The renewable integration challenge
There has always been a mismatch between supply and demand of energy. Previously, we have possessed the ability to modify the supply by turning different type of generation plant on and off. As we integrate more and more intermittent renewable energy into the energy mix, the generation becomes increasingly governed by the strength of the wind and sun. This means that the mismatch between supply and demand needs to be brokered on the demand side.
Even at today’s low level (<10% capacity) of renewable energy generation in the UK, we frequently experience curtailment events. In these scenarios, there is reluctance for the grid operators to accept wind power at times of low electricity demand. This usually results in a penalty – essentially a payment to the wind farm operator not to generate. This equates to negative electricity prices, and under-utilisation of renewable generation assets.
Electrolysis has a significant role to play in enabling more renewable energy to be accepted by the electricity grid. At times of excess supply, the electricity can be converted to hydrogen at a high efficiency. The hydrogen can be exported from the energy sector to the transport sector, seeding an infrastructure of clean fuel. At times of high electricity demand, the electrolysis systems can be turned off. This control can be exercised by the grid operators or utility companies remotely.
Without a step change in energy storage availability – such as that offered by demand side managed electrolysis – there is little chance of reaching the ambitious renewable targets for the UK and Scotland.
All of the electrolyser systems manufactured by ITM Power are capable of following an intermittent input power profile.
The EcoIsland project – which got under way last autumn – brings together within a single island energy system – i.e. the Isle of Wight – a critical mass of smart energy technologies, to demonstrate how a future energy system can be configured, as a prototype for a larger system for the mainland.
With renewable generation including wind, solar, tidal and geothermal, the Isle of Wight will need to match supply and demand using battery energy storage, hydrogen energy storage, and demand side management.
These technologies will be coordinated centrally by smart grid technologies supplied by IBM, Cable&Wireless Worldwide, Scottish & Southern Energy (SSE), and Toshiba.
ITM Power is the hydrogen fuel partner for the EcoIsland initiative, and will supply hydrogen refuelling equipment controlled by smart grid technology to optimise both renewable energy storage and the provision of fuel to both fuel cell vehicles and hydrogen internal combustion engine (HICE) commercial vehicles. (ITM Power has already operated a hydrogen vehicle/refuelling trial with Vestas Wind Systems, which has a facility on the island.)
The intention is that the Isle of Wight will also be a showcase for advanced, low-emission hydrogen vehicles being launched from 2013.
The economic case
While there can be no argument over the environmental benefits of ‘green hydrogen’, nor the independence of a locally produced fuel, the economics are of equal importance.
Hydrogen costs are best expressed in £/kg, and reflect both capital cost amortisation and electricity cost (see Table 1). Based on a 100 kg/day HFuel® system, hydrogen cost ranges from £3.88/kg (based on 4p/kWh and a 20-year capital expenditure amortisation) to £10.71/kg (based on 8p/kWh and a 5-year amortisation).
This compares to €9.90/kg (£8.49/kg), which is the European target (according to a McKinsey/NEW-IG report in November 2010*) for 2015, and coinciding with the planned major rollout of fuel cell vehicles across Europe.
Table 1. Using an HFuel system, hydrogen costs can already beat future European targets.
| ||4p/kWh || ||6p/kWh || ||8p/kWh || |
|Electricity ||2.40 || ||3.60 || ||4.80 || |
|0% ||50% ||0% ||50% ||0% ||50% |
|5 years ||8.31 ||5.35 ||9.51 ||6.55 ||10.71 ||7.75 |
|10 years ||5.35 ||3.88 ||6.55 ||5.08 ||7.75 ||6.28 |
|20 years ||3.88 ||3.14 ||5.08 ||4.34 ||6.28 ||5.54 |
Owing to the ability of HFuel to turn on and off rapidly and to be demand side managed as a smart load, electricity prices of 4p/kWh – and potentially as low as 0p/kWh, or even negative – can be accessed in some parts of Europe utilising a high percentage of intermittent renewable power.
A 100 kg/day HFuel generation system with a 5-year amortisation and 4p/kWh electricity price produces hydrogen at a cost of £8.31/kg, which is lower than the European target for 2015. After the 5-year amortisation period, the hydrogen cost from the same system is £2.40/kg, which is already lower than the European target for 2025.
This analysis assumes 100% uptime. The hydrogen storage unit – which is usually tailored to user-specific requirements – is excluded, to permit comparison with other forms of hydrogen delivery. The maintenance scheme is developed to match the installation site and usage profile.
As Graham Cooley, CEO of ITM Power, comments: ‘What could be more compelling than an economic fuel made from renewable power that has zero emissions?’
About ITM Power
ITM Power designs and manufactures hydrogen energy systems for energy storage and clean fuel production. The company has grown from its original platform of novel polymeric electrolytes (for water electrolysis and hydrogen fuel cells) to that of a technology provider. It now has both a strong base of intellectual property and engineering expertise for providing complete hydrogen solutions and CE-marked products for sale.
About the author: Dr Simon Bourne is Chief Technology Officer of ITM Power, based in Sheffield, UK.
This article was originally published in the Fuel Cells Bulletin – check out the sample Digital Edition, which includes the full original version of this article.