“Biogas and biomethane stand out within the bio circularity ecosystem for their ability to offer immediate and viable solutions in the ecological transition.”

Margarita de Gregorio, CEO of Biocirc.

One of the fundamental aspects in the fight against climate change is the economy. Currently, the linear economy, based on the ‘extract, produce, consume and dispose’ model, contributes significantly to the environmental crisis by prioritising economic profit and ignoring sustainability. This way of acting leads to a depletion of natural resources, the generation of large amounts of waste and the emission of greenhouse gases.

It is therefore crucial to move towards what is known as the ‘circular economy’. This new economic system promotes the management and recovery of waste to keep it in the production cycle for as long as possible. This helps to reduce both the consumption of raw materials, and the amount of waste generated.

The part of the circular economy that addresses the production cycle of those sectors whose raw materials are of biological origin is known as bio circularity. This approach makes it possible to replace raw materials of fossil origin with others of renewable origin, while at the same time reusing organic waste, contributing to the decarbonisation of multiple sectors and to a more sustainable management of waste.

In this context, biogas and biomethane play crucial roles thanks to their ability to regenerate natural systems and contribute to the energy transition. But first things first…

What is biogas and biomethane?

Biogas is a renewable, carbon-neutral gas produced from the anaerobic digestion of organic matter, i.e. from the biodegradation of organic waste in the absence of oxygen. Thus, during this process, which takes place in an airtight tank or digester, the carbohydrates, proteins and lipids present in the waste are broken down by a series of bacteria, releasing a mixture of gases known as biogas. In addition, digestate, a biosolid with high fertiliser capacity, is also obtained as a by-product.

The composition of biogas varies depending on the waste used as raw material or substrate, although it is usually between 50-75% methane (CH₄) and 25-45% carbon dioxide (CO₂), with small amounts of other gases such as hydrogen sulphide (H₂S), ammonia (NH₃), volatile organic compounds (VOC) and water vapour.

Of the aforementioned, the methane concentration is the most relevant factor, as it determines the calorific value of the fuel. 1 m³ of biogas with a composition of 50% CH₄ would produce 5 kWh of energy, replacing 0.50 m³ of natural gas; whereas, if the methane composition is raised to 65%, the same cubic metre of biogas would produce 6.40 kWh of energy, replacing 0.65 m³ of natural gas. [These calculations are based on the lower calorific value of natural gas (10.83 kWh/m³)].

On the other hand, before being used as energy, biogas must undergo a process to remove impurities that can cause damage to the installations and reduce the efficiency of the system. H₂S, for example, is highly corrosive and can damage motors, turbines and other equipment if it is not removed adequately. In addition, water vapour reduces the calorific value of the biogas, which is why it is essential to separate it.

After this process, biogas is suitable for use as a fuel in the production of heat in gas boilers or in the generation of electricity through combustion engines, among others.

However, to broaden its applications, biogas can undergo an additional process, known as ‘upgrading’, for the production of biomethane. This process involves the almost total elimination of CO₂ and other residual compounds, raising the methane concentration to more than 95%. The result is a renewable gas with energy-characteristics comparable to fossil natural gas.

The advantage of biomethane over biogas lies in its higher calorific value and its ability to replace natural gas, thanks to its high methane content. This allows biomethane to be injected directly into the existing gas grid, extending its use to sectors such as transport, industry and residential. Its integration into existing infrastructure makes it an immediate decarbonisation solution, especially compared to other renewable gases, which require the development of specific infrastructures. Moreover, if biogenic CO₂ capture is carried out during its production, biomethane can achieve negative carbon emissions.

Opportunities in the valorisation of organic waste

The dual benefits of biogas and biomethane – as a renewable energy source and a climate mitigation tool – are sufficient to take them into account in the transition to a sustainable, low-carbon energy system. But their use has advantages that go far beyond the simple production of energy, as the production of these biofuels is also emerging as an innovative and sustainable solution for the valuation of organic waste produced by various economic sectors.

Currently, part of this waste is managed inefficiently and it often ends up polluting soil, water and the atmosphere itself, which has a high environmental impact. In this context, anaerobic digestion can play a key role in managing waste such as the following:

• Livestock sector: Livestock waste, such as manure, slurry, animal bedding and cleaning water, can lead to the incorporation of heavy metals into the soil, the pollution of water by excess nitrates or the emission of ammonia into the atmosphere if not properly managed.
• Agricultural sector: Agricultural residues, including pruning, wood and herbaceous waste, are often inefficiently managed through indiscriminate burning or abandonment, contributing to environmental degradation, fires and the spread of pests.
• Food sector: Slaughterhouse rejects, waste from the fishing industry, organic waste and liquid by-products from the dairy industry, or fruit or vegetable scraps that are not reused can end up rotting in landfills, where they emit methane, a gas with a warming potential 21 times greater than CO₂.
• Municipal Solid Waste (MSW): The organic fraction of municipal solid waste (MSW), such as food waste or domestic pruning, can be biodegraded and reused to produce energy or natural fertilisers. This process also contributes to achieving the recycling targets set out in Law 7/2022 on Waste and Contaminated Soils, which allows further progress towards a circular economy by reducing municipal waste.
• Wastewater Treatment Plants (WWTP): Sludge generated in wastewater treatment represents a costly challenge for WWTPs, as its management can account for up to 50% of operational costs. Anaerobic digestion can reduce the volume of sludge and generate biogas, turning a problematic waste into a renewable source of energy.

