Generate electricity. Recover the heat. Understand the full value.

One biogas input. Two useful energy outputs.

Biogas CHP burns cleaned biogas in an engine or turbine to make electricity and captures engine heat for digester heating, hot water or process use. It does not need full upgrading. In Australia, value depends on how much power offsets real site imports, any negotiated export price and how much recovered heat is genuinely used.

Cleaned biogas drives a reciprocating gas engine, turbine or other prime mover. The generator produces power; heat exchangers capture heat from jacket water and exhaust for digester heating, hot water, drying or process needs. CHP economics improve only when heat can be used at the needed temperature, time and location.

Nameplate is not delivered energy.

Installed capacity is not annual delivered electricity. Gross generation is not net export. Recoverable heat is not necessarily useful heat.

Follow every unit of energy.

Electrical, thermal and auxiliary flows.

Biogas source

Volume and composition, fuel HHV or LHV basis, buffer storage.

Cleaning and conditioning

To the engine supplier's fuel-gas specification.

Gas engine or prime mover

Engine size, part-load behaviour and electrical efficiency on a stated basis.

Generator and electrical bus

Gross versus net power; on-site load first, export only under an approved connection and agreement.

Heat recovery

Jacket water and exhaust through heat exchangers to heat demand. Unused heat is rejected and has no value.

Parasitic loads

Fans, pumps, blowers, controls and gas treatment draw power that must come off gross generation.

Choose the prime mover and heat system for the duty.

No single universal CHP efficiency. Confirm figures from documented OEM data on a stated fuel basis.

Reciprocating gas engines

Most common for biogas.

Part-load

Reasonable, modular sets help

Gas tolerance

Per OEM specification

Heat

Jacket water and exhaust

Maintenance

Regular service and overhauls

Scale

Small to large

Microturbines

Compact units for smaller flows.

Part-load

Efficiency falls at low load

Gas tolerance

Usually needs compressed, dry gas

Heat

Exhaust heat

Maintenance

Lower frequency

Scale

Small

Gas turbines

For larger, steady flows.

Part-load

Best near full load

Gas tolerance

Per OEM

Heat

High-grade exhaust

Maintenance

Specialist

Scale

Large

For sites with reliable gas and useful heat.

Illustrative only. Yields depend on measured feedstock tests.

Dairy and feedlots

Manure digestion can support on-site power and heat where collection and heat demand align.

Wastewater treatment

Sludge or co-digestion gas can offset plant electricity, with heat used in treatment.

Food and beverage

Concentrated residues may support digestion; match power and heat loads to operations.

Existing biogas plants

Efficiency, utilisation, treatment and maintenance may justify optimisation before a larger upgrade.

Regional hub

Shared gas supply or local heat demand may warrant assessment; delivery losses and contracts matter.

What is each megawatt-hour really worth to your site?

Use measured interval data and your actual business tariff. A small-business bill or regulated offer cannot by itself set a site's avoided power value, and a gas benchmark is not a delivered boiler-fuel price.

Cost stack

Gas cleaning

Engine service and overhaul

Consumables

Compliance

Capital and finance

What the screen can show

Net on-site and exported MWh/year

Avoided import cost at your tariff

Export revenue only at your negotiated price

Useful heat and displaced boiler fuel

Avoided cost uses only the share of power that reduces imports. Export is valued separately. Heat is credited only for the useful share that displaces another fuel.

Produce energy, or produce a different product?

A: CHP equals offset electricity plus real export plus useful heat, less allocated costs. B: Biomethane equals saleable gas plus qualified attributes, less upgrading, delivery and replacement energy. C: Hybrid is a physically feasible split that keeps digester heat and site reliability. The same input gas constrains every option.

What determines whether CHP runs reliably?

Check each locally with your network and state environmental regulator.

Engine fuel-gas quality and conditioning

Load and electrical interconnection

Heat demand seasonality

Gas storage and buffer capacity

Operational staffing

Air emissions and noise

Cooling, fire and safety compliance

Maintenance and overhaul schedule

Islanding or backup only if engineered

Start with your bill, gas data and heat demand.

12 months of interval electricity data and the actual tariff

Measured gas flow and methane content

A quantified heat customer with temperature and timing

Network export limits and connection status

Engine supplier fuel-gas specification

Build a brief CHP opportunity.

A credible assessment begins with measured utility purchases, operating loads, gas availability and a quantified heat customer. Build an opportunity with Shelby, identify missing measurements, compare CHP against upgrading and decide on specialist next steps.

Frequently asked questions

What does CHP stand for?

Combined heat and power: electricity plus recovered useful heat from the same fuel.

Is biogas CHP renewable electricity?

It can be, based on fuel origin and applicable certification rules. Specific environmental claims need evidence.

Does CHP require biomethane upgrading?

Usually not. The fuel gas must meet the engine's cleaning and conditioning specification.

Can CHP export to the grid?

Potentially, subject to network connection and export limits, metering and commercial arrangements.

Is all recovered heat valuable?

No. It must match real temperature, quantity, timing and distribution conditions.

How much electricity does 1 Nm³ of biogas produce?

It depends on methane content, reference conditions, energy basis and actual engine efficiency. Shelby calculates from your measured inputs rather than promising a generic yield.

Sources & references

Shelby provides preliminary screening and decision support; outputs depend on user-supplied data, published references and validated model boundaries. They are not detailed engineering design, an equipment quote, a guaranteed energy yield, an investment-grade feasibility study, financial advice or a promise of customer demand. Shelby does not build, supply, operate or certify these plants.

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