Feeds

Carbon Trust: Rooftop windmills are eco own-goal

Perhaps we should stop subsidising them

Remote control for virtualized desktops

Analysis Rooftop wind turbines are actually net carbon emitters for most British properties, according to new research. Worse still, it appears that even if small turbines became common they could produce only a tiny fraction of the UK's energy requirements.

The new report (pdf) is titled Small-scale wind energy and is issued by the Carbon Trust, a quango dedicated to reducing greenhouse gas emissions. The research was carried out with the assistance of the Met Office and consulting engineers Arup.

According to the report's authors, the most commonly used UK windspeed database is highly optimistic in the case of urban areas. They suggest that one should be wary of believing any figures offered by the wind-turbine industry.

NOABL [Numerical Objective Analysis of Boundary Layer] is a public domain reference dataset used widely in the UK wind industry ... analysis by the Met Office suggests that NOABL tends to ... over-predict the amount of power it is possible to generate with small turbines in built-up areas ...

The [free from the government biz department] Wind Speed Database (created using the NOABL model) does not reflect the effects of urban areas (the wind speed values are representative of open, level terrain) ...

There is also a technical supplement (pdf) intended for engineers and designers, which goes even further:

There are a variety of sources of wind speed and direction data available ... All of these data types have limitations, either in terms of their temporal or spatial extent, or in terms of their representativity of urban areas ... There are a number of proprietary systems used by the wind energy industry ... Tools such as WindFarmer, WindFarm and WindPRO do not include any functionality designed specifically for siting turbines in urban areas.

The researchers go on to model the expected yields of small wind turbines using a more realistic Met Office database which you have to pay for, rather than the free one, and they allow for the serious reductions in windspeed to be found close above urban rooftops. The results make depressing reading for microgeneration fanciers.

Because small turbines are mounted at relatively low heights, their mean hub height wind speeds may be close to their cut-in speeds. The implications are that, for long periods of time, a small turbine may not operate at all, or if it does operate (and visibly spin), it may not generate much electricity.

Practically speaking, small wind turbines require ... locations which are open, exposed and experience high wind speeds, which generally tend to be found in rural areas.

Because the output to be expected from urban turbines is so low, the cost of the resulting energy is very high. According to the Carbon Trust analysts, electricity prices would need to be double their present levels before any urban turbine could earn its keep. Even if electricity soared to eight times its current price, economically viable urban turbine sites would still be a rarity:

Practically no urban sites have costs of energy below 25p/kWh ... At 100p/kWh, the energy that could be generated at rural sites is about nine times that of urban sites; i.e. the split is 90 per cent rural to 10 per cent urban.

Internet Security Threat Report 2014

More from The Register

next story
Antarctic ice THICKER than first feared – penguin-bot boffins
Robo-sub scans freezing waters, rocks warming models
I'll be back (and forward): Hollywood's time travel tribulations
Quick, call the Time Cops to sort out this paradox!
Your PHONE is slowly KILLING YOU
Doctors find new Digitillnesses - 'text neck' and 'telepressure'
Reuse the Force, Luke: SpaceX's Elon Musk reveals X-WING designs
And a floating carrier for recyclable rockets
NASA launches new climate model at SC14
75 days of supercomputing later ...
Britain's HUMAN DNA-strewing Moon mission rakes in £200k
3 days, and Kickstarter moves lander 37% nearer takeoff
Bond villains lament as Wicked Lasers withdraw death ray
Want to arm that shark? Better get in there quick
prev story

Whitepapers

Go beyond APM with real-time IT operations analytics
How IT operations teams can harness the wealth of wire data already flowing through their environment for real-time operational intelligence.
The total economic impact of Druva inSync
Examining the ROI enterprises may realize by implementing inSync, as they look to improve backup and recovery of endpoint data in a cost-effective manner.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Mitigating web security risk with SSL certificates
Web-based systems are essential tools for running business processes and delivering services to customers.