FAQ about the design, construction and launch of energy centers in Russia


    Cogeneration gas piston unit of workshop design with a rated electric power of 1 MW. Nizhny Novgorod region, Bor.


    External view of the energy center, Nizhny Novgorod region, Bor. The nominal electric power of the energy center is 3.6 MW, the thermal power is 14 MW

    . Last year I wrote about energy centers. During this time, we have handed over several more objects, in particular, now 3 objects are at different stages of development. Somewhere these are completely whole projects, somewhere separate nodes. Demand for energy centers is in full swing, and our team was simply bombarded with questions. So here is the FAQ below.

    - In a nutshell, what kind of energy centers are these?
    Autonomous mini-power station running on gas or other fuel. Like any generator, it emits a certain amount of heat, which is used to heat the object and other tasks. In summer, heat can not be emitted into the atmosphere, but disposed of through an absorption refrigeration machine, which provides a resource for the cooling of data centers and air conditioning of the same shopping centers. The energy center is capable of producing electricity, heat and cold.

    - Is there an example of an object?
    Yes please. For example, we are currently working on an energy center for the data center and several office buildings in Vladikavkaz. All this needs electricity, heat and cold. They are located on the outskirts of the city and it’s not cheap and long to bring electric and heat networks there, and gas has already been supplied. It was decided to build their own energy center. It is small in power - 3 megawatts of electric power and 1.6 megawatts of heat and cold. Cold is needed for central air conditioning of the room and for supplying the data center to the machine room, and heat for domestic hot water and heating is a fairly common situation.

    - And remind what is cogeneration?
    A cogeneration plant produces both electrical and thermal energy. The efficiency of the use of fuel resources in cogeneration plants is 30–40% higher than with separate production of electricity and heat.

    - And what about trigeneration?
    Trigeneration is also the production of cold. Cogeneration plants are equipped with heat exchanger systems that utilize the heat generated during engine operation. This heat can be used for technological purposes (including steam production), for heating and hot water supply. Excess heat can be absorbed to produce chilled water. In the general case - water cooled to 5 degrees Celsius, ideal for air conditioning systems of the same shopping centers, office and public buildings, data centers.

    - Is trigeneration always used?
    No not always. An energy center can produce several types of energy resources: electricity, heat, cold, steam and CO. Depending on the tasks at a particular facility. Sometimes you just need power, sometimes all at once. The use of several energy resources increases the overall efficiency of the energy center. For example, in the Nizhny Novgorod region there is a commercial energy center in a field on the banks of the Volga. It produces electricity and heat. Electricity is supplied both to direct consumers (under a direct contract) and to the network at a protected rate. Heat is supplied to the nearest village through its own heating main.

    - Is there an example of an object where only part of the energy center is being built?
    For example, we are now doing just a boiler room and gas supply infrastructure for one shopping center. This is the simplest example. Sometimes we do only transport infrastructure for fuel and so on - there is a lot of different work.

    Here is a card from one of the objects:
    • Type of construction - new construction.
    • The location of the construction site is the city of Bor, Nizhny Novgorod region.
    • Stage of construction - 3 phases (CROC participated in the implementation of only the second stage).
    • Purpose - the sale of electricity to an external network, and heat supply to the objects of the municipal sphere of the village of Oktyabrsky, Borsky district.
    • The reason is the creation of a commercial Energy Center for the sale of energy resources in the retail energy supply market to external consumers.
    • Nominal capacities of the second stage - electric power 1.6 MW; thermal power - 1.8 MW.
    • The execution of the CHPP is workshop.
    • Equipment of the second stage - KSU - MTU (Germany).
    • Project payback period - 3 years

    - Who needs such energy centers in Russia?
    • Data centers, for them, their own energy center - this is both saving and the ability to get another power / cooling vector.
    • Industrial enterprises, most often - either new or reconstructed. It’s just a matter of saving.
    • To farmers and housing enterprises, as well as to various logistic facilities consuming from 1 to 50 MW of electric power, autonomy comes first.
    • Shopping centers: like data centers, they are an ideal “client” for the energy center, since they use both energy and heat and cold.

