Sustainable Energy and SDG7 – Comprehensive Notes
Course overview and lecture structure
Speaker: Dr. Marcello Solomon, a highly experienced research associate in the School of Chemical and Biomolecular Engineering, will lead the first half of the online prerecord series.
Research focus: Dr. Solomon's work is centered on the development of new materials for direct air capture (DAC) technologies, which are crucial for the net zero transition, as well as exploring leadership attributes essential for achieving a net zero society and the ambitious 2050 targets. This emphasizes the interdisciplinary nature of sustainability.
Online prerecord series: The initial half of the semester's online content will be delivered by Dr. Solomon, providing foundational knowledge. The second half will be presented by Diana, ensuring a comprehensive coverage of topics.
Purpose of prerecords: These online modules are designed to prepare students by fostering critical thinking about sustainability, specifically in relation to the evolving role of engineers in society, highlighting their responsibility in addressing global challenges.
In-person lectures: Complementing the online content, these lectures will delve deeper into engineering concepts, applying them within a practical framing framework that solidifies the theoretical knowledge gained from the prerecord series.
Main aim: The overarching goal is to equip students with a robust understanding of the economic, environmental, and social pillars that underpin sustainability within society, emphasizing their interconnectedness.
Scope: The course will cover the current global and Australian landscape of sustainability, focusing on practical environmental implementation across key sectors: sustainable practices in energy generation, water management, waste management, and the design of the built environment. This broad scope ensures a holistic view of an engineer's role.
Assessment structure for online series: To ensure engagement and comprehension, there will be quizzes every two weeks, directly based on the prerecord content. A total of four quizzes will account for of the final mark, providing regular assessment opportunities.
Final exam: The comprehensive final exam will include a multiple-choice questions (MCQ) section. These questions will draw from both the online prerecords and fundamental engineering principles discussed throughout the course, testing both theoretical and applied knowledge.
Educational goal: The primary educational objective is to motivate students to understand why sustainability is not just relevant but essential for engineers, equipping them with the necessary tools for applying sustainability principles in complex calculations and the design phases of large-scale engineering projects.
SDG seven (Affordable and Clean Energy)
Focus: This section specifically addresses sustainable energy challenges and opportunities within both global and Australian contexts, aligning with the United Nations Sustainable Development Goals.
SDG seven targets discussed:
7.1 Universal access to affordable, reliable, modern energy services by 2030: This target aims to ensure that everyone, especially in developing regions, has access to basic energy needs, moving beyond traditional biomass fuels to cleaner, more efficient sources.
7.2 Substantially increase the share of renewable energy in the global energy mix (2030 context): This goal stresses the urgent need for a significant shift towards renewable sources like solar, wind, hydro, and geothermal, reducing reliance on fossil fuels.
7.3 Doubling the global rate of improvement in energy efficiency: This target emphasizes the importance of using less energy to achieve the same or better outcomes, through technological advancements and behavioral changes across all sectors (industrial, residential, transport).
7.a Increase international cooperation to facilitate access to clean energy research and technology: This highlights the need for collaborative efforts among nations, facilitating knowledge transfer, and ensuring that cutting-edge clean energy technologies, including renewable energy and energy efficiency, are accessible to all, particularly developing countries.
7.b Expand infrastructure and upgrade technology for developing countries to meet their needs for sustainable energy: This target focuses on strengthening the foundational energy systems in developing nations, empowering them to build resilient and sustainable energy infrastructures.
Indicators accompany targets: Each target is supported by specific metrics or indicators (e.g., the proportion of the population with access to electricity for 7.1; the percentage of renewable energy in gross final energy consumption for 7.2; energy intensity of GDP for 7.3). These indicators are crucial for quantitatively measuring progress and accountability.
How indicators and targets interact: The targets provide a clear policy and strategic framework, outlining the desired outcomes for sustainable energy. The indicators then serve as quantitative tools, allowing for the tracking and evaluation of actual progress toward these ambitious targets over time, ensuring data-driven decision-making.
