Electricity is vital to modern day life and is fundamentally important to the economic development of nations such as China and India.
Two-thirds of the world’s electricity is generated by burning fossil fuels. And the International Energy Association has estimated that 37 per cent of the world’s man-made carbon dioxide emissions are the result of electricity generation. Carbon dioxide is the number one greenhouse gas, and a key driver of climate change.
Electricity can be generated using less polluting, renewable resources, and a few countries such as Iceland and Paraguay already supply their entire electricity demand using renewables. These are mainly largescale hydroelectric schemes. Globally renewables account for around 19 per cent
of electricity supply.
But the real growth sector is the so-called ‘new renewables’ such as solar and wind. Wind power, which is already the second most important source of renewable energy, is increasing at a rate of around 30 per cent a year. Worldwide, installed capacity reached 198 GW in 2010. And, for the first time, more than half of all new capacity was added outside of the traditional markets of Europe and North America.
Around the world, more than 80 countries are harnessing the wind on a commercial basis; and in several countries wind power has already achieved a relatively high level of electricity market penetration. For example, more than 20 per cent of Denmark’s electricity is wind generated, with three other European states – Portugal, Spain and Ireland – achieving double figures.
The long-term potential of wind energy is huge. It has been estimated that it could supply more than 40 times current global electricity demand – though achieving this would require wind turbines to be installed over large areas.
While many renewable energy projects are large scale, ‘new renewable’ technologies are also ideally suited to small projects in rural and remote areas. And GEA has been involved in a remarkable project in the caribbean that has seen the development of the world’s largest wind-diesel power station. This is on the Island of Bonaire.
Bonaire is a small (294km2) island that until 2010 was part of the Netherlands Antilles. It is still officially part of the Netherlands – though it lies about 80 kilometers (50 miles) off the northern coast of Venezuela.
It has a resident population of fewer than 15,000. But its white beaches, turquoise sea and coral reefs make it one of the world’s top destinations for scuba diving, snorkeling and wind-surfing. it receives round 75,000 tourists a year – greatly increasing the demand for power.
Bonaire is just one of more than 7,000 islands – and 36 million people – in the Caribbean region. However, most Caribbean populations are too small for major hydroelectric schemes – and there are no facilities for the import of liquid gas. Therefore, the region is heavily reliant on diesel generation. Rising oil prices have meant rising electricity prices.
After bonaire’s only power plant burned down in 2004, the island’s government decided that it wanted to replace it with energy generation from 100 per cent renewable sources. The system that was chosen combines a wind farm and a diesel power plant that by 2015 will be running on locally produced biodiesel.
One inherent problem with wind-based power generation is the variability of wind ‘supply’. A number of hybrid systems have been developed to overcome this and smooth out electricity generation. For example, windhydrogen systems use wind power to produce hydrogen through the electrolysis of water. This in turn is used to generate electricity using fuel cell technology. other hybrids combine wind with solar, compressed air storage, or hydroelectric systems.
But wind-diesel is the most widely used hybrid with isolated communities, from Antarctica to the Galapagos Islands and Alaska to Eritrea, using what is an increasingly reliable technology with low technical support requirements.
The 12 wind turbines on bonaire were intended to provide an average of 40-45 per cent of the island’s total electricity requirements. Since August 2010 when the plant began operating, the highest wind share has been more than 80 per cent. But during periods of calm, generation switches to five MAN Diesel engines. The advantage of these over other forms of hybrid wind generation is that they require only a very short start-up time and are available virtually at the push of a button.
GEA Mechanical Equipment has supplied a heavy fuel oil and lubricating oil treatment facility which ensures the engines run smoothly. In addition a GEA Westfalia Separator® ViscoBoosterUnit enables the viscosity, temperature and pressure of the fuel to be adjusted precisely.
At the moment, the engines use heavy fuel oil. But as part of the Bonaire project, a biodiesel plant is being developed that should produce 10,000 metric tonnes of algae-based fuel each year to run the power station.
This means that within four years, Bonaire will be joining the handful of nations with a 100 per cent clean energy supply.