Goldsmiths’ 2013

The Sustainable Energy Quiz

Serena Marshall and Jennifer Crabtree

Both Serena and Jennifer are in the final year of their PhD studies within the centre for sustainable chemical technologies.

Jennifer is working on molecular modelling of CO2 adsorption, separation and sequestration and Serena is working on responsive vesicles in an aqueous cream emulsion for dermatological applications. Serena hopes that her work will allow the dressing on a wound to show the presence of an infection without the dressing having to be removed first.

As part of their course they have carried out many outreach activities and one of them is the sustainable energy quiz.

Sustainable or not?

When you see the term “sustainable development” what do you think of first?


Economy –> Society –> Environment –> Economy etc.

Sustainable development refers to a mode of human development in which resource use aims to meet human needs while ensuring the sustainability of natural systems and the environment, so that these needs can be met not only in the present, but also for generations to come. The term ‘sustainable development’ was used by the Brundtland Commission, which coined what has become the most often-quoted definition of sustainable development: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

In particular the essential needs of the world’s poor and the environment’s ability to meet present and future needs through responsible use of resources.

Our Common Future, Chapter 2: Towards Sustainable Development

Do you think solar energy is sustainable?


In the quiz 75% of us said that solar energy was sustainable. We were simply thinking about the fact that sunlight is free. However it costs money to make the solar cells.

Solar is from the sun. So how long has the sun been around and how long will it be around? The sun has been around for over two billion years and by some estimates will be around for at least the same time. So is solar the energy from the sun sustainable. The short answer is yes. How do we use the energy from the sun and is that sustainable? The answer to that is Yes and No. Yes if we use the abilities of plants to reproduce and convert sunlight into sugars and starches that fuel our bodies then yes it is sustainable. If we talk about using solar cells and other man made solar technology then the answer is No if we keep the present or higher population levels. If we reduce our population, recycle and measure out our meagre resources than yes it could be sustainable.

There are reasons why we can’t sustain the solar tech industry at present levels.


Can you think of anything that is sustainable?


Heavy metals are needed but we don’t have an infinite supply of them. Efficiency can be increased but nothing is 100% efficient. The sunshine may be free but solar panels and photovoltaics cost money to make. Can the cost ever be recouped?

Do we need to expend energy to make solar panels and photovoltaics and will we end up producing yet more carbon dioxide. Do we also need to create devices for absorbing excess carbon dioxide?

The next question was about what we knew the least about out of the following:

1) Green chemistry

2) Carbon capture

3) Climate change

4) Fuels and biofuels

5) Alternatives

I’m afraid I didn’t note down what the overall percentage was but personally I would have to say green chemistry as I have a physics degree.

1) Green chemistry, also called sustainable chemistry, is a philosophy of chemical research and engineering that encourages the design of products and processes that minimize the use and generation of hazardous substances. It seeks to reduce and prevent pollution at its source. It applies to organic chemistry, inorganic chemistry, biochemistry, analytical chemistry, and even physical chemistry. While it seems to focus on industrial applications, it does apply to any chemistry choice.

In 2005 Ryōji Noyori identified three key developments in green chemistry.


3 September 1938

2) Carbon capture and storage (CCS) (or carbon capture and sequestration), is the process of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation. The aim is to prevent the release of large quantities of CO2 into the atmosphere (from fossil fuel use in power generation and other industries).

3) Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years.

Global warming is the rise in the average temperature of Earth’s atmosphere and oceans since the late 19th century and its projected continuation.


Two millennia of mean surface temperatures according to different reconstructions from climate proxies, each smoothed on a decadal scale, with the instrumental temperature record overlaid in black.

It is now widely accepted that the increasing emission of greenhouse gases (methane, carbon dioxide etc.) is causing a rapid increase in the surface temperatures on Earth.

4) Fossil fuels and biofuels

Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms (prehistoric plants and animals). The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years. Fossil fuels contain high percentages of carbon and include coal, petroleum, and natural gas.


A biofuel is a fuel that contains energy from geologically recent carbon fixation. These fuels are produced from living organisms. Examples of this carbon fixation occur in plants and microalgae. These fuels are made by a biomass conversion (biomass refers to recently living organisms, most often referring to plants or plant-derived materials).

