Wind power can easily replace 40% of Coal, Oil, Gas and Nuclear for electricity generation in the UK. Wind expert David Milborrow shares his 30 years of experience in grid integration and penetration of wind resources and all variability associated with electricity grid supply and demand. David Millborrow in conversation with Matthew Wright of Beyond Zero Emissions.
Milborrow is an expert in large scale wind power integration and penetration on modern electricity grids. He started his work with the Central Electricity Generating Board (CEGB) in the United Kingdom where he worked on aerodynamic research, policy development and plans for UK’s first wind farm. His first foray into variability issues research was in 1988.
He is a mechanical engineer by training and has worked with the CEGB's research laboratory on advanced types of cooling towers. He then turned his thinking to fans for cooling towers and became interested in prospects for wind power in the CEGB when wave energy was the favoured renewable. He had a large wind tunnel to experiment with and was able to simulate large arrays of wind turbines and work out realistic spacing etc.
After seven years research he got involved in planning, technological and economic issues associated with real wind farms and was involved with the construction of the first commercial wind farms in the UK.
CEGB’s last transaction, before privatization, was an equity contribution to that first wind farm.
Milborrow became an independent consultant in 1992.
Under the privatization model, research is still done but is mostly funded on a collaborative basis and contracted out to independent operators.
What level of penetration has wind power achieved?
Milborrow referred to the myth about wind power that it fails when the wind stops blowing. This is not a problem. He indicated that electrical systems are used to coping with variable demand and uncertainty. Wind adds only a little more uncertainty. He offered a useful analogy to help us appreciate the additional uncertainty wind produces:
A pebble thrown into a still pond compared to a pebble thrown into a busy pool of swimmers where the perturbations are hardly noticed. It is the latter perturbation that wind produces.
Similarly the extra cost of dealing with large quantities of wind energy (up to about 40% of all energy provision) is quite modest. The extra cost to the consumer is approximately $11-12 (Aust) per MW hour ie. an additional 5-6% on domestic electricity bills.
There are periods when the available wind exceeds system demand and thus a modest amount of wind needs to be curtailed. Milborrow has been asked by WWF and NGOs to look into possible mitigation measures for “mopping up" surplus wind and reducing costs. He has identified ten mitigation measures including the take-up of electric cars (absorb surplus overnight) and better wind predictability (to reduce cost). (Wind is not, in fact, totally unpredictable. It varies in a manner that can be quantified).
The power of wind turbines can be easily controlled or “turned down”, for example, by pitching the blades.
Variability compared to intermittency
Nuclear, coal and gas-fired stations and conventional thermal generation is intermittent. The output from a nuclear power station can disappear instantaneously. Wind output, however, “swings around in a lazy manner” and the characteristics of the power swings can be quantified to a high level of precision. Consequently, wind power is variable.
Shifting fuel sources and the difference in delivery between base amount of power and peak
If for example, electric cars are charged at night, the load profile is smoother so the electricity system operates more efficiently. Additionally, because electric cars are more fuel efficient, there is also an overall win in fuel economy.
Smart meters could, if properly configured, attenuate the load in return for lower tariffs. This would aid the assimilation of renewables and improve the overall efficiency of the electricity network. Work has been done into the scope for means to reduce the cost of the spinning reserve and thus reduce the cost of variable renewables.
Deferring charging of, say, electric vehicles and space heating and cooling can make use of surplus power at night. Also, moving from gas to electric heating (and using electricity from renewable sources) and allowing for flexibility in terms of when the charge is taken, saves valuable fossil fuel sources.
We can achieve in the order of 40% penetration of wind on our grids!
In conclusion, Milborrow noted that in Australia we have an advantage over the United Kingdom in that our best wind resources line up with our population!
Originally published 2009-10-09 13:18:20 +1000