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Renewable energy needs space

Most of us tend to underestimate what is required of space if coal, oil and gas is to be replaced by wind and solar energy, the leading forms of renewable energy today.

Windmills in Norway. Credit: Hordaland Turlag

Windmills in Scotland. Credit: REUTERS/David Moir

Habitat destruction and loss, from agriculture, urban sprawl, logging, roads and mining, threatens wildlife across the globe and is the main reason for the rapid extinction of species we see today. Land-based wind power adds to this. Wind power, therefore, solves one problem by aggravating another.

Popular opposition is growing and politicians and developers are looking for alternatives at sea. Although the obvious answer may seem to be to move the wind turbines offshore, we must realize that this is only a temporary solution.

Offshore wind is limited to the continental shelves

Offshore winds can only be used in marine areas with a water depth not larger than 100 metres for fixed and maximum 1000 metres for floating wind turbines. And there should be a lot of wind. Suitable areas for offshore wind are therefore limited. There may be conflicts with fishing interests. Negative environmental impact on birds and marine life can also be problematic.

Credit: Improved Offshore Wind Resource Assessment in Global Climate Stabilization Scenarios, National Renewable Energy Laboratory, October 2012.

Figure: Assessment of wind resources on shallow ocean areas around the world.

Solar energy also needs space

Solar cells are also area-demanding. This is acceptable if they can be integrated into buildings, but more problematic where they displace forest or arable land. Besides, they produce energy only during the day. Solar cells combined with battery or grid connection are therefore suitable for decentralized energy production, but less suitable for centralized energy production in highly developed, densely populated areas.

BBC News, March 25, 2020: Climate change: Green energy plant threat to wilderness areas

A growing population needs more energy

Population 2 billion 3 billion 4 billion 5 billion 6 billion 7 billion 8 billion 9 billion

10 billion

Year 1930 1960 1974 1987 1999 2011 2023 2037 2057
        Source: https://www.worldometers.info/world-population

Replacing fossil fuels with renewable energy is a huge task. Solar and wind energy has limitations and cannot do the job alone. In addition, natural gas with carbon capture and storage will certainly be important in the future. Nuclear power is discussed, but faces strong popular resistance.

72% of Earth's surface is covered by the ocean

Tidal energy

Some places on earth have great tidal differences and currents. A number of companies develop solutions to harness this energy. Globally, this is a limited resource.

Wave energy

The west-wind belts, the "westerlies", in the northern and southern hemisphere cover vast areas. Persistent westerly winds over large stretches of sea lead to a wave climate with extremely high energy content.


       Source: Encyclopedia Britannica, Inc. (https://www.britannica.com/science/Ferrel-cell)

Credit: Andrew M. Cornett, A GLOBAL WAVE ENERGY RESOURCE ASSESSMENT, Canadian Hydraulics Centre, National Research Council, Ottawa, Ontario, Canada. Conference Paper in Sea Technology, July 2008.

Wave heights November 27, 2019, southern spring, measured from satellites.
Source: https://earth.nullschool.net/

With wave heights of between 3 and 10 meters, year-round, and with its vast areas, the south-west wind belt is a formidable energy resource. So far, it has been ignored because the energy is considered impossible, or at least, too difficult, and therefore too expensive, to extract.

Today's robotic technology can make this possible. Unmanned solutions will greatly simplify operations and make it cheaper.

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