Following gasworld’s recent ‘green’ themed magazine and features, Robert McGillivray, Director of Renewable Energy for Hydrogenics, explains through this Focus Feature how renewable energy can be utilised to great effect.

Hydrogen electrolysis fuelling stations can be used as a local resource by the grid operator to provide ancillary services and demand response services. Electrolysis loads are very responsive, reliable and efficient over a broad capacity range compared to the power generators that typically serve these functions on the grid. In this way, hydrogen infrastructure can help solve the problem of undispatchable power coming from renewable energy sources.

Renewable energy sources of power, such as wind and solar, are rapidly being adopted worldwide. They are an attractive source of electrical power as they have little or no emissions, are sustainable and provide a domestic energy source rather than relying on costly energy imports.

The costs of these technologies have continued to drop and governments are promoting their adoption with pricing and tax incentives. Wind farms and solar parks are now visible fixtures on the landscape across Europe and the US, and many other countries around the world.

However, there are some problems with renewable energy, the main one being that it cannot be controlled in the same way as traditional power sources. This is having a fundamental impact on the way grids operate. With a coal or natural gas power plant, the utilities and grid operators can more easily ensure that the load and power on a grid stays in balance.

This is the way the grid has traditionally been managed power in the past – as the load fluctuates up and down, signals are sent to power generators to move up and down.

But by deriving more of our power from uncontrollable renewable energy sources, we are upsetting the ability to control and balance the grid.

What is needed is a way to manage this intermittent renewable power. One of the solutions to this is to create more controllable loads that can be managed against the renewable sources. This need for controllable loads is the connection point to hydrogen fuelling. A fuelling station equipped with an electrolysis system uses electricity to generate hydrogen fuel from water, which is both zero emission and can be rapidly controlled over a broad load range. When the grid operator is given control of this production, they effectively have a highly controllable load on their grid.

In this way, the fuelling station provides a service to the grid operator and utilities that either results in a revenue stream and/or lowers the cost of power to the fuelling station. The end result is a more affordable source of hydrogen fuel for vehicle fleets. In addition, this delivery concept is not limited to fuelling applications, which are still emerging. It can also be used with industrial hydrogen applications traditionally served by merchant gas sources of hydrogen.

Modern electrolysis products are based on mature and proven technology that is highly reliable and capable of continuous 24/7 operation in the most challenging industrial environments. The Hydrogenics HySTAT system, for example, is an efficient, easy to install, modular package that can provide high purity hydrogen onsite and on-demand.

Renewable energy incentives
Many of the issues the grids are seeing are a direct consequence of the incentives provided to renewable energy power plants.

One of the difficulties with financing wind farms and solar parks is dealing with the intermittent power profile relative to the way the grid prices power production from conventional sources. Without guarantees to the power prices, it is more difficult to attract the investments required to build these facilities.

Government incentives such as Feed-in Tariff programs have been extremely successful at addressing the energy pricing uncertainty for renewable energy projects. Potential renewable energy developers are providing a guaranteed electrical rate, independent of when they produce the power. Effectively, the grid operator is mandated to pay a set rate for renewable sources of power, but this also passes on the problem of renewable power intermittency to the grid operator.

The grid operator is left to deal with balancing the fluctuating renewable energy power with the load. For small amounts of renewable energy, this can be done with existing assets and conventional control strategies, but as renewable energy becomes a bigger part of a particular grid, the intermittency on the power supply side becomes more and more unmanageable.

The shortest-term control mechanism for grid stability at the disposal of grid operators is ancillary services, which are traditionally supplied only by power generators. As the amount of renewable energy sources on the grid increases, the value of ancillary services will certainly rise. This has been the experience in Germany, Denmark and California, where similar renewable energy incentives are currently in place.

Controllable loads
Loads can provide frequency regulation and operating reserves that meet or exceed power generators and loads will typically have high response rates and short cycle times. In areas such as California and Texas, loads often provide at least 50% of the ancillary services needed and pricing markets have been introduced to economically drive the providers of these services.

Controllable loads can be an important tool for grid operators to: control the grid; balance supply and demand; and alleviate local transmission constraints. Electrolysis can be used to provide utility scale load control for grid balancing purposes. In fact the connections back to hydrogen are already being made.

