GKN s Solid-state Hydrogen Storage System

Transcription

1 GKN s Solid-state Hydrogen Storage System Enables for a Renewable, Residential Energy Supply A new alloy is reinventing an old technology and making engineers take a second look By Nils Bornemann, Director Advanced Technology Hydrogen Storage & E-Motors, GKN Powder Metallurgy

2 Challenges and drivers in energy generation and supply Today there is an intensive discussion about climate change, and high CO 2 levels in the earth s atmosphere. High CO 2 levels stem from burning fossil fuels to power our vehicles, and generate electricity for industries and residences. As our population increases and more countries are developed, CO 2 levels will continue to rise. The desperate search for non-polluting, renewable energy sources has three key challenges: As our population increases and more countries are developed, CO2 levels will continue to rise. Sustainable energy generation Efficient transfer of energy Effective storage of energy These are a few of the challenges GKN s R&D is finding interesting new solutions to generate more sustainable energy. Making this more difficult are regulations and cost. 2

3 Residential use of renewable energy Decentralized photovoltaic solar panels are common in many European countries, and had at least 15-years of public incentives to help drive the adoption of the technology. However, lacking decentralized efficient and affordable storage systems the energy is mainly fed to the public electricity grid rather than being used locally. This way, on many occasions, sustainably generated energy is not used as its availability does not meet the requirements for reliable and predictive supply. Direct local usage requires new and more efficient energy transfer and storage. Private owners of photovoltaic solar panels are dependent on the electricity providers 3

4 Local energy storage limitations In a local system, excess electricity from photovoltaic solar panels, or other sustainable sources, is stored during the day and used throughout the night. Currently, the technologies for day energy buffers are batteries. Storage size ranging from 3 kwh up to 14 kwh work well, as since the electric energy demand per house is roughly 11 kwh per day. The system costs for this battery storage dropped recently to 430 /kwh based on Tesla s Power Wall 2 concept. stored during the day and used throughout the night While this sounds cost-effective, battery costs rise quickly when creating a buffer system for seasonal energy. For a residential system, roughly one-third of the yearly electricity demand should be stored during summer time to be available in winter. The yearly electricity demand for a four-person household is roughly 4,000 kwh/year, not considering additional energy for heating. Thus, the battery size for a seasonal electricity buffer is 1,300 kwh. To scale a battery solution to this size it would cost around 560,000, making battery storage less attractive. 4

5 New cost-effective technology A better solution for large-scale energy storage is a hydrogenbased system. The system consists of three main modules: Hydrogen generation Hydrogen storage Converting Hydrogen into electricity Hydrogen is able to store more kwh per volume than batteries. The increased energy density reduces costs and size for larger energy systems that make a hydrogen solution ideal for seasonal energy storage. Water Oxygen Air Water House Hydrogen generation Hydrogen storage Fuel cell Electric energy Thermal management Heat 5

6 Hydrogen storage systems aren t new, but there are efficiency issues that need to be considered. Efficiency and Costs of Hydrogen Storage Systems Generating hydrogen for energy storage with electricity is about 50% efficient. Converting the stored hydrogen back into electricity is about the same. Therefore, the electric efficiency for a hydrogen system is only 25%. Fortunately, our engineers are creative. They considered that the main energy demand of a house is not only electric, but also thermal. Heating accounts for nearly double the amount of energy compared to electricity. Generating thermal energy with a hydrogen system increases its efficiency to 90%. This is comparable to the efficiency of a battery system and is more cost-effective. Fig 02 6

7 How do You store Hydrogen? Hydrogen is normally stored in two ways For stationary applications, hydrogen is stored in pressure vessels around 40 bar For mobile applications, hydrogen is stored in pressure vessel over 300 bar Base material GKN low temperature metal hydride storage Compressing hydrogen consumes large amounts of energy. Powder compact At GKN we challenged our engineers to find a more efficient solution. They developed a new metal alloy powder from hydrides. By compacting the alloy powder into a highdensity pellet, we created an efficient solid-state storage material for hydrogen gas. GKN s metal hydride system for hydrogen storage applications 7

8 The metal hydride storage... is a low-pressure solution with less than 30 bar. The advance alloy and maximum surface area of the powder is a cost-effective way to provide long-term hydrogen loading and de-loading. We found this new solid-state storage design is more beneficial when compared to other hydrogen technologies. Controlling the pressure and temperature is important to enable the hydrogen loading and de-loading of the GKN storage system. ABSORPTION DESORPTION heat pressure Hydrogen storage in a metal hydride is controlled by heat and pressure pressure heat 8

9 The Knappenhaus Project This new system will be on display as a demonstrator in the second half of A residential home in South Tirol uses a small river-connected turbine to generate electricity. The project will validate the solid-state hydrogen system by providing powering the private home. The system will operate locally, independent off the grid for environmental friendly living. This demonstrator will also validate the system s cost. The main costs are the 5kW hydrogen generator and the 5kW fuel cell systems. The solid-state hydrogen storage costs vary depending on the energy storage size. For the example above, we said a private home should have 1300 kwh for an electric seasonal buffer. If the energy for heat doubles, a 2600kWh seasonal buffer could be used for heat. Environmental friendly living off the grid, powered by hydrogen storage. This means the hydrogen storage should offer 160 kg hydrogen capacity. 9

10 A hydrogen energy storage system could clearly achieve cost competitiveness for heat and electric energy. If mass-produced, the hydrogen based seasonal energy buffer system for combined heating and power supply (CHP) could cost 80 to 200 /kwh. Therefore, compared to the battery system cost of 430 /kwh a hydrogen energy storage system could clearly achieve cost competiveness for heat and electric energy. This renewable seasonal energy buffer will work for both residential and industrial applications. This GKN technology solution is pushing the boundaries of powder metallurgy, and is delivering a great renewable energy innovation to the market. At GKN we do not let challenges stand in the way. Instead, we push forward with technology to create sustainable innovations to build a stronger product and a better tomorrow. 10

11 Dr. Nils Bornemann Vice President Advanced Technology GKN Powder Metallurgy 2017