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Alan Titchall spends a morning at the MetService head quarters in Wellington, which, along with its international commercial subsidiary Metra, is a global leader in providing services to the energy industry.
You can access it either via a short, steep taxi ride from the city’s CBD or a gut-busting climb up Bolton Street. Market manager Peter Hollingsworth (pictured below) kindly tells me that, once I arrive, he will give me 15 minutes to recover from the climb option before showing me around – I take the cab option. Hollingsworth is responsible for market development and sales within the energy, construction and transport sectors and has been with the MetService office for almost three years. Before that he was the European market manager for Metra, the State-owned enterprise’s, 15-year-old subsidiary that supplies weather and TV services around the world. Since forming in 1992, MetService has grown into a large and very successful international organisation, with offices and agencies in Australia, Asia and Europe. Operating revenues in 2009 exceeded $36 million. Taxi driver jokes about wet fingers out-the-window weather guessing aside, the MetService is tasked with very serious responsibilities as its weather information is relied on by the likes of the marine, aviation, agriculture and fishing industries. Services that go way beyond weather shows for TV stations around the world, including the BBC, TV4 in Ireland, and all the Australian channels with the exception of Sky. Not commonly known is that every energy generation sector in this country other than geothermal is reliant on the weather rooms in Wellington. “When I started working with Metra in 2000 we wanted to enter the European marketplace but were not sure what we wanted to sell with the exception of our very good television product,” recalls Hollingsworth at the beginning of our tour.
Deregulation in Europe at the time presented a huge opportunity he adds. “The way energy is traded nowadays, it is very weather sensitive.” And, surprisingly, it is not the hydro generation sector that leads the demand for accurate weather forecasting in this tempestuous, climate-wise, country. Gas turbine plants and wind generation are perhaps more weather reliant because hydro generation in New Zealand does not have long storage periods in our lakes. Gas turbine generation is exceptionally sensitive to temperature, says Hollingsworth. Having been an aviation writer before joining EnergyNZ magazine, I shouldn’t have been surprised to learn that the combine cycle gas turbines are very sensitive to temperature and pressure changes and therefore weather temperature forecasts. “Gas fuelled generation is hugely sensitive to weather, the higher the temperature the less efficiency from a gas turbine,” says Hollingsworth. “A gas turbine generator is basically a giant jet engine and works in exactly the same way. The reason aircraft fly at over 30,000 feet is because it is cold and dry at this altitude and efficiency gains are huge.” Using an example, the combined cycle gas turbine plant at Huntly, which is nominally around 450MW, has a weather sensitivity that means it will loose around 2-3MW for every one degree Celsius increase, he says. Which means if it is generating 450MW at 18 degrees Celsius then the air temperature only has to go up to a modest two degrees to loose up to 6MW. It’s not possible to put air coolers in front of the larger turbine air intakes (as they do with the new “peakers” at Stratford). “6MW in a stressed marketplace where the price is set at around $100 a megawatt hour means that two degrees represents a loss of $600 per hour.” When you get to 20+ degrees Celsius and above then the costs are “nasty” in terms of lost megawatts, adds Hollingsworth. Weather and the gridWith the sensitivity of the modern grid systems it is not surprising that Transpower is the MetService’s largest Kiwi energy customer.
There is also a close relationship between the MetService, the grid and wind generation. “In the early days of wind there was a fear of how the grid would handle large volumes of generation and it hasn’t been easy. With wind you really need to know in advance what generation is going to be available, and forecasting that is a real challenge.” However, wind generation has been controlled, adds Hollingsworth who also believes this renewable generation is going to become “massive” in New Zealand. “The turbines are getting bigger and the technology more controllable. Five years ago the maximum wind speed wind turbines could safely operate at was 25 metres per second – now its 30 metres and that will get higher, along with the size and output of the turbines which are already up to 6MW.” Hydro generation in this country is dependant on short-term water storage and, therefore, rainfall forecasts. “We have only a few weeks of storage in Taupo and with Tekapo and Te Anau storage is down to days. So if we get long periods of no rainfall then they become very stressed because you can’t take these lakes below their consent levels, and we don’t have pump shortage.” Even the country’s only coal generation is weather sensitive, because the used water from the Huntly Power Station is feed back into the Waikato River. “If the river temperature gets above a certain point they can’t put heated water back into the river and they can’t get the volume of water cooled down quickly enough, so generation has to be restricted.” While MetService doesn’t forecast river temperatures, “We are meteorologists not hydrologists,” says Hollingsworth, it can forecast cloudy and sunny days that greatly effect water temperatures. Energy clientsAlthough a lot of energy trading is based around the long-term energy market, the MetService weather forecasting service is short term, up to 15 days.
