Preliminary Investigation into the Current and Future Growth and Affordability of ORC Electricity Generation Systems
The Organic Rankine Cycle (ORC) provides a way to produce power from heat resources that are at too low of a temperature to be competitively converted using steam-Rankine cycles. While ORC systems using geothermal, biomass, waste-heat, and solar resources currently provide less than 0.1% of worldwide electricity generation, their market growth has been historically steady, with new resource opportunities helping to marginally increase the installed capacity growth rate in recent years. This paper explores the current growth of ORC electricity generation systems, the theoretical limit of their future growth, and to what extent policy-based market changes will push ORCs towards meeting this potential. The results from a survey of ORC manufacturers are presented, looking into the prevalence of existing ORC systems and the heat resources which they use. Estimates for the potential for future growth are made based on existing literature, and this is compared with current development. The historic trend for the growth of ORC generation capacity is presented, and it is proposed that if the low current annual growth rate continues, then ORCs are unlikely to become a globally significant energy conversion technology at meeting current demand levels. The final part of this paper looks at the competitive advantage that ORCs get from GHG pricing, a non-technological factor that affects the growth rate of installed capacity. It is concluded that a truly significant penetration of ORC generation into the global energy mix would require a step change in the amount of resources that can be affordably developed; either through the introduction of new ways to cheaply access and deliver resources, or through a massive shift in expenditure on energy systems, which may be unfeasible in future economic scenarios.