5 minute read
Unlocking the potential of green hydrogen technologies in sustainable buildings
Dr. Robert Himmler
Sustainable building construction considers many variables, including human health and well-being, the use of eco-friendly materials, biodiversity and water consumption, but one of the most important aspects is the reduction of carbon emissions during operation. To significantly reduce these emissions, the following design approach has been widely adopted:
• Step 1: Sustainable architecture (e.g. external shading, self-shading, reasonable window-to-wall ratio, consideration of façade orientation, natural ventilation, etc.)
• Step 2: High performance building envelopes (e.g. thermal insulation, glazing, airtightness, etc.)
• Step 3: Energy efficiency measures (e.g. lighting, VSD drives, energy recovery in ventilation, high efficiency chiller, heat pumps, etc.)
• Step 4: Decarbonisation of the energy supply onsite (e.g. photovoltaic, solar thermal collectors, wind, etc.)
The implementation of this 4-step approach, combined with a photovoltaic system (PV) to produce solar energy, especially in buildings with large roof areas (and on days with low energy consumption, such as office buildings on weekends) can lead to an overproduction of solar energy and hence the potential feed in of electricity into the public grid. In Thailand, feed in tariffs are limited, and often forbidden, but even when they’re allowed the feed in tariff is significantly lower than the retail price of electricity.
The challenge of solar overproduction by day, and the lack of renewable energy by night, or on days with reduced solar radiation, in combination with rapidly dropping energy storage prices, has led to the development of a fifth step:
• Step 5: Renewable energy storage (e.g. electric storage, thermal storage)
Energy storages help to increase the self-use of renewable energy in a building and reduce the amount of renewable energy which must be fed into the grid, or, if feed in is forbidden, to reduce the time the renewable energy production must be shut off. Depending on the decarbonisation goal of the building, the size of the energy storage and the PV system can be designed such that the building can be operated carbon neutral and without connection to the public grid (off grid).
Due to the significant drop in battery prices, storage technology sales have risen significantly. Another technology gaining popularity is using green hydrogen (H2) as an energy storage, which consists of three main components:
An electrolyser to convert renewable electricity to hydrogen
The hydrogen tank to store the energy
A fuel cell or hydrogen generator to re-convert the hydrogen back to electricity
While the hydrogen tank is relatively inexpensive, compared to batteries, the energy conversion technologies (electrolyser, fuel cells) are still expensive. This often leads to a combination of batteries for short term energy storage (day → night), and green hydrogen for long term (sunny days → cloudy days). In Thailand, two green hydrogen pilot projects in sustainable buildings have already been implemented: the EGAT Learning Center in Bangkok, and the Phi Suea House in Chiang Mai, which is off-grid (see Figure 1 and 2). These pilot projects have proven the technical feasibility of green hydrogen technologies.
For economic feasibility, the energy designer must optimise the capacity of the battery, electrolyser, H2 tank, and fuel cell. The main parameter to be optimised is the levelised cost of energy (LCOE), which considers capital, maintenance, and the operation costs of the system. The estimated LCOE of PV is around 50 per cent lower than market price in Thailand (depending on the size and complexity), while the LCOE for batteries and green hydrogen systems depends on the decarbonisation goal and the electric load pattern of the building. Regardless, it can be stated that currently a combination of solar energy with energy storage will increase the LCOE compared to a pure solar solution without energy storage. With further decreasing capital costs of PV, batteries, and H2 storage technologies, and increasing energy prices in combination with a future taxation of CO2 emissions, the decarbonisation of buildings will become economically more viable.
Interestingly, there is an application of green hydrogen in buildings which is already economically attractive: buildings and microgrids which are off-grid and supplied by diesel generators. The electricity cost in these locations are four to six times higher than the average electricity price in Thailand of around 5 THB per kWh. However, due to the high degree of electrification in Thailand, only a few places are off grid, such as the islands of Koh Lipe, Koh Phayam and Koh Munnork, and remote locations near the borders.
Across Southeast Asia, the potential of green hydrogen as an energy storage in buildings and microgrids is huge. Around 4,200 to 5,800 islands here are inhabited yet have no electric connection to their respective mainlands, and are supplied by diesel generators or hybrid systems (PV and diesel generators). In many cases, the main energy consumers are hotels and resorts, particularly in Thailand.
Due to the significant drop in battery prices, storage technology sales have risen significantly. Another technology gaining popularity is using green hydrogen (H2) as an energy storage […]
This has led to the development of a Public-Private Partnership (PPP) project with the German development agency GIZ, under the International Hydrogen Ramp-up Programme (H2Uppp). The name of the PPP project is ‘Green Hydrogen for Energy Self-sufficient Hotels, Resorts and Islands’, and the goal is to assess the financial and technical feasibility of decarbonising the energy supply of hotels and resorts in remote locations by applying solar energy in combination with green H2 and battery technologies. The project is co-funded by German Federal Ministry for Economic Affairs and Climate Action (BMWK) and implemented by EGS-plan (Bangkok) Co. Ltd., in cooperation with GIZ GmbH / GIZ Office Bangkok and the German-Thai Chamber of Commerce.
Contact details:
Dr. Robert Himmler
Managing Director & DGNB Auditor
EGS-plan (Bangkok) Co., Ltd.
Tel: +66 2 214 6146
www.egs-bkk.com
