Located in Northern Europe, Denmark is a country with a population of less than 6 million, but is well-known for its developed new energy industry and ambitious energy transition goals . Water consumption and carbon emissions are decoupled. At present, Denmark's wind power generation accounts for about 42% of its total power consumption, and it is planned to reach 50% by 2020. In 2011, the Danish government proposed to completely say goodbye to fossil energy by 2050, and 100% of energy demand will be provided by clean energy. The most important reason why Denmark dares to set such a radical goal is the widespread use of "district heating" and combined heat and power.

District heating experience brings Danish "energy fairy tale" to millions of households

The biggest feature of district heating is its flexibility. It is a collective power, which means that you can not only use a certain boiler to burn the heat generated by coal, oil or natural gas, but also have the flexibility to choose the cheapest fuel in the heating network. Much of the heat in Denmark is from industrial waste heat, waste incineration, or combined heat and power (CHP).

In 2014, almost 50% of district heating in Denmark was generated by renewable energy. These renewable energy sources include biomass (wood, waste, straw and bio-oil), biogas, solar energy, geothermal energy and electricity (heat pumps and electric boilers).

Denmark is one of the most energy efficient countries in the world. The key is that 63% of Danish households use district heating for heating and hot water. In addition, about 60% of the electricity comes from cogeneration with an efficiency of up to 92%.

This makes district heating an integral part of Danish heat and electricity supply. The efficiency and flexibility of district heating and combined heat and power systems is the core technology for Denmark to escape the goal of fossil fuels by 2050. Taking Copenhagen, the capital of Denmark, as an example, 98% of the thermal energy comes from district heating.

Denmark, as a country based on agriculture, has residents scattered in towns and villages, large and small. In 1971, it became the first country to establish the Ministry of Environmental Protection. In 1976, the Energy Agency was set up to take charge of energy. Quickly clarified the formulation of new energy policies that prioritized energy conservation, mainly wind energy and biomass energy, in line with Danish national conditions.

In the new century, the context of Denmark's "energy fairy tale" is clearer. In 2008, the Danish government also set up a Danish Climate Change Policy Committee, which formulated an overall action plan and roadmap for the country to completely end its dependence on fossil fuels. The most important law concerning heating is the Heating Act, which governs public heating systems.

In accordance with the "Heating Act", local city governments are responsible for preparing heating plans for municipal areas. The general principles of heating planning are: promote heating methods in accordance with the maximum social benefits; promote the most environmentally friendly heating methods; vigorously promote the promotion of combined heat and power; and minimize the dependence of energy supply on petroleum and other fossil fuels.

The bill stipulates that when a local heating system is newly built or expanded, there are clear rules on which fuels must be used. In the case of combined heat and power, almost all types of fuels can be selected. But for dedicated heating equipment (without cogeneration), the type of fuel that can be selected depends on whether natural gas is available in the area where the equipment is located. If natural gas is available in the area, the dedicated heating equipment can only use natural gas. If there is no local natural gas supply, you can choose to use biomass, garbage, biogas, landfill gas and other gasified biomass as fuel.

As of 2014, nearly 70% of Danish national district heating came from combined heat and power plants, which saved a lot of fuel compared to individual heating and power generation systems.

Economic measures encourage public participation, technological innovation cannot be ignored

On the one hand, the Danish government subsidizes heating companies. Enterprises that use combined heat and power and renewable energy can enjoy a certain amount of subsidies. For example, generating electricity from biomass fuel will receive a subsidy of 20 Euros per MWh.

On the other hand, the Danish government also uses tax and price leverage to increase business and public participation. For example, the Danish government has introduced an “energy saving account” mechanism in the construction sector. The so-called energy-saving account means that the building owner pays an energy-saving fee to the energy-saving account every year. The amount is calculated based on the building energy efficiency standard multiplied by the heating area, and is divided into several levels. Buildings that have undergone energy efficiency retrofits can be regraded as a basis for reducing or eliminating this energy saving expense.

For the public, Danish law requires that all households have to install a heat meter, paying as much heat as water and electricity.

Energy-saving measures at the user end, such as energy-saving accounts, heat metering, and charging, while cultivating citizens' awareness of low-carbon and conservation, solve problems at the source and form a virtuous cycle of "pulling" energy-saving from the consumer side.

