Suchergebnisse

This policy brief presents a long term assessment of low-carbon energies including renewables, nuclear and fossil energy with CCS. It targets the electricity sector from a global to a regional perspective and from centralized to decentralized energy systems. The policy brief aims at finding answers to the following questions: What role can and should renewable energy play in the next decades on the way to a low-carbon energy future? What is the optimal electricity mix (now and in the future)? What are the impli-cations of the optimal mix regarding renewable energy investment and policy? What framework would be needed to enhance international coordination?

Water and agriculture are intrinsically linked. Water is essential for crop production and agriculture is the largest consumer of freshwater resources. However, this link is commonly ignored by economic models mainly because water use is not reported in the national economic accounts. Few regions have markets for water. This paper describes the new version of GTAP-W, a multi-region, multi-sector computable general equilibrium model of the world economy. The new version of GTAP-W distinguishes between rainfed and irrigated agriculture and introduces water as an explicit factor of production for irrigated agriculture. Moreover, the new production structure accounts for substitution possibilities between irrigation and other primary factors. The new model has been used to study a variety of topics including: irrigation efficiency, sustainable water use, climate change and trade liberalization. This paper is a technical description of the data and features added to the standard GTAP model.

We use the new version of the GTAP-W model to analyze the economy-wide impacts of enhanced irrigation efficiency. The new production structure of the model, which introduces a differentiation between rainfed and irrigated crops, allows a better understanding of the use of water resources in agricultural sectors. The results indicate that a water policy directed to improvements in irrigation efficiency in water-stressed regions is not beneficial for all. For water-stressed regions the effects on welfare and demand for water are mostly positive. For non-water scarce regions the results are more mixed and mostly negative. Global water savings are achieved. Not only regions where irrigation efficiency changes are able to save water, but also other regions are pushed to conserve water.