Hybrid Solar Wind Power Plants
Introduction
Renewable energy costs have come down, a number of
solar and wind power plants added to the system all over the world.
Introduction of wind and solar to the system presents some problems as
well. A hybrid i.e. solar and wind at
the same site will mitigate some of these issues besides bringing down the cost
of this combined power plant. As
technology costs come down, combining wind, solar and energy storage looks like
the way to integrate renewables at least cost. In most
countries legacy generation plants base load, coal or combined cycle gas fire
were built by the state. These plants cannot run economically past their
operational lifetime. Eventually they have to be replaced with the cheapest,
and also the cleanest, form of generation. Wind and solar will replace the lion’s
share of legacy generation over the next 20 years or so. Those who recognise this and act fastest will benefit sooner,"
Number of renewable energy projects that pairs
wind and solar to create a hybrid power source is planned. It's a rare combination
now, but one that's expected to become more common because of its potential to
cut costs while providing a more consistent flow of clean energy
Variations include the combined power
generating system by wind mill and solar energy panel. It also includes a
battery which is used to store the energy generated from both the sources.
Using this system power generation by windmill when wind source is available
and generation from PV module when light radiation is available can be
achieved. Both units can be generated power when both sources are available. By
providing the battery uninterrupted power supply is possible when both sources
are idle. Investment
per megawatt remains low with weighted average of the individual investments
minus land cost plus some additional investment in batteries.
Benefits
The wind and solar energy complement
each other. They hit their peaks at different times of day and night, allowing
them to provide a steadier output together than if each was alone. And they
save money because they can The benefits of wind-solar hybrids start with a simple
idea: Solar power is strongest when the sun is brightest, often in the middle
of the day. Wind power is stronger at night in many areas of the World . By combining the two, a hybrid project has
the potential to produce power around the clock share
equipment, power lines and workers
Solar
and wind power suffers from intermittency and variability. In simple words, Sun
shines in the day and wind starts blowing in the afternoon and continues till
past midnight, but mostly in summers. In western countries, it is the opposite
where wind blows hard in winter coinciding with their peak energy demand thus,
solar covers one part of the daily peak demand and wind covers the second peak
at night hours. In summers, it is handy for us.
25% of the costs goes into land and
transmission which is saved in the hybrid concept. Transmission facilities are
under-utilized in case of individual solar and wind plants proportional to
their capacity factors – solar 17% of the time and wind about 35% of the time.
Hybrid
accumulates it to the sum of the two minus some overlapping portions. Thus, it
is not uncommon to get a capacity factor (utilization) of 45% to 55% which is a
much improvement.
The consistency is increasingly
important as renewable energy partly replaces coal-fired plants or gas fired
combined cycle power plants, which can provide 24-7 power, higher hybrid
availability will reduce dependence upon fossil fuels. This is valid both at
the aggregate level as well as at the local level, where a hybrid properly
dimensioned may eliminate the need of flow from the grid, except at rare
extraordinary occurrences. .
Most renewable energy development so
far has targeted either the sunniest or the windiest areas, without considering
locations that could be good for both solar and wind. That's changing as wind
and solar costs decrease and the technology advances. Today, there are many
parts of the World. Where both wind and solar can be profitable It will create
economic opportunities for wind in parts of the World. Where wind farms are not
present . In areas, where wind farms are more common than solar, it's the other
way around, with opportunities to put solar panels alongside wind turbines
Solar-wind
hybrid means integration of solar and wind energy production by installing both
solar and wind power plants at one piece of land or at nearby plots utilising
common transmission facilities.
Solar and wind are not available all
the time and require back up generation to dill then gaps, this besides other
issues requires flow reversals This needs to be managed .This is important
because one of the challenges of managing a power grid is dealing with the
intermittent nature of renewable energy.
Power grids have to provide the
right amount of power to match customers' power demand moment-to-moment, so
natural gas power plants are often kept at the ready to power up when needed.
That could include being used on a cloudy day when a region's solar power output
is down.
The ability of a gas plant to
quickly ramp up and down helps keep the grid reliable . The fossil fuel plants
emit more pollutants per megawatt-hour when increasing or decreasing their
output than they do when running at a steady rate. If wind and solar plants
built together can provide a more consistent power supply, other power plants
could run on a more predictable schedule, with lower emissions and lower costs.
In addition, operators of solar-wind
hybrids can save money by sharing assets, wind and solar will be located right
next to each other and feed power into the same equipment that connects to the
grid, with a single substation. They likely also will share a maintenance
building and other operations.
