Scotland: Seaweed for Biogas?

Study for the Crown's estate management suggests considerable potential.

Scotland’s seaweed could be the latest weapon in the fight against climate change, according to a new report commissioned by The Crown Estate and conducted by researchers at The Scottish Association for Marine Science. The report details the potential of farming marine algae to be used to produce biomass to heat homes and fuel transport while avoiding the problems associated with biofuels, such as the use of valuable agricultural land.

Although Scotland has the capacity to generate much, or all, of its electrical energy needs from wind, hydropower, wave and tidal streams, less is known about its potential for generating alternative transport fuels.

The report suggests that marine biomass from seaweed could provide the answer, but states that more research is needed on how to maximise productivity and on the economic, environmental and social impacts of large-scale seaweed farming.

Professor Mike Cowling, Science and Research Manager at The Crown Estate, said, “Given Scotland’s rugged western coastline and island groups, and relatively clean seas, it is sensible to examine the farming of seaweeds and sustainable harvesting of natural supplies as a source of energy, to heat our homes and fuel our vehicles. Heating and transport make up around three quarters of our energy use so it’s vital that we find new ways of meeting that demand.

“Extracting energy from seaweed is a particularly efficient and reliable method of producing green energy, and the growing of seaweed could have positive impact on local marine biodiversity. Crucially, using seaweed as a source of biomass avoids the problems associated with agricultural crop biofuels such as pressure on supplies of arable land and fresh water. Although more research must be done to establish the practicalities, it seems that seaweed could play an important role in providing a secure and reliable supply of green energy, particularly for coastal and island communities.”

The benefits of marine biomass include:

  • it can be anaerobically digested to produce methane which, in turn, can be used to generate electricity for heat or transport (potentially attracting a subsidy under the Renewables Obligation Certificate Scheme)
  • it avoids the problem of switching agricultural land from food to fuel production
  • unlike terrestrial biomass, it is not be limited by freshwater supplies
  • seaweed has high conversion efficiencies and rapid conversion rates
  • the residues are suitable for use as nutrient supplements for agriculture
  • seaweed farms may also increase local biodiversity, absorbing some of the excess nutrients in run off from agricultural land, which can cause problems such as algal blooms.

The Crown Estate manages Crown Land, the property belonging to the British monarch.

Further information
Report Marine Biomass for Anaerobic Biogas Production (Free download on after registration)


The Crown Estate, press release, 2008-10-27.


Scottish Association for Marine Science (SAMS)
The Crown Estate