energy + envioronment issues

Question 1

Describe the disadvantages of using fossil fuels for electricity

Answer 1

disadvantages
- non-renewable
- release carbon dioxide and greenhouse gases into the atmosphere, worsening the greenhouse effect
- release sulphur and nitrate gases which then react to become sulphur dioxide and nitrogen oxide, then react with condensed water vapour in clouds to form acid rain
[] these impurities can be removed from the fuel before burning it to prevent this

Question 2

Describe the advantages of using fossil fuels for electricity

Answer 2

• reliable energy source
• provide a lot of energy
• carbon emissions could be circumvented by wider implementation of CCS (carbon capture storage)
  [] captures and condenses carbon dioxide from air, then pumps it deep underground under sea
• short start-up time so can fulfil changing energy demands throughout the day easily

Question 3

Describe the disadvantages of using nuclear fuels for electricity

Answer 3

disadvantages
- long start-up time
- fuel is non-renewable
- produces radioactive waste that remains dangerous for many years that has to be stored safely deep underground
- risk of nuclear accidents like Chernobyl if stations not handled properly

Question 4

Describe the advantages of using nuclear fuels for electricity

Answer 4

advantages
- no release of greenhouse gases
- much more energy transferred per kg of fuel than fossil fuels, so is overall more energy efficient

Question 5

Describe the advantages and disadvantages of using biofuels for electricity

Answer 5

advantages
- carbon-neutral
- renewable
- relatively reliable

disadvantages
- if using plants as biofuel, could be used to feed people instead of being burnt

Question 6

How are the varying energy demands of the UK met throughout the day ?

Answer 6

• using nuclear and coal fired power stations to provide a constant amount of electricity ( base load demand)

-using gas fires power stations and pumped storage schemes to meet daily variations in deamd and in the winter ( extra demand).

-using renwable energy resources when deamd is high and when the conditions for renewable energy generation are suitable (e.g. use of wind turbines in winter when wind speads are high enough)

-using renewable energy resources when demand is low to store energy in pumped storage schemes

Question 7

Compare the costs of running nuclear power, fossil fuel and renewable energy power stations

Answer 7

• capital costs are lower for gas fired power stations and highest for wind power and nuclear staions

-overall costs the lowest for hydroelectricity and greatest for offshore wind farms.

Question 8

cons of renewable energy

Answer 8

not able to meet world’s demand yet
not available all the time
unreliable

Question 9

define base load deamnd

Answer 9

• minimum level of electricity demand on an electrical grid over span of time e.g. on week
• demand met by power stations thhat provide constant supply of electricity

Question 9

define start up time

Answer 9

• how quickly a power station can get running
• natural gas has fastest start up times

Question 10

big energy issues

Answer 10

-supply and demand- demand for electricity is higher than in winter than summer.

• electricity needs to match these change to demand

Question 11

national grid systems

Answer 11

-The National Grid is a high-voltage power transmission network in Great Britain that connects power stations to consumers, ensuring electricity is delivered to homes and businesses