Potential sustainable locations for photovoltaic water pumping systems

Introduction

In China, the grassland area amounts to nearly 4 million km², accounting for more than 40% of the national land surface. Grassland plays a key role in achieving sustainable development and enhancing the food security of the country, supporting the foraging of 100 million livestock [1]. In 2009 the Asian Development Bank (ADB) supported Qinghai Province in developing and demonstrating pasture conservation through the innovative use of photovoltaic water pumping (PVWP) systems for irrigation [2]. The aim of this project is to identify the suitability and optimal location of grassland areas for the implementation of PVWPs across the whole of China.

Methodology

The grassland areas suitable for implementing PVWP technology were evaluated by assessing spatial data on land cover and slope, precipitation, evaporation, and water stress. The optimal locations for installing PVWP systems were evaluated on the basis of two different approaches:

1. the benefit-cost ratio (BCR) methodology;
2. using IIASA’s renewable energy systems model BeWhere, an optimization model for location of bioenergy production facilities.

Results

The grassland areas suitable for PVWP represent about 25% of China’s total grassland area. The estimated suitable grassland locations were compared with previous assessments that followed an approach used by the ADB. The comparison shows a significant disagreement with respect to spatial distribution, as the ADB approach does not take into account the spatial water stress factor. The analysis of the optimal locations according to the BCR methodology shows that the location profitability is very sensitive to the depth of groundwater resources and potential forage production. The BCR is also affected by the optional surplus electricity generation by the PV systems. Results from the BeWhere model indicate that forage produced under irrigation from PVWP systems is presently only competitive at high forage prices, mainly due to high investment and transportation costs. The potential forage production from domestic grassland cannot meet the estimated domestic demand. Finally, hybrid maps functioning as a basis for optimal planning of PVWP systems were developed to provide a handy tool for policymakers, farmers, investors, and consultants interested in solar pumping applications.

Conclusions

PVWP systems can become a crucial part for optimal solutions to support the sustainable development of the agriculture and livestock sector in China. The potential of PVWP systems in China is large. Nevertheless, the suitable and optimal locations are sensitive to important environmental and economic parameters, such as forage water requirements, ground water depth, grass price, and subsidies; these need to be carefully taken into account in the planning process. 

Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.

Last edited: 29 September 2015