Power to gas

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Power to gas is a technology which converts electrical power to a gas fuel. There are 2 methods, the first is to use the electricity for water splitting by means of electrolysis and inject the resulting hydrogen into the natural gas grid. The second method is to combine the hydrogen with carbon dioxide and convert the two gases to methane, (see natural gas) using electrolysis and a methanation reaction such as the Sabatier reaction or biological methanation. The excess power or off peak power generated by wind generators or solar arrays is then used for load balancing in the energy grid.


Efficiency

 Efficiency by method
(ggf. Methanisation of Biogas)[1]
Method Efficiency Remarks
Electricity → Gas
Hydrogen 54–72 % 200 bar compression
Methane (SNG) 49–64 %
Hydrogen 57–73 % 80 bar compression
(Natural gas pipeline)
Methane (SNG) 50–64 %
Hydrogen 64–77 % Without compression
Methane (SNG) 51–65 %
Electricity → Gas → Electricity
Hydrogen 34–44 % 80 bar compression
up to 60% back to electricity
Methane (SNG) 30–38 %
Electricity → Gas → Electricity & heat (cogeneration)
Hydrogen 48–62 % 80 bar compression and
electricity/heat for 40/45 %
Methane (SNG) 43–54 %


Power to Gas - Hydrogen

Units like ITM Power's HGas generates hydrogen to be directly injected into the gas network as Power to Gas

In December 2013, ITM Power, Mainova and NRM Netzdienste Rhein-Main GmbH injected hydrogen into the German gas distribution network using ITM Power HGas which is a rapid response proton exchange membrane electrolyser plant. The power consumption of the electrolyser is 315 kilowatts. It produces about 60 cubic meters per hour of hydrogen and thus in one hour can feed 3,000 cubic meters of hydrogen- enriched natural gas into the network. [2]

On August 28, 2013 E.ON Hanse, solvicore and Swissgas inaugurated the commercial Power to Gas unit in Falkenhagen Germany. The unit, which has a capacity of two megawatts, can produce 360 cubic meters of hydrogen per hour.[3] The plant uses wind power and Hydrogenics[4] electrolysis equipment to transform water into hydrogen, which is then injected into the existing regional natural gas transmission system. Swissgas, which represents over 100 local natural gas utilities, is a partner in the project with a 20 percent capital stake and an agreement to purchase a portion of the gas produced. A second power to gas project is started in Hamburg/Reitbrook district[5] expected to open in 2014.

In August 2013 a 140 MW wind park in Grapzow, Mecklenburg-Vorpommern from E.ON received an electrolyser, the hydrogen can be used in an ICE or can be injected into the local gas grid.[6] It produces 210 Nm3/h of hydrogen and is operated by RH2-WKA.[7]

The GRHYD project (2013-2020) from GDF SUEZ and Areva in France started in 2012 for injecting hydrogen into the natural gas network of 200 houses.[8]

The INGRID project started in 2013 in Puglia, Italy, a 4 year project with 39 MWh storage and a 1.2 MW electrolyser for smart grid monitoring and control.[9] The hydrogen is used for grid balancing, transport, industry and injection into the gas network.[10]

The surplus energie from the 12 MW Prenzlau Windpark in Brandenburg [11] will be injected into the gas grid from 2014 on.

Power to gas and other energy storage schemes to store and utilize renewable energy are part of Germany's Energiewende, energy transition, program.[12]

H2 injection without compression

The core of the system is a proton exchange membrane (PEM) electrolyser. The electrolyser converts electrical energy into chemical energy, which in turn facilitates the storage of electricity. A gas mixing plant ensures that the proportion of hydrogen in the natural gas stream does not exceed two per cent by volume, the technically permissible maximum value when a natural gas filling station is situated in the local distribution network. The electrolyser supplies the hydrogen-methane mixture at the same pressure as the gas distribution network, namely 3.5 bar. [13]

