Waves, currents and tides provide an endless source of clean energy that is now being harnessed by a wide range of technology. Marine energy involves providing heating and cooling using the thermal energy found in seawater, which itself comes from the sun's rays and accumulates on and just below the surface of seas and oceans. In this sense, it is also a source of renewable energy.
Marine energy is particularly suited to highly populated coastal areas and is increasingly being used in the Mediterranean region, where there is a dense urban population living by the sea, no tides and favourable bathymetry. However, the technology is also highly developed in Nordic
How it works
The concept is simple: seawater is sourced at a temperature of 12-25°C just off the coast at a depth of 5-10 metres. This water is used to warm or cool a freshwater loop using heat exchangers according to seasonal needs. (The corrosive nature of the salt requires the exchangers in the seawater loop to be made of titanium, an expensive but highly resistant metal.)
The freshwater loop is linked to heat pumps that are either centralised or located near buildings, which warm the water to the required temperature to provide heating, hot water and air conditioning. These pumps can supply end users via a district heating network spanning a distance of several kilometres.
Dalkia‘s marine energy solutions
Dalkia currently operates four marine energy facilities in France and one in Monaco.
We cover all aspects of this advanced technology:
- from designing and building bespoke systems through our specialist subsidiary Optimal Solutions
- to operating and maintaining facilities and related heating networks, handled directly by Dalkia.
The benefits of marine energy
Marine energy offers a wealth of environmental benefits:
- Eco-friendly - Marine energy releases very little CO2 into the atmosphere.
- Safe and reliable - Marine energy is not dangerous and is not subject to the intermittent nature of other renewables like solar and wind power, or, in some cases, the biomass chain.
- Local - Marine energy provides a permanent source, available on site. It requires no transport and suffers no energy loss, with water drawn from the sea returned to the sea at a temperature in keeping with the environment to continuously regenerate natural resources and energy supplies.
- Inexpensive - Most of the heating costs come from the initial investment rather than the outlay required to purchase the fuel. The price of the heating or cooling provided by marine energy is therefore stable over time and in the long term. Just as importantly, it is not vulnerable to the volatile nature of oil and gas prices.
- Unlimited - Unlike oil and other fossil fuels, marine energy provides an unlimited supply that does not diminish as it is used.
- Flexible - Marine energy is extremely versatile, enabling the simultaneous production of heating and cooling.