| Authors |
Chris J. Bromley, Mike Mongillo, Gerardo Hiriart, Barry Goldstein, Ruggero Bertani, Ernst Huenges, Arni Ragnarsson, Jeff Tester, Hirofumi Muraoka, Vladimir Zui |
| Abstract |
A special report on renewable energy has been commissioned by the IPCC (Inter-Governmental Panel on Climate Change) to provide guidance on future mitigation options for climate change through reducing CO2 emissions. To achieve this, a better understanding is required of potential global and regional geothermal resources. These range from convecting high-grade hydrothermal to conduction-dominated stored thermal energy, and are hosted in volcanic, sedimentary or crystalline crustal rocks. Important issues affecting future utilisation include: energy security and sustainability, status of current applications, future technology advances, cost predictions, projected deployment rates, energy integration and infrastructure requirements, environmental risks and benefits, technology transfer, and policy options. Increased geothermal energy development is well suited to climate change mitigation because it provides base-load power and heating (or cooling) from a large energy resource that is well-distributed globally. It has a good track record of sustainable production using existing technology, applicable to both developed and developing countries, and for generating cost-effective and highly-dispatchable power. Geothermally-heated fluids are available for space heating and cooling and a variety of other industrial applications, ranging from small-scale to district-wide installations. In addition, geothermal heat pumps (GHPs) are deployed worldwide, enabling substantive gains in heating and cooling efficiency of buildings. Relative to other renewable energy technologies, geothermal resources are utilised at high average availability factors (typically > 90% for electricity generation). Overall, geothermal has been shown to be socially acceptable with some positive social and environmental impacts, including a relatively small land-use footprint. Adverse impacts are manageable using best practice reservoir management practices, including water resource conservation. Wider deployment of existing technology and application of new technologies under demonstration will significantly increase the use of geothermal resources at all temperatures. Enhanced or Engineered Geothermal Systems (EGS) offer the potential for global scale utilization when and where it is needed. For this potential to be realised, research and field testing at commercial scale is required with multi-year government and private support and investment. The benefits will include mitigation of climate change through provision of CO2 offsets at competitive costs, and improved energy security. |