Compared to European countries, where today distributed generation facilities account for almost 30% of all generation, in Russia, according to various estimates, the share of distributed energy today is no more than 5-10%. Let's talk about whether the Russian catch up with global trends, and consumers are motivated to move towards independent energy supply.
Apart from numbers. Find differences
The differences between the system of distributed generation of electricity in Russia and Europe today are not reduced to numbers - in fact, these are completely different models both in structure and from an economic point of view. The development of distributed generation in our country had motives somewhat different from those that became the main driving force of such a process in Europe, which sought to compensate for the lack of traditional fuels by involving alternative energy sources (including secondary energy resources) in the energy balance. In Russia, the issue of reducing the cost of purchasing energy resources for consumers in a planned economy and centralized tariff setting was much less relevant for a long time, so they thought about their own power generation mainly in cases where the enterprise was a particularly large consumer of energy and, due to its remoteness, had difficulties connected to networks.
By the standards of distributed energy, the facilities of their own generation had a fairly high capacity - from 10 to 500 MW (and even higher) - depending on the needs of production and in order to provide the nearest settlements with electricity and heat. Since the transfer of heat over distances is always associated with significant losses, there was an active construction of hot water boilers for the own needs of enterprises and cities. In addition, own energy sources - whether it be CHPs or boiler houses, were built on gas, fuel oil or coal, and RES (renewable energy sources) technologies, with the exception of hydroelectric power plants, and SER (secondary energy resources) were used in isolated cases. Now the picture is changing: small-scale power generation facilities are gradually appearing, and alternative energy sources are being involved in the energy balance, albeit to a lesser extent.
In the West, much is being done to develop small-scale generation, and recently the concept of a virtual power plant (WPP) has become widespread. This is a system that unites most of the players in the electricity generation market - producers (from small generators of private households to cogeneration stations) and consumers (from residential buildings to large industrial enterprises). WPP regulates energy consumption by smoothing out peaks and redistributing loads in real time, using all available system capacities. But such an evolution is impossible without stimulating the distributed generation market by the state and without corresponding changes in legislation.
In Russia, in the conditions of fierce competition and the monopoly of centralized power supply, the sale of excess electricity produced to the external network remains, although solvable, but far from being an easy task in terms of organization and cost of the process. Therefore, at present, the chances of becoming a full-fledged market participant among large suppliers for distributed energy facilities are extremely small.
Nevertheless, the development of its own generation is certainly in trend today. The main factor of its growth is the reliability of power supply. Dependence on generating and grid companies increases the risks for producers. Most of the large generation facilities in Russia were built back in the days of the USSR, and their considerable age makes itself felt. For an industrial consumer, the interruption of power supply due to an accident is a risk of stopping production and obvious losses. If the desire to reduce risks is accompanied by economic motives (determined mainly by the tariff policy of the regional supplier) and investment opportunities, then own generation justifies itself by 100%, and more and more industrial enterprises today are ready (or are considering such an opportunity) to follow this path.
Therefore, the development prospects for distributed power generation “for own needs” in Russia are quite high.
Own generation. Who benefits from it
The economics of each project is strictly individual and determined by many factors. If we try to generalize as much as possible, then in regions with a greater concentration of generating capacities and industrial enterprises, higher tariffs for electricity and heat, own power generation is an objective chance to significantly reduce the cost of purchasing energy resources.
This should also include hard-to-reach and sparsely populated regions with a poorly developed or non-existent infrastructure of power grids, where, of course, the highest tariffs for electricity.
In regions where there are fewer consumers and suppliers of electricity, as well as a large share of electricity generated by hydroelectric power plants, tariffs are noticeably lower, and the economics of such projects in industry are not always beneficial. However, for enterprises in certain industries that have the opportunity to use alternative fuels, for example, production waste, own generation can be an excellent solution. So, in the figure below - a CHP plant on the waste of a woodworking enterprise.
If we are talking about generation for public utilities, public buildings and commercial and social infrastructure, then until recently the economics of such projects was largely determined by the level of development of the region's energy infrastructure and, to no lesser extent, by the cost of technological connection of electricity consumers. With the development of trigeneration technologies, such restrictions actually ceased to be decisive, and it became possible to use side or generated heat in the summer for air conditioning, which greatly increased the efficiency of power centers.
Trigeneration: electricity, heat and cold for the facility
Trigeneration is a fairly independent direction in the development of small-scale power generation. It is distinguished by individualism, since it focuses on meeting the needs of a particular facility in energy resources.
The very first project with the concept of trigeneration was developed in 1998 by the joint efforts of the US Department of Energy, the national laboratory ORNL and the manufacturer of ABCM (absorption lithium bromide refrigeration machines) BROAD and implemented in the USA in 2001. Trigeneration is based on the use of absorption refrigeration machines, which use heat as the main source of energy and allow the generation of cold and heat depending on the needs of the facility. At the same time, the use of conventional boilers, as in cogeneration, in such a scheme is not a prerequisite.
In addition to traditional heat and electricity, trigeneration ensures the production of cold in the ABHM (in the form of chilled water) for technological needs or for air conditioning. The process of electricity production one way or another occurs with large losses of thermal energy (for example, with the exhaust gases of generator machines).
