If you were to assess the situation, how would you draw the balance between meeting demand loads, as a part of the demand-side strategic plan, and meeting the constant need for energy efficiency?
Our campuses have been growing but not our budgets. We added two million square feet last year, and more than just providing energy-efficient cooling, we have to provide energy, which must be reliable, efficient and sustainable. We have multiple power generation sources and often consider ourselves at risk if we are connected to the normal grid. We produce our own energy and always operate net zero. An important aspect to meeting demands is to have access to a good control system, which determines the ability to connect to a grid and to detail whether I need to import power or export power. When you have five different plants and two thermal storage tanks, the challenge is in deciding which one is better to run, with the lowest amount of energy. Using natural steam for heating and cooling is another very diverse challenge, but we’ve worked out the method of dispatching – that is, to know which chiller or turbine to run, in order to get enough energy to the building.
Where does the campus stand in terms of system efficiency, and what measures have you taken to ensure you’re constantly moving towards the 90% annual energy-efficiency goal?
On the supply side, in 2002, the annual system efficiency was 1.5 kilowatts per tonne, which was bad. In 2008, we dropped it to 0.8 kilowatt per tonne and, then, further to 0.65 kilowatt per tonne in three years. Last year, we were at 0.62 kilowatt per tonne, and now my goal is to get to 0.6 kilowatt per tonne. In terms of the amount of power generation, in 1976 we were delivering around 150 million kilowatt hours; we now deliver 320 million kilowatt hours, with less fuel and an efficiency of 0.62 kilowatt per tonne on an annual basis. In my opinion, if you are truly interested in efficiency, you never rest. We have also cut our fuel use in the past two months, which is five per cent less, when compared to the previous year. The idea is to look at the situation holistically and make our own steam, cooling and power.
The main campus at Austin features a Combined Heat and Power (CHP) plant with a total capacity of 134 MW of power and 1.2 million lb/hr of steam generation capacity. The single largest electrical load on campus is the cooling system, with the capacity to provide 60,600 tonnes of refrigeration to the campus. Does the cooling system run at full capacity to date?
Eight years ago, our cooling systems were running at full capacity, but not at present. Though it may sound like a bad thing, it is not. Plants are one aspect, but what’s even more essential is having a good distribution system. If you don’t have the right size of piping to support the load of the building, it’s not going to work. Even though our system is large, it is all looped, hence it does not matter which system and plant are running. With the help of a central control, I can access all five plants. We are soon getting to the point, where one plant will be located 10 miles away and can be monitored remotely, without the need for people.
You mentioned that the power plant’s new equipment is more efficient. Could you elaborate on how technology, when combined with a control system, helps deliver on efficiency?
I think the challenge is that most people don’t know what they can do with technology. What we’re trying to do is to set the gold standard. We work with a company, who created a control system for us. In addition to the system, we use Variable Frequency Drive (VFD) systems to control the chillers, water pumps and the chilled water pumps and the tower fans, and it is all in one integrated system. What it does is it makes all simultaneous decisions. It uses its own networks after considering all the options, it shows the least number of equipment I need to run to make the tonne. We have evolved, and the plant we implemented this with was a brand new one. Now, the system has evolved from just controlling a plant to also managing distribution and multiple plants at the same time. We have learnt a lot during the journey. The plants are also monitored independently from Seattle, so if there’s something wrong, the operators there will call my operators.
What role does cost play? Is it an overruling factor in opting for energy-efficient solutions?
When it comes to capex and opex, it is a balancing act. At the campus, we finance ourselves and are moving into a process, where we are picky when it comes to designs for our plants and buildings. We also analyse lifecycle costs, and typically, the cost of a building is one-eighth of the lifetime cost of a building. This means that the operational cost is eight times more than the cost of a building; hence, you want to build it right, but you also want to be able to operate it right. Here is where the mistake lies. Very often, campuses and commercial buildings are looked at with a maximum lifecycle cost of 3-10 years, when we think 100 years. Another important aspect is to have specific design standards for buildings.