Germany is one of Europe’s leaders in solar power. Vast photovoltaic installations, rooftop systems, and utility-scale solar farms already produce a significant share of the country’s electricity.
Yet there is another renewable energy source that often receives far less attention: landfill gas.
Landfills containing large amounts of organic waste naturally produce methane as buried material decomposes. Instead of allowing this gas to escape into the atmosphere, operators can collect it and use it to generate electricity and heat.
In some situations, this can make landfill biogas economically attractive compared with building a new solar farm.
But the comparison needs an important clarification: landfill gas is not universally more profitable than solar energy in Germany. Its advantage appears mainly where the landfill already exists, methane is already being produced, and the gas collection infrastructure can be installed or upgraded at relatively low additional cost.
What Is Landfill Gas?
Landfill gas forms when organic waste decomposes without oxygen.
This process is known as anaerobic decomposition.
The resulting gas typically contains:
- Methane
- Carbon dioxide
- Water vapor
- Small quantities of other gases and impurities
Methane is the valuable part.
It can be burned in an engine, turbine, or combined heat and power system to produce useful energy.
Instead of treating methane as a waste product, a landfill can therefore become a small energy facility.
Why Methane Capture Has Extra Value
Methane is not only a fuel.
It is also a powerful greenhouse gas.
If landfill methane escapes directly into the atmosphere, it contributes substantially to warming.
Capturing and burning it converts much of the methane into carbon dioxide and water.
Carbon dioxide is also a greenhouse gas, but methane has a much stronger warming effect over shorter climate timescales.
This means landfill gas projects can provide two benefits at once:
- Producing energy
- Preventing uncontrolled methane emissions
Solar panels generate clean electricity, but they do not simultaneously eliminate an existing waste-gas problem.
That additional environmental service can improve the overall value of landfill gas projects.
The Fuel Is Already Being Produced
Solar farms require land, photovoltaic modules, mounting structures, electrical connections, inverters, and other infrastructure before they produce electricity.
Landfill gas projects also require equipment, but their fuel source already exists inside the waste.
A landfill that has been receiving organic material for years may continue producing methane for decades.
There is no need to mine or purchase fuel.
The waste has already been collected.
From an economic perspective, this makes landfill gas unusual: the energy resource is being generated automatically as a by-product of waste decomposition.
Landfill Gas Can Produce Power Day and Night
Solar power has one obvious limitation.
It only produces electricity when sufficient sunlight is available.
Germany has good conditions for solar energy, but winter days are short and cloud cover can reduce output.
Landfill gas production is different.
Methane generation continues day and night.
The gas can be collected continuously and stored temporarily before being used in generators.
This makes landfill gas more dispatchable than solar power.
An operator can potentially produce electricity during periods when market prices are higher rather than only when the Sun is shining.
That flexibility can increase the economic value of each kilowatt-hour.
Capacity Factor Can Be an Advantage
A solar farm may have a very large installed capacity but produce its full rated output only during favorable daylight conditions.
Its annual capacity factor in Germany is therefore much lower than 100%.
A well-operated landfill gas engine can run for far more hours during the year.
That means a smaller generator may produce a surprisingly large amount of annual electricity.
The economic advantage is not necessarily higher peak power, but more continuous utilization of the equipment.
This can be especially attractive when the generated electricity is consumed locally.
Combined Heat and Power Changes the Economics
One of the strongest advantages of biogas is that it can produce both electricity and heat.
A gas engine generates electricity, but it also releases large amounts of thermal energy.
In a combined heat and power system, that heat can be captured and used.
Potential users include:
- Industrial facilities
- Greenhouses
- Municipal buildings
- Waste treatment facilities
- District heating networks
- Nearby commercial sites
Solar photovoltaic farms mainly generate electricity.
If a landfill gas project can sell both electricity and heat, the same methane can generate multiple revenue streams.
This can significantly improve project economics.
Germany Already Has the Infrastructure for CHP
Germany has extensive experience with combined heat and power systems, district heating, biogas plants, and decentralized energy production.
This matters because technology becomes easier to deploy when engineers, operators, equipment suppliers, and maintenance companies already understand it.
Gas engines and CHP systems are mature technologies.
A landfill located near an industrial or urban area may therefore integrate relatively easily with existing electricity and heating infrastructure.
The economics become particularly attractive when heat that would otherwise be wasted has a nearby customer.
Why Solar Farms Can Face Land Costs
Utility-scale solar requires space.
Germany is densely populated and has valuable agricultural, industrial, and residential land.
Solar developers may need to lease or purchase land and obtain planning permission.
They may also face competition for suitable grid connections.
Landfill gas projects use a site that already exists.
The land has already been dedicated to waste disposal and may have few alternative uses.
Turning an existing landfill into an energy-producing site can extract additional value from land that would otherwise have limited economic productivity.
Grid Connection Can Make or Break the Project
Both solar farms and landfill gas facilities need access to the electrical grid unless the electricity is consumed directly on site.
Grid connection costs can be substantial.