The involvement of this heat in the process of obtaining cold, firstly, minimizes losses, increasing the final efficiency of the cycle, and secondly, it allows to reduce the power consumption of the facility compared to traditional technologies for generating cold using vapor-compression refrigeration machines.
The ability to work on various heat sources (hot water, water vapor, exhaust gases from generator sets, boilers and furnaces, as well as fuel (natural gas, diesel fuel, etc.) is available to the company.
So, in industry, waste heat can be used:
And at municipal facilities, in commercial and public buildings, various combinations of heat sources are possible:
A trigeneration energy center can be calculated and built based on the needs for electricity, or it can be based on the cold consumption of the facility. Depending on which of the above is the defining criterion for the consumer. In the first case, waste heat utilization in ABHM may not be complete, and in the second case, there may be a limitation on own generated electricity (replenishment is made by purchasing electricity from the external network).
Where is trigeneration profitable?
The range of application of the technology is very wide: trigeneration can be equally well integrated into the concept of some public space (for example, a large shopping center or airport building), and into the energy infrastructure of an industrial enterprise. The feasibility of implementing such projects and their productivity strongly depend on local conditions, both economic and climatic, and for industrial enterprises also on the cost of products.
The first and most important criterion is the need for cold. Its most common application today is the air conditioning of public buildings. These can be business centers, administrative buildings, hospital and hotel complexes, sports facilities, shopping and entertainment centers and water parks, museums and exhibition pavilions, airport buildings - in a word, all objects where many people are located at the same time, where to create a comfortable microclimate requires a central air conditioning system.
The use of ABCM is most justified for such objects with an area of 20-30 thousand square meters. m (mid-sized business center) and ending with giant facilities of several hundred thousand square meters and even more (shopping and entertainment centers and airports).
But at such facilities there should be a demand not only for cold and electricity, but also for heat supply. Moreover, heat supply is not only space heating in winter, but also year-round supply of hot water for hot water needs. The more fully the possibilities of a trigeneration energy center are used, the higher its efficiency.
Throughout the world, there are many examples of the use of trigeneration in the hotel industry, construction and modernization of airports, educational institutions, business and administrative complexes, data processing centers, and many examples in the industry - textile, metallurgy, food, chemical, pulp and paper, engineering, etc. .P.
As an example, I will give one of the objects for which the company "» developed the concept of a trigeneration energy center.
When the need for electrical energy at an industrial enterprise is about 4 MW (generated by two gas piston units (GPU)), cooling is required at the level of 2,1 MW.
The cold is generated by one absorption lithium bromide refrigeration machine operating on the exhaust gases of the GPU. At the same time, one GPU fully covers 100% of the heat demand of ABCM. Thus, even with the operation of one GPU, the plant is always provided with the necessary amount of cold. In addition, with both gas piston units decommissioned, ABKhM retains the ability to generate heat and cold, since it has a backup source of heat - natural gas.
Trigeneration energy center
Depending on the needs of the consumer, on his category and redundancy requirements, the trigeneration scheme (shown in the figure below) can be very complex and may include power and hot water boilers, waste heat boilers, steam or gas turbines, complete water treatment, etc.
But for relatively small objects, a gas turbine or a piston plant (on gas or diesel) of relatively low electric power (1-6 MW) usually acts as the main generating plant. They produce electricity and waste heat from exhaust and hot water, which are utilized in the ABCM. This is the minimum and sufficient set of basic equipment.
Yes, you can't do without auxiliary systems here: a cooling tower, pumps, a reagent treatment plant for recycled water to stabilize it, an automation system and an electrical facility that allows you to use the electricity generated for your own needs.
In most cases, a trigeneration center is a stand-alone building, or containerized units, or a combination of these solutions, since the requirements for the placement of electrical and heat generating equipment are somewhat different.
Power generating equipment is quite standardized, unlike ABHM, although it is technically more complex. The terms of its production can be from 6 to 12 months and even more.
The average production time for ABCM is 3-6 months (depending on the cooling capacity, on the number and types of heating sources).
As a rule, the production of auxiliary equipment will not exceed the same time frame, so the total duration of the project for the construction of a trigeneration power center is on average 1,5 years.
Experience the Power of Effective Results
First, the trigeneration center will reduce the number of energy suppliers to one - a gas supplier. By eliminating the purchase of electricity and heat, it is possible, above all, to eliminate any risks associated with power outages.
Working with heat using relatively inexpensive "surplus energy" reduces the cost of electricity and heat generated compared to buying it. And year-round loading of generating capacities in terms of heat (in winter for heating, in summer for air conditioning and technological needs) allows us to ensure maximum efficiency. Of course, as for other projects, the main condition is the development of the right concept and its feasibility study.
Additional benefits are environmental friendliness. By using exhaust gases to generate useful energy, we reduce emissions into the atmosphere. In addition, unlike traditional refrigeration technologies, where ammonia and freons act as refrigerants, ABCM uses water as a refrigerant, which also reduces the environmental burden to a minimum.
Source: habr.com