Australia in the global energy landscape
Australia is resource-rich: The nation possesses a robust mining sector and significant reserves of traditional fossil fuels such as coal, oil, and natural gas. Simultaneously, it holds immense potential for renewable energy, particularly abundant solar and wind resources across vast land areas.
Strategy discussed: Australia aims to leverage its natural advantages to become an energy “superpower” by 2050. This strategy envisions a future where Australia becomes a major exporter of clean energy and green products, aligning its economic development with global net zero goals.
Australia participates in international finance programs related to SDG 7; deepening regional cooperation (Southeast Asia, broader Asia-Pacific): The country is actively involved in multilateral initiatives to facilitate clean energy transitions, supporting regional energy security and sustainability through financial mechanisms and collaborative projects aimed at mutual benefit.
Energy production vs. consumption in Australia:
Major energy production has historically been dominated by coal and natural gas, destined largely for export markets.
A substantial portion of Australia's total energy production (estimates vary, but often or more) is exported, making it a key global energy supplier. Domestic consumption, while significant, represents a smaller share of the overall energy produced.
Major domestic energy use by sector: Transport (including heavy haulage for mining), industry (e.g., mineral processing, manufacturing), and the built environment (residential and commercial buildings) are the primary drivers of domestic energy demand, each presenting unique challenges for decarbonization.
Transformation losses and energy flow considerations are highlighted for future discussion (to be covered in in-person lectures): This pertains to the inefficiencies and energy losses that occur during the conversion, transmission, and use of energy from its primary source to its final application. Understanding these losses is critical for optimizing energy systems and achieving greater efficiency.
Energy generation versus electricity generation; sectoral demand
Distinction: Energy generation is a comprehensive concept encompassing all forms of energy harvested (e.g., from fossil fuels, renewables, heat for industrial processes). Electricity generation is a specific subset, referring only to the production of electrical power, which is then used across various sectors. Not all energy generated is converted into electricity.
Major sectors driving energy demand in Australia: The transport sector (including extensive mining-related transport like rail and shipping) accounts for a large share; the industrial sector (e.g., smelting, refining, manufacturing) requires significant process heat and power; and the built environment (residential and commercial buildings) consumes energy for heating, cooling, lighting, and appliances.
Electric vehicles (EVs) uptake in mining and transport is still emerging, particularly for heavy-duty applications, representing a significant future decarbonization opportunity. Meanwhile, electricity already dominates building energy use for powering appliances, lighting, and HVAC, although the thermal energy in buildings often still relies on gas.
Materials and energy flows: The extraction, refining, transport, and export of minerals and alloys are highly energy-intensive processes. Concurrently, substantial energy is allocated to meet the diverse needs of the population, spanning residential consumption, commercial operations, and service industries, highlighting complex interdependencies.
Importance of efficiency improvements to reduce energy demand while maintaining economic activity: Enhancing energy efficiency across all sectors, from industrial processes to household appliances, is crucial. It allows for sustained economic output and improved quality of life with a reduced energy footprint, alleviating pressure on energy supply and infrastructure.
Energy mix and policy context in Australia
Coal and natural gas remain dominant in energy production, with a substantial portion of this production designated for export, reinforcing Australia's role as a major energy exporter. Domestically, they still contribute significantly to the energy mix.
Coal generation assets are aging; by , two-thirds of Australia's coal capacity, comprising approximately of power generation, may reach its end-of-life. This necessitates a rapid transition to new energy sources to maintain grid stability and meet demand.
Renewables are needed to replace of capacity: This figure underscores the massive scale of renewable energy deployment required to cover the shortfall from retiring coal plants, highlighting an urgent imperative for investment and infrastructure development.
Policy signals show a strong trend toward renewables, with various government initiatives, subsidies, and regulatory frameworks designed to accelerate their uptake. A decline in coal and gas production is beginning in some sectors, influenced by both policy and market forces.
Electricity generation mix (illustrative, 2021): In 2021, coal accounted for approximately of Australia's electricity generation. This emphasizes the significant challenge of reducing this share as Australia strives to meet its net zero goals and transition to a cleaner grid.