    - And how does AbXM work for the production of cold?
    This is such a healthy cast-iron apparatus the size of half an apartment. There are complex chemical processes based on lithium bromine solution, continuous evaporation, condensation, in three cycles. As a result, you give hot water to the entrance, and you get chilled at the exit. Here on Wikipedia there are details .

    - What is the difference between turbine energy centers and gas piston centers?
    The type of engine that rotates the generator. A piston is like an internal combustion engine in a car, a turbine one is like in an airplane. Capacities up to 50 megawatts are more convenient to close with piston engines. Those that are 50 megawatts and more, this is already a big energy discharge, here there is a turbine. But the choice is not only in terms of power, but also in the selection mode.


    Element of the piston energy center. At the top there is an air manifold with a filter, at the bottom there is a system of cylinder blocks.

    - What is the power take-off mode?
    The turbine accelerates for a long time to enter the mode. For example, in Moscow at TPPs 21 and 24 there are almost the same 300 MW turbines from Siemens as at Boeings (only larger and with some design differences). For a full exit to the mode, you need from 20 to 25 minutes. If the power jumps constantly, two situations can arise: when one of the turbines is not turned on (and its resource is very needed) and when the turbines are turned on more than necessary (in this case we will warm the atmosphere). For gas piston engines, the exit time to the regime is much shorter - 5-7 minutes. In practice, objects of more than 50 megawatts in our segment of data centers and shopping centers are almost absent, therefore we use mainly gas piston units.


    Appearance of MTU gas piston unit


    GPU dry cooler system

    - And what happens during consumption spikes?
    The first energy centers, built almost at the time of electrification of the country, had difficult balancing. Modern do everything onboard, like the same internal combustion engine car. When you turn on the music in the car, the headlights do not start blinking - and here, the internal generator control system instantly responds to changes in the current consumption, adjusts the sampling power so that all consumers are fed without any deviations in quality and frequency. To date, this technology is well developed. Typically, a large number of controllers are installed in power centers: on the gas unit itself, on KGU, roughly speaking, on an engine with an attached generator. The load changes all the time depending on external consumers. The controller controls power, crankshaft speed, fuel supply and all engine modes in such a way

    So, one of the parameters - the step of surge and discharge of electric power - is a question of a design solution depending on the needs of the customer. For some consumers, for example, for supplying electricity to data centers, a sharp surge in capacities is very important, for others, for example, for industrial enterprises, a surge of 10% -15% of the nominal capacity of the installation per minute is acceptable. For example, for typical consumption of a shopping center of 2-4 MW, you can use the GPU, but it is important that the power surge is not more than 20% of the nominal power per minute. To illustrate, on average, the standard step of power increase at a gas turbine is 15-20%, and a gas turbine is lower. But even if the step of power surge at the installation is insufficient for the consumer, this can be corrected, for example, by backing up the external network (at the initial stage, the power will be taken additionally from the network), either by a combination with uninterruptible power supplies, or by installing a soft-start system on the consumer side, or by setting up the controller in this way. All these options for the study of transients are individual for the object and can be taken into account at the design stage.


    Schematic diagram of electric power output control

    - How is heat removed from the engine?
    The engine is equipped with heat exchangers, there are many different schemes. Heat is removed from the shirt, from the intercooler, from the exhaust, and so on. In general, everything that would otherwise go into the atmosphere goes to heat consumers.


    External heat recovery unit

    - What about exhaust fumes?
    They are formed in the same way as during the operation of a conventional ICE in a car. We use American or European equipment. Natural gas is a relatively clean fuel. The content of harmful impurities in the exhaust corresponds to half or even one quarter of the German standard TA-luft, which in turn is much tougher than Russian standards. Often in an urban environment, the existing high background does not allow us to measure our exhaust.

    - What about the ecology of energy generators?
    Environmental consequences are in any generation. Hydro-energetics influences nature through changes in the level and direction of rivers. Nuclear is known for emissions and the need for disposal / processing of spent fuel. Pure solar and geothermal energy, but its use is limited. The gas generation we use is much cleaner than coal-fired and black oil CHP.

