3.3) Energy Flashcards
1
Q
- What are the main CAUSES for a global increase in energy consumption?
A
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Increased population growth: 👪
➞ and the need for power to supply the increasing demand, particularly in developing countries, such as China and India. -
Urbanisation: 🏙️
➞ particularly in the developing world in recent years. As humans move away from a subsistence way of life in rural areas to living in towns, their energy footprint increases. -
Consumerism: 🛍️
➞ and the desire for more energy intensive lifestyles, including an increase in the use of cars and electrical appliances in homes.
2
Q
- What are the CONSEQUENCES of a global increase in energy consumption?
A
- As the use of fossil fuels (i.e. coal, oil and gas) increases, so too does the amount of pollution produced.
- When fossil fuels are burned by industry, in power stations and by vehicles and planes, unwanted by-products known as carbon emissions enter the atmosphere.
- Carbon dioxide (CO2), in particular, is given off when fossil fuels, such as coal, oil and gas, are burned. Although these gases have always been present in the world’s atmosphere, their concentration is gradually increasing as more and more fossil fuels are burned.
3
Q
- What are the social, economic and environmental IMPACTS of a global increase in energy consumption?
A
-
SOCIAL:
➞ Increased inequality and the gap between the rich and the poor could widen 💵
➞ Elderly and those on low-incomes in fuel poverty ⛽
➞ People are forced to change their lifestyle, which is unpopular 🛍️ -
ECONOMIC:
➞ Increased costs for the exploration and extraction of existing energy sources 📈
➞ Funding will be needed for research into alternative energy 🧪
➞ As energy sources are depeleted, energy prices will increase (e.g. higher petrol prices and domestic fuel bills in the UK) 💰 -
ENVIRONMENTAL:
➞ Ecosystems, such as rainforests, are under threat from exploitation as countries (e.g. Brazil) exploit their resources for development 🌳
➞ Air pollution from factories could increase as countries industrialise and exploit resources 🌫️
4
Q
- What is shale gas?
A
-
Shale gas:
is a form of natural gas (mostly methane) found underground in shale rock. - It is classified as “unconventional” because it is found in shale, a less permeable rock formation than sandstone siltstone or limestone in which conventional gas is found, and it is generally distributed over a much larger area. It does not flow easily.
5
Q
- Explain the process of hydraulic fracturing (aka. fracking).
A
- Deep holes are drilled down into the shale rock.
- This is followed by horizontal driling to access more of the gas reserves, as shale reserves are typically distributed horizontally rather than vertically.
- Fracking fluids, containing sand (prevents fractures from closing), water and chemicals (chemicals dissolve minerals) are then pumped at high pressure into the drilled holes to open up fractures in the rock, enabling the trapped gas to flow through the fractures into collection wells.
- From there it is pumped away for commercial use. Recovery rates for shale gas are much lower than for conventional gas.
6
Q
- What are the BENEFITS of the extraction of shale gas?
A
- Natural gas has the lowest carbon content of all fossil fuels and not a mixture of other carbon containing compounds with other inorganic impurities. It is the cleanest “burning fossil fuel” 🫧
- Fracking made extraction of natural gas from shale layers commercially viable (more value for money) 💵
- Shale gas could also decrease energy costs because massive shale gas prodcution would likely cause a significant decline in natural gas prices 📉
- Massive shale gas production would also help improve energy security, and help reduce our dependence on expensive foreign fossil fuels 🔐
7
Q
- What are the CHALLENGES of the extraction of shale gas?
A
- Shale gas, despite being a significantly cleaner energy source compared to coal, is still connected with signficant carbon emissions, thus being less acceptable from an environmental point of view than renewable energy sources 🌫️
- Potential leakages of methane gas from shale gas wells could offset the carbon dioxide reductions and climate benefit of switching from coal to natural (shale) gas ⚠️
- The fast development of the shale gas industry could slow down the further development of the renewable energy industry, especially if shale gas (as it is expected) becomes one of the cheapest energy options 📉
- The costs of extracting shale gas are higher compared to the costs of extracting conventional gas or coal, but the further advancements in drilling techniques could help to decrease shale gas extraction costs 💵
8
Q
- What is hydrogen power?