Both types of fuel have the disadvantage of releasing carbon dioxide when they are burnt. Biofuels are the better option as plants and microorganisms capture carbon dioxide during the process of photosynthesis before being processed into biofuels.

5) Alternatives

Alternative energy is any energy source that is an alternative to fossil fuel. These alternatives are intended to address concerns about such fossil fuels. Besides biofuels these include solar energy, wind energy, geothermal energy, nuclear energy and hydrogen.

Why fossil fuels?

Despite the problems with carbon emission we are still using fossil fuels in our power stations.


Fossil-fuel power stations may use a steam turbine generator or in the case of natural gas-fired plants may use a combustion turbine. A conventional coal-fired power station produces heat by burning coal in a steam boiler. The steam drives a steam turbine and generator that then produces electricity. A side-effect of burning coal is the production of combustion gases such as sulphur dioxide, nitrogen oxides and carbon dioxide and these can contribute to environmental harm such as global warming or acid rain.



Large energy generation; Relatively cheap; Efficient; Infrastructure already in place.


Pollution; CO2 causes greenhouse effect; SO2 causes acid rain; Non-renewable resource; Environmental damages/danger.

Which of these is not a fossil fuel?

Coal? Natural gas? Crude oil? Bio-ethanol?

We all knew the answer was bio-ethanol. Bioethanol is a form of renewable energy that can be produced from agricultural feedstocks.

We are running out of oil


But biofuels have their problems too


Can we feed everyone on the planet and still grow plants to be turned into biofuels.

The next question we were asked was “Do you think this is sustainable?” Our answer was unfortunately no.


Solar energy

Solar energy, radiant light and heat from the sun, is harnessed using a range of ever-evolving technologies such as solar heating, solar photovoltaics, solar thermal electricity, solar architecture and artificial photosynthesis.

Common form: Photovoltaics

Photovoltaics (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect.

The photovoltaic effect is the creation of voltage or electric current in a material upon exposure to light.

The standard photovoltaic effect is directly related to the photoelectric effect, though they are different processes. When the sunlight or any other light is incident upon a material surface, the electrons present in the valence band absorb energy and, being excited, jump to the conduction band and become free. These highly excited, non-thermal electrons diffuse, and some reach a junction where they are accelerated into a different material by a built-in potential (Galvani potential). This generates an electromotive force, and thus some of the light energy is converted into electric energy. The photovoltaic effect can also occur when two photons are absorbed simultaneously in a process called two-photon photovoltaic effect.

In the photoelectric effect, by contrast, electrons are ejected from a material’s surface into vacuum, upon exposure to light. This also generates some electric energy (as the ejected electron is eventually captured on another electrode), though there is typically a high photon energy threshold. The photovoltaic effect differs in that the excited electrons pass directly from one material to another, avoiding the difficult step of passing through the vacuum in between.

Sun light → Electrical via the Photoelectric effect


RESLAB research interests lie in developing high-performance energy devices with engineered components fabricated by novel technologies.

The source of energy of the sun is…?

nuclear fission? chemical reaction? nuclear fusion? photoelectric effect?

We all knew it was nuclear fusion.

Nuclear fusion is a nuclear reaction in which two or more atomic nuclei collide at very high speed and join to form a new type of atomic nucleus (e.g. the energy that the Sun emits into space is produced by nuclear reactions that happen in its core due to the collision of hydrogen nuclei and the formation of helium nuclei). During this process, matter is not conserved because some of the mass of the fusing nuclei is converted to photons (energy). Fusion is the process that powers active or “main sequence” stars.


Hydroelectric power


Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16% of global electricity generation – 3,427 terawatt-hours of electricity production in 2010, and is expected to increase about 3.1% each year for the next 25 years.

Wind power

image  image

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power, wind pumps for water pumping or drainage, or sails to propel ships.

It is free, renewable and the fastest growing energy technology.

Unfortunately it is dependent on wind blowing and it is not an efficient transfer of wind power to mechanical energy.


Blades → hub → shaft → transmission box → high speed shaft → generator

Brake prevents turbines turning too fast

What is a disadvantage of wind turbines?

They cannot be used when it rains? They require fuel to work? They produce no air pollution? Bat and bird fatalities?

We felt the only answer was the last one although they have an undeserved reputation for this. Domestic cats kill far more birds than wind turbines.