Growth trends: Solar and wind generation are increasing rapidly due to declining costs and supportive policies. This expansion in the electricity sector is a key component of the broader energy system transformation, paving the way for decarbonization.
Energy cost context: Energy-related expenditure is a significant component of the Australian economy. A figure cited, such as (in units related to petajoules consumption’s impact on GDP), contextually links energy use to economic performance, indicating the substantial financial flows associated with energy.
Energy flows: A large portion of the energy produced in Australia is exported, meaning energy input and domestic pricing are heavily tied to international demand and global energy price dynamics, exposing Australia to global market volatility.
Overall direction: Australia is moving towards diversifying its energy mix away from fossil fuels, significantly reducing emissions, and simultaneously maintaining energy security and export competitiveness in a rapidly changing global energy landscape.
Fossil fuels and renewables: dynamics and evolution
Fossil fuel energy flows show that oil and coal are plateauing or declining in their relative share of the global energy mix due to environmental concerns and the rising competitiveness of renewables. Natural gas, often considered a “transition fuel,” maintains a role for its flexibility and lower emissions compared to coal.
Renewables rise in the global energy mix: Solar, wind, and other renewable energy sources are experiencing rapid growth, increasing their share due to technological advancements, cost reductions, and increasing policy support for decarbonization efforts worldwide.
Nuclear energy discussed as a potential part of the mix, but with safety, waste, and policy considerations: While a low-carbon energy source, nuclear power faces significant challenges related to public perception, the safe disposal of radioactive waste, and complex regulatory hurdles.
Nuclear specifics highlighted:
Fission basics: Nuclear fission typically involves the splitting of heavy atomic nuclei, such as uranium-235, when struck by neutrons. This process releases a tremendous amount of heat, radiation, and additional neutrons, leading to a chain reaction. Controlled neutron economy is vital for safely managing the reactor and preventing runaway reactions.
Waste considerations: High-level radioactive waste, a byproduct of nuclear fission, remains dangerously radioactive for thousands to hundreds of thousands of years due to its long half-lives. Its permanent storage and end-of-life management (e.g., deep geological repositories) present one of the most significant and unresolved barriers to broader nuclear adoption.
Global trends: Some countries, like China, Russia, and South Korea, are actively expanding their nuclear energy programs to meet growing energy demand and reduce reliance on fossil fuels. Conversely, others, such as Japan (post-Fukushima) and several European countries (e.g., Germany, Belgium), are reducing or phasing out their nuclear capacity due to safety concerns and public opposition.
Australian context: Australia possesses some of the world's largest and most accessible uranium reserves, making it a significant global supplier. However, its future role in domestic energy generation is TBD, pending major policy decisions, infrastructure development, and public acceptance.
Comparison with renewables: On a per-MWh basis, solar and wind generally offer lower lifecycle costs and significantly fewer long-term waste considerations compared to traditional nuclear power. While Small Modular Reactors (SMRs) are proposed to address some cost and safety issues, their viability and public acceptance remain subjects of ongoing debate.
The lecture emphasizes policy-driven, technology-driven, and governance factors in shaping future energy mixes: This highlights that the trajectory of energy transitions is not solely a technical challenge but also heavily influenced by government regulations, technological innovation, and robust governance frameworks that balance economic, social, and environmental objectives.
Energy system considerations: intermittency, storage, and integration
Renewables (solar and wind) are intermittent: Their generation depends on variable natural phenomena—sunlight for solar and wind for turbines. This inherent variability poses a significant challenge to grid stability and reliable energy supply.
Storage and grid integration are critical: To counter intermittency, large-scale energy storage solutions (e.g., batteries, pumped hydro, hydrogen) and advanced grid infrastructure are essential. Smart grids are needed to manage fluctuations, balance supply and demand, and ensure reliable power delivery.
Storage technologies discussed include large-scale batteries (e.g., in South Australia and New South Wales): These grid-scale battery systems, primarily lithium-ion, are deployed to store excess renewable energy during periods of high generation and release it when demand is high or generation is low, providing stability and ancillary services to the grid.
