Investor Presentaiton
GLOSSARY/DEFINTIONS
Words and phrases defined here are coloured in
Capacity Factor: the ratio of actual output to nameplate output.
Geothermal has the highest factor of any form of electricity generator.
Dispatchable Power is flexible and predictable and can be rapidly ramped
up or down to meet demand: e.g., hydroelectric, gas, geothermal. In
contrast to base-load only (e.g., coal) and variables such as wind and solar.
Firming Capacity: a power source such as gas, geothermal or battery.
used to smooth out (or firm) varying supply from (e.g.) wind and solar.
Frequency Control and Auxiliary Services (FCAS): a group of services
used to maintain grid stability. Increasingly required with increasing VRGs.
(Mass) Flow Rate is the amount of water and/or steam delivered to a
power plant. Usually expressed in kg/sec (or litres/sec) per well.
Hydrothermal Geothermal System (HGS): High temperature with plentiful
water; heat source is usually of (shallow) volcanic origin: see figure.
Heat Flow: the amount of heat (in milli-Watts per m²) leaving the earth's
near-surface. Used to locate high temperatures at depth. Average
continental heat flow is ~65mW/m² (Lemont recorded 118mW/m²).
LCOE: Levellised cost of electricity is the break-even price (usually per kWh)
over the life of the project. Used to compare different types of generators.
Steam Plant
reservoir
HGS Existing
'WET'
Boiling
HEAT
Spa*ark Energy_3
Binary Plant
Depth
(km)
Thermal
Blanket
PGS 2-
Man-made
"enhanced"
'DRY' 3 reservoir
5-
250G
HEAT
Geothermal systems can be broadly classified into two types: Hydro-
thermal (HGS) and Petrothermal (PGS). The former are (usually) very
hot and shallow with plentiful water to transfer energy to the surface.
The latter are deeper with lower temperature and permeability.
Previous Australian projects were PGS. Lemont is interpreted to be
closer to (non-volcanic) HGS with moderate to high temperature and
permeability.
The USA's Energy Information Agency (EIA) assigns geothermal the lowest of all LCOES, largely due to its very high capacity factor.
LGCS (large scale generation certificates): cash incentive for renewable energy. Due to be phased out in 2030.
MT (magnetotellurics): a geophysical method which maps the earth's electrical resistivity to depths of several km. A high permeability (non-uniquely)
produces a low resistivity.
Permeability is the ease with which water can flow through rock. Porosity is the amount of space occupied by the water.
Petrothermal Geothermal System (PGS): (usually) moderately hot rocks with low permeability; heat source is usually deep and granitic. The system
has to be stimulated to obtain a viable water flow. Includes Enhanced Geothermal Systems (EGS). See figure.
(Electrical) Power, (= volts x current); usually expressed in Mega-Watts (MW). (Electrical) Energy = power x time; usually expressed in Mega-Watt-
hrs (MWh). The average volume-weighted Tasmanian spot price for the 2018-19 financial year was $88 per MWh (= 8.8c per kWh).
Temperature: a measure of energy in the form of heat. The earth's near-surface temperature gradient averages ~25-30°C/km
VRGS: variable renewable energy generators (sometimes referred to as VRES); mostly wind and pv_solar in Australia.View entire presentation