In other words, biogas and biomethane stand out not only as renewable energy sources and tools for decarbonisation, but also for their ability to reduce dependence on fossil fuels, bringing greater flexibility to the energy system.

Their ability to decarbonise sectors that are difficult to electrify is particularly valuable in the transition to a cleaner energy model.

In addition, anaerobic digestion technology is already well established, and the necessary infrastructure is available, making biogas and biomethane an immediate solution.

A crucial added value of these sources is their contribution to the circular economy, since, as we have seen, they allow the revalorisation of organic waste generated by various sectors. Not only do they significantly reduce waste, but they also create new opportunities in sustainable and circular value chains, especially on a small scale and in rural environments. This approach favours the dynamisation of these areas, while contributing to the fulfilment of the objectives of the bioeconomy in Spain, promoting a more balanced and sustainable model of economic development.

Picture 1. Biogas value chain

Biogas and Biomethane Genesal Energy gensets

Genesal Energy is fully aware of the enormous potential of renewable gases and the importance of the circular economy. We participate in projects that promote the valorisation of waste to transform it into valuable resources such as biofuels. These gases can be used on gas power gensets, taking a further step towards a sustainable energy model by not only using a renewable source instead of conventional fossil diesel, but also a source generated from the reuse of waste that would otherwise end up representing an environmental problem.

Hand in hand with FACSA, SMALLOPS, AIMEN and UVA, we are part of the ENEDAR project – ‘Improving the energy efficiency and sustainability of wastewater treatment plants through the valorisation of WWTP sludge’, financed by the Ministry of Science, Innovation and Universities and the European funds NextGeneration UE/PRTR.

Genesal Energy is here responsible for designing and validating the operation of a generator set powered by fuels from the anaerobic digestion of sewage sludge from a pilot plant; reaffirming our commitment to the energy transition and the creation of immediate and practical solutions for a sustainable future.

For several years now, one of the biggest challenges in the fight against climate change has been related to the energy safety supply.

Although progress has been made, the energy sector is still the largest emitter of greenhouse gases and further efforts are needed. Also, energy production needs to be renewable and adaptable to already occurring climate conditions. Erratic weather patterns, rising global temperatures and the intensification of extreme weather events challenge the ability of energy systems to provide secure, continuous and affordable supply highlighting this need for adaptation.

Growth in energy demand

Climate change, combined with population growth and economic development, increases energy demand globally. E.g. The use of air conditioning systems in countries with emerging economies and warm climates, where income growth is allowing greater access to cooling technologies. In 2000, the global energy demand for residential air conditioning in summer was 300 TWh, but this is projected to increase to 4,000 TWh by 2050 in regions such as India, Brazil and other developing countries.

As global temperatures rise, these countries will experience longer and hotter summers, which will increase cooling use and thus electricity demand. Although in the more advanced economies and colder climates the need for heating during the winter is likely to decrease, overall energy demand will continue to increase due to the use of air conditioning in the summer months. This change in energy consumption patterns will require a reassessment of global energy strategies, with particular attention to the growing needs of developing countries.

Impact on power generation

Climate change is also affecting power generation. Thermal power plants, which currently produce around 80% of the world’s electricity, are reducing their efficiency due to higher ambient temperatures. Thermal conversion is less efficient in extremely hot conditions. In addition, the availability cooling of water is decreasing forcing them to operate at reduced capacities or even to temporarily halt power production. Thermal plants are designed to operate under more stable climatic conditions and, although most energy transition plans involve the closure of most of these, it must be kept in mind that this process will be gradual. During this transition period, thermal plants will remain a key part of the global energy supply, especially in countries where the infrastructure for renewable energy is not yet fully developed.

Nuclear power plants are particularly vulnerable to extreme weather events, such as hurricanes or storms, which can damage their cooling systems and other critical equipment necessary for the safe operation of reactors. Events such as Hurricane Harvey in 2017, which affected nuclear plants in Texas, highlight the need to strengthen energy infrastructures in the face of such events.

On the other hand, hydroelectric power, which depends on the hydrological cycle, is also at risk. In regions such as the Zambeze River in Africa, hydropower generation capacity is projected to decline by up to 35% by 2050 due to reduced rainfall and rising temperatures. However, in Asia, projections suggest an increase in hydropower capacity, showing that climate change will affect different regions differently.