Storage challenges: Li-ion battery capacity limitations, reliance on critical mineral supply chains (e.g., lithium, cobalt, nickel), high initial costs, complex lifecycle management, and end-of-life recycling issues are key hurdles to widespread deployment at the necessary scale.
Solar thermal with molten salt storage as an approach to address intermittency: This technology captures solar energy as heat, which is then stored in molten salt tanks. This stored heat can later be used to generate steam for electricity, allowing power generation even after sunset or during cloudy periods, significantly improving dispatchability.
Parabolic trough solar collectors and solar thermal plants: These Concentrating Solar Power (CSP) systems use large, curved mirrors (parabolic troughs) to focus sunlight onto a receiver tube containing heat transfer fluid (e.g., synthetic oil or molten salt). The heated fluid then generates steam to drive turbines, creating electricity, making CSP a significant utility-scale renewable option.
Conceptual overview of heat-to-steam-to-turbine cycles: This fundamental thermodynamic cycle, common in thermal power plants (fossil, nuclear, solar thermal), involves heating a working fluid (like water) to produce high-pressure steam. The steam then expands through a turbine, rotating it to generate electricity, before being condensed and returned to be reheated. Cycle efficiency is paramount.
Thermal energy storage and heat capacity considerations: Materials used for thermal energy storage (e.g., molten salts, concrete, ceramics) must possess a high specific heat capacity, allowing them to absorb and retain large amounts of heat at high temperatures. This ensures longer discharge durations and higher efficiency during sunless periods.
Solar thermal advantages: Potential for high-temperature heat enables efficient thermodynamic cycles, leading to higher power output and better conversion efficiency. It is also compatible with various energy sources (e.g., solar, nuclear, waste heat), allowing for hybridization and more diverse energy portfolios, and it can provide dispatchable power.
Practical considerations: Deploying large-scale solar thermal plants requires substantial land use, which can lead to competition with biodiversity, agriculture, or existing land uses. Optimizing the balance between energy efficiency, power output, and land footprint is a critical engineering challenge.
Solar energy in Australia: potential, challenges, and applications
Solar density is highest near the equator; Australia’s northwest has high solar irradiance and large land areas suitable for solar farms with relatively low population density: This makes Australia geographically advantaged for large-scale solar project development due to intense solar radiation and available space, especially in regions like the Pilbara.
Regional opportunities: Siting large solar installations near mining regions with existing grid infrastructure and open spaces can minimize transmission losses, as energy can be consumed locally by energy-intensive industries, reducing the need for extensive new long-distance transmission lines.
Solar capacity growth drivers: Continuous improvements in photovoltaic (PV) efficiency (how effectively solar cells convert sunlight into electricity), advances in solar cell materials (e.g., perovskites, thin-film technologies), and the increasing availability and refining capacity of critical minerals (e.g., silicon, silver, copper) essential for PV manufacturing.
China’s leadership in PV manufacturing since : China has become the dominant global manufacturer of solar PV cells and modules, driving down costs and accelerating worldwide adoption. Other players like Japan and Germany, facing space limitations, have focused on efficiency improvements and niche applications.
Rooftop solar incentives in Australia: Government buy-back schemes and feed-in tariffs encourage homeowners and businesses to install rooftop PV systems. These incentives reduce grid dependency, lead to lower electricity bills, and significantly boost distributed generation, making individuals prosumers.
Rooftop solar uptake potential: With supportive policies, up to 30% or more of Australian households could integrate rooftop PV. This distributed capacity potentially contributes a significant portion, perhaps 10% or more, of total electricity generation. Current rooftop PV capacity is growing, but still represents only a fraction (around ) of its full potential capacity.
Large-scale solar farms: Proposals exist for massive solar projects, some envisioned to cover areas the size of Tasmania, designed to supply major cities or industrial needs. Challenges include substantial grid interconnection costs, land acquisition, and complex transmission planning to deliver power efficiently over long distances.
