Page 34 - Fundamentals of Ocean Renewable Energy Generating Electricity From The Sea

Introduction Chapter | 1 25

Wave R&D Prototype Demonstration Precommercial Industrial roll-out
Tidal Demonstration Precommercial Industrial roll-out
stream
Tidal Precommercial Industrial roll-out
range

2015 2020 2030 2040 2050

FIG. 1.16 Timeframe for the development of ocean energy technologies. (Based on a timeline
presented in the Ocean Energy Forum, Ocean Energy Strategic Roadmap—Building Ocean Energy
for Europe, 2016.)

to construction. The wave energy industry has suffered several setbacks over the
last few years, not least of which was the demise, in 2014, of Pelamis Wave
Power—previously considered to be one of the leading developers with their
Pelamis P2 device. The wave energy sector is challenging, because sites that
are economically viable from a resource perspective are, by their very nature,
rather energetic. However, following on from the discontinuation of previously
planned large-scale developments, the focus now appears to have shifted more
towards the implementation of smaller wave energy projects [22]. The outlook
at present is optimistic for the tidal stream industry, with single demonstration
devices grid connected, for example, the 1.2-MW SeaGen device that was
installed in the Strangford Narrows, Northern Ireland, 11 and the development
of the 6 MW phase 1A of the MeyGen project in the Pentland Firth (Scotland),
amongst other projects.

1.5 ENERGY AND POWER
Energy is difficult to describe, but a popular and practical definition is:
Energy is the ability of a system to perform work.
Work is energy transferred to or from a body—it requires an applied force
moving a certain distance. Therefore, work requires an expenditure of energy,
and energy spent performs work.
According to the first law of thermodynamics, energy can neither be created
nor destroyed—it can only be transformed from one form to another. It is
therefore important when discussing energy, within the context of electricity
generation, that the term energy is used in the correct way. We do not ‘generate
energy’, we convert energy, and generate power. Therefore, phrases such as

11. The SeaGen device generated over 8 GWh of electricity; www.seageneration.co.uk.