A
-
Hydrogen power
is a zero-emission fuel when burned with oxygen. It can be used in electrochemical cells or internal combustion engines to power vehicles or electric devices.
9
Q
- What are the SOURCES of hydrogen power?
A
- Hydrogen doesn’t occur naturally as a gas on the Earth - it’s always combined with other elements.
➞ Water, for example, is a combination of hydrogen and oxygen (H20) - Hydrogen is also found in many organic compounds, notably the hydrocarbons that make up many of our fuels (i.e. gasoline, natural gas, methane and propane).
➞ Additionally, hydrogen can be sourced from coal and biomass.
10
Q
- Explain the process of steam methane reforming (1)
A
- Natural gas contains methane (CH4) that can be used to produce hydrogen with thermal (heat) processes, such as steam methane reformation.
- Steam methane reforming involves the reaction of natural gas with steam in the presence of a catalyst to produce hydrogen and carbon.
11
Q
- Explain the process of gasification (2)
A
-
Gasification
is an efficient process to obtain valuable products (hydrogen) from biomass and coal. -
Coal gasification:
1. Coal is burned by combustion to turn water into steam.
2. A gasifier (a cylindrical pressure vessel) operates at high temperatures which causes the coal to undergo different chemical reactions.
3. The first of these is pyrolysis, which occurs as coal’s volatile matter degrades into several gases, leaving behind char, a charcoal-like substance.
4. Then, reduction reactions transform the remaining carbon in the char to a gaseous mixture known as syngas - carbon monoxide and hydrogen are the two primary componenets of syngas.
12
Q
- Explain the process of electrolysis (3)
A
-
Electrolysis
involves the splitting of water molecules into hydrogen and oxygen using electricity and an electrolyser device (fuel cell). The fuel cell generates energy by creating a chemical reaction which produces an electrical current. Some of the main by-products are hydrogen, oxygen and water.
13
Q
- What are the BENEFITS of the using hydrogen as a fuel?
A
- Hydrogen fuel is a renewable energy source and is in bountiful supply.
➞ There is no possibility of it running out (e.g. access to water) like other sources of energy 🌿 - It’s practically a clean energy source. When hydrogen is burned to produce fuel, the by-products have no known side effects ☀️
- Reduces reliance on fossil fuels 📉🛢️
- Hydrogen energy is non-toxic. This means that it does not cause any harm or destruction to human health ✨
- It’s far more efficient than other sources of energy. Hydrogen is a solidly efficient energy type since it has the ability to convey a lot of energy for every pound of fuel.
➞ This categorically means that an automobile that utilises hydrogen energy will travel more miles than one with an equal amount of gasoline 🚗🔋
14
Q
- What are the CHALLENGES of using hydrogen as a fuel?
A
- Using hydrogen as a fuel requires energy from fossil fuels which releases greenhouse gases and contributes to anthropogenic climate change 🏭
- Hydrogen power is expensive. The two main processes of hydrogen extraction (electrolysis and steam methane reforming) are extremely expensive.
➞ This is the main reason that it is not heavily used across the world 💵 -
Storage complications. One of hydrogen’s properties is that it has a lower density.
➞ This means that it has to be compressed to a liquid state and stored the same way at lower temperatures to guarantee its effectiveness and efficiency as an energy source ❄️ - It is not the safest source of energy. Hydrogen is highly flammable and frequently makes headlines for its potential dangers.
➞ Compared to gas, hydrogen lacks smell, which makes any leak detection almost impossible 🔥 - Hydrogen energy cannot sustain the population. Despite the fact that hydrogen is bountiful in supply, the cost of harnessing it limits extensive utilisation 🫰
15
Q
- What is nuclear energy?
A
-
Nuclear energy
comes from splitting atoms in a reactor to heat water into steam, turn a turbine and generate electricty.
