Technology

C-Energy’s technical refinements include six Rolls Royce gas cogeneration units, which constitute by far the largest power source of this type in the Czech Republic as regards both number and capacity. This is also a unique installation across the whole of Europe in terms of the wide range of services this technology provides.

The first four units were commissioned in 2014, each with a power output of 9.25 MW and weighing 133 tonnes. Starting from zero, they are able to run up to their maximum power output and connect to the high voltage grid in under five minutes. They can therefore help balance out fluctuations in electricity flow in the transmission system and increase its stability – in extreme cases even preventing a blackout.

Two further Rolls Royce gas gensets commissioned in 2020 have a unit power output of 11.5 MW, and their installation at Planá nad Lužnicí in 2019 was a world first for this largest new type of generators launched by Rolls Royce. They achieve efficiencies of over 47% in electrical power generation mode and exceeding 84% for combined heat and power.

When it was commissioned in 2019, this was the largest battery storage facility in the Czech Republic, with a power output of 4 MW and a capacity of 2.5 MWh. For C‑Energy’s Planá CHP plant, however, the size of the storage facility is not as important as its unique functionality, in particular the resulting greater flexibility of C‑Energy’s existing power generators, which increases its ability to ensure affordable energy. The batteries installed at the facility could power the electrical devices of an average Czech household for up to a year, and a single charge would be enough to send an electric car 12,500 km (roughly the distance from Planá nad Lužnicí to Phnom Penh, Cambodia).

The battery storage facility is unique in that it is connected alongside the existing CHP plant. Even with a relatively low capacity, the battery provides high power output, allowing coverage of C-Energy customers’ peak power consumption to be efficiently optimised, along with the provision of balancing services. The Planá nad Lužnicí battery is part of a block used to provide stabilisation services on the national grid. At the same time, though, it also enhances the functioning of the CHP plant itself, and significantly increases power supply security for our customers connected to the local C-Energy Planá distribution grid.

The storage facility is built on Siemens SIESTORAGE technology, and has a 10-year guaranteed power output of 4 MW with a minimum usable capacity of 2.5 MWh.

As part of our complete rebuilding and modernisation work, new gas-fired cogeneration units were installed, consisting of four gas reciprocating engine generator sets, each with an electrical power output of 9.17 MW, plus four heat recovery steam generators (HRSG) for steam production. A new hot water station was also constructed, and the heat distribution network was thoroughly renovated.

Part of the district heating for apartments in Sezimovo Ústí II, and some commercial buildings in the Planá industrial zone, which was originally supplied in the form of steam is now supplied via hot water. This eliminates the need for customers to have a substation with a heat exchanger installed in order to produce hot water from steam, and distributing heat via hot water significantly reduces thermal losses and makes supply more efficient. In addition, losses have been further reduced by replacing the old, oversized steam pipes with new ones, whose parameters are better suited to current customer needs.

At the end of the first stage of the project, the backup oil-fired boiler K4 was rebuilt as a natural gas-fired unit with a thermal power output of 13.3 MWt. Using gas as fuel means that this unit can start up relatively quickly if there is a sudden failure in one of the CHP plant’s main production facilities. 

In the next stage, a new coal-fired boiler was installed to replace one of the three dry‑bottom boilers. The original boiler K3 was decommissioned in March 2014, gradually dismantled, and in its place a coal-fired boiler K5 using elements of fluidised bed technology was constructed. This is a single-drum, negative-pressure, four-pass boiler with natural circulation, a rated steam output of 40 t/h (32.9 MWt) and rated superheated steam parameters of 4.5 MPa/ 486°C.

In the final stage of the project, another of the existing dry‑bottom boilers, K2, was replaced by a second coal-fired boiler K6 of the same type as K5 and with the same parameters. In parallel with the construction of boiler K5, a wet flue gas desulphurisation unit was also installed, enabling the CHP plant to meet the strict emission limits applicable both today and in the future. The flue gases leaving the boilers are first cleaned of particulate matter using modernised electrostatic precipitators, and then directed into the new desulphurisation unit, where they are treated in a desulphurisation absorber using wet limestone scrubbing to reduce their sulphur content.

At the end of the modernisation project, the original steam turbine, with an electrical power output of 46.5 MWe, was rebuilt as a unit adapted to the new steam parameters of boilers K5 and K6, with a rated capacity of 26 MWe, thus increasing the efficiency of electrical power production. While working on the turbine, a new live steam pipeline, proportioned to the parameters of the new boilers, was also installed.

EVECONT is an environmentally friendly facility for the recovery of non-reusable plastic waste, entirely housed in a shipping container design. This small waste‑to‑energy (WTE) plant, which began operation in 2020, contains within it state‑of-the-art combustion technology, and heat production from this unit is more environmentally friendly than conventional coal combustion.

The EVECONT pilot unit has been built on the site of C-Energy Planá’s modern CHP plant in Planá nad Lužnicí using less than 1,200 sq m of space. From 2,400 tonnes of non-recyclable plastic the unit will produce 40,000 GJ of heat each year for the needs of C-Energy’s industrial customers and the towns of Sezimovo Ústí and Planá nad Lužnicí. The primary role of the EVECONT unit is to recover types of waste that are unsuitable for material recovery, and ideally waste that is generated in the unit’s immediate vicinity – i.e. mainly in the Planá nad Lužnicí industrial zone.

Future areas where the EVECONT waste-to-energy plant can be of use are hospitals, smaller municipalities, wastewater treatment plants, industry and many other areas. All of these now sort their plastic waste, but a large part of it is not suitable for further processing. Hundreds of thousands of tonnes of non-recyclable plastics are therefore transported to distant incinerators for disposal. Thanks to the EVECONT unit, waste plastics can in the future be processed directly at their point of origin, without the need for transport and with the potential for further recovery in energy production.

For more information, visit www.evecont.cz.