Dispatchable electricity generation is the new frontier for renewables. There is general agreement that electricity systems need a significant share of dispatchable generation to complement and balance the increasing share of variable renewable generation. To better understand the renewable options, the Australian Renewable Energy Agency (ARENA) commissioned a team lead by the ITP Energised Group (ITP) working with The Institute of Sustainable Futures (ISF) and ITK consulting (ITK) to compare technology combinations that are commercially available at large scale.
The combinations studied were wind and /or PV driven; batteries, pumped hydro and hydrogen production. These were also compared with the inherently dispatchable technologies; bioenergy, concentrating solar thermal and geothermal. Costs of installation and cost of energy and other aspects were compared as a function of hours of delivery or storage.
The study has developed an innovative subsystem based approach to modelling installed cost as a function of configuration and system size for each technology combination. This has been used to examine the LCOE of optimised systems under real input conditions as a function of duration of storage or operation. In addition the additional cost of reserving an additional amount of stored energy for infrequent strategic use (the cloudy windless week question) has been considered along with a range of other points of comparison.
Whilst this is an Australian study with costs in AUD and based on Australian conditions, much of the information and many of its findings are expected to hold independent of jurisdiction.
Study findings include:
- There are multiple affordable options for firm dispatchable renewable electricity generation over all time scales at 1.5 – 2 x cost of Variable Renewable Energy
- Likely least cost is a mix of technologies, durations and locations
- Achievable growth rates could keep pace with coal retirements and enable an orderly transition to a large share of Renewable Energy
- In parallel, long term energy reserves can be added to ensure generation in critical periods at 2 to 3 times the cost of VRE alone.