In addition, renewable energies such as solar and wind are also exposed to the effects of climate change. Increased cloud cover in certain areas will affect the efficiency of solar panels, while more frequent and severe storms could damage both solar and wind installations. Extreme weather events and changes in wind patterns will complicate the integration of these sources into electricity systems, which may require greater investment in energy storage technologies to mitigate their intermittency.

Threats to energy infrastructure

Energy transmission and distribution infrastructures are particularly vulnerable to climate change. Higher temperatures, rising sea levels, melting permafrost, floods and landslides will put energy transmission networks and pipelines at risk. In coastal areas, rising sea levels may damage pipelines and energy facilities, while in permafrost areas, thawing could affect the stability of infrastructure. In addition, heat waves and forest fires that are becoming more frequent also pose a threat to power lines, as has already been seen in countries such as the United States and Australia.

The fossil fuel sector, in particular oil and gas, is also exposed to extreme weather events. Tropical cyclones, such as Hurricane Katrina in 2005, can disrupt operations on offshore extraction platforms and affect onshore infrastructure, leading to disruptions in global energy production and supply. Although the melting of ice in the Arctic presents an opportunity for exploration of new oil and gas reserves – which could increase the global supply of these resources – the exploitation of these reserves would entail new environmental and logistical risks.

The role of generating sets in energy safety

In this context of increasing energy demand and infrastructure vulnerability, gensets emerge as a vital solution to improve energy security. They act as back-up systems that ensure a continuous supply of electricity during outages or interruptions. Particularly useful for critical facilities, such as hospitals, data centres, wind farms and emergency services, which cannot afford interruptions in their power supply.

In addition, gensets are versatile and can be used in a variety of applications, from industrial operations to residential areas, providing an independent power source that can be tailored to the specific needs of each user. In regions where the electrical infrastructure is more vulnerable to disruptions, gensets can provide an effective emergency power solution, ensuring that communities and industries continue to function even during the most severe weather events.

Finally, the deployment of cleaner and more efficient gensets, powered by renewable fuels or clean energy technologies, can contribute to mitigating greenhouse gas emissions, aligning with long-term sustainability goals.

In this sense, gensets not only act as a temporary solution to energy supply insecurity but can also be integrated into a broader climate change adaptation and resilience strategy, offering both energy security and opportunities to move towards a more sustainable future.

In the industrial sector, the choice of a genset is not only about finding the most economical equipment, but also about selecting the one that best fits the operational and strategic needs of the company.

Understanding which factors influence the price of a generator set is crucial to making an investment that guarantees reliability, efficiency and durability in the long term. We review them below.

Power

A critical factor that has a direct impact on cost. This value, expressed in kilowatts (kW) or kilovoltamperes (kVA), defines the load carrying capacity of the equipment. In an industrial environment, it is essential to select a generator set that not only meets current power demands, but also has room for future upgrades.

Higher power equipment is not only more expensive, but also requires a larger infrastructure for proper installation and operation.

Fuel type

Diesel generators, although more expensive than petrol generators, are preferred in industrial environments due to their durability, efficiency and lower maintenance costs.

On the other hand, gas gensets offer a more sustainable option with lower emissions, although their implementation requires the availability and cost of gas supply.

Technology and functionalities

The advanced features of a genset can significantly influence its price. Some aspects to consider include:

• Automatic start-up: Ideal for ensuring operational continuity in the event of power outages.
• Remote monitoring: Allows efficient and preventive management, reducing downtime and optimising maintenance.
• Protection systems: Integration of systems to protect against overloads, short circuits and other operational risks.

Each of these features adds value to the equipment, but also increases its base cost.

Soundproofing options

The choice between an open-type or soundproofed genset will depend on its intended location. Soundproofed gensets are the choice in areas where noise control is a priority, such as hospitals or city centres, but are more expensive due to the additional sound insulation and materials required in their manufacture.

Applications and environment

The type of application for which the genset is intended also influences its price. Equipment designed for industrial use, capable of operating in extreme conditions or critical applications, is usually more robust and therefore more expensive.

When assessing the needs of a project, it is crucial to consider:

• Environmental conditions: Equipment designed to operate in extreme climates, from sub-zero temperatures to desert conditions, will require specific modifications.
• Regulations: Complying with emissions or noise regulations may require additional components that increase the price.

Summary of factors affecting the price of a generator set

• Power: Directly proportional to the load capacity.
• Fuel: Diesel, petrol or natural gas have different costs.
• Technology: Automatic start, remote monitoring, or advanced protection. These are features that will increase the price.
• Design: Open vs. Soundproofed. Soundproofing requires materials that come at an additional cost.
• Application: Industrial, commercial, or extreme conditions.

By considering these factors, it is possible to choose the generator set that best fits the needs of each project, optimising the investment and ensuring reliable performance.

Genesal Energy is committed to offering tailored, high-quality solutions, backed by solid experience and specialised technical support.