IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group III: Mitigation of Climate Change

4.3.7 Transmission, distribution, and storage

A critical requirement for providing energy at locations where it is converted into useful services is a system to move the converted energy (e.g. refined products, electricity, heat) and store it ready for meeting a demand. Any leakage or losses (Figure 4.23) result in increased GHG emissions per unit of useful consumer energy delivered as well as lost revenue.


Figure 4.23: Comparison of net electricity production per 1000MWe of installed capacity for a range of power-generation technology systems in Japan.

´╗┐Source: Data updated from Uchiyama, 1996.´╗┐Note: Analysed over a 30-year plant life, and showing primary fuel-use efficiency losses and transmission losses assuming greater distances for larger scale plants. Transport and distribution losses were taken as 4% for fossil fuel and bioenergy, 7% for nuclear.

Electricity transmission networks cover hundreds of kilometres and have successfully provided the vital supply chain link between generators and consumers for decades. The fundamental architecture of these networks has been developed to meet the needs of large, predominantly fossil fuel-based generation technologies, often located remotely from demand centres and hence requiring transmission over long distances to provide consumers with energy services.

Transmission and distribution networks account for 54% of the global capital assets of electric power (IEA, 2004d). Aging equipment, network congestion and extreme peak load demands contribute to losses and low reliability, especially in developing countries, such that substantial upgrading is often required. Existing infrastructure will need to be modernized to improve security, information and controls, and to incorporate low-emission energy systems. Future infrastructure and control systems will need to become more complex in order to handle higher, more variable loads; to recognize and dispatch small-scale generators; and to enable the integration of intermittent and decentralized sources without reduced system performance as it relates to higher load flow, frequency oscillations, and voltage quality (IEA, 2006a). New networks being built should have these features incorporated, though due to private investors seeking to minimize investment costs, this is rarely the case. The demands of future systems may be significantly less than might be otherwise anticipated through increased use of distributed energy (IEA, 2003c).

Superconducting cables, sensors and rapid response controls that could help to reduce electricity costs and line losses are all under development. Superconductors may incorporate hydrogen as both cryogenic coolant and energy carrier. System management will be improved by providing advanced information on grid behaviour; incorporating devices to route current flows on the grid; introduce real-time pricing and other demand-side technologies including smart meters and better system planning. The energy security challenges that many OECD countries currently face from technical failures, theft, physical threats to infrastructure and geopolitical actions are concerns that can be overcome in part by greater deployment of distributed energy systems to change the electricity-generation landscape (IEA, 2006g).