In 2017 Windlab published a study that found
one way to avoid excessive curtailment or huge investments in energy-storage
capacity in regions such as North Queensland, characterized by very high levels
of solar generation combined with a complementary wind-generation profile, is
to add more wind. According to the study, even when solar PV only reaches 60%
levels of penetration, curtailment levels exceed 45%. A 30:70 solar PV to wind
mix would see curtailment levels reduce to less than 10% when renewables
penetration levels are at 60%. The study assumes Queensland reaches its 50%
renewables energy mix by 2030 target.
If this goal is reached entirely with solar PV,
then 50GWh of storage will be required, but if more than half the 50% comes
from wind, no storage will be needed. In practice, this means identifying
quality high-capacity wind sites, giving wind connections priority and
investing in transmission infrastructure to unlock good wind resources, so that
wind and solar together ensure a clean, reliable, low-cost network. But where actual hybrid plants like Kennedy
may have a place is in areas that need new capacity and have good wind and
solar resources that are complementary. Two generation sources can be connected
to the grid for the same cost as a single source, but output is optimized,
reducing the levelised cost of energy.
Better use of grid access
India, which has seen a big boom in wind and
solar PV installation in recent years, passed a wind-solar hybrid policy
earlier this year to make better use of scant grid access points.The Solar
Energy Corporation of India launched a 2.5GW wind-solar
hybrid tender in June, although it has gone quiet after
extending the deadline from August to September.
The US Trade and Development Agency has
provided a grant for the technical design and planning of a hybrid project
being developed by Indian energy firm IL&FS Energy Development Company
Limited (IEDCL) in the state of Andhra Pradesh. About three years ago, IEDCL
proposed to the Andhra Pradesh government that hybrid renewable-energy plants
would be suitable to support high levels of renewable-energy penetration on the
grid.
Preventing
curtailment
Kennedy’s
otherwise curtailed output will end up in the battery, which is programmed to
either sell electricity into the grid when prices are high — arbitrage — or
inject power to provide grid ancillary services, such as frequency regulation.
As an example of how lucrative arbitrage is becoming, wholesale prices during
the past year have been around A$75/MWh (US$53/MWh).
However, due to high levels of solar
penetration in the region, consisting of more than 6GW, of mainly rooftop
panels, surplus solar generation is driving wholesale prices into zero
territory. As the solar build-out continues, this disparity between prices
during peak demand and during periods when solar output is highest but demand
is not, creating a surplus, is expected to increase.
Windlab’s existing software covers Kennedy’s
dispatch and market operations. As well as supplying the turbines, Vestas has
developed the hybrid plant’s software controls that manage all components,
including wind, solar and battery, as one integrated and interoperable system.
The system knows when to feed power into the grid, when to divert it to the
battery, and when the battery needs to release power in response to commands
from Windlab’s dispatch and market operations software. Vestas completed its
first wind-plus-storage project and wind-plus-solar PV demonstration projects
in 2012 to test the concepts and apply other relevant competencies, such as
system controls and grid-integration.
Plants built or planned
In India, a captive hybrid power plant (HERO) has been installed and commissioned recently. The plant has wind power capacity of 50MW and solar capacity of 28.8MW. With a wind power capacity factor of 28% and solar power capacity factor of 18.7%, the combined capacity factor of the hybrid reaches 41.8%.
In India, a captive hybrid power plant (HERO) has been installed and commissioned recently. The plant has wind power capacity of 50MW and solar capacity of 28.8MW. With a wind power capacity factor of 28% and solar power capacity factor of 18.7%, the combined capacity factor of the hybrid reaches 41.8%.
Invenergy's Grand Ridge project in
Illinois is one of a small number of hybrid power projects to combine wind and
solar energy in one site. A larger one with more solar is planned for
Ohio. Invenergy is starting with a 175
megawatt wind farm. Within the wind farm, it plans to build a 150 megawatt
solar farm.
Bloomberg New Energy Finance, which
tracks energy developments, also lists small wind-solar hybrid projects in
Wales and Chile, among other locations.
In several parts of China & India, there are lighting
pylons with combinations of solar panels and wind-turbines at their top. This
allows space already used for lighting to be used more efficiently with two
complementary energy productions units. Most common models use horizontal axis
wind-turbines, but now models are appearing with vertical axis wind-turbines,
using a helicoidal shaped, twisted-Savonius system.
The Pearl River Tower inGuangzhou,
China, will mix solar panel on its windows and several wind turbines at different
stories of its structure, allowing this tower to be energy positive.