Storage implications for solar: The inherent intermittency of solar generation necessitates large-scale energy storage solutions (e.g., batteries, pumped hydro, hydrogen) to address daily and seasonal variations. Active research in improving critical minerals (like lithium, cobalt, nickel) for storage materials is crucial to support next-generation technologies.
Solar thermal potential: Heating liquids (e.g., molten salts) to generate steam for power cycles allows for thermal energy storage, extending generation into non-sun periods. This leverages the high heat capacity of materials and the ability to operate at high temperatures for efficient power generation.
Practical examples: Spain hosts several large-scale solar thermal plants, such as Gemasolar, which utilize salt-based storage to provide dispatchable power. These examples highlight the engineering challenges and success of integrating high heat capacity materials and managing material stability at elevated temperatures.
Rooftop PV economics: The capital costs of installing rooftop PV systems, their payback periods (how long it takes for energy savings to offset initial costs), and the availability of policy incentives (like rebates or feed-in tariffs) significantly influence adoption rates and enable greater energy independence for consumers.
Solar energy advantages: Solar power systems can directly convert diffuse sunlight into usable energy, making it a decentralized energy source. It can be integrated with existing steam-based power cycles (e.g., via solar thermal) and hybridized with other energy sources (e.g., fossil fuels, biomass, wind) to enhance reliability and diversify the grid.
Wind energy in Australia: potential, challenges, and integration
Wind energy capacity could supply around one-third of Australia’s clean energy, making a substantial contribution to the overall electricity mix and playing a critical role in decarbonization efforts.
Onshore vs offshore wind: Onshore wind farms are typically easier and less expensive to install but face more land-use and aesthetic objections. Offshore wind farms benefit from higher, more consistent wind speeds but require specialized marine construction techniques, larger turbines, and more complex grid connections.
Offshore wind potential: Southern latitudes, particularly those influenced by the strong and consistent 'Roaring Forties' winds (between and south latitude), offer exceptional wind resources and potentially higher average capacity factors for offshore wind projects compared to onshore sites. This vast potential is a key focus for future development.
Wind turbine scale: Modern offshore wind turbines are enormous, with rotor diameters and hub heights that can rival or exceed the height of iconic towers (e.g., compared to the Eiffel Tower at or Sydney Tower at ). These massive structures are designed to capture more energy from higher altitudes.
Installation and regulatory considerations: The development of wind farms, especially offshore, involves complex challenges including stringent safety frameworks, managing public perception (e.g., visual impact, noise), addressing aesthetic concerns, and ensuring robust local community engagement to secure social license to operate.
Longitudinal site studies: Essential for accurately estimating average wind speeds, wind distribution patterns (e.g., Weibull distribution), and expected energy generation over the project lifespan. Long-term wind data collection helps in precise capacity factor calculations and financial modeling.
Capacity factor and Betz limit: Current wind capacity factors typically range around to , meaning they produce power for that percentage of their maximum theoretical output over a year. The Betz limit (approximately ) will be discussed in in-person lectures as the fundamental theoretical ceiling for the efficiency of converting wind kinetic energy into mechanical energy by a rotor.
Operational and economic considerations: This includes high capital costs for initial construction, ongoing lifecycle costs (maintenance, repair, and operational expenses over the design life of the turbine), and eventually end-of-life recycling. However, significant reductions in levelized cost of energy (LCOE) are observed as technology matures and economies of scale are achieved.
End-of-life and recycling: Wind turbine blades, made of composite materials (fiberglass, carbon fiber, resins), pose significant recycling challenges due to their complex structure and large size. Similar to solar panels, addressing the end-of-life management and circularity of these materials is a key environmental responsibility for engineers.
Transmission and grid integration: Australia's best wind resources are often located in remote areas, far from major demand centers. This necessitates substantial grid upgrades, including new high-voltage transmission lines, and the implementation of demand-side management strategies to accommodate the variability of wind power and integrate it effectively into the national electricity market.
Nuclear power: safety, waste, and policy considerations
Nuclear energy is discussed as a potential part of the future energy mix, but its adoption comes with notable caveats and significant considerations.
