Swedish Stirling’s PWR BLOK provides cheap electricity and large CO2 savings

A unique recycling solution

PWR BLOK is a container-based solution in which Swedish Stirling’s Stirling engines are used to harness energy from industrial residual gas combustion or waste heat.

This allows for significant electricity and cost savings to industries, as well as reducing the global carbone dioxide emissions. The PWR BLOK 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  is about five to seven years. 

The company estimates the technology’s service life at up to 25 years , 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.


Reduced electricity costs

The South African ferrochrome industry is a clear example which illustrates the benefits of the PWR BLOK technology. It generates vast amounts of residual gases that are today simply burned, while having the cost of electricity constituting over 40 percent 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. The waste (the residual gas) becomes free fuel in the process and the reduced need for purchased electricity creates major cost savings for the industry.


Reduced CO2 emissions

Just like in other forms of recycling, PWR BLOK is not only a cost-effective solution but also a environmentally friendly one. In South Africa, where Swedish Stirling introduced the technology, around 87 percent of all electricity in the country is generated today with fossil fuels, according to figures from the South African electricity company ESKOM. 

As PWR BLOK reduces the need for purchased electricity produced with a very large proportion of fossil fuels, the technology also contributes to a strong reduction of carbon dioxide emissions in South Africa. According to ESKOM, each MWh of electricity produced in the country produces an average CO2 emission of 1 ton. This means that each PWR BLOK reduces carbon dioxide emissions in South Africa by approx. 3,500 tonnes per year, and the customer also receives the corresponding emission rights in the country.