Transformation of heating using a hybrid system composed of a Gas Turbine, a Thermal Solar Farm and a Heat Accumulator

The transformation of district heating in Poland is one of the key areas of activity of our engineers. The market expects systems that enable a departure from conventional coal technologies in favor of low-emission solutions while maintaining the current heat prices for the end user.

The Renewable Energy, Decarbonization and Development team established as part of Eneria’s operations is developing concepts for hybrid gas-RES systems, the implementation of which is an excellent way to decarbonize generating capacity.

It is this decarbonization that is currently a challenge for the Polish heating sector. For the most part, it concerns larger heating systems with ordered capacities above 20MWt, for which it is necessary to meet the requirements of an Effective Heating System.

Effective Heating System

By the end of 2025, we consider an energy-efficient heating system to be one in which at least 50% is used for heat production. energy from renewable energy sources or utilized waste heat, or 75%. heat from cogeneration. The regulator also allows a mix of the above sources.

In the coming years, the requirements will become more stringent and building a system that meets the new requirements will be an even greater challenge.

By December 31, 2027, the energy-efficient heating system is to use 50 percent. renewable energy or 50 percent waste heat, or 80 percent heat from cogeneration, or at least 50%. combination of energy and heat sources mentioned earlier. This tightening of requirements for CHP installations makes it very difficult to balance a system based on large gas engines above 5 MWt.

The perfect CHP unit for this scale of investment is a gas turbine, which is explained in more detail later in this publication.

The concept of a hybrid system – a case study

In response to an inquiry from a given thermal energy company, we have prepared a concept for comprehensive decarbonization of generating capacity. Currently, the discussed heating plant uses 8 coal-fired boilers with a total power of 98 MWt. The system supplies heat energy to individual consumers and public utility facilities. We analyzed various technologies to meet the following assumptions:

• Replacement of current generation capacity;
• Maintaining system heat prices;
• Possibility of expanding the system by scaling;
• Compliance with the requirements of an efficient heating system after 2028;
• Diversification of revenues (sale of electricity);
• Ensuring self-financing of the enterprise;
• 60MW of gas available,
• with no possibility of increasing transmission;
• Budget up to PLN 150 million.

We have identified a system based on the following elements as the variant that best fits the profile and the boundary conditions given above:

• Cogeneration systems based on the Caterpillar Solar Turbines gas turbine;
• Gas peak boilers heat accumulator;
• A renewable energy source built on the basis of TVP Solar solar collectors

Cogeneration System – Gas Turbines

Being the exclusive distributor of Caterpillar equipment in Poland, we have also analyzed the possibility of using CAT gas engines in various power variants, but we do not see the need to offer them here. At high power levels, this is simply not an economical solution. The engines are perfect for systems with lower power, below 5 MWt. In the case of such comprehensive decarbonization with a small amount of available gas, this solution is not only more expensive, but also would not meet the requirements of an Effective District Heating System.

We have analyzed several variants of cogeneration systems for PEC. This concept presents two of the most advantageous ones in terms of the expenditure and work profile of the company. We were provided with data regarding the available power in gas fuel and gas pressure. Both variants are equipped with the possibility of fueling with diesel fuel to ensure coverage of the power ordered when the amount of gas fuel is insufficient. Burning diesel fuel in cogeneration allows you to avoid excise tax and sell electricity. Oil must be used regularly to avoid its degradation, because combustion in a gas-oil boiler is not economical from the point of view of resource management.

Variant 1:

2x Mars 100 Gas Turbine, 10.3 MWe & 19 MWt

Variant 2:

3x Taurus 60 Gas Turbine, 5.67 MWe & 12 MWt

Both variants are compatible with a heat accumulator, which is an excellent solution for the PEC company.

Gas Turbines in ready-made PGM (Power Generation Module) container buildings.