Safety and regulatory concerns: The history of major accidents, such as Chernobyl (1986) and Fukushima Daiichi (2011), has profoundly shaped public perception and led to stringent international safety standards and complex regulatory frameworks globally. These events highlight the need for robust safety measures.
Waste management: High-level radioactive waste, a highly hazardous byproduct of nuclear fission, contains isotopes with incredibly long half-lives (e.g., plutonium-239 has a half-life of ). This necessitates secure, long-term storage and disposal solutions, often involving deep geological repositories, which remain a globally unresolved challenge.
Availability and policy: Australia possesses significant uranium resources, making it a major global supplier. However, the future role of nuclear power in Australia's domestic energy mix heavily depends on achieving public acceptance, developing appropriate regulatory frameworks, and making substantial investments in new infrastructure.
Comparative economics: For large-scale deployments, solar and wind generally demonstrate lower levelized costs of electricity (LCOE) compared to conventional large-scale nuclear power plants. While Small Modular Reactors (SMRs) are intended to offer better economics, their cost competitiveness against increasingly cheap renewables is still debated.
Small modular reactors (SMRs) and modular approaches are discussed as a potential alternative to traditional large-scale nuclear plants. SMRs aim to offer different risk/cost profiles, potentially being safer, quicker to deploy, and more flexible in terms of siting. However, their commercial viability, scalability, and public acceptance are still subjects of intense debate.
Global patterns: Countries like China, Russia, and South Korea are pursuing expansion of their nuclear programs, viewing it as a reliable, dispatchable, low-carbon power source. Conversely, countries like Japan (in the wake of Fukushima) and several European nations (e.g., Germany) are reducing or actively reevaluating their nuclear programs due to safety concerns and political decisions.
Net effect on emissions: While nuclear power produces very low operational CO2 emissions per unit of energy generated, its lifecycle emissions include energy-intensive processes such as uranium mining, milling, enrichment, fuel fabrication, and significant energy demands for plant construction. Decommissioning and long-term waste handling also add to the overall lifecycle carbon footprint.
Australia’s decision context: Any future role for nuclear power in Australia will largely be shaped by a combination of factors: public safety concerns, the feasibility and cost of long-term waste management, the degree of public acceptance, and the overarching policy choices made by the government regarding the national energy strategy.
Net-zero targets, critical materials, and just transition
Net-zero 2050 targets framed as a coordinated national effort across multiple sectors: Achieving net-zero emissions by 2050 requires a comprehensive, economy-wide transformation, encompassing energy, industry, transport, agriculture, and land use, necessitating unprecedented coordination.
Critical minerals and materials: These are essential for the production of core energy technologies (e.g., rare earth elements for wind turbines, lithium for batteries, silicon for photovoltaics, catalysts for hydrogen production). Onshoring processing and refining of these minerals is a strategic question for supply chain security and economic value.
Hydrogen and synthetic fuels: Development of low- or zero-emission fuels, such as green hydrogen (produced via electrolysis using renewable electricity) and synthetic fuels derived from captured CO2, is crucial for decarbonizing hard-to-abate sectors like heavy transport, industry, and aviation. The exploration focuses on fuels with significantly lower CO2 footprints.
Carbon removal and CO2 feedstocks: This involves technologies that actively remove CO2 from the atmosphere (e.g., direct air capture, bioenergy with carbon capture and storage). Additionally, research explores the potential to repurpose captured CO2 as a feedstock for producing fuels or chemicals, creating a circular carbon economy. Evaluating life-cycle impacts and scalability is key.
Transition challenges: A just transition is paramount, requiring active involvement and equitable consideration of diverse stakeholders to ensure the benefits and burdens of the energy transition are fairly distributed.
Land-use and consent considerations with First Nations communities in mining regions: Large-scale renewable projects, grid infrastructure, and critical mineral mining often impact Indigenous lands. Gaining free, prior, and informed consent and ensuring fair benefit-sharing with First Nations communities are crucial for social justice and project success.
