3.3 2.b, 2.c - Ocean energy, minerals and resource governance

Offshore oil and gas

Oil and gas are non-renewable resources formed from organic material transformed over geological timescales. A usable deposit requires suitable source rocks, migration, a porous reservoir and a trap preventing further escape. Offshore fields are not distributed evenly across the sea floor; sedimentary basins such as the North Sea provide important settings. Extraction depletes a stock that does not regenerate on a human management timescale.

Offshore production involves surveying, drilling, platforms or subsea equipment, and transport by pipeline or vessel. It can provide energy, industrial feedstocks, employment, tax revenue and export earnings. These benefits are uneven: specialist workers and shareholders may be distant from communities experiencing environmental risk, while an economy dependent on production is vulnerable to price fluctuations and eventual depletion.

Costs include disturbance from construction and seismic surveys, accidental releases, operational emissions and the climate effects of burning the fuels. Deep or storm-exposed locations increase engineering and emergency-response demands. A profitable field is therefore not automatically a socially desirable project. Evaluation should compare benefits and costs over its full life, including the consequences after production ends.

Management can involve licensing, environmental assessment, operational standards, monitoring and financial provision for decommissioning. The UK's offshore strategic environmental assessment programme considers wider implications of plans and licensing. Government decommissioning guidance explains obligations to address disused infrastructure on the UK continental shelf. Neither a licence nor a removal plan eliminates every accident or ecological risk; enforcement, design and operators' financial capacity matter.

Wave and tidal energy

Wave and tidal energy draw on continuing physical flows rather than consuming a finite underground fuel stock. Wind transfers energy to waves; devices can convert wave motion into electricity. Tidal flows arise from the tide-generating effects of the Moon and Sun and the response of ocean basins. Turbines can extract energy from moving water, while tidal-range schemes use a water-level difference. These are related but different technologies.

Wave resources are often strongest on exposed coasts with long wind fetches. Strong tidal streams occur where geography concentrates flow, including narrow channels and headlands. The European Marine Energy Centre's facilities in Orkney include the Billia Croo wave test site and Fall of Warness tidal site. Their separation demonstrates that the best wave location need not be the best tidal location.

Tidal timing is highly predictable, but output varies through the tidal cycle and falls around slack water. Predictable is therefore different from continuous. Waves also fluctuate with weather, season and ocean swell; devices must survive extreme conditions while generating economically during ordinary conditions. Grid connections, maintenance access, construction costs and the maturity of a design influence viability as much as the size of the theoretical resource.

Lower operational carbon emissions are a benefit, but manufacturing and installation still have environmental footprints. Devices may affect habitats, noise, sediment movement and animal behaviour; tidal barrages can substantially change inter-tidal conditions. Research, environmental assessment, staged deployment and monitoring can identify effects and adjust designs or operating conditions. EMEC's consenting account illustrates the link between demonstration and regulation. A renewable flow does not imply impact-free extraction, and removing too much energy from a local system can alter its processes.

Worked explanation — marine-energy geography

Explain how physical geography influences opportunities to generate wave and tidal energy. Long wind fetches allow waves to gain energy before reaching an exposed coast, so an ocean-facing site can provide a stronger wave resource than a sheltered bay. In Orkney, EMEC separates wave testing at Billia Croo from tidal testing at Fall of Warness because the useful flows have different controls. Tidal turbines benefit where channels concentrate moving water; the same narrow passage can accelerate flow as water moves between adjoining sea areas. A tidal-range scheme instead uses the height difference between high and low water. These settings therefore favour different designs. Predictable tidal timing aids planning, but slack-water intervals reduce current speed and generation. Physical geography creates the energy opportunity and its temporal pattern, while grid access, maintenance and investment determine whether it becomes viable electricity supply.

Sea-bed mineral extraction

The sea bed contains non-renewable mineral deposits with different origins and potential uses. Polymetallic nodules occur on some abyssal plains; mineral-rich fluids can produce sulphide deposits near hydrothermal systems, while ferromanganese crusts form on hard surfaces such as seamounts. Their slow formation means removal is not replaced within an ordinary human planning period.

Ferrous resources are iron-bearing: iron oxides in some sea-floor deposits contribute to their composition, and iron is important for steel production. Non-ferrous metals include copper for electrical wiring, and nickel and cobalt for certain alloys and battery technologies. Nodules and crusts can contain several metals together, so extraction is not necessarily a single-metal operation. Demand depends on technology, recycling and substitution as well as economic growth. The International Seabed Authority's exploration-contract information distinguishes nodules, sulphides and cobalt-rich ferromanganese crusts.

Extraction could diversify supply and provide revenues, including for participating developing states. However, equipment can remove habitat directly and generate sediment plumes, noise and disturbance. Some organisms depend on hard substrates or grow and recover slowly, making rapid restoration uncertain. A global demand for minerals does not show that a particular deposit must be mined: comparison should include terrestrial supply, recycling, material efficiency and the full environmental and social costs of each option.