Cost and Environmental Impact

Small-Si ait Hydro Wind Flioto Voltaic

Neariiorc wave

Csmbned Cycle

Uiii Turbine

Average UK Mix (1993) Modem Coal Ptaii

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Lit Cycle

Figure 1.1: Comparison of life cycle emissions of CO2[6]

Although waves represent a 'free' and clean source of energy, capturing this energy inevitably costs money and impacts the environment. An interesting comparison of energy sources, made more relevant by the Kyoto Protocol and so-called carbon credit scheme, is to examine the expected amount of carbon dioxide emitted to the atmosphere over the entire lifecycle of a device, divided by the expected energy yield of that device,

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Lit Cycle

Figure 1.1. Noting the logarithmic scale of the diagram, the utilisation of wave energy can offer a significant reduction in life cycle emission when compared to fossil fuel generation. The device used for this comparison was the OSPREY device [4] and the emissions were primarily during material manufacture with construction, decommissioning and disposal anticipated to be an order of magnitude less.

Nuclear power stations emit zero CO2 in use, although there will be emissions during construction and decommissioning, of which the extent of the latter is unclear.

Estimating the economic lifecycle cost of technology still at the concept stage is difficult and hence a variety of estimates have been proposed over the years. There are two main methods of cost prediction, 'engineering assessment' and 'learning curves'. The former is based on expert opinion about the potential for cost reduction over time explicitly for the application being considered and is based, for example, on closely related technology. Learning curves take a more general look at the relationship between the volume of production and the cost per unit, the trend being that the greater the cumulative production worldwide the lower the cost. A further variable is the assumptions made about financing conditions, in particular discount rates and amortisation periods, typically 8-15% and 15-20 years respectively. The general trend of these predictions over the last 20 years has been falling. A recent comparison for cost estimates, which attempts to encompass the range of predictions, is provided in Table 1-1.

Table 1-1: Comparison of predicted costs for energy sources [5]

Off shore wind

2-3 p/kWh

On shore wind

1.5-2.5 p/kWh

Wave

3-6 p/kWh

Nuclear

3-4 p/kWh

Combined cycle gas turbine

2-2.3 p/kWh

Photo Voltaic

16-10 p/kWh

Using this information, optimistic wave energy estimates put it on a similar level to nuclear energy, but more expensive than offshore wind.

Using this information, optimistic wave energy estimates put it on a similar level to nuclear energy, but more expensive than offshore wind.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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