Alternatives to fossil fuels: costs and benefits

Renewable and Recyclable Energy

Key Terms

• Recyclable Energy → Forms of waste that can be reused to produce more energy
• Photovoltaic Cells → The main method by which solar power is generated - they convert energy from the sun into an electric current
• Insolation → Incoming solar radiation
• Biofuel → Fuel derived from organic matter, such as agricultural crops, timber etc

*Sources Of Energy *

Energy Sources

Energy source	Nature	Benefits	Costs
Nuclear power	Use of radioactive energy produced by nuclear reaction Heat released by the reaction is used to produce steam, which drives turbines to generate electricity	● Only small amount of Uranium are needed to produce a given output of heat compared w/ other forms of fuel ● There is no shortage of Uranium and operating costs are v competitive ● Produces less CO2 than fossil fuel sources (low carbon footprint) ● Very efficient ● Safety is improving	● Expensive to construct and decommission ● Disposal of radioactive waste ● Technological demands are complex and high ● Risks related to safety (accidents) & security ● Threats of large-scale disaster eg. Chernobyl, Fukushima
Wind power	Using the force of wind in exposed areas and offshore Turbines often grouped together in farms	● Many land and sea areas have potential for wind power ● The time profile is favourable, wind is strongest in the winter (favours countries w/ more variable weather) ↳ Can be used yr round ● Low running costs	● Large areas of land and offshore are needed ● Some people regard them as unsightly, noisy & dangerous for birds
Solar power	Generation if electricity by the use of photovoltaic cells Often grouped in 'farms'	● Generates large amounts of electricity where there are high levels of sun ● Costs are decreasing rapidly ● Large potential in desert areas	● Some large population areas are distant from suitable sites ● Less effective in clouds and low angle of incidence areas ● Not very efficient yet
Tidal power	Incoming tides drive turbines in a similar way to hydropower	● Has significant potential ● Reliable source of energy once installed	● Very expensive ● Few schemes currently operating in the world ● Impact on marine life
Geothermal	Water is pumped beneath the ground to hot areas and the steam from the water drives turbines to produce electricity	● Low maintenance costs ● Suitable where other technologies may not be	● High installation cost ● Risk during earthquakes etc

Costs and Benefits of Renewable and Recyclable Energy

Overall

• Claims that renewable energy can completely replace non-renewable Unlikely because…
  • Many countries do not have renewable sources to exploit for geographic reasons (eg. no coasts, lack of strongly flowing rivers)
  • Financial costs
  • Often has environmental impacts
  • NIMBYism - although people are pro renewables, they do not like it if construction occurs near to where they live | | Benefits | Costs | |---|---|---| | Economic | ● Can be used at scales suitable for developing countries
    ● Low maintenance costs once running
    ● Cheap costs once economies of scale reached
    ● Reduces dependence on fossil fuels for electricity production | ● Needs investment in new technology
    ● Electricity costs per unit may be higher than from conventional sources
    ● Dependence on fossil field is only reduced if they are directly substituted | | Social | Solar and wind
    ● Safe and clean
    ● Can be used by individual houses | ● Nuclear produces radioactivity
    ● Solar may take up farmuland, reducing food production | | Environmental | ● No greenhouse gas emissions once operations
    ● No air pollution | ● Solar and wind need large areas, can spoil scenery
    ● Nuclear produces radioactivity | | Energy Security | ● Electricity produced can be used or transmitted by existing systems | ● Difficult to store for later use
    ● Solar and wind are climate dependent |

Biofuels

↳ A fuel derived immediately from living matter, such as agricultural crops, forestry or fishery products and various forms of waste. They come in both Primary and secondary forms:

• Primary biofuels → Inc fuelwood, wood chops and pellet, and other organic materials that are used in an unprocessed form, primarily for heating, cooking or electricity generation
• Secondary biofuels → Derived from the processing of biomass and inc liquid biofuels such as ethanol and biodiesel, which can be used by vehicles in industrial processes Biomass → Organic matter used as a fuel, es;cially in power stations for the generation of electricity

Issues with Biofuels

• Large-scale cultivation could change carbon fluxes between soil, vegetation and atmosphere and reduce food production (& ↑ fuel prices) and water availability of irrigation used

• In some countries there may be forced changes in land ownership, taking land away from small farmers and reducing incomes for disadvantaged groups

• Deforestation may take place to make room for biofuel crops, so decreasing CO2 absorption

• Cultivation in marginal farming areas could stress the natural environment

Radical Technologies

Carbon Capture & Storage	● Involves capturing the CO2 released by the combustion of fossil fuels and burying it deep underground + Suitable for fixed points + Can reduce emissions by 75% - High costs can be passed on to consumers due to the complex tech involved - Concerns that the CO2 may leak to the surface - Concerns about the pressure in rocks may cause a small earthquake
Hydrogen Fuel Cells	● Combine hydrogen and oxygen to produce electricity, heat & water + Will produce electricity as long as H is supplies + Can be used as a source of heat & electricity for buildings and as a power source + The only by-product is water + H is available from several sources + Can be used in vehicles - It is not a primary energy source, instead a method of storing energy - A lot of energy is needed to extract the H from its sources and emits greenhouse gases
Electric Vehicles	+ On avg there is a 70% reduction in emissions compared w/ petrol vehicles - Emissions depend on vehicle and manufacturing processes and how the electricity for the vehicles is produced