In Germany, 2G Energy AG, a leading manufacturer of gas-driven combined heat and power (CHP) systems, has received an order to deliver a purely hydrogen-driven CHP system to Stadtwerk Haßfurt GmbH. Together with the customer, 2G Energy is thereby realizing a project that is groundbreaking in renewable energy supply in combination with wind and solar energy
Hydrogen (H2) burns without emitting any carbon dioxide (CO2) and almost without any harmful emissions at all, making it significantly more environmentally and climate compatible as a fuel than natural gas. The higher costs incurred in the production of hydrogen to date and the problem of its availability are resolved commercially in the project by making recourse to local renewable wind and solar power producers.
The hydrogen is produced by a power-to-gas (PtG) system located at Mainhafen. This utilizes surplus electricity generated by the wind park in the adjacent Sailershäuser Wald wind farm along with other solar PV and wind power operators for the electrolysis of water.
High-efficiency on-demand heat and power
The combined heat and power (CHP) system then reconverts the hydrogen into electricity and heating in line with demand, achieving efficiencies of > 90 percent. The electricity from the CHP system is fed into the city’s electricity grid. The heating is to be transferred to a neighbouring malt factory, a school, and a kindergarten via a heating grid that has yet to be constructed.
According to 2G Energy, hydrogen CHP systems represent an important building block to offset volatile energy production capacities through solar and wind power, making an important economic contribution to future supply security – especially given the enormous generating capacities that are to exit the grid with the phase-out of nuclear power plants by 2022, around 13 percent of production capacity, and the planned exit from coal, which represents approximately 39 percent of generation capacity.
The power-to-gas method enables surplus electricity from wind and solar power to be stored in the form of hydrogen on a cost-efficient basis over long periods and within the already existing natural gas network as well as in tanks, from where it can be reconverted into electricity in response to demand. Hydrogen CHP systems thereby provide balancing energy in combination with regenerative producers.
Engines suitable for high-hydrogen-content gases
Implementing only slight adjustments to a standard natural gas module, 2G has achieved technical success in enabling the highly efficient exploitation of hydrogen on a cost-sensitive basis. Compared to an equivalent basic motor, an electric output of 168 kW is reached in hydrogen operation compared to 210 kW when using fossil gas, on a CO2-free basis.
The mechanical motor efficiency is higher than that of conventional fossil gas-driven CHPs thanks to the rapid combustion of hydrogen. The utilization of standard components already makes hydrogen CHPs only slightly more expensive than a comparable natural gas-operated system.
The hydrogen modules comprise an expedient addition to 2G’s existing product range and support the company in its strategy of producing generation units for both balancing and offsetting energy. The 2G hydrogen technologies are also suited to other high-hydrogen-content gases and can be deployed without a problem with variable (natural) gas mixtures.