However, some landfills are located near municipal or industrial infrastructure and may already have useful electrical connections.
If the electricity can be used locally, grid-related costs may fall further.
For example, landfill gas electricity could potentially power:
- Waste sorting facilities
- Pumps
- Recycling plants
- Municipal equipment
- Nearby industry
Self-consumption can be economically valuable because the operator avoids purchasing some electricity from the grid.
Solar Has One Huge Advantage: It Keeps Getting Cheaper
Landfill gas should not be seen as a replacement for solar power.
Photovoltaic technology has become dramatically cheaper over recent decades.
Solar systems have relatively few moving parts, require no fuel handling, and can operate with comparatively low maintenance.
Large German solar projects can therefore produce electricity very cheaply.
Landfill gas engines require regular servicing.
Gas must be collected, cleaned, compressed, and monitored.
Impurities can damage equipment.
The amount of methane also declines as a landfill ages.
For this reason, solar is often the better long-term investment where good land, grid access, and financing are available.
Landfill Gas Is a Declining Resource
A solar farm can continue producing electricity as long as the panels remain functional and sunlight is available.
A landfill behaves differently.
Methane production usually rises after waste is deposited, reaches a peak, and then gradually decreases.
Older landfills may eventually produce too little gas to operate large generators economically.
This means the energy system must often be designed around a declining fuel supply.
Operators may need to replace large engines with smaller units over time.
Landfill gas is therefore best viewed as a way to recover useful energy from an unavoidable waste stream, not as an infinitely renewable source.
Germany’s Waste Policy Changes the Picture
Modern waste management increasingly separates organic waste from material intended for landfills.
Organic waste can often be treated more efficiently in dedicated anaerobic digesters.
There, methane production can be controlled much more carefully.
Germany has also significantly reduced the disposal of untreated biodegradable municipal waste in landfills.
As a result, the future potential of new landfill gas projects is more limited than in countries where large quantities of organic waste are still buried.
However, older landfills can continue emitting methane for many years.
Capturing that gas remains environmentally and economically useful.
Expert Perspective: The Best Comparison Is System Value
Energy specialists increasingly evaluate renewable technologies based not only on the cost of generating electricity, but also on their value to the wider energy system.
Solar provides extremely inexpensive electricity during sunny periods.
Landfill gas offers a different advantage: it can provide controllable electricity and potentially useful heat while reducing methane emissions from an existing waste site.
This makes the technologies complementary rather than direct competitors.
A region may benefit from solar during daylight hours and use biogas, storage, hydropower, or other flexible sources when solar production falls.
When Landfill Gas Can Be More Profitable Than Solar
Landfill gas can be especially attractive when several conditions occur together.
The landfill already produces substantial methane.
Gas collection infrastructure is available.
A nearby electricity connection already exists.
There is demand for useful heat.
Electricity can be consumed locally.
Methane would otherwise have to be flared or released.
Under those conditions, the project can create revenue from something that was previously a waste-management problem.
That is where landfill gas can outperform a new solar farm economically: not because the technology is universally cheaper, but because it can turn an existing environmental liability into several useful products.
Interesting Facts
- Landfill gas is produced mainly by microorganisms breaking down organic material without oxygen.
- Methane is the main combustible component of landfill gas.
- Landfill gas can continue to be produced for decades after a landfill stops accepting waste.
- Gas engines can generate electricity continuously rather than only during daylight hours.
- Combined heat and power systems can use energy that would otherwise leave the engine as waste heat.
- Capturing landfill methane can reduce greenhouse-gas emissions even before the electricity benefit is considered.
- Solar farms generally require less mechanical maintenance than gas-engine power plants.
- Modern landfill gas systems use networks of wells and pipes to collect methane from inside waste deposits.
- Gas quality changes over time as the landfill ages.
- Dedicated anaerobic digesters can produce biogas more efficiently than uncontrolled landfill decomposition.
- Germany’s waste-management system has greatly reduced the amount of untreated biodegradable waste sent to landfill.
Glossary
- Landfill Gas — Gas produced when organic waste decomposes inside a landfill, typically containing methane and carbon dioxide.
- Biogas — A combustible gas produced through anaerobic decomposition of organic material.
- Methane — A combustible greenhouse gas with the chemical formula CH₄.
- Anaerobic Decomposition — Biological breakdown of organic material in the absence of oxygen.
- Combined Heat and Power (CHP) — A system that produces electricity and captures useful heat from the same fuel source.
- Capacity Factor — The percentage of maximum possible electricity that a power plant actually produces over a period of time.
- Dispatchable Power — Electricity generation that can be increased or decreased when needed.
- Photovoltaic (PV) — Technology that converts sunlight directly into electricity.
- Grid Connection — The infrastructure linking an electricity generator to the wider power network.
- Self-Consumption — Using electricity at the same site where it is generated.
- Gas Flare — Equipment that burns unwanted combustible gas without recovering most of its energy.
- Anaerobic Digester — A controlled facility where microorganisms break down organic material and produce biogas.
- District Heating — A system distributing heat from a central source to multiple buildings.
