Cogeneration, also called combined heat and power (CHP), generates electricity and useful heat at the same time from one fuel, on your own site. Evo Energy Technologies supplies, installs and maintains 2G cogeneration plants across Australia, running on natural gas or biogas, from 20 kW to 4,000 kW.
What is cogeneration?
Conventional power generates only around 35% of primary energy as usable electricity. The rest, around 65%, is released into the atmosphere as heat and CO2 emissions. Even more energy is lost as electricity travels through the grid to reach its destination.
Cogeneration fixes that waste. A gas engine drives a generator to make electricity, and the heat that the engine produces anyway (from its cooling circuit and its exhaust) is captured and used on site as hot water, steam or process heat. Because both outputs are used, far more of the energy in the fuel does useful work. That is why a 2G cogeneration plant reaches an overall energy efficiency of between 90% and 104%, where a grid supply and a separate boiler together use the same fuel for a fraction of the result.
Historically it has been a massive global problem for businesses and governments to manage energy in the most environmentally and economically beneficial way. Combined heat and power uses a fuel source (natural gas or biogas) and integrates the production of usable heat and electricity into one process.
How does cogeneration work?
- Fuel in. Natural gas from the network, or biogas produced on site from organic waste, feeds a reciprocating gas engine.
- Electricity out. The engine turns a generator. The electricity is used on site first, cutting what you buy from the grid, and any surplus can be exported where the connection allows.
- Heat recovered. Heat exchangers capture the heat from the engine’s jacket water, oil and exhaust gas. It leaves the plant as hot water or steam for heating, hot water systems, process heat or pools.
- Controlled as one unit. The plant arrives connection-ready in a single module (container or acoustic enclosure) with an integrated control system that adjusts itself to changing energy demand and gas quality.
Add an absorption chiller and the same recovered heat can also produce chilled water. That is trigeneration: electricity, heat and cooling from one plant.
Supreme energy efficiency of up to 104%
Heat and electricity are generated on site, where the energy and heat are needed. The combination of thermal and electrical energy generation means that up to 104% of primary energy is used. This means enormous cost savings as well as massive reductions in carbon emissions. 2G cogeneration has a superior energy efficiency of between 90% and 104%, which is set to make other CHP and micro-turbine systems redundant.
Main advantages of cogeneration
- Enormous energy savings
- Substantial reduction in carbon emissions
- Fast return on investment
- Independence from rising energy prices
- Full cost control
- Highest reliability and efficiency
- Stable operation in case of power outages within the utility grid
- Highest environmental standards
- Sustainable energy investment
- Compliance with governmental carbon emission regulations
Natural gas cogeneration
Natural gas has one of the lowest CO2 emission values of the fossil fuels, and there is a readily available supply through the national grid. The Evo 2G natural gas CHP offers a reliable, powerful and clean means of getting more than 90% energy efficiency at the point of use.
A 2G natural gas cogeneration plant is connection-ready and stand-alone. Manufactured in Heek, Germany, the 2G cogeneration system is industry-leading, engineered and manufactured to the highest standards. Although CHP runs on natural gas, it significantly reduces a business’s reliance on the national grid, with far less vulnerability to power outages and price fluctuations. It comes in a variety of fully customisable configurations between 20 kW and 4,000 kW.
See the natural gas CHP plant range: G-Box 20 to 50 kW, Aura 100 to 420 kW, Agenitor 95 to 500 kW and Avus 550 kW and up.
Biogas cogeneration
A biogas generator uses biogas derived from a fermentation process of natural biodegradable products. Usually this is the bacterial decomposition of organic material in landfill, organic process waste from food manufacturing, livestock waste products, or the fermentation and processing of sewage sludge at wastewater treatment plants.
This fuel has the added benefit of being sustainable and carbon neutral. Using a biogas generator to process the fuel provides up to 90% energy efficiency at the point of use. 2G biogas CHP systems are composed of specially calibrated biogas engines, components and materials, designed to be highly reliable and to provide powerful and efficient biogas power generation. Evo Energy Technologies offers biogas cogeneration in fully customisable configurations between 50 kW and 3,000 kW.
See biogas power generation, the Agenitor 80 to 500 kW and Avus 550 kW and up biogas units, and the biogas treatment that keeps the engine running on raw gas. Where the gas is to be upgraded and injected into the network instead, see biomethane plants. 2G engines are also hydrogen-ready.
Where cogeneration fits
Cogeneration pays off where a site has a steady demand for both electricity and heat for most of the day. In Australia that is typically:
- Food and meat processing, where hot water, steam and refrigeration run around the clock. Kilcoy Global Foods and Simplot are among the Evo projects in this sector.
- Wastewater treatment plants, which produce their own biogas from sludge digestion and use the heat to keep digesters warm. Coombabah, Kawana, Mount Martha, Boneo and Colac are examples.
- Landfill and agriculture, where landfill gas or piggery and dairy waste becomes fuel. Hyland Highway Landfill offsets 80% of Latrobe City Council’s electricity from landfill gas; Kia Ora Piggery and Rivalea run on piggery biogas.
- Aquatic centres and sports hubs, which need pool heating, space heating and power all year. Pimpama Sports Hub, Cook and Phillip Park, Geraldton and Fremantle aquatic centres are Evo installations.
- Cold storage and data centres, which need reliable on-site power before the grid can supply it, as at NewCold Truganina.
Frequently asked questions
What is the difference between cogeneration and trigeneration?
Cogeneration produces electricity and heat. Trigeneration adds an absorption chiller that turns part of the recovered heat into chilled water, so the plant produces electricity, heat and cooling. Trigeneration suits sites with a large cooling load, such as aquatic centres, food production and data centres. Read about trigeneration.
What fuel does a cogeneration plant use?
2G plants run on natural gas from the network, on biogas produced on site from waste, or on hydrogen. The engine is calibrated for the fuel, so the choice is made at design time around what your site has available.
What size cogeneration plant do I need?
Plants are sized to the site’s base electrical and thermal load, not its peak, so the engine runs long hours at high efficiency. The 2G range covers 20 kW to 4,000 kW on natural gas and 50 kW to 3,000 kW on biogas, and multiple units can be combined, as at Kilcoy Global Foods’ 4,000 kW multi-unit project.
How long does cogeneration take to pay back?
It depends on your electricity and gas prices, how many hours a year the plant runs, and how much of the recovered heat you can use. Evo models the economics for each site from your actual energy data before recommending a plant, so the answer is specific to you rather than a rule of thumb.
Can a cogeneration plant keep my site running during a grid outage?
Yes, where it is designed for island operation. A 2G plant can be configured for stable operation during power outages within the utility grid, which is one of the reasons cold storage, data centres and critical infrastructure choose on-site generation.
Who installs and maintains the plant?
Evo Energy Technologies is the authorised Australian partner for 2G Energy. Our engineers handle design, installation, commissioning, testing and ongoing service and maintenance from our base in Bundamba, Queensland, for sites across Australia.
Start your journey to net zero with Evo Energy Technologies
Tell us about your site’s electricity, heat and cooling needs and we will model what a cogeneration plant would save. Call 1300 012 471 or contact us.