Regional community impacts and benefits; ensuring fair distribution of economic gains: The shift from fossil fuel industries to renewables will affect regional economies and employment. Strategies are needed to retrain workers, diversify local economies, and ensure that new sustainable industries provide tangible economic gains and new job opportunities for affected communities.
Youth engagement and leadership development for the next 5–10 years: Empowering and involving young people in the transition is vital, as they will inherit and manage the net-zero economy. This includes education, skill development, and fostering leadership in climate action and sustainable innovation.
Equity and inclusion across stakeholders to ensure broad-based support: Ensuring that policies and initiatives for the energy transition are equitable and inclusive of all societal groups—including vulnerable populations, workers, and businesses—is essential to build broad-based support and prevent social division.
Governance and policy integration: Achieving net-zero targets demands cross-sector coordination, extending beyond mere technological deployment to integrate social, economic, and environmental dimensions into all policy-making processes, ensuring a coherent and holistic approach.
Overall sustainability framing: The overarching goal is to achieve an energy system that robustly supports human development (social well-being, economic prosperity, environmental health) while giving full consideration to long-term ecological balance and intergenerational equity, creating a truly sustainable future.
Challenges in moving toward sustainable energy
Economic and technological challenges of new energy technologies:
Early-stage cost penalties due to capital intensity and immature efficiencies: Many nascent sustainable energy technologies, such as advanced hydrogen production or direct air capture (DAC), often require high upfront capital investment and may initially exhibit lower efficiencies compared to mature fossil fuel technologies. For example, direct air capture materials currently achieve CO2 capture efficiency, whereas solar PV panel efficiencies have dramatically improved from historical levels of to around today. These efficiency gaps typically narrow as technologies mature and benefit from economies of scale and R&D.
Intermittency of solar and wind leading to demand for storage, grid flexibility, and backup generation: The variable nature of renewable energy sources necessitates significant investment in energy storage solutions, smart grid technologies to manage fluctuations, and, in some cases, traditional backup power generation to ensure grid stability and reliability.
Intermittency management strategies:
Energy storage technologies and materials research (critical minerals) to improve storage capacity and reduce lost energy during non-generation periods: This includes research into advanced battery chemistries (e.g., sodium-ion, solid-state), flow batteries, and other forms of energy storage (e.g., hydrogen, pumped hydro) to increase storage duration and reduce curtailed renewable energy.
Solar thermal storage as a method to store heat and generate steam when sunlight is unavailable: Concentrating solar power (CSP) systems with molten salt storage can provide dispatchable power by releasing stored thermal energy to generate electricity even hours after the sun has set.
Hybridization of energy sources to smooth supply (e.g., Solar + Wind + Hydro + Nuclear) where appropriate: Combining different renewable and dispatchable energy sources can create a more stable and reliable electricity supply. For example, coupling solar with wind (which often have complementary generation profiles) or integrating dispatchable hydro or, potentially, nuclear power.
Environmental and land-use considerations:
Land footprint for solar farms and wind farms; balancing biodiversity, agriculture, and energy production: Large-scale renewable energy installations require significant land area, leading to potential conflicts with agricultural land, natural habitats, and local ecosystems. Careful planning is needed to minimize environmental impact.
Environmental impact assessments and community engagement in siting decisions: Thorough environmental impact assessments are crucial to identify and mitigate potential negative effects. Effective community engagement ensures local populations are informed, their concerns are addressed, and they have a voice in the decision-making process for new projects.
Technology development and deployment timelines:
Some technologies may not yet be fully developed or commercially available at scale: While promising, many emerging clean energy technologies (e.g., advanced DAC, green hydrogen production at scale, next-generation SMRs) are still in research, pilot, or early commercialization phases and require more time and investment to reach widespread commercial viability.
Need for continued R&D and pilot projects to scale up energy technologies while reducing costs: Ongoing research and development are essential to improve efficiency, reduce costs, and address technical barriers. Pilot projects help de-risk new technologies, demonstrating their viability at a larger scale before full commercial deployment.
