According to the concept for the transition of the Republic of Kazakhstan to a "green" economy, the share of renewable sources in the total volume of electricity production by 2030 should be 10%, in 2050 – 50%. At the end of 2020, this factor was 3%, and the total installed capacity of renewable energy facilities in Kazakhstan exceeded 1,500 MW.

The high rate of generation development at the RES requires the adoption of proactive measures to ensure the integration of the planned volumes of the RES without reducing the reliability of the Kazakhstan’s UES.

KEGOC JSC together with the USAID project's experts “Future Energy” conducted a study on the impact of the actual modes of renewable energy sources operation on the imbalances of the Kazakhstan's UES.

Research perimeter

The study covered 63 RES facilities with a total installed capacity of 1,250 MW (Table 1). There were analyzed the hourly, planned and actual generation of RES, the deviation of the balance of power flows at the border of the Northern and Western zones of the Kazakhstan's UES with the UES of Russia (imbalances of the Kazakhstan's UES) for 2020.

Table 1. Installed capacity of RES facilities covered by the study [MW]:

The studywas conducted according to the data of the AMRCS (Automated Meter Reading and Control System) and BEMS (Balancing Electricity Market Systems), that is, only the average hourly performance of RES and the power utility system was taken into account.

Assessment of the actual generation by RES facilities

In 2020, the RES covered by the study produced 2,101 million kWh of electricity, with a planned production of 2,051 million kWh.

However, the profile of electricity generation by RES facilities during the period under review has a significant unevenness both in the context of days and in the context of months. Figure 1 shows the diagram of RES generation by type for the typical periods of the year (January, July). The maximum total peak capacity of all RES facilities was up to 700 MW (in May 2020), and the average base of RES generation in 2020 (guaranteed minimum total generation for all RES facilities) in the monthly context was 50 MW.

Maximum generation by type: -SPP367MW, - WPP200MW, - SHPP 16,5 MW. Total for all RES: 447 MW

Maximum on by type: - SPP 478 MW, - WPP 148 MW, -SHPP62MW.  Total for all RES: 590MW

ESTIMATION OF DEVIATIONS OF THE RES FACILITIES GENERATION FROM THE PLANNED VALUES

In accordance with the rules of the Kazakhstan wholesale electricity market, the subjects plan their regime day ahead. It is clear that in the context of the RES facilities, which generation is highly dependent on the flow of unstable solar and wind energy, planning is carried out with errors that lead to deviations of the actual generation of RES from the planned values on the operating day, which creates an additional imbalance of electricity production and consumption in the UES of Kazakhstan.

Figure 2 shows the diagrams of the total deviations of the actual RES generation from the plan for the typical periods of the year (January, July). As can be seen from the figure, with the maximum generation of RES in January of about 450 MW, the maximum deviations were up to 230 MW for re-processing of energy into the system and up to 113 MW for reduced production of electricity. In July, with the maximum generation of RES of about 600 MW maximum deviations were up to 102 MW for re-processing of energy into the system and up to 250 MW - for reduced production of electricity. In the annual context, the range of deviations of RES generation from the plan was about ± 250 MW, the average values of deviations in the range of 200 MW for reduced production of electricity and up to 150 MW for re-processing. In relative terms, the deviation of RES generation from the plan was on average up to 30%.

Note: positive values of deviations mean that the actual generation of RES exceeds the planned values (unplanned delivery of electricity to the power system).

Due to the lack of flexibility of generation in the UES of Kazakhstan, due to the high share of low-maneuverable coal generation, and the lack of regulatory capacity, the attracted regulatory resources are not enough to fully compensate for the unstable generation of renewable energy sources and deviations of the regime of other market participants. The imbalances of the UES of Kazakhstan that are not covered at the expense of its own resources are compensated by the Russian energy system (in the form of unplanned balances of power flows at the borders of the two energy systems).

Further, studying the impact of RES on the UES regimes of Kazakhstan, work was carried out to determine the share of RES imbalances in the total imbalance of the UES of Kazakhstan, which is not covered by its own sources of regulation. Methodologically, the calculation was made as follows. Based on the readings of the AMRCS system for each hour of 2020, an unplanned balance of power flow at the border of the UES of Kazakhstan and the UES of Russia was determined, without taking into account flows from the UES of the Central Asia (the own imbalance of the UES of Kazakhstan). Also, the total difference between the actual and planned generation of the RES facilities (the imbalance of RES) was determined by the AMRCS and, accordingly, the share of RES imbalances in the total imbalance of the UES of Kazakhstan was calculated.