A large meta-analysis of 616 individual studies on electricity production and its effects on avian mortality concluded that the most visible impacts of wind technology are not necessarily the most flagrant ones, as:

“Wind turbines seem to present a significant threat as all their negative externalities are concentrated in one place, while those from conventional and nuclear fuel cycles are spread out across space and time. Avian mortality and wind energy has consequently received far more attention and research than the avian deaths associated with coal, oil, natural gas and nuclear power generators [although] study suggests that wind energy may be the least harmful to birds”.

Sovacool, Benjamin K (2012). “The Avian Benefits of Wind Energy: A 2009 Update”. Selected papers from World Renewable Energy Congress – XI. Renewable Energy (journal). Retrieved 6 December 2012. “ISSN: 0960-1481”

Tidal power

Converts energy of tidal flows into electricity and is more predictable than wind or solar.

image   image

Climate change

Causing rising temperatures and sea levels and producing extreme weather e.g. storms.

The Greenhouse Effect


The radiation absorbed by the ozone layer is?

infra-red? ultra-violet? Visible? gamma rays?

As we were all science teachers we knew the answer was ultra-violet.

The ozone layer is a layer in Earth’s atmosphere which absorbs most of the Sun’s UV radiation. It contains relatively high concentrations of ozone (O3), although it is still very small with regard to ordinary oxygen, and is less than ten parts per million, the average ozone concentration in Earth’s atmosphere being only about 0.6 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30 kilometres (12 to 19 mi) above Earth, though the thickness varies seasonally and geographically.

A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth’s atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone.


A relationship between Global temperature and CO2

Global temperature has always fluctuated, however within the last 100 years a rapid increase has been seen.

image   image

Which of these is not a greenhouse gas?

Methane? Water vapour? Nitrogen? Carbon dioxide?

I knew that methane, water vapour and carbon dioxide were greenhouse gases so the answer had to be nitrogen.

Which of these do you think is the most important in reducing global warming?

Banning cars? Alternative energy to fossil fuels? Carbon capture and storage? Vegetarianism? Recycling?

I jokingly said it was vegetarianism but the majority of us thought it would be banning cars.

Carbon emissions need to be cut by at least 80% by 2050. Some countries, have committed to reducing their greenhouse gas emissions in line with targets – many countries have not. Expensive technological solutions exist for reducing greenhouse gas emissions.

image   image

The future is in our hands.

Carbon capture and storage

Carbon capture and storage (CCS) (or carbon capture and sequestration), is the process of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation.

Storage sites include geological storage (e.g. used oil wells), ocean storage (e.g. at depths over 3000m, where the high pressure keeps CO2 as a liquid denser than water) and mineral storage (conversion of CO2 to minerals such as calcium carbonate).


Green chemistry

Nothing to do with colour and not related to size.


Which of these would make a reaction green?

Increasing the temperature? Using excess water solvent? Good atom economy?

Even though I am not a chemist I correctly thought the answer was good atom economy.

What is atom economy?

The trading of atoms between reactant and product? A measure of the amount of starting materials that become useful products in a chemical reaction? How much an atom in a reaction costs?

I’m afraid I didn’t know the answer to this.

Atom economy

Atom economy (atom efficiency) describes the conversion efficiency of a chemical process in terms of all atoms involved (desired products produced). In an ideal chemical process, the amount of starting materials or reactants equals the amount of all products generated and no atom is wasted. Recent developments like high raw material (such as petrochemicals) costs and increased sensitivity to environmental concerns have made atom economical approaches more popular. Atom economy is an important concept of green chemistry philosophy, and one of the most widely used ways to measure the “greenness” of a process or synthesis.


What is the atom economy for making hydrogen by reacting coal with steam?


Mass of atoms in reactants = 12 + 18 + 18 = 48 g

Mass of atoms in desired product = 4 g

Atom economy = 4/48 x 100 = 8.3%

So the answer is “A measure of the amount of starting materials that become useful products in a chemical reaction”.

Green chemistry, like many chemical processes, requires solvents an catalysts.


Water is the solvent we are all used to but there are many others such as ethanol.


A solvent is a substance that dissolves a solute (a chemically different liquid, solid or gas), resulting in a solution. A solvent is usually a liquid but can also be a solid or a gas.

What is a Catalyst?

A substance that can increase the rate of a reaction, without itself being changed.

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