Sustainable development

What is sustainable development ?

development that meets the needs of the present without compromising the ability of future generations to meet their own needs

3 pillars:

society

economy

environment

Why is it so difficult to achieve sustainable development ?

Jevons Paradox

Population growth

What is the Jevons paradox

Increased efficiency in the use of a resource can lead to increased consumption of that resource, offsetting or even exceeding the expected savings.

Why is population growth a challenge for sustainable development?

A growing population increases demand for food, water, energy and shelter, putting greater pressure on resources and the environment.

Why is population growth generally higher in less economically developed countries?

Lower access to education, healthcare and contraception contributes to higher birth rates and faster population growth.

What are some environmental issues ?

climate change

ozone layer depletion

acid rain

loss of biodiversity

summer and winter smogs

eutrophication

human and eco-toxicity

resource depletion

What are the main causes for loss of biodiversity ?

Habitat destruction/degradation

hunting

ocean acidification

competition for resources

causing extinction rates far above natural background levels

What is resource depletion ?

The consumption of natural resources faster than they can be replenished, including water, land, fossil fuels, minerals and metals.

What are the main social and economic sustainability issues?

Unequal global wealth distribution, poverty and unsustainable levels of debt

What does life cycle thinking consider when meeting consumer needs?

It considers the resources, environmental impacts, economic costs and benefits, and social impacts and benefits across a product’s whole life cycle.

Food life style thinking

What does the carbon footprint of tomatoes demonstrate?

The same food can have a very different carbon footprint depending on where and how it is produced; UK tomatoes have a much higher GWP than Spanish tomatoes

Transport life style thinking

What does comparing the carbon footprints of different fuels show?

Carbon footprint depends on the fuel and how it is produced; some biofuels have lower emissions than petrol, while others can be higher

What are our energy supply options ?

Fossil fuels

Renewables

Nuclear

Hydrogen

What are the sustainability issues associated with fossil fuels?

• Sufficient to meet energy demand this century

• Climate change implications make them an unsustainable option

• Carbon capture and storage: reduces efficiency and can leak

• Efficiency improvements: crucial, but still reliant on fossil fuels

What are the sustainability issues associated with renewables?

• High costs

• Often high resource depletion

• Social issues

What are the sustainability issues associated with nuclear?

• High risks

• Socially unacceptable

What are the sustainability issues associated with hydrogen?

• Not a source! Not sustainable if from fossil-based resources

• Consumer resistance - explosive

The ultimate solution to improve our efficiency with energy use is

to reduce our demand

Energy life cycle thinking

Direct emissions vs life cycle emissions

Life cycle emissions are higher than direct emissions because they include the entire life cycle (e.g. extraction, construction and decommissioning)

Water life cycle thinking

What are the solutions to water sustainability issues?

• Provision of water to developing countries.

• Increased efficiency of use – e.g. using grey water for toilets or gardens.

• Reducing demand – changes in consumer behaviour.

• New water sources – e.g. seawater desalination.

Housing life style thinking

What are the sustainability issues associated with housing?

Energy use in buildings constitutes 30–50% of total energy requirements of a society

Contributes to more CO₂ emissions than traffic or industry.

What are the reasons for sustainability issues related to housing ?

• Poor insulation and inefficient combustion systems.

• Relatively cheap fuels and excessive use of energy.

What are the sustainability benefits of eco-houses?

• Reduced use of energy.

• Reduction of CO₂ emissions.

• Reduced water use.

• Savings on bills.

• Healthy and pleasant to live in.

Why is sustainable development important for chemical engineers ?

What is a Life Cycle Assessment (LCA)?

An environmental sustainability tool that applies life cycle thinking to assess environmental consequences of human activities

What does Life Cycle Assessment (LCA) involve?

• Quantification of environmental burdens of a product, process or activity

• Quantification of environmental impacts:.

• Identification of opportunities for environmental improvements along the whole life cycle of a product, process or activity.

What can Life Cycle Assessment (LCA) be used for?

• Assessing environmental sustainability.

• Identifying improvement opportunities.

• Comparing alternatives.

• Sustainable design.

How do you conduct a LCA?

• Goal and scope definition

• Inventory analysis

• Impact assessment

• Interpretation

What is the goal and scope definition stage of LCA?

Defining the goal – Why the LCA is being conducted (e.g. identifying hotspots, improvement opportunities or comparing alternatives).

Defining the scope – Establishing the system boundaries and functional unit.

What is the difference between cradle-to-gate and cradle-to-grave in LCA?

• Cradle-to-gate: Includes raw material extraction, processing and manufacturing, up to the point where the product leaves the factory.

• Cradle-to-grave: Includes the entire life cycle, from raw material extraction through manufacturing, transport and use to recycling or final disposal.

What is cradle-to-cradle in Life Cycle Assessment (LCA)?

Where materials from a product at the end of its life are reused or recycled back into the first processing stage rather than being disposed of as waste.

What is a functional unit in LCA?

defines the function of the system being studied and provides a basis for comparing alternatives on an equivalent basis.

Example: Packaging 1 litre of water using:

• A 600 g glass bottle

• A 35 g PET bottle

What does inventory analysis involve in LCA?

• Flow diagrams.

• Data collection.

• Calculation of environmental burdens:

  • Materials and energy used.

  • Emissions to air, water and solid waste

What are the inputs and outputs of the flow diagram ?

Inputs: materials and energy

Outputs: emissions

What is the equation for total environmental burdens ?

What is impact assessment ?

. Selection of impact categories

. Estimation of impacts

What are some environmental impacts ?

• Resource depletion

• Global warming

• Ozone layer depletion

• Acidification

• Photochemical smog

• Eutrophication

• Ecotoxicity

• Human toxicity

What is characterisation ?

Quantification of potential impacts based on burdens already found

What is the equation for total environmental impact (Total global warming potential) ?

What is global warming potential ?

Can be used to describe the impact category like ‘carbon footprint’ or characterisation factor

What is the definition of global warming potential as a characterisation factor ?

A CO₂-equivalent emission is the amount of carbon dioxide emission that would cause the same integrated radiative forcing, over a given time horizon, as an emitted amount of a GHG or their mixture.

What is normalisation in LCA?

An optional step in impact assessment that involves comparing the environmental impact of a system with the total environmental impact in a certain area over a given period of time.

What is valuation in LCA and what is its equation?

Valuation is an optional step in impact assessment that involves weighting environmental impacts to reflect social values and preferences.

What does interpretation of results involve in LCA?

• Identification of major environmental burdens and impacts.

• Identification of hotspots.

• Evaluation of results.

• Sensitivity analysis.

• Selection of the best alternative.

What are some impact categories ?

Global warming potential/carbon foot print

Acidification

Eutrophication

Human toxicity

Abiotic depletion potential

Ozone layer depletion

Photochemical smog creation

Terrestrial ecotoxicity

Freshwater and marine ecotoxicity

How do emissions lead to environmental impacts in LCA?

Emissions are released into the air, water or land.

They are transported and dispersed through the environment.

Humans and ecosystems are exposed through different pathways

What is the difference between midpoint and endpoint impacts in LCA?

Midpoint impacts: Potential environmental impacts at an intermediate stage of the cause-and-effect chain (e.g. global warming)

Endpoint impacts: Final damage caused to humans and ecosystems (e.g. loss of human life or species extinction)

What is the recipe methodology ?