SO JUST HOW MUCH POWER
IS YOUR SHOW’s LIGHTING USING?
Often, you just don’t know.
Usually, it’s not as much as you fear.
But if people ask, can you actually answer?
Sometimes, but not always, you can measure it.
If you can’t, we have PowerTrack, the tool to calculate it…
A few years into the life of FocusTrack, our show lighting documentation software, we had a conversation with someone about the energy use of show lighting. They knew the total power of all the lights they had plugged in, but how much did it actually use during a show? Because of the design of their building, they had no easy way of figuring this out by connecting a meter and measuring the power.
We thought about this. FocusTrack already knew an awful lot about the rig – what each light was, how much power it used. But it also knew what level each light was on at in each cue. And it could also be taught how long each cue was on stage for. Given all that, didn’t we have enough information to calculate how much power was being used at any moment in the show and, from that, to calculate how much was used by one performance.
We set to work, adding a new function to FocusTrack: PowerTrack.
THE TEST CASE
DID MATHS MATCH MEASUREMENT?
Of course the question was, did it give the right answers. We needed a test case. The Children’s Hour at the Comedy Theatre in 2011 provided it. We had the showfile and rig information. More usefully, the theatre owners were, independently, taking some power measurements during performances. We had real, measured figures to compare our calculated results to…
And they were pretty close. Not identical – they never would be, since the measurements also included ice cream fridges, wig over and much else besides. But the shape of the graphs were roughly the same, and the figures were ballpark the same. But it proved that often if you only wanted to look at lighting power, this was the way to do it.
Plus it was fascinating to look at the graph and be able to identify moments in the show…
Of course, no-one much used it. As soon as a show opens most people’s attention turn to the next one. If you’re specifying the power for a tour you’ll make a guess and round it up a bit. If you’re in a big theatre you usually have enough power available so don’t need to worry.
But as people started becoming more concerned about the environment, the global climate crisis, and the part the entertainment industry might be playing in that, a few people started to call…
THE SEATTLE STUDY
THE CASE FOR LED?
One of those people was theatre consultant Katie Oman. Seattle Rep were planning a new theatre, and they had some questions: how big a power supply should they specify? And was it worth investing in the coming LED technology.
Using PowerTrack, we helped Katie model the power use across one complete season of shows at the theatre. It was fascinating to draw the overlapping graphs, which let you clearly see the difference in shows (the ones with very high power use almost always had a cyc), and to realise that particular moments in the show – the interval, the curtain calls – always had very distinctive patterns.
Katie wrote a great overview of the project for Lighting&Sound America magazine, which you can find here:
THE LES MIS STUDY
ARE WE GETTING ANY BETTER?
The Seattle study showed that lighting wasn’t the biggest power user in theatre – it’s usually heating and cooling that’s guilty of that. Particularly as more shows moved from tungsten and arc to LED. This surely meant lighting was using less power – but how much less?
That’s an interesting question to try to answer because no two shows and no two lighting rigs are the same, so how to make a comparison?
The current production of the musical Les Misérables provided an opportunity: the same show, but with the rig evolved over time to use new technology. But with the same LD present each time to make the show look the same.
It also presented a new challenge: additive-colour LED fixtures are harder to model because their power is different for each colour, and you can’t always get the power data about their different LED sources.
But we carried on, and made some really interesting discoveries (not always what you”d expect). The result was published in Light+Sound International magazine in 2020:
YOUR STUDY
BECAUSE IF YOU DON’t ASK, YOU’LL NEVER KNOW
PowerTrack is still built in to FocusTrack. Own FocusTrack and you can use it yourself to figure out how much power your show lighting is using. That’s useful information for many reasons – particularly as publicly funded venues and organisations are asked to carry out energy audits. You can also carry out ask ‘what if?’ questions – what happens if I swap these lights to LED? The data from the Seattle and Les Mis studies has also been useful in making the case for entertainment lighting to the EU and UK Governments as new environmental regulations governing lighting are considered.
If you want to know but don’t have the time to do this yourself, or particularly if you need to model lighting rigs with additive colour-mixing lighting fixtures where you need to research their power use in different colours, why not let us do it for you? We love a good research project, and would be happy to help.