Ocean Energy Market Development

Between 2004 and 2008, it has been estimated that the world capital expenditure (CAPEX) on wave energy will be US$140 million, with almost 50% of this in the UK. In the same period, it has been estimated that the world CAPEX on tidal projects will be around US$110 million, with almost 90% of this being related to the UK market. Together wave and tidal energy represent a global market of US$250 million, with US$180 million earned in the UK.

While committed tidal projects are primarily off the East Asian Pacific coasts of Korea and China, the bulk of wave energy projects are being developed in Europe. The UK and Portugal are the countries with the most current activity. In the last year, there has been an advance in the progress of tidal energy, with one barrage already under construction on the Korean coast, the 254 MW Shihwa tidal power plant, and a contract agreed for a second 300 MW tidal lagoon power plant in China. Both are larger than the barrage at La Rance in France, presently the largest in the world.

The technology that is most advanced toward commercialisation is the Pelamis (named after a seasnake), under development by Ocean Power Delivery Ltd. in Scotland. Pelamis is a series of cylindrical segments connected by hinged joints. In August 2004, Pelamis was connected to the UK grid at the European Marine Energy Centre (EMEC) in Orkney in order to be tested. This was the first offshore wave energy to be exported into the UK electricity system.

Sea trials are underway of the Wavegen commercial scale wave energy converter, LIMPET, which is feeding electricity into the supply of the Scottish island of Islay. Ocean Power Technologies’ floating Powerbuoy has undergone successful trials off the coast of New Jersey and is on the way to commercialisation. A number of oscillating water columns have been tested and are also under trial in various parts of the world. Seagoing trial of the 20 kW prototype Wave Dragon tapchan device has proven its offshore survivability since March 2003.

The first commercial grid-connected marine current turbine is currently being test operated at Lynmouth in the UK. A UK£3 million turbine has been built into the seabed about 1.5 km (one mile) offshore from Lynmouth. The single 11 metre-long rotor blade will be capable of producing 300 kW of electricity and will be a test-bed for further tidal turbines.

The first ship to use the technology of oscillating water wings may be the Orcelle, a cargo vessel
transporting up to 10,000 cars from Britain to Australia, New Zealand, and other countries.
The marine renewable sector is currently the focus of much academic and industrial research around the world. Many universities and institutes are engaged in marine renewable research, either developing new concepts or performing fundamental research to support the sector.

An economic analysis indicates that, over the next 5 to 10 years, ocean thermal energy conversion (OTEC) plants may be competitive in four markets:

• Small island nations in the South Pacific and the island of Molokai in Hawaii.
• American territories such as Guam and American Samoa.
• Hawaii, where a larger, land-based, closed-cycle OTEC plant could produce electricity with a
second-stage desalinated water production system.
• Puerto Rico, the Gulf of Mexico, and the Pacific, Atlantic, and Indian Oceans for floating, closedcycle plants rated at 40 MW or larger.

The Hydrogen Economy

The energy sectors in both the United States and Europe are on the cusp of immense change. New technologies are being developed and opportunities for entrepreneurial ideas and innovative approaches are ripening at a time when capital-intensive, aging energy infrastructure is in need of improvement.

The world currently exists in a carbon economy. 80% of the primary energy which drives the world is derived from hydrocarbon fossil fuels; oil 35%, coal 24% and natural gas 21% and 11% is contributed by renewables, almost all renewable biomass. In the last two centuries the volume of carbon consumption has increased exponentially with the world’s industrialisation.

The carbon economy has given great economic benefits to mankind but it is subject to two limitations. Although new reserves of hydrocarbons and new technologies to exploit them are being discovered all the time, these resources are not limitless. Secondly, fossil fuels emit greenhouse gasses and other pollutants when they are burned and these emissions have reached dangerous proportions. Alternatives to the carbon economy are feasible although wide scale use is some years in the future. A hydrogen economy is one such option, in which the sustainable energy supply system of the future features electricity and hydrogen as the dominant energy carriers. Hydrogen will be produced from a diverse base of primary energy feedstocks, or from water using renewable electricity in the process. The use of hydrogen energy would reduce dependence on petroleum and the pollution and greenhouse gas emissions caused by carbons.

The development of the hydrogen economy will advance on two fronts. The development of another technology, the fuel cell, is essential to the exploitation of hydrogen; the two are interlinked. It is important to understand that hydrogen is not a primary energy source like coal and gas; it is an energy carrier, like electricity. Hydrogen can be converted to energy via traditional combustion methods and through electrochemical processes in fuel cells. Initially it will be produced using existing energy systems based on different conventional primary energy sources and carriers. In the longer term renewable energy sources could become the most important source for the production of hydrogen.

