maintenance policy to respond to the gradually changing conditions

Electricity transmission and distribution

Increasing frequency of heatwaves Increased cooling requirements caused by extreme temperatures, which will cause greater electricity demand with overload on transmission and distribution lines.

When these lines approach maximum transmission capacity, resistance to electric current flow increases exponentially,

generating a proportional increase in losses and temperature. High ambient temperature decreases the possibility of dissipating excess heat and strongly increases the occurrence of failures (blackouts). Similar impacts disturb voltage transformers.

Low regret or win–win/technical — improved maintenance and renovation of infrastructure Maintain, repair and renovate components of the transmission and distribution systems* Manage temperature related limitations on generation by improving cooling capacity through design modifications

TABLE 10. CLIMATE CHANGE VULNERABILITY OF THE ELECTRICITY SYSTEM (cont.) RiskVulnerability before adaptationAdaptation strategy and options Electricity transmission and distribution: fuel pipeline transport and biofuel

Increase in river stream flows and floods in the whole country

, except in San Juan,

Mendoza, Comahue and northern Patagonia

Floods in waterways, which can affect energy

infrastructure that crosses or runs parallel to them, such as high voltage and/or distribution lines and under

ground pipelines (gas and oil transport).

Low regret or win–win/technical — verification of designed excess flow and plant capacity

, and risk

assessment for siting high voltage lines and fuel transport routes Verify and expand the designed excess flow dischar

ge

and/or augment the plant capacity by increasing the number of turbines Re-route high voltage transmission lines and natural gas and oil pipelines (may be advisable under persistent adverse conditions)

Increasing frequency of extreme precipitation in most of the central and eastern regions of the country Prolonged flooding, which can reduce soybean harvest, the main feedstock for biodiesel production.

The vulnerability of electricity

generation to this shortage is minimal because only a mar

ginal share of biodiesel is used in

electricity generation. Heavy rainfall and flooding, which can undermine tower structures through erosion. Flooding can damage under

ground cables and infrastructure in general.

Low regret/informational — risk assessment for siting Replace biodiesel by with gas oil Relocate cropland to non-flooded areas, and use other biofuel crops that are suitable for production in these new areas Increase power generation from sources that do not depend on fossil fuels or biodiesel Reinforce the structure of towers in high voltage transmission lines Put distribution lines under ground * Currently, no records are available about the effects of high temperatures on thermal power plants in Argentina.

8.4. CASE STUDY: ADAPTATION TO THE IMPACTS OF CLIMATE