Global equity and the just transition:
Ensuring developing countries have access to clean energy technologies and infrastructure: This involves addressing the technology gap and financial barriers that prevent developing nations from adopting sustainable energy solutions, ensuring climate justice.
Addressing financing barriers and ensuring affordable access to sustainable energy worldwide: Mobilizing sufficient capital for clean energy projects in developing economies and ensuring that the transition does not exacerbate energy poverty or create new inequalities are critical aspects of a just global transition.
Sustainable energy system design challenges:
Balancing extraction of critical minerals with environmental protection and social licensing: The increased demand for critical minerals required for clean energy technologies raises concerns about the environmental impact of mining and the social implications for local communities. Responsible sourcing practices are essential.
Evaluating trade-offs between short-term costs and long-term environmental and societal benefits: Decision-makers must weigh the immediate economic costs of transitioning to sustainable energy against the substantial long-term benefits in terms of climate change mitigation, public health improvements, and economic stability.
Practical and educational implications
Contextual reasoning for energy balances and thermodynamics will be revisited in in-person lectures (the upcoming Monday session): This indicates that the theoretical underpinnings of energy systems, including the First and Second Laws of Thermodynamics, will be applied to real-world energy scenarios.
Future topics to cover include: detailed energy and power calculations (e.g., power output of wind turbines, energy potential of solar farms), energy densities of various fuels (comparing calorific values of fossil fuels vs. hydrogen), siting decisions for solar and wind projects (considering resource availability, land use, grid access), and a comprehensive comparison of different energy generation options using thermodynamic principles and life-cycle assessments.
Preview of next topics: A deeper dive into fundamental energy balance equations, core thermodynamics principles (e.g., entropy, efficiency limits), and calculation-based approaches specifically tailored for analyzing and designing solar and wind energy deployments.
Quick reference: key figures and numbers cited
Net-zero target year: (Australia's commitment for economy-wide decarbonization)
SDG 7 targets and related year contexts: 2030 timeframes for achieving universal energy access (7.1), substantially increasing renewable energy share (7.2), and doubling the global rate of improvement in energy efficiency (7.3).
Installed capacity reference: Estimated replacement need of of coal capacity by 2032 as aging plants retire.
Coal electricity share (2021): Approximately of Australia's total electricity generation in 2021, highlighting its dominant past role.
Solar PV efficiency benchmarks: Current commercial PV efficiencies around ; historical efficiencies were significantly lower, around in earlier stages of development.
Energy cost proxy cited: (unit context: a figure representing the economic impact or expenditure related to Australia's petajoules energy consumption, illustrating the significant energy-economy linkage).
Intermittency/modes of operation: Solar generation varies daily (daytime only); wind varies unpredictably. This necessitates substantial storage, grid flexibility, and backup generation during non-generation periods.
Capacity factors for wind (approximate): Typically around to for operational wind farms, varying by site and turbine type.
Offshore vs onshore wind considerations: Offshore turbines are generally larger, benefit from stronger winds, and often have higher capacity factors but come with greater installation challenges and costs compared to onshore.
Nuclear waste and life-cycle considerations: High-level radioactive waste has extremely long half-lives (thousands to hundreds of thousands of years), requiring complex and perpetual end-of-life planning and secure disposal.
Summary takeaway
Australia’s energy system stands at a pivotal crossroads, balancing its rich traditional energy resources (coal, gas, uranium) with its immense renewable potential (solar, wind) and ambitious net-zero targets. The national strategic plan prioritizes a diversified energy mix, emphasizing substantial investment in renewable energy sources. This transition mandates thoughtful consideration of crucial supporting elements like advanced energy storage solutions, robust grid integration, and comprehensive social governance to achieve sustainable energy. The ultimate goal is to foster economic growth while ensuring equitable development. The lecture frames sustainability as a foundational backdrop for all engineering practice, with SDG 7 serving as a guiding principle for energy policy and technology development. It also transparently acknowledges the practical challenges inherent in this transformation, including energy intermittency, economic costs, potential environmental impacts, and the overriding imperative for a just transition that involves and benefits all stakeholders.