Saturday, August 17, 2013

I've Been Misled on wind forecast accuracy, and the cost of renewables

A couple of stories that caught my attention this week.

The global wind industry was repeating claims from IBM (International Business Machines Corp.).
Home News TechnologyIT IBM taps Big Data to boost renewable power output | Business Green
IBM has officially launched a new weather modelling system specifically designed to help renewable energy generators and utilities accurately predict output from wind and solar farms, allowing them to reduce back-up power requirements and increase output from renewable energy plants.
The so-called 'Hybrid Renewable Energy Forecasting' (HyRef) system combines advanced weather modelling with detailed information on windturbine and solar panel output to allow utilities to model output in near real time.
Sounds great, but ...
I've Been Misled on the claims of accuracy in forecasts before.  In May, Ontario's Independent Electricity System Operator presented on "Centralized Forecasting Accuracy":

IESO, slide 5 of Centralized Forecasting Accuracy

I sought out the IBM definitions for accuracy on their HyRef system, but found nothing - except a hint in references to where they've been developing the programming:
This project builds upon another IBM smarter analytics initiative at Denmark's Vestas Wind Systems, the world's manufacturer of wind power turbines. Vestas, together with IBM's big data analytics and supercomputing technology, is able to strategically place wind turbines based on petabytes of data from weather reporters...
If you look at Ontario's IESO forecasting reporting/data using Google's Chrome browser, as I have, you'll be asked if you wish to translate the page from Danish.

So it looks to me as the standard indicates accuracy differently than people who aren't mislead would: output of 100MW when 200MW is forecast is a 10% error if capacity is 1000MW, and a 2% error if the capacity is 5000MW.  The IESO's target for an hour ahead was 4.5%; with a desire for 8000MW of wind capacity, this is close to expecting a nuclear unit at Pickering to trip off, or suddenly come back at full strength, each and every hour.

The IESO also indicated forecasting accuracy had ceased improving - making me think IBM's announcement is more likely indicative of finding an "industry standard" for measuring accuracy that masks inaccuracy than one that reflects the ability to know what is about to be generated.

OPG 2013 Q2 Page 7
On the topic of what's about to be generation...

Ontario Power Generation released their 2nd quarter financials yesterday.  My attention was drawn to how little the public generator - which has been blocked from pursuing wind and solar generation -receives for producing the majority of Ontario's electricity compared to other produces.

The cost of private generators increased at double the rate of public generation.

My belief is the only increasing accuracy with variable renewable energy sources (vRES) is in targeting marketing messages.

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