“For the first three days they are interested on what is going to happen on an hourly basis, or even half hourly basis, because of their half-hour trading windows and peak periods.” MetService offers a probability density forecast with accuracies within the upper and lower limits of the forecast. “This is useful from a trading perspective. The amount of energy used in this country goes down with a rise in temperature, so a trader can use this information to buy less or more power from the market.” Through a lack of air-conditioning, New Zealand has winter peaks (rather than summer ones) and it may surprise some to learn that peak demand is not just about low temperatures, as wind speed is a critical element. “It’s not just low temperatures creating demand. You need a lot more energy when the wind is blowing, as it is the wind that sucks heat from buildings and influences the chill factor.” Heated air inside a building and cold air outside remain static unless the cold air moves away from the building, he iterates. “Air is a very good insulator, but also a terrible conductor of heat. Heat will stay inside and close to a building, but bring along a wind and that heat gets pulled away and disperses into the atmosphere.” Energy clients get their service information through a number of mediums. The smaller companies access information through a website called MetConnect, while the bigger clients have raw data transmitted direct via an FTP (file transfer protocol) which they run through their own models. Tempestuous New Zealand“New Zealand is by far one of the most difficult countries in the world to forecast weather,” says Hollingsworth. “It’s remote, in the middle of vast oceans, and very topographical with mountains that create very different weather patterns that are difficult to run through models.”
“If we were fine-tuning forecasting for a hydropower station, then we would expect our temperature forecast to be within two degrees throughout a 24 hour period. “Wind forecasts are very much the same, and within two metres per second of wind speed and while rainfall is difficult to forecast, through a combination of models and human intuition, accuracy is of a very high standard.” Hollingsworth says the service’s temperature forecasting is so fine it can pinpoint an air intake on the side of a power station. “We supply weather data to a power station with four air intakes with individual forecasts for each intake, and we are talking only 60 metres from one side of the power station to the other and sometimes we see and forecast three degrees of temperature difference.” MethodologyModern weather forecasting is all about computers and mathematical modelling using data from three main centres around the world – the UK met office, the NCEP in the US, and the ECMWF in Europe. “We take a patch from these global models from roughly around New Zealand and put it into a high resolution model. The global data is of a 25 kilometre resolution and we will bring that down to eight kilometres to make a far more detailed topographical forecast.” Weather balloons are still a useful and vital tool, he adds. Balloons are released from Hokitika, New Plymouth, Auckland and Pacific Islands three times a day to take ‘snaps’ of a cross section of atmosphere, featuring temperature, moisture, wind speed and direction, and pressure. Radar also plays an important part in forecasting and the service is installing them at the rate of one a year. “Four years ago we only had four radar installations in the whole country, now we have seven and another two planned for the next two to three years. “They are invaluable for the real-time information that they deliver, particularly in regard to severe weather forecasting and short term shifts – we can pick up thunderstorms and the likelihood of tornadoes, and intense periods of rain.” Satellites are a significant tool in weather forecasting, he says, but human knowledge and intuition still play a huge part. “You will never get exactly the same weather in the same place twice. The meteorologists will interpret and refine data modelling according to what they know will happen. They are very highly skilled and trained, while a model is pure mathematics - one plus one is two. “We take data and fine tune it as only a human brain can, to deliver a more robust forecast. Every model will give a slightly different answer – so it’s always down to the meteorologists.” Is there a computer around the corner that will make human input redundant? “I have been involved with meteorology for 27 years, and over that time is has been mooted the next generation of modelling is going to be the end of human input – it never is.” Hollingsworth does concede that a lot more modelling and mathematical skill is required in modern weather forecasting. “Having said that, the forecast room is a very diverse place – it is a symphony of different stories that has to say the same consistent thing, but told in different ways by different people.” The weathermanWe are up on the roof of the MetService with its commanding view over the city and Wellington Harbour. A bruised and fast changing sky soars above us while under our feet 200 MetService staff gaze intensely at the kaleidoscope of graphics on their computer screens, or the waves of depression lines on their A3-size weather maps.
“We want to be a global leader in local weather. And people don’t recognise how successful we have already been, particularly in the energy sector. There isn’t a major energy company in north western Europe that doesn’t know about Metra.” Getting towards the end of my two hour tour, Hollingsworth’s enthusiasm for his job and focus on the energy industry has never waned, and he never tires of pushing the success of the service. “I joined meteorology when I was 20 years old. Some 27 year later and it is still a passion, and I wake up in the morning and I look forward to what is going to happen in the day ahead.” Before jumping into the cab for the downhill ride into a wet wind ripping in from Cook Strait I had to ask, on behalf of every taxi driver in the city, ‘do friends and family rely on him as a weatherman’? “They do ask, but don’t necessarily believe the answer.” And do you usually get it right? “Yeah. You don’t get involved in this industry for 27 years without something rubbing off on you.”
Energy NZ Vol.4 No.6 November-December 2010 |
From its lofty position in Wellington’s Botanic Garden, the multi-storey New Zealand MetService building, with its exposed post-war concrete and earthquake-proof design, is a formidable sight.
“One of the markets I suggested we get into was energy.”
The Transpower-owned lightning detection network, now a decade old, that was installed and is maintained by MetService and which still provides the data for the programme that has become an important part of the country’s grid protection. Transpower also relies on MetService for many other weather forecasts.
“Transpower’s main focus is on the day ahead and the next three days. The focus of ‘gentailers’, as we call generators/retailers in this country, is anything from two hours time to weeks, and even months ahead.
Despite this, he says the level of forecasting accuracy is high.
“The company still has fantastic ambitions,” Hollingsworth says as spits of rain threaten to douse us with a light shower.