Geothermal energy for sustainable development: A review of sustainability impacts and assessment frameworks

Abstract

Sustainable development calls for the use of sustainable energy systems. However, the way in which a geothermal resource is utilized will ultimately determine whether or not the utilization is sustainable. Energy usage is set to increase worldwide, and geothermal energy usage for both electricity generation and heating will also increase significantly. The world׳s geothermal resources will need to be used in a sustainable manner. The sustainable utilization of geothermal energy means that it is produced and used in a way that is compatible with the well-being of future generations and the environment. This paper provides a literature review of the linkages between geothermal energy developments for electricity generation and sustainable development, as well as a review of currently available sustainability assessment frameworks. Significant impacts occur as a result of geothermal energy projects for electricity generation and these impacts may be positive or negative. The need for correct management of such impacts through a customized sustainability assessment framework is identified and the foundation for sustainability assessment framework for geothermal energy development is built in this paper.

Introduction

Energy is a principal motor of macroeconomic growth, prosperity and economic development, a prerequisite for meeting basic human needs, while at the same time a source of environmental stress. Energy in itself is a vital component of sustainable development [1]. Different energy types have different types of impacts during their development. Along all energy chains, from the extraction of the resource to the provision of energy services, pollutants are produced, emitted or disposed of, often with serious health and environmental impacts. During an energy project׳s lifecycle, emissions and wastes may be also associated with the manufacture or construction of energy systems. Yet, the impact differs widely. Fossil fuels are largely responsible for urban air pollution, regional acidification and climate change. The use of nuclear power has created a number of concerns, such as the storage or disposal of high-level radioactive waste and the proliferation of nuclear weapons. Biomass use in some developing countries contributes to desertification and loss of biodiversity, as well as energy crop cultivation having significant impacts on food prices worldwide [2]. Other renewable energy sources such as hydro- and wind power have significant implications for land-use as well as significant ecosystem and visual impact.

Geothermal energy has not until recently become a significant source of electricity and heat, with of course exceptions in countries such as the USA, Indonesia, Iceland and Italy [3]. In 2008, geothermal energy represented around 0.1% of the global primary energy supply, but estimates predict that it could fulfill around 3% of global electricity demand, as well as 5% of global heating demand by 2050 [4]. Geothermal energy is usually considered a renewable energy source, but its development and use can however have significant multi-dimensional sustainability implications [5]. Given the certainty that geothermal energy usage is set to increase substantially, it is important to ensure that geothermal resources are developed in a sustainable manner, in particular for electricity generation projects. As well as this, the international community has called for the development of indicators to measure progress towards sustainable development [6]. Until now no framework however exists that enables formal assessment of the sustainability of geothermal energy development and use.

The objectives of this study are to

• Review the literature on sustainability impacts of geothermal power development for electricity generation and thereby identify the most important issues of concern whilst assessing the sustainability of geothermal energy projects.

• Review the available sustainability assessment frameworks and thereby determine the best structure for an assessment framework for geothermal energy projects.

• Demonstrate the need for assessing sustainability in the geothermal energy sector and to provide the scientific basis for the creation of a formal sustainability assessment framework.