Dispatchability, Energy Security, and Reduced Capital Cost in Tidal-Wind and Tidal-Solar Energy Farms

Peter Osman,Jean-Roch Nader,Mark A Hemer,Saad Sayeef,Irene Penesis,Mike Herzfeld,Uwe Rosebrock,Philip Marsh,Remo Cossu,Alistair Grinham,David Griffin,Jennifer A Hayward

doi:10.3390/en14248504

Abstract

The global tidal energy resource for electricity generation is small, and converting tidal kinetic energy to electricity is expensive compared to solar-photovoltaic or land-based wind turbine generators. However, as the renewable energy content in electricity supplies grows, the need to stabilise these supplies increases. This paper describes tidal energy’s potential to reduce intermittency and variability in electricity supplied from solar and wind power farms while lowering the capital expenditure needed to improve dispatchability. The paper provides a model and hypothetical case studies to demonstrate how sharing energy storage between tidal stream power generators and wind or solar power generators can mitigate the level, frequency, and duration of power loss from wind or solar PV farms. The improvements in dispatchability use tidal energy’s innate regularity and take account of tidal asymmetry and extended duration low-velocity neap tides. The case studies are based on a national assessment of Australian tidal energy resources carried out from 2018 to 2021.

Highlights

The need for electricity grid stability drives the cost of dispatchable power as electricity supplies increasingly rely on renewable energy (RE)
This study evaluated the relationship between capital expenditure (CAPEX), energy storage and generated power dispatchability for hypothetical tidal farms at locations identified by the Australian Tidal Energy (AUSTEn) project [6,12,20,21]
The replacement reduced low power events above the dispatchability threshold and provided a CAPEX reduction of 20% (A$105m) for an offshore tidal-wind farm and 5% (A$20m) to 11% (A$43m) for a land-based hybrid farm depending on its location

Summary

Introduction

The need for electricity grid stability drives the cost of dispatchable power as electricity supplies increasingly rely on renewable energy (RE). Reliability Obligation requires National Electricity Market retailers to cover a share of peak demand and the Australian Energy Market Commission is changing energy market regulations to ensure electricity grid security and facilitate RE generation [1,2]. Fossil-fuel-powered generators that run continuously, coupled with rapid control of pumped hydro and natural gas power generation, can manage intermittent or variable renewable energy [3], or rapid changes in demand [4]. As RE displaces fossil fuel, it will be necessary to increase demand management and energy storage to help stabilise electricity grids. Batteries, pumped hydro, hydrogen, biomass, and thermal energy storage are likely candidates to help provide dispatchability, in remote area power supplies. The tidal resource may be insufficient to meet the capacity needs of a remote power station that is not connected to a

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Discussion

Conclusion