Cogeneration, also known as Combined Heat and Power (CHP), is the on-site production of multiple types of energy – usually electricity, heat, and/ or cooling – from a single source of fuel. The principle of cogeneration, capturing the heat that would otherwise be wasted to provide useful thermal energy, has long been known and used in a wide variety of applications. In recent years however, advancements in research and development have made CHP an increasingly useful tool for multiple reasons.
One of the main benefits of utilizing this technology is that, depending on the application, the integration of power and heating/cooling productions into one on-site cogeneration system can often produce savings of up to 35 percent of total energy expenditures when compared to the ‘traditional’ method of purchasing energy.
Today, advances in lean-burn gas reciprocating generator technology, heat exchangers, and digital system controls make cogeneration both practical and economical for applications as small as 300kW. This has resulted in a variety of facilities, large and small, to reconsider cogeneration in order to improve energy efficiency, cut greenhouse gas emissions, and reduce costs. Facility types that are good candidates for cogeneration include agriculture, hospitals, hotels, swimming pools, universities, and factories.
Gas-powered generators also have a significant benefit over their diesel-powered counterparts in cogeneration set-up – they operate with an uninterrupted supply of fuel via natural gas pipelines, negating the need to transport, store, polish, and maintain diesel onsite, therefore reducing lost costs through inefficiencies and reducing interruption risks due to fuel delivery.
At Cummins, we’re meeting the growing need for cogeneration systems by delivering tried and tested gas genset solutions. The Cummins HSK78G and QSK60G sit in a portfolio of integrated solutions that spans capabilities from 500kW to 2MW. The HSK78G was first introduced to market in 2019 and has quickly developed its reputation as a proven and trusted power solution within the sector. It has achieved this status by providing innovative fuel flexibility and dependability in extreme conditions, with high power density down to 40MN fuels and full power capability up to 55°C (131°F) when used with high ambient turbo technology.
Cogeneration replaces the traditional methods of acquiring energy, such as purchasing electricity from the power grid and separately burning natural gas or oil in a furnace to produce heat and/or steam.
The traditional method of purchasing electric energy from a utility is convenient, however it is inefficient and wastes almost 75 percent of the energy in the original fuel due to production and transportation losses. On-site cogeneration systems can convert 70-90 percent of the energy of the fuel that is burned into electricity and heat that can be used. This efficiency directly leads to significant OPEX savings. The traditional electrical utility has been experiencing unprecedented interruptions due to climate crisis related weather events in the last few years. As hurricanes, wildfire, extreme cold, and heat become more and more common, having an on-site electric power generator can provide additional resiliency, ensuring business continuity.
With systems powered by natural gas, Cummins provide a cogeneration solution that captures ‘waste heat’ – this has potential to cut facilities fuel consumption in half whilst also saving up to 35 percent on overall energy costs. Our gas genset portfolio will ensure that facilities receive improved electric supply reliability and eligibility for CHP tax credits and ‘carbon credits’ for reduced CO2 emissions.
A more environmentally-friendly option
Arguably the biggest benefit of cogeneration systems is that they support businesses and the environment. When it comes to emissions, burning natural gas in an on-site reciprocating engine generator produces less than half of the CO2 produced by an equivalent amount of coal burned in a central power plant. In addition, since CO2 production is directly related to the amount of fuel burned, cogeneration’s high level of fuel efficiency reduces overall CO2 emissions, while conserving natural resources and lowering costs.
In the context of developing global emissions standards, the Cummins HSK78G can operate with emissions as low as 250 mg/Nm3 (0.5g/hp-hr) NOx without the need for aftertreatment, using a broad spectrum of fuel qualities. This range of generators is suitable for continuous operation in most geographic areas of the world, as they are emissions compliant on a global scale.
With the addition of exhaust aftertreatment, even lower emissions can be achieved with the Cummins HSK78G whilst still providing market-leading thermal efficiency at 47.1 percent and 2110 kW of thermal output for heating, cooling and steam generation. These systems also feature fast starting and installed costs that are about one-half that of cogeneration systems based on gas turbines. Practical internal combustion engine driven cogenerations systems range in size from 300kWe to 40MWe or more electrical output, and 1.5 MBtu to 45.2 MBtu thermal output.
Why cogeneration is here to stay
The United State Department of Energy (DOE) has established a goal of having cogeneration comprise 20 percent of generation capacity by 2030. With countries across the world making bold emissions targets, cogeneration systems will continue to be in demand.
Cogeneration systems are extremely reliable. The traditional electricity service, which has become increasingly unreliable, represents a huge safety and health risk for many companies and organizations. Cogeneration systems are an on-site electrical and thermal resource that can be specifically designed to support continued operations in the event of a disaster or disruption.
Cogeneration systems that produce both electricity and heat and/or cooling from the same fuel can offer energy savings of up to 35 percent for a wide range of facilities, while at the same time contribute to building sustainability, reliability, and protecting the environment. The potential for cost savings in energy expenditures is usually the motivating reason to consider cogeneration, but sustainability is becoming a reason on its own to investigate the potential benefits further.
At Cummins, we see the trend for cogeneration growing. The HSK78G provides a clear solution to successfully reduce greenhouse gases with a reliable power system, capable of producing electric power and thermal energy for heat, steam, and air conditioning. The lean-burn gas Cummins HSK78G provides reliable power no matter how extreme the fuel source or operating conditions. From sports centers in China to greenhouses in Belgium, Cummins is focused on implementing successful cogeneration projects worldwide.
Jaimie Hamilton-Antonson is Technical Leader-Energy Management at Cummins. Cummins Inc., a global power leader, is a corporation of complementary business segments that design, manufacture, distribute and service a broad portfolio of power solutions. Headquartered in Columbus, Indiana (US), since its founding in 1919, Cummins employs approximately 57,800 people committed to powering a more prosperous world through three global corporate responsibility priorities critical to healthy communities: education, environment and equality of opportunity. For further information please visit: www.cummins.com/generators-power-systems