From blue sky thinking to green solutions

Biomass, CHP, Anaerobic Digestion and Composting

Renewable energy, as part of the wider switch to a low carbon economy, plays a vital part in tackling climate change and maintaining secure energy supplies. The Government is proposing to introduce the Renewable Heat Incentive (RHI), (which is similar to the Feed In Tariff for electricity), to assist in meeting the government target of 15% renewable energy by 2020 while potentially providing a financial return on installations of about 12% p.a. It is proposed that the RHI scheme will support a range of technologies, including air, water and ground-source heat pumps, solar thermal, biomass boilers, renewable combined heat and power systems, use of biogas and bioliquids and the injection of biomethane into the natural gas grid.

Biomass is an all round description for renewable organic materials, such as wood, agricultural crops or wastes, including municipal wastes, when used as a source of fuel or energy. Biomass can be burned directly or processed into biofuels such as ethanol and methane. Biomass includes a vast array of diverse materials, all with different properties, which effect both logistic efficiencies and their suitability as fuel or bioenergy feedstock.

Biomass heating systems, generally burn wood pellets, chips or logs to power hot water boilers or to provide direct heating to part of a building.

There are also systems that run on biogases – useful if there is a nearby biogas source (for example from a digester on a farm).

Strateco can assist organisations in the planning and installation of biomass systems as well as assisting in ensuring they benefit from the Renewable Heat Incentive which will take effect in April 2011.

Combined Heat and Power

Combined Heat and Power (or CHP) is a concept rather than a single technology. Invariably when generating electricity a large amount of heat is also produced and it therefore makes sense from an efficiency perspective to generate electricity where there is a demand for heat.

Renewable CHP systems use a variety of technologies to convert the energy in biomass to electricity and useable heat; examples include the use of wood chip to raise steam for a steam turbine and the use of biomethane in gas engines to drive a generator.

Unfortunately, although the overall energy efficiency of CHP may be attractive, the economic scale of available technologies and the effect of the conventional energy market can make realising a renewable CHP project a very challenging and complex journey.

Strateco can help organisations considering renewable CHP from preliminary ideas to detailed feasibility and installation.

Anaerobic Digestion

Anaerobic digestion is the natural breakdown of organic materials into methane and carbon dioxide. An anaerobic digester (or AD plant) is a sealed vessel, or series of vessels, in which bacteria act without oxygen. The organic material contents need to be fully mixed and warmed.

Biogas is the name given to the mixture of gases formed during the anaerobic digestion of organic wastes and comprises about 70% methane and 30% carbon dioxide. The refined methane is known as Renewable Natural Gas or Biomethane which is virtually identical to natural gas and its production will be rewarded by the Renewable Heat Incentive. All resultant compostable material can be treated through aerobic digestion.

Aerobic Digestion is defined as the bacterial process of decomposition or rotting occurring in the presence of oxygen and is more commonly known as composting. It is a process in which bacteria are used to rapidly consume organic matter and convert it into carbon dioxide. Aerobic digestion is commonly used to decompose the remaining organic matter in the sludge from an anaerobic digester. The residual material which remains from the Aerobic Digester may then be spread on agricultural land or sold as compost.

Strateco can assist organisations who require permits to operate Biomass or Composting Systems and can advise on a range of solutions.