The Ministry of New & Renewable Energy in India plans to build
world’s largest solar-wind hybrid project.. The project will have a capacity of 160 megawatts and would be built over a land
area of 1000 acres. The project is expected to entail an investment of
approximately INR 1000 crores ($155 million). The World Bank has agreed to
provide funding for the project. The project is expected to have 120 megawatts
of solar power and 40 megawatts of wind energy capacity installed and will be
equipped with a battery storage system to ensure it remains operational even
during nighttime when there is no sun and decline in wind speed.
Windlab is developing what it says will be the
largest utility-scale clean hybrid power plant. When it becomes operational in
early 2019, the Kennedy Energy Park will comprise 43MW of wind, 15MW of solar
PV and 2MW/4MWh of battery storage. All the components — solar, wind, battery
and synchronous generation — are integrated and sitting behind the connection
point. To the utility, Ergon Energy, they all look like a single generator.
When Windlab started work on the project four years ago, it set out to see how
high penetrations of renewable-power generation could be integrated into the
grid.
In North Queensland the solar resource is
excellent and the wind resource is good in parts, with a capacity factor of
about 45%. They are also complementary in some areas. Typically, later in the
afternoon, as the sun starts setting, at around 4-5pm the wind starts up and
blows until around 9am the following morning
The plant is sited in a fairly remote location,
connected to a 66KV cable, with a 50MW capacity. An existing standalone 18MW
solar PV plant is already connected. Adding 58MW of wind and solar capacity
would have far exceeded the cable’s capacity, resulting in curtailment,
especially on occasions when Kennedy’s wind and solar output are both high.
Wind,
solar sites in Pakistan
In
Pakistani wind sites and new technologies, the capacity factor of 45% is
becoming possible, giving even better opportunities. Hybrid power plants should
have a lower capital expenditure per megawatt as well as lower production cost.
Hybridisation will be possible in Sindh
(Jhimpir and Gharo) and in Baluchistan. Western Baluchistan has many sites
where hybridisation is possible due to availability of both wind and solar
resources of high quality. Sindh government has announced a 2x 50 MW hybrid
wind solar farm at Jhimpir
In
the context of Gwadar, this hybridisation possibility may be of special
importance. Gwadar today suffers from both lack of water and energy. At
present, a coal power plant of 300MW is proposed to be installed.
Hybrid
may also be promoted at kilowatt level in schools, hospitals and other institutional
buildings in wind power corridors like Hyderabad and around in Sindh and
western Balochistan like Turbat etc.
Ten-to-twenty-kilowatt
facilities can be installed at such locations in combination with roof and
ground space and its main advantage is almost round-the-clock availability in
half part of the year
Policy - NEPRA
The
Alternative Energy Development Board (AEDB) in consultation with the National
Electric Power Regulatory Authority (NEPRA) and other stakeholders need to
announce a policy .. Also under
deliberation is the reverse auction of the projects that has been instrumental
in bringing down solar and wind tariff in India and elsewhere. The previous
government failed to address this issue the new administration will have to tackle
these issues, the issue is that AEDB has failed to produce documents needed to
carry out competitive bidding.
India
has released a policy in this respect recently and a captive hybrid project has
been commissioned there. In Pakistan also, several investors are examining the
feasibility of this useful mode of power generation. AEDB has already issued 8 licences of solar / hybrid in jJhimpir wind corridor only the tariff mechanism needs to be defined.
System Costs
The Australian
government estimated in a 2016 report that integrating solar and wind energy would cut costs by 3
to 13 percent.
Other options
The likely next step for
wind-solar hybrids in the broader market is that developers will begin to
consider adding wind or solar to existing renewable energy sites Energy storage
is also likely to become a key part of the mix as renewable energy projects
increasingly operate like traditional power plants.
ReplyDeleteG. Murtaza Uqaili •
2nd
Co-Founder and Chief Executive Officer Indus Clean Energy
please update that AEDB has already issued 8 licences of solar / hybrid in jhimpir wind corridor only the tariff mechanism needs to be defined. huge potential of solar hybrid is available only in jhimpir region, you are right Baluchistan is also a region but due to lack of transmission infrastructures it will takes time in both regions Sindh and Baluchistan
ReplyDeleteSohaib R. Malik •
2nd degree connection
2nd
Energy Transition | Strategic Market Analysis
Good analysis, Javed Sb. Let’s hope the gov’t realises the potential you’ve highlighted here soon.