After many years of efforts, Denmark's green technology is far ahead of the world, becoming the largest exporter of the most developed EU countries. Green technology exports account for more than double-digit percentages of Danish exports for a long time. Ranked number one for many years.

Denmark vigorously promotes energy-saving technologies and prioritizes the development of "first energy sources". In the eyes of the Danes, unused energy is the best energy source, so energy conservation and energy efficiency improvement are considered "first energy sources", while new energy sources are "secondary energy sources" that immediately follow "energy efficiency".

Denmark is located in Northern Europe and has a long heating period. Many buildings need heating throughout the year. A large number of innovative heating and energy-saving technologies have emerged at the historic moment, which is a major feature of the Danish energy fairy tale. The Danfoss District Energy System uses waste heat generated during production for heating and domestic hot water. Not only has it improved energy efficiency, but it has also reduced its dependence on coal and other fossil energy sources. At present, there have been many successful cases around the world.

So far, the world's leading regional energy technology, represented by Denmark, has developed to the fourth generation, and the urban energy supply system has been upgraded from a single fossil energy source as the main heat source, to both “throttling” and “open source”. Multi-energy complementary modern green regional energy system.

The so-called fourth-generation district heating, that is, low-temperature district heating, uses low-grade heat from various renewable energy sources or waste heat as much as possible. Through the upgrading of heating system technology, the system can still ensure efficient operation. Because renewable energy is low-grade heat and the water supply temperature of the heating pipe network is relatively low, a pipe network with high transmission efficiency is required to complete this task. It is in this area that Denmark has always led the way in global district heating technology innovation.

Continue to reduce fossil fuels and actively develop "secondary energy". At present, more than 60% of buildings in Denmark use “secondary energy”, that is, renewable energy technology for district heating, including wind, solar, biogas centralized heating, ground source heat pumps, straw and waste incineration. The share of renewable energy in Denmark's heat supply has surpassed natural gas and coal, ranking first.

There is an island in Denmark called Samsu, with about 4,000 residents. The residents of the island have long relied mainly on fossil energy imported from the island to generate electricity and heating, and the forms of heating are also scattered. About 11 tons of carbon dioxide are produced per person per year. After the energy crisis began in the 1970s, the island's residents decided to change this situation. A revolutionary breakthrough occurred in the decade after 1997. After 2006, the island successfully used solar energy and wind energy to completely replace fossil energy sources such as coal, achieving "carbon neutrality", and becoming the world's first "zero carbon" area in modern life and production. After the Copenhagen Climate Change Conference in 2009, it became a world-renowned "green sanctuary".

At present, in addition to being completely self-sufficient, the electricity produced by clean energy in this area can also be exported to the island, which has become a "negative carbon" area. It is worth mentioning that the island, consisting of more than 20 villages, has mostly achieved district heating, and the heat source is completely sourced from local sources.

The zero-carbon project has achieved a lot of gains, and China can actively learn from its good experience

The Danish energy fairy tale is realized, and eventually it will be implemented in specific places and cities. Different cities and regions have formulated their own development goals and action plans based on the national overall strategy for energy conservation and emission reduction. Among them, the most typical is the "zero-carbon project" in Soenderborg.

This city located in the southern tip of Denmark, under the framework of the "zero-carbon project" launched in 2007, plans to build a zero-carbon society by 2029, 21 years ahead of Denmark's goal of completely saying goodbye to fossil energy. To ensure the implementation of relevant policies, the City of Soenderborg takes a holistic approach based on public-private partnerships (PPPs), covering technology, business, tourism, education, public participation, and other aspects.

Soenderborg encourages companies to use regional energy technologies to transform local heating facilities, and jointly launches local energy companies, heat companies, and financial institutions to work together to participate in the development of a zero-carbon economy.

In this context, Soenderborg has successfully established Denmark's most typical green and efficient regional energy system: it has realized a high degree of localization of heat sources, heat networks and heat users, and built a combined heat and power generation, heat storage technology and peak-shaving boiler room. As a whole, the district heating system that extensively uses all waste heat including biomass, geothermal, solar energy, wind energy and waste incineration, and even supermarkets, ensures the flexibility and high efficiency of the entire system.

The “Zero Carbon Project” encourages widespread participation of local residents. For example, a “zero-kindergarten to doctoral student” (fromkindergartentoPhD) zero-carbon education project has been established to “start from the baby”, forming a good atmosphere for everyone to be a “zero-carbon ambassador”.

