Climate change and the electricity sector

Argentina has a predominantly oceanic climate, except in its northern part.

The Andes mountain range on the western border, with an average height of about 4000 m from the 40° S latitude to the north, completely blocks air exchange in the lower atmosphere, preventing the movement of humidity from the Pacific Ocean to the country. As a result, the climate in north-western Argentina is dry and continental. On the basis of these atmospheric circulation patterns, two large regions are distinguished: north and south of the 40° S latitude.

Climatic and hydrological trends in Argentina over the last 30–40 years that are potentially associated with climate change and are likely to affect the electricity system include the following:

(a) Increasing mean annual precipitation in almost the entire country, especially in the north-east and in the marginal western zone of the humid Pampas [131]:

This explains the increased frequency of flooding and why some areas are becoming almost permanent lagoons [132].

(b) Increasing frequency of extreme precipitation in most of the central and eastern regions of the country since the late 1970s: The frequency further increased in the 1990s and probably intensified in the first decade of this century [133].

(c) Increasing river stream flows and floods in the whole country, except in Comahue, Mendoza, San Juan and northern Patagonia: The stream flows of major rivers of the La Plata basin show strong interannual variability [134].

The increase in rainfall in southern Brazil and north-east Argentina has not been accompanied by significant warming that could increase evaporation and compensate higher levels of precipitation. The increased precipitation resulted in more runoff into rivers, and stream flows have increased since the mid-1970s [135].

(d) Decreasing trends in stream flows, which have been recorded since 1980 in rivers of the regions Cuyo (provinces of Mendoza and San Juan) and Comahue (provinces of Neuquén and Rio Negro) [136].

(e) Rising mean minimum temperatures and decreasing mean maximum temperatures north of the 40° S latitude. The analysis of temperatures in recent decades shows that warming in southern South America has been much less than in the northern hemisphere. These trends varied spatially between 1°C and 3°C during the twentieth century [137].

(f) Increasing temperatures in the Andean region of Cuyo and Patagonia, resulting in glacier retreats. A different trend has been observed north of

the 40° S latitude. This region shows an increase in the number of warm days and nights in winter and a decrease in the number of cold days and nights in summer. Summer maximum temperatures have increased. Thus, a significant increasing trend in mean temperatures has been observed, with larger increments (>1°C) towards the south. Most glaciers (48 out of 50) of the South Continental Ice Sheet, located in southern Chile and Argentina, have been receding for decades [138, 139].

Regional projections of climate change in Argentina that may have an impact on the electricity system concern increasing temperatures in all seasons, both in the near (2015–2030) and distant (2075–2099) future. The biggest changes are projected for tropical and subtropical latitudes and the Andes, with values for the near future of 1.5°C and more than 3°C for the distant future. The smallest increases are projected for the central and south-eastern zones in winter [140].

Changes in precipitation vary substantially from season to season and across regions in response to changes in large scale circulation. Therefore, this assessment considers projections made for Argentina and for a larger geographical region, including neighbouring countries. The seasonal patterns are as follows [140]:

— Summer: Most projections indicate increases in most regions, except for southern Chile.

— Autumn: Increases are expected for central and northern Argentina by the end of the century, and large decreases are expected for the southern and central areas of Chile.

— Winter: Projections indicate less precipitation in the entire continent. By the end of the century, increases for the south of Chile and decreases for central Chile are projected.

— Spring: Models project increases in south-eastern South America in the distant future.

8.2.2. Overview of the electricity sector

The Argentine Interconnection System (SADI, Sistema Argentino de Interconexión) is divided into eight regions (see Fig. 16). The total national electricity demand in 2012 was 121.2 TW·h, with a maximum power demand of 21.9 GW. Most of this demand is concentrated in the metropolitan area of the City of Buenos Aires and the province of Buenos Aires, representing 50.9% of the national demand.

The electrification rate is close to 100%. A diversified supply portfolio consisting of fossil thermal (65.8%), hydropower (29.2%), nuclear generation

(4.7%) and non-conventional renewable energy (0.3%) (mini hydro, solar and wind) met the demand in 2012. While fossil based generation remains the largest source because of historically available national resources, the Government is seeking to change this by increasing the contribution of other sources. Fuel consumption (in TW·h) in 2012 was the following: natural gas (136.7), fuel oil (32.6), uranium (20.9), gas oil (18.1) and coal (6.1). The consumption of natural gas and liquid fuels varies significantly across seasons, particularly because the residential and commercial sectors have priority in using natural gas in winter, imposing supply constraints on industry and electricity generation, which meet their demand with imported natural gas and by switching to liquid fuels.

Power distribution is operated by a company that manages the wholesale electricity market. A combination of technologies supplies the amount of electricity to satisfy the demand. Run-of-river hydro and nuclear power plants are the first to be dispatched to satisfy the daily minimum or the baseload demand, which does not vary on an hourly basis. Conventional thermal generation, mainly combined cycle and steam turbine plants, meet part of the baseload demand and supply peak demand in high consumption periods. Reservoir hydropower plants FIG. 16. Argentine Interconnection System, mainland only. Note: artographical data were obtained from Compañía Administradora del Mercado Mayorista Eléctrico [141].

BSAS — Province of Buenos Aires; GBA — City of Buenos Aires; NEA — North-east Argentina;

NOA — North-west Argentina.

and gas turbines complement the generation in times of peak demand. Owing to the random nature of their availability, renewable technologies benefit from a special scheme that allows them to supply power to the grid system whenever they are operational.

The electricity transmission networks are operated by national carriers (extra high voltage) and regional carriers (high and medium voltage). In recent years, major expansion of the 500 kV network has taken place, expanding the interconnection between different regions of the country to increase the security of supply and the quality of service.

8.3. CLIMATE RELATED RISKS FOR THE ELECTRICITY SECTOR