The results of this part of the study for the characteristic periods of the year (January, July) are shown in Figure 3. On average, in 2020, the deviations of renewable energy generation in the overall imbalance covered by the UES of Russia amounted to 20%. In some months, the share of non-balances of renewable energy sources in the total deviations of the UES of Kazakhstan reached a value of up to 30%. It is important to note that in accordance with the agreement on the parallel operation of the energy systems of Kazakhstan and the technologically permissible deviation of the balance of power flows along the borders of the UES of Kazakhstan and the UES of Russia from the planned values is ±150 MW, and the deviations of RES, even without taking into account the imbalances of other power system subjects, exceed the permissible value.

Regulation of the RES facilities

To ensure the reliability of energy supply to consumers, the reliability of the operation of the UES of Kazakhstan as a whole, the instability of renewable energy generation should be compensated by attracting the regulatory capabilities of the energy system.

Such regulation is carried out, starting from the planning of modes for the day ahead, and up to the regulation in real time on the operating day.

Figure 4 illustrates the basic, that is, at the planning stage for the day ahead, regulation of renewable energy sources (for example, one day on January 27, 2021). As you can see, in the daytime, when the share of SPP generation is high, customary power plants are regularly unloaded, and after 16 hours, as the natural generation of SPP decreases, customary power plants regularly replace the retired SPP generation.

Figure 5 shows the planned schedule of the RES generation (based on the example of one day on January 27, 2021). As you can see, the average hourly generation is about 300 MW, with a maximum of 600 MW and a minimum of 200 MW. Accordingly, the full integration of planned generation of RES into the daily schedule required an increase in the number of customary power plants by 300 during the day MW and a reduction of 100 MW. That is, the attracted range of basic regulation at the planning stage was 400 MW.

Also, during the operating day, the system operator uses all the possibilities of regulation, giving commands for loading and unloading power plants. For example, the range of use of the reserve at epy Bukhtarminskaya HPP, in the context of the day, can be 400 MW, Moinak HPP — 200 MW, Ekibastuz GRES-1 — 200 MW. Other power plants are also used, if there is a reserve. However, as mentioned above, the available regulatory resources are not sufficient to fully compensate for the existing imbalances in the UES of Kazakhstan, which leads to the involvement of Russian regulation.

Results of the study

Let us briefly summarize the results of the study.

·            The base of renewable energy generation is 50 MW with an installed capacity of 1,250 MW.

·            The peak of generation in total for all RES facilities at the end of 2020 was 700 MW.

·            The required volume of regulation of the operation of RES is 650 MW (for 2 MW of the installed capacity of RES — 1 MW of regulation).

·            The basic regulation involved (at the planning stage) is about 400 MW.

·            The amount of the required reserve to compensate for deviations of RES from the planned generation is not less than ±250 MW.

Institutional measures

·            Introduction of a balancing electricity market

·            Gradual increase in the share of spot trades "day ahead"

·            Development of the auxiliary services market (stations, adjacent power systems, Demand Response)

System flexibility

·            Construction of anew regulating capacity (gas + large hydroelectric power plants)

·            Maximum development of the ALFC system

Digitalization

·            Launch of pilot projects on the possibilities of using storage systems

·            Research and modeling of the impact of RES on the Unified Energy System of the Republic of Kazakhstan

·            Engaging Consumers in Regulation (Demand Response Research)

·            Technical and economic dispatching of the production schedule

·            Reducing the planning horizon from a day to 12 hours — 6 hours — 1 hour

Renewable energy

·            Fixing the obligation for forecast and responsibility of RES for deviations

·            Development of wind and solar generation through project auctions and RES zones

·            Changing approaches to auction bidding (buying at certain hours, buying in a certain

Of course, this list is not exhaustive and was mostly presented as possible options. What activities should be started with and how they should be implemented are, of course, open questions. We expect that market participants will be active and offer their options, which will also be widely discussed and considered.

We are convinced that all market participants, including RES representatives, are interested in solving the problems of integrating renewable energy variables and maintaining the stability of the Unified Electric Power System of Kazakhstan.