After ten years of hard work, the "Zero Carbon Project" has achieved very impressive results. During the period 2007-2016, carbon dioxide emissions were reduced by 35.5%, creating nearly a thousand green jobs. In particular, after receiving the European Union's "Zero Carbon Demonstration Town" award from Soenderborg, it has received widespread attention from the international community. Former US President Clinton, who has visited it, calls it "global demonstration significance."

Denmark's successful experience in the field of zero-carbon economic development, especially in the area of district heating, has a very positive reference for China and the world.

In fact, Danish district heating-related technologies and experience have already been implemented in some parts of China, with considerable results. Benxi City in the south of Liaoning has adopted Danish regional energy solutions to carry out heating reconstruction in a heating area of about 3 million square meters. After nearly three years of successful implementation, the project has achieved initial results: the first year of project implementation The Bengang Thermal Power Company turned a profit and turned a profit to achieve profit while reducing the amount of coal burning by more than 20,000 tons, and the local air quality improved significantly. The latest data shows that Bengang Thermal Power Company achieved a profit of more than 8 million yuan in 2016. In the next two years, it is estimated that the use of waste heat for heating will exceed 5 million square meters, reduce the use of coal by about 200,000 tons, and return to the city.

This case proves that if Denmark's successful practices and best practices are combined with the specific national conditions in China, and they are used reasonably, a sound regional heating policy and management system in line with China's actual conditions will be established and China will accelerate the construction of an ecological, civilized, and conservation-oriented society. Is very helpful. From this perspective, Denmark's "energy fairy tale" can certainly become a "beautiful China" reality.

Link: Learn from other green heating experiences sent to the country

The heating methods of western developed countries such as North America and Europe are related to the type of building, location and energy resource endowment. Different heating methods are often adopted for energy saving and comfort. In the northern United States and northern Europe, the latitude is high and there are dedicated heating facilities. The northern United States mainly uses oil or gas for heating. The central United States mainly uses electric heating; in the southern United States and southern Europe, cooling and heating air conditioning is commonly used for heating.

Establish corresponding standards for residential heating energy consumption. This is the fundamental requirement for green and low-carbon heating. The United States and Germany have comprehensive heating energy standards. In the process of promoting green and low-carbon heating in China, we have also formulated a systematic heating energy consumption standard. However, in terms of energy-saving renovation of buildings, construction of centralized heating systems, and use of heating equipment with low energy consumption and low emissions, more incentive policies should be introduced to encourage reduction of building heating energy consumption and promote the green and low-carbon process of heating.

Implement heating charging methods that are conducive to energy conservation. Both Germany and Denmark have experienced the evolution from simple fixed-area charging methods to household-based metered charging methods. At present, China's heating charging methods are mainly based on area charging, which causes a large amount of heat loss and energy waste, which is not conducive to the green and low-carbon development of heating.

Heating technology is developing towards intelligent comfort and safety. Developed countries attach great importance to the role of new technologies in improving heating efficiency. Germany's advanced control system can make the heat pump air conditioner finely adjust according to the indoor and outdoor temperature and humidity changes. Denmark has achieved unique intelligent energy management, which has greatly improved heating efficiency. China should strongly encourage heating-related enterprises to actively study new heating modes and technologies. At the same time, advanced heating technologies in developed countries should be fully absorbed and introduced, and heating efficiency in China should be improved through improvements in heating technologies.

Active use of renewable energy as heating energy. As countries pay more attention to climate change and are affected by fluctuations in fossil energy prices, more and more countries are committed to heating with renewable energy and clean energy to reduce the impact of heating on the climate and the environment. For example, Denmark encourages the use of renewable energy such as wind power and biomass energy as energy for heat consumption, and the United States uses clean energy such as natural gas and electricity as the main energy source for heating. Among heating energy sources, the use of clean energy such as solar energy, wind energy, and biomass energy should be encouraged. Especially under the current situation of relatively surplus electricity, electric energy can be vigorously used as the main energy source for heating.

Focus on economic incentives to advance the process of green heating. The green heating mode cannot be achieved overnight, and the transition from the traditional function mode to the green heating mode requires a certain investment. Countries actively adopt a combination of multiple economic incentives to promote the green heating process. The Chinese government should set up special funds for energy-saving renovation of buildings, research and development of heating technology for enterprises, and encourage residents to adopt more environmentally friendly heating modes to reduce carbon emissions and improve energy efficiency.