In 2009, Germany announced projects to implement both hydrogen energy storage and hydrogen vehicle fueling as a means to dispatch this power.

Electrolysis systems
Electrolysis systems have the ability to ramp-up and down very quickly without any adverse effects. The Hydrogenics HySTAT electrolyzer systems can operate over a wide range of capacities from 10%-100% of rated load for large, multi-stack systems. If the system has storage, as is the case with fuelling stations, the electrolysis can be operated at different times from the fuelling of the vehicles.

Hydrogenics current HySTAT electrolysis product line is highly modular with building blocks of 365 kW (60 Nm3/h hydrogen output). Multiple systems are often delivered to a single site, achieving 1-5 MW, and very large-scale system concepts could achieve 10-100 MW. The hydrogen generator is fully containerized and available with a compression, storage and dispensing package to match the needs of the vehicle fleet.

Hydrogen can be used as a transportation fuel with over 150 fuelling stations around the world supporting demonstration programs for buses, cars and off-road vehicles such as forklifts. A fleet of 100 municipal buses would consume about 3.8 tonnes of hydrogen per day, given typical bus routes. If supplied with electrolysis, this would represent about 10 MW of continuous load.

This is not a new concept. Hydrogenics has provided electrolysis systems for over 35 fuelling stations worldwidel including the European CUTE program and many stations in California supporting both bus and car fleets. The fuelling stations and the load could be in several locations, allowing control of load to address transmission constraints – as well as load balance and ancillary services. With the appropriate amount of extra hydrogen storage, there would be no impact on the station’s bus users for potentially many hours or even days.

In the industrial market, hydrogen is used for both its mechanical or chemical properties in applications such as float glass, semiconductor manufacture, optics production, metal annealing and sintering, high temperature flames and hydrogenated oils.

The benefits of renewable hydrogen fuelling
The ability to use an electrolysis load to provide ancillary services gives the grid operator an additional tool to manage grid intermittency. Using a controllable load can offer significant advantages over using controllable power sources for ancillary services and demand response.

1. Zero Emission Link: Hydrogen electrolysis produces no incremental emissions and provides a totally clean and green connection between renewable energy sources and zero-emission transportation using hydrogen fuel
2. Additional Income Stream: By delivering ancillary services, the electrolysis system is able to generate an additional income stream, effectively lowering the cost of delivered hydrogen for either industrial or transportation hydrogen applications
3. Frees Power Resources: Using load for ancillary services frees the power generation systems to focus on only providing power
4. Better Response Rates: Using loads also provides a better response to the control centre requests. Loads can typically respond more quickly as opposed to large systems that have slower response rates
5. Alleviate Transmission Problems: The modular nature of electrolysis loads also allows it to be distributed broadly across a particular grid. This provides the additional opportunity to balance load, provide ancillary services as well as allow transmission constraints to be addressed. For instance, if an area had five large electrolysis fuelling stations and a transmission problem occurred in a location with one of the fuelling stations, then that station could be temporarily turned-off until the problem was resolved
6. Modularity and Redundancy: The modularity makes the overall system less prone to large-scale failure, decreasing the need for redundancy in overall ancillary services contracted

Efforts to promote the adoption of renewable energy sources on our grids and hydrogen vehicles for our transportation do not need to be independent efforts. They can be linked with hydrogen electrolysis in a way that is highly complementary.

Hydrogen vehicles and fuelling can provide the important controllable load that renewable power sources critically need to allow high penetration into the modern grid. We have the opportunity to simultaneously change the way we generate, storage and use energy on both our grids and in our transportation.

Hydrogenics background
Hydrogenics is a world-leading manufacturer of hydrogen electrolysis and fuel cells, organised into three lines of business:

• Onsite Generation – Electrolysers for industrial and energy applications
• Power Systems – Fuel cells for backup power and mobility applications
• Renewable Energy – Community energy storage and smart grid applications

The company is headquartered in Toronto, Canada, with sales and manufacturing offices in Belgium and Germany. The company has deployed over 1700 hydrogen products into over 100 countries since 1948.

Hydrogenics Germany is specialised in both planning and building complete hydrogen systems for stationary and mobility applications.

About the author
Robert McGillivray
Director, Renewable Energy