Swedish Stirling’s PWR BLOK provides the cheapest electricity and the most CO2 savings

A unique recycling solution

PWR BLOK 400-F is a container-based solution in which Swedish Stirling’s Stirling engines are used to harness energy from flare and industrial residual gas combustion. This allows for significant electricity and cost savings to industries, as well as reducing the global CO2 emissions. The PWR BLOK 400-F contains 14 Stirling engines and delivers a net output of 400 kW. The container is placed next to facilities where combustion of residual gases occurs and converts the energy in the gas to electricity. At the price Swedish Stirling can offer, a customer’s payback period for the PWR BLOK 400-F is about five years. The company estimates the technology’s service life at 25 years as a minimum, allowing customers to reduce the volume of electricity purchased from the grid by up to 15 percent.

This is how the PWR BLOK technology works for the metal industry


Converts residual gases into 100 % carbon-neutral electricity

Many industrial applications produce by-products in the form of gases (residual gas) that are currently burned without harnessing its energy content. For decades different  solutions have been tried to recycle the energy in the gases. In the ferrochrome industry in South Africa producers has been tried to recover the energy using internal combustion engines, gas and steam turbines, but all solutions have failed. The reason is usually that the gas is of such uneven quality that most engines with internal combustion doesn’t work, or the technical solutions are extremely costly. The Stirling engine, on the other hand, is, due to its external combustion, almost insensitive to the type of gas that is burned or the quality of the gas in question. Therefore, it is now possible to start converting these residual gases into 100 % carbon-neutral electricity with PWR BLOK.


Record low electricity price

The South African ferrochrome industry is a clear example which illustrates the benefits of our technology. It generates vast amounts of residual gases that are today simply burned, while having the cost of electricity constituting almost a third of the business’ total production costs. Swedish Stirling’s solution makes it possible to recover parts of the energy in the residual gas by using the heat to produce electricity with the Stirling engines in PWR BLOK. In a study publish in May 2019, the levelized cost of energy (LCOE) generated using PWR BLOK was 19.5 EUR/MWh, which was verified by the independent verification company Lloyd’s Register. That was 44 percent lower than, for example, geothermal electricity, which at the time was the cheapest source of energy according to Annual Energy Outlook 2019. Other renewable energy sources like solar and wind, with or without storage capacity, was at least twice as expensive per MWh, but in most cases considerably higher.


Reduces CO2 emissions

South Africa generates 87 percent of all its electricity from fossil fuels, based on numbers from Eskom. The reduced electricity consumption made possible by Swedish Stirling’s technology would entail an annual 3500-tonne reduction in carbon dioxide emissions per PWR BLOK installed.

The certification from Lloyds in May 2019 also shows that PWR BLOK provides greater carbon dioxide savings in South Africa than any other applicable type of energy, and that every invested Euro in PWR BLOK provides an annual CO2 saving of about 5.51 kg. This can be compared, for example, to solar energy (Solar PV Utility Scale), where each euro invested is expected to yield an average annual CO2 reduction of 3.3 kg. Despite the fact that the PWR BLOK was primarily developed in order to generate cheap electricity, the technology also yields greater CO2 reductions per euro invested than any other renewable method for electricity generation, and does so without any form of government support or subsidy.