PGM is the generation unit of the future. Modern heating requires clean and economic sources of heat energy for individual consumers. The use of gas turbines instead of coal boilers enables the diversification of PEC’s revenues and maintaining stable heat prices.

By choosing such a product, the customer shortens the implementation time, design and construction work to a minimum. PGM is a built-in gas turbine, complete with all necessary installations, ready for operation within a few days of its installation at the customer’s site. We offer this product in capacities ranging from 3.5 MWe to 16.5 MWe.

PGM by Solar Turbines is:

• An energy source you can rely on;
• The path to decarbonization;
• Solution supported by a number of proprietary IT systems;
• Effective cogeneration;
• Lowest emissions and fuel consumption;
• Compact dimensions;
• Fast service and installation;
• Maintenance-free solution for years.

If a prefabricated PGM solution does not meet the customer’s requirements, we can design and build a tailor-made cogeneration system using any of the turbines from the Caterpillar Solar Turbines portfolio.

Thermal Solar Farm – TVP Solar Thermal solar panels have so far been considered the domain of Southern countries, the solution seemed to be replaced by the very popular PV installations. However, this solution may have a significant contribution to the decarbonization of district heating in Poland and other countries in the region. The key is to select the right technology to meet the challenges facing the sector.

In cooperation with the Swiss company TVP SOLAR SA, we have introduced a unique product to the market: vacuum, high-temperature Thermal Solar Panels designed for installations with high thermal power above 500 kWt. The panels are manufactured in Europe, and former CERN employees in Switzerland are responsible for the entire program.

 

What makes our installations unique?

Perfect mastery of high vacuum technology, which captures solar heat, retaining it behind the thick glass of the panels to heat the water to 200°C. Without any heat loss. Thanks to the efficiency of 3MWt per hectare of area, our installation always reaches the set temperature, regardless of the season. TVP Solar panels, unlike other technologies available on the market, receive energy from direct rays and diffused light, which, in Polish conditions, allows operation all year round. Thus, we are able to generate heat also in winter.

• The installed power was assumed to be 5 MWp, which corresponds to half of the available plot (building area 14,000 m2).
• Throughout the year, we are able to generate approximately 8,000 MWh of thermal energy in the form of network water.
• During the summer period (June – August) we will cover the demand generated by customers during the day (8 – 10 hours a day). The system will operate all year round.
• It is possible to build a larger installation within the available area.
• The warranty is 25 years and with this assumed operating time, the price of heat does not exceed PLN 45 / GJ.
• In the presented system, the share of heat from renewable energy sources is approximately 8 percent, which meets the requirements of an effective heating system.

Day/night battery

The solution we propose includes a heat accumulator with a capacity of 20 MWh / 700 m3. This is the minimum size that ensures effective operation of the entire system. The battery is the clutch between the cogeneration installation and TVP panels.

It allows you to charge the battery in the summer only when the production of electricity is profitable for the user.

 

Hybrid System – summary

The solution we present is the simplest way to decarbonize PEC while maintaining rational investment costs.

 

Gas turbines in a CHP system supplemented with water boilers and a heat accumulator are:

• Possibility to work all year round;
• Meeting the requirements of an effective heating system; Utilization of available power in fuel;
• Highest system redundancy; 6 – 7 years of operation of the main equipment for renovation;
• Revenue diversification;
• Low expenditure compared to competing technologies;
• Maintenance-free solution for peace of mind;
• Possibility of construction in stages;
• Possibility of multi-fuel power supply;
• Readiness for hydrogen / ethanol / biogas without technology replacement.

The hybrid system proposed by Eneria based on gas turbines, TVP Solar panels and heat accumulators allows for efficient use of energy both during the day and at night. Thanks to this solution, it is possible to meet the heat and electricity demand of consumers at different times of the day while achieving the goals of decarbonization and energy efficiency.

mail: jbigoszewski@eneria.pl

Author: Jakub BIGOSZEWSKI

Product manager, Gas Turbines Expert