Power to Gas - Methane

The first large power to gas demonstration project with a capacity to convert 250 kilowatts was put into operation by the Centre for Solar Energy and Hydrogen Research (ZSW) on October 30, 2012 in Stuttgart.[12] The "e-gas" project, an industrial scale 6 megawatt plant, is planned for 2013 at Werlte in Lower Saxony to be constructed by SolarFuel for Audi using lessons learned from ZSW's 250 kilowatt research plant.[14]

ITM Power won a tender in March 2013 for a Thüga Group project, to supply a 360 kW self-pressurising high pressure electrolysis rapid response PEM electrolyser Rapid Response Electrolysis Power-to-Gas energy storage plant. The unit produces 125 kg/day of hydrogen gas and incorporates AEG power electronics. It will be situated at a Mainova AG site in the Schielestraße, Frankfurt in the state of Hessen. The operational data will be shared by the whole Thüga group – the largest network of energy companies in Germany with around 100 municipal utility members. The project partners include: badenova AG & Co. KG, Erdgas Mittelsachsen GmbH, Energieversorgung Mittelrhein GmbH, erdgas schwaben GmbH, Gasversorgung Westerwald GmbH, Mainova Aktiengesellschaft, Stadtwerke Ansbach GmbH, Stadtwerke Bad Hersfeld GmbH, Thüga Energienetze GmbH, WEMAG AG, e-rp GmbH, ESWE Versorgungs AG with Thüga Aktiengesellschaft as project coordinator. Scientific partners will participate in the operational phase.[15] It can produce 60 cubic metres of hydrogen per hour, in 2016 the system is expanded to be able to produce methane for grid injection.[16]

Electrochaea is developing a power to gas process based on biocatalytic methanation. The company uses an adapted strain of the thermophilic methanogen Methanothermobacter thermautotrophicus and has demonstrated its technology at laboratory-scale in an industrial environment.[17] A pre-commercial demonstration project with a 10,000-liter reactor vessel was executed between January and November 2013.[18]


See also

Notes

  1. ↑ (German) Fraunhofer -Energiewirtschaftliche und ökologische Bewertung eines Windgas-Angebotes
  2. ↑ http://www.itm-power.com/news-item/injection-of-hydrogen-into-the-german-gas-distribution-grid/
  3. ↑ http://www.eon.com/en/media/news/press-releases/2013/8/28/eon-inaugurates-power-to-gas-unit-in-falkenhagen-in-eastern-germany.html
  4. ↑ Hydrogenics and Enbridge to develop utility-scale energy storage
  5. ↑ E.on Hanse starts construction of power-to-gas facility in Hamburg
  6. ↑ German wind park with 1 MW Hydrogenics electrolyser for Power-to-Gas energy storage
  7. ↑ RH2-WKA
  8. ↑ The GRHYD demonstration project
  9. ↑ INGRID Project to Launch 1.2 MW Electrolyser with 1 ton of Storage for Smart Grid Balancing in Italy
  10. ↑ Grid balancing, Power to Gas (PtG)
  11. ↑ Prenzlau Windpark (Germany)
  12. ↑ 12.0 12.1 Quirin Schiermeier (April 10, 2013). "Renewable power: Germany’s energy gamble: An ambitious plan to slash greenhouse-gas emissions must clear some high technical and economic hurdles.". Nature. Retrieved April 10, 2013. 
  13. ↑
  14. ↑ "World's largest Power-to-Gas plant for generating methane enters operation: Stage prior to industrial application achieved". Distributed Energy. December 5, 2012. Retrieved April 10, 2013. 
  15. ↑ http://www.itm-power.com/news-item/first-sale-of-power-to-gas-plant-in-germany/
  16. ↑ Ground broken at ITM Power Power-to-Gas pilot plant in Frankfurt
  17. ↑ http://www.hindawi.com/journals/archaea/2013/157529/
  18. ↑ http://www.electrochaea.com/technology.html

External links

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