ZUL-QA'ADAH 1 1430 A.H.
WEDNESDAY NOVEMBER . 18 2009.
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Wind energy in Nigeria: Time is now (II)
By Olumide Ogunleye
Bat species appear to be at risk during key movement periods. Almost nothing is known about current populations of these species and the impact on bat numbers as a result of mortality at wind power locations. Offshore wind sites 10 km or more from shore do not interact with bat populations.
Aesthetics have also been an issue in some areas. In the USA, the Massachusetts Cape Wind project was delayed for years partly because of aesthetic concerns. In the UK, repeated opinion surveys have shown that more than 70 per cent of people either like, or do not mind, the visual impact. According to a town councillor in Ardrossan, Scotland, the overwhelming majority of locals believe that the Ardrossan Wind Farm has enhanced the area, saying that the turbines are impressive looking and bring a calming effect to the town. The turbines are more than three kilometers from the town.
Nigeria is in dire straits with reference to her power supply needs for industries and general usage. Nigeria is therefore not in a position to pick and choose what her sources of power generation should be, based on cosmetics. Nigeria should diversify and integrate her power sources with a mix of gas, wind, solar, nuclear, hydro, biomass etc with each contributing to the national grid.
Aesthetics and environmental impact considerations are both good but let us have enough to power our needs and necessities first. An African adage says ‘the dog that is full should not play with a hungry dog.’
Intermittency of wind power
Intermittent energy source is a term usually used to refer to some sources of renewable energy, such as wind and solar,( but not to geothermal generated electricity or nuclear electricity), because these sources of electric power generation may be uncontrollably variable or more intermittent than conventional power sources. However it needs to be borne in mind that conventional sources are also intermittent to the extent that they cannot be relied on 100 per cent and therefore means have to be provided to deal with their intermittency - such as multiplication of sources, fast acting reserves and interconnection with other systems.
The Nigerian environment is not different. Nigeria needs to diversify her types and sources of power generation. Nigeria’s almost total dependence on hydro and gas powered turbines is the cause of her inability to have steady power supply.
Even as it were, for very large penetrations of the most intermittent source, wind energy, such sources become highly reliable, and whilst the aggregate output can change with weather changes, this is highly predictable, and much more reliable than say a single large power station which can (and do) fail suddenly and unpredictably.
Technological solutions to deal with large scale wind energy type intermittency already exist and studies by academics and grid operators indicate that the cost of compensating for intermittency is expected to be low even at levels of penetration substantially higher than those prevailing today.
Large, distributed power grids are better able to deal with high levels of penetration than small, isolated grids. For a hypothetical European-wide power grid, - ( European super grid] analysis has shown that penetration levels as high as 70% are viable, and that the cost of the extra transmission lines would be only around 10% of the turbine cost, yielding power at around present day prices. Smaller grids may be less tolerant to high levels of penetration.
Matching power demand to supply is not a problem specific to intermittent power sources. Existing power grids already contain elements of uncertainty including sudden and large changes in demand and unforeseen power plant failures. Though power grids are already designed to have some capacity in excess of projected peak demand to deal with these problems, significant upgrades may be required to accommodate large amounts of intermittent power. But again, large amounts of large inflexible plant (nuclear, supercritical coal, coal plus CCS) will also require grid upgrades and increased interconnection or incur financial costs – e.g the French nuclear programme necessitated its 2 GW HV link to UK, and increased imports and exports to neighbouring countries.
The International Energy Agency (IEA) states: "In the case of wind power, operational reserve is the additional generating reserve needed to ensure that differences between forecast and actual volumes of generation and demand can be met. Again, it has to be noted that already significant amounts of this reserve are operating on the grid due to the general safety and quality demands of the grid. Wind imposes additional demands only inasmuch as it increases variability and unpredictability.
However, these factors are nothing completely new to system operators. By adding another variable, wind power changes the degree of uncertainty, but not the kind..."
The US Federal Energy Regulatory Commission (FERC) Chairman Jon Wellinghoff has stated that “baseload capacity is going to become an anachronism” and that no new nuclear or coal plants may ever be needed in the United States implying that his organization does not see intermittency as an issue.
At present, the penetration of intermittent renewables in most power grids is low, but wind for example provides nearly 20 per cent of the electricity generated in Denmark (where plans are underway to increase this substantially) 11 per cent in Spain and Portugal, nine per cent in the Republic of Ireland, and seven per cent in Germany.
The use of small amounts of intermittent power has little effect on grid operations. Using larger amounts of intermittent power may require upgrades or even a redesign of the grid infrastructure. However, it should be borne in mind that large amounts of large inflexible plant, such as nuclear or supercritical coal or coal plant equipped with CCS will also require significant grid upgrades to deal with their inflexibility.
Small-scale wind power
Small scale wind power is the name given to wind generation systems with the capacity to produce up to 50 kW of electrical power. Isolated communities, that may otherwise rely on diesel generators may use wind turbines to displace diesel fuel consumption.
Individuals may purchase these systems to reduce or eliminate their dependence on grid electricity for economic or other reasons, or to reduce their carbon footprint. Wind turbines have been used for household electricity generation in conjunction with battery storage over many decades in remote areas.
Grid-connected wind turbines may use grid energy storage, displacing purchased energy with local production when available. Off-grid system users can either adapt to intermittent power or use batteries, photovoltaic or diesel systems to supplement the wind turbine.
In urban locations, where it is difficult to obtain predictable or large amounts of wind energy (little is known about the actual wind resource of towns and cities, smaller systems may still be used to run low-power equipment. Equipment such as parking meters or wireless Internet gateways may be powered by a wind turbine that charges a small battery, replacing the need for a connection to the power grid.
A new Carbon Trust study into the potential of small-scale wind energy has found that small wind turbines could provide up to 1.5 terawatt hours (TW·h) per year of electricity (0.4 per cent of total UK electricity consumption), saving 0.6 million tonnes of carbon dioxide (Mt CO2) emission savings. This is based on the assumption that 10 per cent of households would install turbines at costs competitive with grid electricity, around 12 pence (US 19 cents) a kWh.
Distributed generation from renewable resources is increasing as a consequence of the increased awareness of climate change. The electronic interfaces required to connect renewable generation units with the utility system can include additional functions, such as the active filtering to enhance the power quality
Report prepared by Olumide Ogunleye
Guenergycorp@yahoo.com
Source: nigeriavillagesquare.com
