HBOX SOLAR 3A SOLAR POWERED ELECTROLYSER CASE STUDY 03
Case Study 03 HBox Solar: A Solar-Powered Electrolyser Background ITM Power is a developer of hydrogen energy systems based on electrolysis. There are a numerous applications for such systems in energy storage, clean fuel production and vehicle refuelling. This case study describes the development of the HBox Solar electrolyser, which provides a technology platform for maximising the benefit of solar power generation. Solar power varies with local weather conditions and time of year, and its production is often outof-phase with energy demand. Usually this supply/ demand mismatch problem is simply passed to the operator of the electricity grid, but as the renewable penetration grows this conventional approach can result in power systems management problems (local voltage rise and grid instability). In weak-grid and offgrid applications, the solar power generation must be stored efficiently for later use, and stored for long periods if the site latitude exceeds ±40 degrees. An alternative approach is to provide on-site fuel generation and energy storage by converting some or all of the generated solar power to hydrogen by electrolysis. This requires an electrolyser that can load-follow the variable power generation and output hydrogen at high efficiency to an energy store. As the use of photovoltaic solar panels, wind turbines, and micro-hydro stations becomes more widespread, so does the requirement to store energy to cover periods of low/zero generation. The electrolysis of water to form hydrogen offers a unique means of energy storage; storing excess power as a compressed gas indefinitely, so that it may be used year-round whenever it is required. Hydrogen is an efficient way to store electricity, especially the renewable electricity generated by intermittent sources (solar, wind, hydroelectricity). Fuel Cell and Hydrogen Technologies in Europe 2011 Financial and Technology Outlook on the European Sector Ambition 2014-2020, NEW-IG Secretariat
Case Study 03 HBox Solar: A Solar-Powered Electrolyser The Challenge of Intermittent Renewable Energy Sources The increasing need for capturing intermittent renewable energy at times of high availability prompted ITM Power to develop an effective solar hydrogen generation solution. High efficiency PEM electrolyser High overall system efficiency and very low parasitic balance-of-plant (BoP) loads Capable of operating off-grid and load-following the fluctuating nature of a PV power source Intelligent control for maximum power point tracking (MPPT) the available PV input A novel PEM electrolyser stack design integrating hydrogen generation and balanced pressurisation, with passive water-gas separation and passive electrolyser cooling A thermal management system for maximising the gas production rate after each period of darkness or bad weather No moving parts for high reliability and unsupervised operation in remote locations for extended periods HBox Solar Exploded View
Case Study 03 HBox Solar: A Solar-Powered Electrolyser PRODUCT DESCRIPTION HBox Solar is a novel passive PEM electrolyser design which doesn t employ a conventional stack of planar cells. It generates 14 bar hydrogen and oxygen via a direct DC-DC connection to solar PV panels. Detailed attention has been given to minimising the power load associated with the balance-of-plant, in order to maximise the annual hydrogen yield. The product has no fans, pumps or heat exchangers; it achieves passive water/ gas separation, passive cooling and passive selfpressurisation. A proprietary control algorithm enables HBox Solar to track the Maximum Power Point of the panels and a thermal management system maximises the gas production rate after periods of darkness or bad weather. Consequently the HBox Solar s overall (system) efficiency never falls below 78%. The HBox Solar electrolyser will absorb 1.3kWp but generate hydrogen from as little as 20W during low irradiance conditions. It is sized to provide 20-50kg/ year of green hydrogen (depending on latitude) to a compressed gas or hydride store, and thus provide a source of renewable fuel for distributed telecom and residential applications. HBox Solar can operate autonomously for long periods without maintenance. The electrolyser s ability to follow transient power inputs from dawn-to-dusk in summer and winter has been demonstrated in field trials. Also HBox Solar has been designed to operate at high latitudes where hydrogen production may be interrupted for periods of up to several weeks due to snow cover on the solar panels. Technical Specification HBox Solar Hydrogen yield 20 50 kg H 2 /Year System working pressure 14 bar (g) System design pressure 14.7 bar (g) Hydrogen gas purity* 99.99% Atmospheric dew point* -60 C System efficiency at peak output 4.5 kwh/nm 3 PV power rating (peak) Electrical power supply 1.3 kw DC Maximum hydrogen inventory 1.35g H 2 Typical water consumption rate (at peak output) 150 cc/h Maximum amount of water stored in electrolyser 8 Litres Required water quality and conductivity Deionised ASTM Type 2 DI water Dimensions (H x W x D) 675 x 1260 x 920mm Operating conditions Indoors, well ventilated Ambient temperature 15-25 C * Depending on drying solution employed
ITM Power PLC 22 Atlas Way Sheffield S4 7QQ T: +44 (0) 114 244 5111 W: www.itm-power.com 6588