Advantages of Gas-Fired Distributed Combined Cooling, Heating, and Power Systems
Advantages of Gas-Fired Distributed Combined Cooling, Heating, and Power Systems
Advantages of Gas-Fired Distributed Combined Cooling, Heating, and Power Systems
The main advantages of gas-fired distributed energy systems for combined cooling, heating, and power (CCHP) are as follows.
1. Optimizing the energy structure
Gas-fired distributed CCHP systems mainly use clean primary energy sources such as natural gas and renewable energy. This aligns with national energy planning and energy-saving and emissions-reduction policies. It helps improve and optimize China’s long-standing coal-dominated energy structure. In addition, the use of natural gas in distributed energy systems can improve the utilization of gas transmission pipelines, help balance seasonal mismatches such as surplus natural gas in summer and shortages in winter, and relieve pressure on the power system through peak shaving and valley filling.
2. Improving overall energy utilization efficiency
In theory, the centralized energy model of “large generating units, large power grids, and ultra-high voltage transmission” is highly efficient, but this is true mainly at the conversion and transmission stages. If the entire energy system is considered, the conclusion is different. Although large thermal power units can generate electricity efficiently, waste heat from power generation often cannot be effectively utilized because of limitations in heating scale and heating radius. As a result, their overall energy utilization efficiency cannot compare with that of gas-fired distributed CCHP systems.
Even with some of today’s most advanced generation technologies, such as 1000 MW ultra-supercritical coal-fired units, coal-fired power generation efficiency is about 50%, while natural gas power generation using 300 MW triple-pressure reheat combined-cycle units reaches about 58%. By comparison, gas-fired distributed CCHP systems can simultaneously provide users with cooling, heating, and electricity, while also enabling cascade and highly efficient use of high-quality natural gas energy. This significantly improves comprehensive energy efficiency and offers an effective way to conserve energy, improve energy utilization, increase energy supply, and address energy shortages, energy crises, and energy security concerns.
3. Lower transmission and distribution losses with relatively strong economic benefits
Gas-fired distributed CCHP systems typically use small or micro-scale power generation equipment, such as gas internal combustion engines, small gas turbines, micro gas turbines, and fuel cells. These are integrated with heating, cooling, dehumidification, and domestic hot water systems. Because these systems are generally small in scale, they allow users to meet their own energy needs directly. By improving overall energy efficiency, they can reduce energy expenses and generate investment returns. As a result, their rate of return is often relatively high, the upfront investment per unit of power is comparatively low, and operation and maintenance are convenient.
At the same time, gas-fired distributed CCHP systems are usually installed close to the user side, supplying electricity, heat, and cooling nearby. This not only avoids the need for long-distance transmission facilities and multiple layers of substations and distribution networks, but also improves power supply reliability, optimizes the power system, and reduces transmission and distribution losses. In addition, these systems can reduce or replace the need for centralized district heating plants, heating pipe networks, and heat exchange stations, thereby lowering municipal infrastructure investment and fiscal subsidies.
4. Low emissions and strong environmental benefits
Gas-fired distributed CCHP systems perform well environmentally. By using natural gas as fuel, they reduce total emissions of harmful pollutants. Because they enable rational cascade utilization of high-quality energy, SO2 emissions and solid waste emissions are close to zero; greenhouse gas and CO2 emissions can be reduced by more than 50%, NOx by about 80%, and total suspended particulates by about 95%, showing clear emissions-reduction benefits. At the same time, the share of renewable energy in distributed CCHP systems continues to grow, and in some cases hydrogen, solar, and wind energy may also be used, substantially reducing fossil fuel consumption. These systems can also adopt denitrification, carbon dioxide removal, and other auxiliary emissions-reduction technologies, further decreasing harmful gas emissions and improving environmental protection outcomes.
Because gas-fired distributed CCHP avoids the construction of large-capacity, long-distance, high-voltage transmission lines, it not only reduces electromagnetic pollution from high-voltage lines, but also decreases the need for transmission corridors and related land occupation. It also reduces the cutting of trees beneath transmission routes, effectively saving land resources, and can reduce water consumption by more than 60%, contributing to a green economy.
The power equipment used in gas-fired distributed CCHP systems, such as gas turbines and boilers (or heat exchangers), can achieve relatively high levels of pollution control and are more environmentally friendly than conventional separated energy supply facilities. The application scope of gas-fired distributed CCHP continues to expand across industry, commerce, public buildings, and residential housing, with emissions-reduction ratios steadily increasing. In the building sector in particular, green buildings and even future “zero-energy buildings” are emerging.
Gas-fired distributed CCHP systems can also be coupled with renewable energy and create favorable conditions for renewable energy development. Through the use of solar energy, geothermal energy, biomass energy, and other renewable resources, they help promote harmonious development between humans and nature and support ecological balance. Like renewable energy itself, distributed energy systems are decentralized and small in scale, making them well suited for integration with renewable energy and for complementary use with fossil fuels. This helps solve common renewable energy challenges such as low energy density and intermittency. In addition, combining distributed energy systems with the utilization of industrial waste heat, waste pressure, wastewater, waste gas, and solid waste supports the development of a circular economy, the construction of industrial eco-parks, and further emissions reduction.
5. Improving the security and reliability of energy supply
Gas-fired distributed CCHP is an energy system deployed on the user side. Compared with energy sources such as solar, hydropower, and wind, which are more affected by geography and climate, it offers greater operational flexibility in terms of energy supply security and reliability. In the event of a public grid failure, the system can disconnect from the grid and continue supplying power independently to users, thereby improving the reliability of their electricity supply. If a fault occurs on the user side, it can also actively disconnect from the public grid, reducing the impact on other users.
The widespread use of electric cooling and heating equipment can sharply increase grid load and seriously threaten the reliability and safety of power supply systems. By contrast, with a gas-fired distributed CCHP system, the generator can operate as a self-owned power source connected to the urban grid. This can ease grid pressure, improve power quality, ensure reliable electricity supply, and help avoid power supply crises.
6. Intelligent control and management
Because the network of a gas-fired distributed CCHP system can connect the automatic control of each energy device, it can achieve intelligent command and dispatch. Based on overall demand for electricity, heat, and cooling, as well as energy storage and fuel fluctuations, the system can optimize adjustments accordingly. This enables comprehensive balancing of peak and valley variations in electricity, heating, cooling, hot water, and fuel use, resulting in intelligent control and management.
At the same time, gas-fired distributed CCHP systems are generally small in capacity, and their units can start, stop, and adjust quickly. They are suitable for unattended operation, making them highly flexible and easy to operate.