    - What is the usual cost of producing resources in your energy center?
    Depends on the details for a particular object. In the general case, it is 1.5-2 times lower than the tariffs of local energy retail companies. In our practice, the annual savings from the introduction of a local energy center is 25-30% (in comparison with the use of the resources of the energy sales company).

    - Is it possible to commission capacities in stages?
    Yes, and this is very convenient when you need to distribute investments for 1-2 years: the commissioning of capacities is done in stages as the demand for them grows. But, of course, in good hands, in those hands that are able to organize the operation process, any energy center, even poorly designed, will work well, and the costs will be constantly low for operation. And, on the contrary, it is possible to make an energy center well, but to give it to crooked hands, then, due to the human factor, the costs will constantly increase, and ultimately they can kill the whole business in general. This is a human factor, this is a factor in the organization of the operation process. The last cavity of our project (mentioned in Vladikavkaz) is made quite accurately and conveniently for operation. The minimum number of people is engaged in maintaining the normal functioning of the suitability of this complex and conducting regular routine maintenance. Now there is only one person present at the facility - the dispatcher.

    - When is MOT done?
    On standard units - every 2000 hours. In practice, this is an inspection by 1-2 engineers 4 times a year. Sometimes we do this, but more often - the operational teams of customers.

    - What kind of fuel can I use?
    Natural gas, biogas from waste wood processing and livestock farms, biogas treatment plants and waste processing plants, coal, fuel pellets. In my practice, 98% of energy centers operate on natural gas.

    - The gas price is not fixed: if electricity tariffs rise, can it also rise?
    The growth rates of electricity and gas tariffs may vary, but the plug between them will always be approximately the same, since electricity is a product of gas. The final product is always more expensive than raw materials.

    - What is most often asked before ordering?
    In approximately 20% of cases, process engineers call me and ask specific technical questions. In the remaining 80% of cases, the questions relate to financial and time indicators: how to get an internal rate of return of 30% (easy), how much does such and such an energy center cost in such and such an area with such and such capacity, what is the area for building, how long is it how much the external gas pipe will cost in our practice, and so on. Accordingly, since there are a lot of such calls, we made a special calculator. It is approximate, but it gives an excellent idea of ​​how much it will cost for a data center or shopping center. If you understand finances and have already read the FAQ above, you can easily see the parameters of your energy center - namely, to estimate whether it is worth building or not, to understand the order of costs.

    UPD : not habrazhitel send me questions in mail, some, I think, will be interesting to all. They are lower.

    - What is the approximate efficiency provided by the piston unit when working on gas and generating heat and electricity?
    Up to 43% electric, up to 50% thermal. In total up to 93%.

    - You write that it is more convenient to close capacities up to 50 MW with the described installations, in reality there is a huge amount of gas turbine power plants with capacities from 10 to 50 MW. Why is it more convenient? It means that GPU is more convenient than GTU.
    Cheaper and the cost of equipment, and operation.

    - How many personnel are required to maintain and control a ~ 25 MW installation?
    It is necessary to separate the personnel operating and performing maintenance. At least 2 people are usually at the station around the clock, while up to 6-7 people can work on a day shift. Maintenance is carried out by contractors, the number of personnel from about 1 to 3 people, depending on the complexity of the work performed

    - How long does PP2000 last?
    6 to 8 hours, taking into account the cooling time of the equipment

    - You write that the time for a full-fledged exit to the GTU nominal mode takes 20 - 25 minutes. In fact, from the state of the hot reserve (the circuit is assembled, the rotor does not rotate), the time is about 12 minutes - this is a complete cycle with all the warm-ups and reaching the nominal value, in an emergency, the time is ~ 4 minutes. If the gas turbine does not work at nominal speed, then the load build-up speed greatly depends on the type of engine, if the engine is aviation, then with 10% of the load at a nominal value of ~ 5 sec, the ship will naturally last longer.
    GTU consider energy. Their inertia is much higher than the GPU.

    - And another question, what is the automated control system of the installation implemented on?
    Fundamentally, ACS & Rs are built on controllers that are determined by the equipment supplier; most often, Siemens and ComAp controllers are used.

    Calculator right here.
    Last post with a card for the construction of one of the objects in 2012 and photographs.

    I will be happy to answer your questions here in the comments or by mail to dmarkin@croc.ru .

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