Renewable Energy Capacity
Renewable energy capacity is the maximum amount of electricity that installations such as wind turbines & solar panels can produce.
New energy commodities such as green hydrogen and green ammonia will be produced by GGE on Boolathana.
The most common green hydrogen production method is through electrolysis where renewable energy is used to split water into hydrogen and oxygen.
A key challenge for green energy projects is reducing power supply variability or intermittence to reduce loss of production potential by the electrolyser.
As an energy carrier and way to transport hydrogen, ammonia is more energy efficient hydrogen.
Ammonia can transport larger amounts of energy over long distances in less space. The GGE Boolathana project plans to export green ammonia to international markets, taking advantage of its coastal location and proximity to Asian nations.
Producing green ammonia (NH3) from green hydrogen is energy intensive and reliant on a consistent power supply.
Capacity refers to the maximum amount of electricity that can be produced under specific conditions.
The size of plant required to produce green energy is determined by the location’s potential renewable energy capacity.
Load is the maximum production potential of the green energy system.
Variability follows the natural output pattern of renewable energy sources, such as the alternation of night and day or seasons.
Intermittence refers to random renewable energy events such as cloud formation or still conditions.
Areas in lower wind resources will be predominantly reliant on high levels of solar energy for green energy production. To mitigate periods where the the sun is unavailable (eg. during the night) larger energy storage systems are necessary. Large scale storage systems are extremely capital intensive, adding significant expenditure to those projects in these locations.
Additional energy storage systems such as battery energy storage system (BESS), are required to capture power spill and as power supply for the plant to draw on to maintain capacity.
Regions like Boolathana, that experience a more balanced mix of wind and solar resources require a lower investment in energy storage systems.
Locations where high wind resources are consistently available (day and night), also like Boolathana, have an advantage over those with less wind, even if favourable solar resources are present.
Maintaining output from the variable, intermittent wind and solar resources to enable a constant supply of energy to the plant is known as firming.
In practice, areas which have the potential for more energy to be captured can justify construction of of a larger plant to facilitate higher output and more efficient production of green energy.
A high load factor implies that the electrical load is consistent and predictable, enabling the plant to operate at optimum capacity.
A low load factor suggests a reduced available energy resource relative to a plant’s installed capacity. In these circumstances a smaller electrolyser is necessary, leading to lower production.
Green energy production requires a balance between ensuring renewable energy and system reliability, maximum output and avoidance of shutdowns and disruptions.
When there is more renewable energy than the system’s demand requires, overcapacity generation must be evacuated at a loss to avoid overloading existing transmission and distribution assets, defined as spill.
When power output is lower than the system’s capacity it is referred to as intermittence
Solar infrastructure is less expensive than its counterpart, wind.
Due to cost, solar firming is preferable for load factor consistency when producing green hydrogen/green ammonia.
Boolathana has a comparative solar capacity factor advantage over many locations because of:
- the abundance of cloud-free days annually and associated low rainfall profile
- more moderate temperatures experienced year-round, due to coastal proximity.
Reduced load factors require larger storage systems. However, areas with higher load factors, like the western areas of the Gascoyne, have reduced intermittency periods as more even wind and solar conditions occur, creating less spill due to favourable climate conditions. The outcome is a more efficient green energy production system as the plant works at optimal capacity.
Load Factor Modelling
Modelling using data from Renewables Ninja was completed for 5* renewable hub regions in Australia over a calendar year with the same production objective as the GGE Boolathana project. The data indicates that higher load factor equates to better energy efficiency and high production yield potential. The Gascoyne region, where the GGE Boolathana project is located has the highest potential related to the most conducive conditions for keeping the load factor consistently high. * Hub 1 & 2 in same geographic area
Capacity factor (CF) is a direct measure of the efficiency of either a wind turbine generator (WTG) at its nominated watt capacity (eg.7.2MW) or a solar panels array (eg. 6GW).
CF is calculated by dividing the installed capacity by the ratio of energy generated over a designated time period.
Australian Wind & Sun
In Australia, onshore wind capacity factor percentages (CF%) vary from below 30% to in excess of 50%.
Daily CF% for solar are lower, ranging from 20% to above 24% for fixed array solar projects. Those using trackers can achieve CF% of above 30%.
Boolathana experiences consistent night winds and has the advantage of being able to continue generating power during times when solar is at 0% CF%.
Regions where a significant amount of wind occurs in the day along with the sun being at full capacity reduces the renewable energy load factor.
As a result, high wind CF% is not always beneficial to a project.
Boolathana’s coastal location has a unique advantage in terms of prevailing winds throughout the year. In combination with the regularity of night winds experienced, the available wind capacity enhances the load factor and makes the load more consistent over a 24 hour period. Therefore, green energy production will be higher on Boolathana compared to other potential regions.
Optimum solar capacity occurs at 10° more or less than 25°C.
Factors that affect solar capacity include:
- Low irradiance
- Excessive cloud experienced in regions with higher rainfall
- Consistent high daily temperatures (higher than 35°C)
Some regions experience prolonged periods of above 40°C which reduces hourly solar capacity. Related issues such as heat shutdown periods and infrastructure depreciation due to heat stress are also common.
While cool climates are beneficial to potential solar production levels, cloud cover interferes with actual power production in these regions.
Bringing it together
In the analysis above, the load factor is the actual kilowatt-hours of power delivered to an electrolysis plant over a 24 hour timeframe, calculated for 1 year per green energy hub.
Get in touch
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