Fuel cells utilise the chemical energy of hydrogen to produce electricity and thermal energy. A fuel cell is a quiet, clean source of energy. Water is the only by-product it emits if it uses hydrogen directly. Fuel cells are similar to batteries in that they are composed of positive and negative electrodes with an electrolyte or membrane. The difference between fuel cells and batteries is that energy is not recharged and stored in fuel cells as it is in batteries. Fuel cells receive their energy from the hydrogen or similar fuel that is supplied to them. No charge is thereby necessary.

Fuel cells are already used in a wide variety of products, ranging from very small fuel cells in portable devices such as mobile phones and laptops, mobile applications like cars, delivery vehicles, buses and ships, to heat and power generators in stationary applications in the domestic and industrial sector. Fuel cells are customarily classified into the three categories; stationary, portable and mobile or transport. Within these three overall groupings there are sub-categories.

Although there are many positive factors in the concept of a hydrogen economy, there are arguments against it. The potential benefits include high efficiencies, decentralised power generation, security of supply, reduced emissions, reliable and silent operation, energy savings, multiple uses and opportunities for hybrids. On the downside there are huge technological challenges and massive investment is needed to create capacity and infrastructure for the production and delivery of hydrogen. The environmental benefits are only as good as the sources and processes of production, and finally there are competitive technologies.

New technologies include large scale electrification in conjunction with plug-in hybrid vehicles and Li-ion batteries in transport. In the stationary applications market, distributed electricity generation or cogeneration present an alternative to hydrogen. Other significant competitors are a new level of power generation technologies, such as large, increased efficiency coal and gas-fired power plants, possibly using underground coal gasification (UCG) with CO2 capture and storage (CCS), renewable electricity supply technologies which are already widespread in the market (wind and solar PV) or now being commercialised (ocean and tidal energy), and new nuclear power technologies. At the same time, new technologies such as micro-turbines and Stirling engines are being introduced in combined heat and power applications. All of these technologies are in the pipeline and will not simply be overridden by hydrogen.

Virtually all of the OECD countries treat research into hydrogen and fuel cells as an important and in most cases an increasingly important, element of their overall public policy and programme planning activities. An important feature of hydrogen and fuel cell research and development is the exceptionally strong involvement and commitment of industry as well as governments. The US federal government proposes spending $2.7 billion over the next five years on hydrogen and fuel cell research and development, and advanced automotive technologies. The Japanese government plans to spend over $380 million a year on fuel cell research, development and commercialisation. The FP- Framework Programme - is the EU’s main instrument for research funding in Europe and was first adopted in 1984, each lasting for a five year period. FP 7 has a total budget of over €50 billion and some €275 million is earmarked for hydrogen and fuel cells, in addition to national expenditures.

It cannot be taken as a forgone conclusion that an exclusive hydrogen economy will emerge.

Hydrogen is coming but it may consist of a hybrid of hydrogen applications side by side with conventional fossil fuels, nuclear and renewable energy. The final evolution is so far in the future and the waters are so uncharted that many variants are possible. Iceland, although small, has a high proportion of renewable energy, mainly geothermal and is interesting because the government has determined that the country should be the first with a hydrogen economy.

Tidal Energy Potential

Most countries which have investigated the potential exploitation of tidal energy have concentrated on the use of tidal barrages that can be used to control the natural tidal flow, which is directed to drive turbines.

Only around 20 sites in the world have been identified as possible tidal power stations. Three countries have tidal energy schemes in operation: France, with the 240 MW tidal barrage at Rance, the largest tidal power station in the world and the only one in Europe, built in 1966; Canada, with the 20 MW Annapolis tidal barrage; and China, with an 11 MW tidal power scheme of small tidal plants.

Experimental tidal energy projects are being tested in Russia, UK, Australia, USA, Argentina, Canada, India, Korea, and Mexico. Potential sites for tidal energy stations are few and far between, but a number have been identified in the UK, France, Eastern Canada, the Pacific coast of Russia, Korea, China, Mexico, and Chile. Other sites have been identified along the Patagonian coast of Argentina, Western Australia, and Western India.

Tidal ranges along the west coast of England and Wales are unusually large, averaging 7 to 8 metres on the spring tides in several estuaries and as much as 11 metres in the Severn. The Severn estuary is the site for the most ambitious tidal barrage that has been proposed for the UK so far, and it has been discussed for many years.

Tidal energy is expensive to install, costing UK£1.5 /US$2.4 million per megawatt, compared with about US$1 million per megawatt for wind turbines. It also has environmental problems including effects on tidal waters and ecosystems. On the positive side, it is cheap to maintain once installed and the electricity output is completely predictable.

Tidal energy barrages would modify existing estuarine ecosystems to varying degrees, and environmental considerations are some of the barriers which have to be overcome to develop them.