For a growing number of companies, reducing their environmental footprint means looking at the energy used by their IT systems.
But some other businesses, especially utilities and those involved in infrastructure or transport, have to look at the problem the other way round. They are increasing their investments in IT, in order to meet their environmental targets.
In the case of Spanish power distribution company Red Eléctrica de España (REE), the investment in new software technology amounted to €300,000 ($400,125).
The company’s international division manages the power supply systems in non-peninsular Spain: the Canary and Balearic Islands and the cities of Ceuta and Melilla. REE International (REI) does not generate electricity, but has an obligation to buy energy at the lowest cost, while meeting environmental targets.
In mainland Spain, electricity generators compete by way of a national market, with prices set daily. Off the mainland, however, local markets are too small for this approach to work. Instead, REE manages the electricity networks through the “unit commitment”.
Unit commitment systems are used in other electricity markets, particularly in North America. Under its rules, the distributor must buy power from the generators as cheaply as it can, while maintaining safe and consistent supplies.
The system for non-peninsular Spain, however, has another criterion built in: managing the environmental impact. The company has a target to reduce emissions by 2.5 per cent or 100,000 tonnes of CO2 annually.
Furthermore, REI has to distribute all available renewable energy before buying from other sources. In the Canary Islands, for example, this means ensuring that all the abundant wind energy is dispatched.
Meeting the unit commitment – and ensuring a constant supply of power – requires advanced planning techniques.
Because levels of power from renewable sources, especially from wind, vary with the weather, REI has to calculate likely supplies from renewables, based on operators’ predictions, and also know what other capacity will be available, should these supplies fall short.
It also has to know how quickly this capacity can come on stream, and its cost.
Javier Revuelta, senior consultant operation planning expert at REI , says calculating the unit commitment requires complex algorithms. Managing these meant using a tool developed and programmed in the Fortran computer language.
“We see quite a few changes in legislation and in technology in the electricity system, so we often have to make modifications to the software. That was quite complicated to do in the tool. We wanted a more exact method [of calculating the unit commitment] in order to reduce costs, and software we could modify easily to model the constraints.”
Mr Revuelta expects to need to make constant changes to the mathematical models over the next few years – new wind generation capacity, for example, is expected to come on line every six months.
The company will also need to accommodate other changes, such as rising demand, environmental regulations, and an under-sea interconnector between the Balearic Islands and mainland Spain, which will give access to a broader range of electricity generators.
As a result, REI decided to introduce a new, more flexible method for modelling the unit commitment system, based on optimisation software rather than handwritten code.
The new system is based on three tools from ILOG, the software vendor: CPLEX®, OPL and ODM. CPLEX® provides a library for the algorithms; OPL allows developers to program the application; and ODM – the optimisation decision manager – enables REI to deploy the optimisation application and, if need be, for staff to customise it.
While hardly an off-the-shelf solution, the software enabled a prototype to be developed in just two months. And REI’s modelling staff, who are experts in their field but not necessarily IT experts, can now make changes directly without having to call in Fortran programmers.
REI is currently running both the Fortran and ILOG-based systems side by side, but expects to move entirely to ODM over the next few months. One reason is that the more accurate models are saving the company up to €100,000 a day in more efficient energy purchasing.
It is also bringing significant environmental improvements, by allowing REE to balance supply from renewable and conventional energy sources better.
“We are not generators, but system operators,” Mr Revuelta explains. “We program the generators’ capacity with our algorithms. We decide which [plants] have to be started up or shut down, at what times of the day. We don’t, for example, decide to build more, or less, wind generation capacity, but we have to use, in the best possible way, the renewable capacity other people own.”
This is why REI’s initial investment in a new modelling system will pay environmental, as well as financial, dividends.
Planned expansion of wind farms in the Canary Islands, in particular, is likely to lead to all the islands’ off-peak, or night time, power demand being met by wind energy, and up to 50 per cent of peak demand. Because weather changes, REI’s modelling will need to be all the more precise, as well as updated to reflect new capacity.
“Currently, in extra-peninsular Spain, renewables supply less than 10 per cent of energy,” says Mr Revuelta. “But by 2012 that will rise to 20 per cent …Our mandate is to program in as much [renewable energy] as producers tell us they can provide. Every time a new wind farm is installed, and that happens at least once or twice a year, we will need to update our models.”
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