Fuel Cell Technologies

The United States Department of Energy (DOE) has stated that fuel cell technology has the potential to revolutionise the way nations are powered, offering cleaner, more efficient alternatives to the combustion of gasoline and other fossil fuels. A comparison of fuel cell technologies in Figure 34 provides a summary of fuel cell type, efficiency, applications, together with their advantages and disadvantages. Stationary power includes both large scale (>200 kW) and small scale (5–100 kW) systems and also encompasses fuel cell units used for telecommunications back-up (1-20 kW). The feasibility of siting a fuel cell needs to take into account the availability of a suitable fuel source (i.e. reticulated natural gas or biogas), supply chain factors, engineers and labour production, government or regional incentives (if any) and energy costs.

Innovation and the ability to scale-down fuel cell technology to make it possible for this technology to be utilised by domestic and small to mid-sized businesses will be a key challenge and focus of companies involved in the sector.

For example, Australian manufacturer Ceramic Fuel Cells has used SOFC technology to develop the BlueGen® small-scale electricity generator, which delivers approximately 13,000 kWh of low-emission electricity per year (http://www.bluegen.info/What-is-bluegen) Optional waste heat from BlueGen can be recovered to provide 200 litres of domestic hot water per day; increasing total efficiency by 25% from 60% to 85%

making it the world’s most efficient in terms of size. Annual CO2 emission savings achieved by SOFC technology compared with solar PV technology are shown in Figure 33. Although inimical to the notion of government subsidies there could be merits for the renewable energy sector in introducing programs (e.g. feed-in tariffs) and capital subsidies for an interim period to encourage the uptake of cleaner energy systems if it results in a reduction in energy use and CO₂ emissions.

Figure 33: Energy Savings using BlueGen

Source: Fourth International Workshop Report Stationary Fuel Cells

Figure 34: Comparison of Fuel Cell Technologies

Efficiency Applications Advantages Disadvantages

Polymer

Figure 34: Comparison of Fuel Cell Technologies

Efficiency Applications Advantages Disadvantages Phosphoric Acid

Figure 34: Comparison of Fuel Cell Technologies

Efficiency Applications Advantages Disadvantages Solid Oxide Yttria stabilised

Fuel cells are complimentary, not competitors, to other electricity generation technologies, particularly renewable ones. “Fuel cell benefits include the following:

 Fuel flexible – operation on conventional or renewable fuels.

 High quality, reliable power.

 Exceptionally low/zero emissions.

 Modularity/scalability/flexible installation.

 Not dependent on the power grid.

 Silent operation.

 Lightweight.

 Rugged.

 Can be used with or instead of batteries and diesel generators.

 Can partner with solar, wind, and other renewable technologies.

 Increased productivity.

 Cost savings via high electrical and overall efficiency” (http://www.fuelcells.org).

Renewable energy sources provide 77% of New Zealand’s electricity supply with 58%

coming from hydro-electricity. Around one-sixth of hydro-generated electricity from the southern lakes is sent to the North Island via the HVDC transmission inter-island link to meet increasing power demands. However, in recent years a lack of water in the South Island lakes has resulted in reduced electricity production and this creates a great deal of supply uncertainty which is not good for manufacturers and the economy. This is even more concerning given the New Zealand Government has a 2025 target of generating 90% of electricity from renewable sources. Fuel cell technology is one form of infrastructure that can meet future demand for power and heat in times of uncertainty.

Much of the future development and success of distributed generation, or power generation at the point of consumption, will come down to the fuel source required to power the devices such as PAFC, PEM, and SOFC. “Natural gas will grow fast enough to overtake coal for the number two position behind oil. Demand for natural gas will rise by more than 60% through 2040. For both oil and natural gas, an increasing share of global supply will come from unconventional sources such as those produced from shale formations” (ExxonMobil, 2012.) The global energy demand by fuel type is shown in Figure 35 and indicates that gas will continue to be a mainstay source of energy for electricity production.

Figure 35: Global Energy Demand by Fuel Type

Source: ExxonMobil, 2012 The World Outlook for Energy: A View to 2040

No matter the source, it takes a significant amount of energy to make electricity.

Globally, more than 35% of the primary energy consumed on a daily basis is being used to make electricity. Also important to know is that a significant amount of energy is lost

in the electricity generation process. For example, “new turbines powered by coal or nuclear (which produce about 55% of global electricity) are, at most, about 40%

efficient. That means that for every 100 units of primary energy that go into these plants, only 40 units or less are converted to useable electrical energy. New natural gas plants are more efficient, with a 60% efficiency rate. In addition to the losses during electricity production, a significant amount of electricity is also lost as it is sent to consumers across transmission lines. These “line losses” total about 10% in OECD nations and 15% or more in the non OECD. Improving efficiency in power generation and transmission represents one of the biggest opportunities for curbing growth in energy demand and CO2 emissions in coming decades” (ExxonMobil, 2012). Bloom Energy and UTC Power (for larger scale dairy processing plants) and ClearEdge (for dairy farm operations) that deliver a continual supply of electricity at the source of where it will be used could provide certainty of supply and meet increasing electricity demands from producers and consumers. It is also a clean technology that serves more than one purpose – water and heat are a by-product and SOFC can be teamed with renewable energy sources like solar.

The fuel cell technology manufactured by Bloom Energy, UTC Power, and ClearEdge Power are capable of net-metering. This is an arrangement between the utility and the customers who generate their own electricity with qualifying systems. “Net-metering measures the difference between the electricity delivered by the utility and the excess electricity produced by the customer using their own generation equipment. Any energy produced that is not used is fed back into the utility grid and is deducted from the customer’s utility bill” (UTC Power).

The flow diagram in Figure 36 provides an example of how the technology is utilised with a combination of fossil fuel and renewable energy streams.

Figure 36: SOFC Practical Application

Source: CRL Energy Ltd