The renewable energy sector provides numerous options, and we’re dedicated to helping you find the perfect solution or combination for your needs. These options can work synergistically; for instance, we often recommend pairing power-from-waste (our favourite!) with solar energy.

Slurry covers for farms with livestock

Covering slurry stores helps keep rain out while containing odorous gases like ammonia, which result from microbial activity. Ammonia emissions from manure storage contribute 9% of the UK’s agricultural ammonia emissions. By covering your slurry store, you can substantially reduce these emissions. Conventional slurry store covers aren’t airtight like anaerobic digester covers, so gas escapes at a reduced rate compared to open stores.

Slurry store covers can be impermeable or permeable, fixed or floating. Impermeable covers prevent rainwater from entering, reducing slurry volume and increasing storage capacity. In areas with moderate to high rainfall, these covers can be cost-effective.

Captured fugitive emissions can be converted into biomethane to power onsite tractors or be sold to the transport industry.

Pros

• Relatively low-cost and quick deployment.
• In some countries, like the UK, government grants may cover initial costs.
• Effective in reducing emissions.

Cons

• Covers are not airtight, so some methane may still escape.
• If biogas cannot be used on site, finding an off-taker is necessary.

Anaerobic digestion

Anaerobic digestion (AD) is a process where microorganisms break down biodegradable material without oxygen. This produces biogas, which can be used for electricity, heat, renewable natural gas, or transportation fuels. Various AD technologies convert diverse organic waste streams into biogas continuously.

Digested solids can be composted, used for bedding, applied to cropland, or made into other products. Nutrients in the liquid stream serve as agricultural fertilizers. AD is applicable across the human food supply chain, from farm animal waste to restaurant food waste. The scale can range from thousands of tonnes per annum to just a few kilograms per day.

Pros

• Suitable for most parts of the human food supply chain, significantly reducing environmental impact.
• Smaller units for food waste are relatively affordable and usually don’t require planning consent.

Cons

• Larger units for sizable operations can be expensive, take 12-18 months from feasibility to operation, and may face local objections due to odor.
• Bigger units require planning consent, necessitating expert support. We have partners who can help with this process.

Pyrolysis

Pyrolysis is a thermochemical process applied to any organic material, involving chemical and physical separation into different molecules at high temperatures and without oxygen. Unlike combustion and gasification, which involve oxidation, pyrolysis is an endothermic process resulting in high-energy products.

Pyrolysis products include solid (charcoal, biochar), liquid, and non-condensable gases (H2, CH4, CnHm, CO, CO2, and N). In some applications, liquid and gas phases can be used together when supplying hot syngas directly to a burner or oxidation chamber.

During pyrolysis, materials are heated to a specific temperature inside a pyrolysis unit until the process is complete. The chosen temperature influences the composition and yields of pyrolysis oil, syngas, and char.

Renewable, synthetic gases (H2, CH4)

Syngas produced during biomass pyrolysis contains a mixture of molecules, including CO, CO2, nitrogen, H2, CH4, and higher hydrocarbons. The quantity of these molecules can be increased through syngas post-treatment, making it a valuable source of biomolecules. Companies like ETIA are developing dedicated processes for this purpose. Concurrent production of biochar and oil can also enhance the business model.

Plastics to oil, power and heat

Plastic debris, containing high energy content, can be transformed into high-quality syngas and oil. Syngas, a calorific mix of molecules (CH4, C2H6, H2, etc.), can be converted into energy (steam, heat, electricity) after cleaning. Pyrolysis oil, a high-energy blend of hydrocarbons, has applications across various industries.

Plastics to heat – conventional fuel replacement in boilers

Industrial gas boiler operators seeking to reduce conventional fuel costs can consider pyrolysis, which produces synthetic gas with energy values similar to natural gas. By using a specially designed burner, existing boilers can replace natural gas and continue operation without investing in new equipment.

RDF to power and heat

Pelletized, calorific fractions of municipal waste serve as excellent feedstock for high-temperature continuous pyrolysis. This process generates high-quality syngas, which can then be used in generators or CHP systems to produce electricity, heat, or steam.

Biochar and heat / steam production

Pyrolysis converts clean wood biomass into biochar, which has multiple applications, such as soil nutrients, bioremediation products, and filtration materials. Additionally, the energy produced during the process can be transformed into useful heat (for drying), steam (for industrial purposes), or other forms of power.

Plastics / RDF to hydrogen

Both plastics and RDF waste can be converted into quality syngas to be treated further in order to boost its content of hydrogen.

Plastics / RDF to methane

ETIA is working on developing a process with significant market potential, aiming to produce renewable methane from calorific waste fractions.

Sludge carbonisation

Low or medium temperature pyrolysis of dry sewage sludge produces sterilized, odorless, and easily stored products that serve as an additional source of renewable energy.

The good news
This process benefits various sectors of manufacturing, distribution, retailing, and medical supply chains, dramatically reducing their environmental impact. Smaller units, designed for low volume and simple waste streams, are relatively affordable and can be deployed on-site to generate electricity, heat, chill, or biogas.

The less good news
Larger units for extensive operations can be expensive and may take 12-18 months from feasibility to operation. They might face local objections due to past associations with incineration plants. These units require planning consent and support during the process, which our partners can help with.