A new report has found that pumped hydro
storage could help secure a 100% renewable electricity future for the
Australian electricity grid.
A new study published this week by the
Australian National University (ANU) claims that pumped hydro storage
could be used to help build a secure and cheap Australian electricity
grid with 100% renewable energy sources. Specifically, the 100%
renewable energy grid would rely primarily on wind and solar PV
technology, and supported by off-river pumped hydro storage.
Lead researcher Professor Andrew Blakers
from ANU also believes that this system would eliminate the need for
coal and gas-fired power.
“With Australia wrestling with how to
secure its energy supply, we’ve found we can make the switch to
affordable and reliable clean power,” said Blakers, with the ANU Research School of Engineering.
The scenario put forward in the report
estimates wind and solar PV contributing 90% of annual electricity,
together with existing hydroelectricity and biomass sources contributing
the remaining 10%. The report depicted an energy mix based on widely
spread wind and solar sources to take advantage of different weather
systems. The energy balance between supply and demand is maintained by
adding sufficient pumped hydro storage and high voltage transmission, as
well as excess wind and solar PV capacity.
“We term the cost of these additions as
the levelised cost of balancing (LCOB). LCOB plus the levelised cost of
annual generation (LCOG), combine to give the levelised cost of
electricity (LCOE),” the authors of the report write.
“Using 2016
prices prevailing in Australia, we estimate that LCOB is AU$28/MWh, LCOG
is AU$65/MWh and LCOE is AU$93/MWh. This can be compared with the
estimated LCOE from a new supercritical black coal power station in
Australia of AU$80/MWh. Much of Australia’s coal power stations will
need to be replaced over the next 15 years. LCOE of renewables is almost
certain to decrease due to rapidly falling cost of wind and PV. With PV
and wind in the price range of AU$50/MWh, the LCOE of a balanced 100% renewable electricity system is around AU$75/MWh.”
Interestingly, the report takes its figure for new supercritical black coal power stations from a report published in 2015 by CO2CRC —
“the only company in Australia to have undertaken carbon capture and
storage as an emissions reduction technology from end to end.” While the
figures need not necessarily be called into question as a result of
this, a more recent report published by Bloomberg New Energy Finance
(BNEF) earlier this year showed that the Levelized Cost of Electricity
(LCoE) of new ultra-supercritical coal-fired power in Australia
currently sits somewhere between AUD$134-$203/MWh — compared to current
LCoE for new build wind (AUD$61-$118/MWh), solar (AUD$78-$140/MWh), and
combined-cycle gas (AUD$74-$90/MWh).
This serves only to further the
underlying case of the ANU report, by decreasing the LCoE of wind and
solar, and highlighting the gap between new-build coal and new-build
renewables.
This is vitally important in Australia
especially, considering that many coal-fired power plants around the
country are set to reach the end of their operational lifespan in the
next 15 years, and would need to be replaced regardless of
environmental and climate concerns. This only serves to heighten the
role that renewable energy can play in Australia’s energy mix, and
increases the need for policy and business support for the development
of the renewable energy industry in the country.
Researchers
from ANU are also working to map potential short-term off-river pumped
hydro energy storage (STORES) sites that could support a larger share of
renewable energy in the grid. STORES sites are pairs of reservoirs,
around 10 hectares each, which are separated by an altitude difference
of a around 300 and 900 meters, in hilly terrain, and connected via a
pipe with a pump and turbine. According to Dr Matthew Stocks from the
ANU Research School of Engineering, STORES needs much less water than
power generated from fossil fuel, and had a minimal impact on the
environment because the water is recycled between small reservoirs.
“This hydro power doesn’t need a river
and can go from zero to full power in minutes, providing an effective
method to stabilise the grid,” he said.
“The water is pumped up from the low
reservoir to the high reservoir when the sun shines and wind blows and
electricity is abundant, and then the water can run down through the
turbine at night and when electricity is expensive.source: https://cleantechnica.com
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