Demand side response adds up for Aggregate Industries

It started with bitumen tanks and who knows where it might end? Donna Hunt, Head of Sustainability at Aggregate Industries, relates how her company is broadening its thinking to take full advantage of the possibilities of demand side response (DSR).

Aggregate Industries knows a lot about building roads so it’s appropriate we’re blazing a trail when it comes to making the most of DSR opportunities.

We’re well known in the industry for being pioneers in the use of new technology and we’re always looking for ways to reduce our energy consumption and costs, and at the same time reduce our emissions. When we found out that DSR can help us do all these things – and generate revenue – we became very interested.

We teamed up with energy specialists Open Energi to identify those activities of ours that fit the dynamic frequency response management profile. In other words, activities where we can safely automate the switching on or off of power – without affecting quality – in order to help balance the grid.

The first plant we included in the scheme was our bitumen tanks which heat bitumen for the making of asphalt for road surfaces. We found that turning off our bitumen tank heaters to respond to short-term fluctuations in supply and demand doesn’t affect the quality of our product at all; bitumen is stored at between 150-180 degrees centigrade and the heaters on modern, well-maintained and insulated bitumen tanks can be switched off for over an hour with only a one-degree change in temperature.  The tanks’ temperature bands act as control parameters; if the temperature is within those bands switching can take place automatically, or if not, nothing happens.

The clever part is that the equipment uses frequency signals as a cue, which are instantaneous indicators of the balance between electricity supply and demand. National Grid has to maintain frequency at 50hz to balance supply and demand, so if it falls below 50hz our plant is automatically switched off if conditions are right; if it rises above 50hz, it is switched on.

The average duration of a switch is less than five minutes. Essentially the intervention is invisible and has no impact on our operations, yet we are providing a valuable service to National Grid 24 hours a day, 365 days a year. We are paid for being available, regardless of how often we are required to respond.

We’re well known in the industry for being pioneers in the use of new technology and we’re always looking for ways to reduce our energy consumption and costs, and at the same time reduce our emissions. When we found out that DSR can help us do all these things – and generate revenue – we became very interested.

Equipment was initially fitted to 244 of our bitumen tanks at 40 asphalt plants around the country. So successful has it proved that we’ve extended it to 11 quarry pumps at two quarries, and we are also reviewing all our sites, operations and equipment to identify further activities to bring into the scheme.

Embracing this innovative technology has helped us achieve 3.6MW per year of flexible demand for the grid.  In terms of emissions that is almost 50,000 tonnes of CO2 avoided over five years – equivalent to saving 390,000 flights between Paris and London!

And thanks to Open Energi’s metering and monitoring equipment, we have new data which can help us identify where the bitumen tanks may be inefficient or not running correctly, which in turn we can use to make adjustments to achieve even more energy savings.

We’re really pleased to be part of the DSR scheme with National Grid and Open Energi and we want to help get the message out how well it works. Through our partnership with the Living Grid network, we’re happy to share our experience of this emerging technology and encourage others to take up the opportunity too. Together we can create a positive change in the energy system that extends beyond our own organisation.

A Welcome Hotel Reception for DSR

After successful trials, Marriott International Europe has embraced Demand Side Response (DSR). John Conlon, Head of Engineering and Facilities, tells us why the chain has rolled out the red carpet for DSR.

At Marriott International the first thing we needed in order to understand the benefits of DSR for our business was a positive mindset as. Initially, it seemed to make little sense – it’s 6pm, it’s been a hot day, the hotel is full of people getting ready for the evening and we are being asked to reduce our demand for electricity. Really?

Once we came to understand the concept however, we wanted to be involved. From a small beginning with a pilot in just four of our hotels, we have expanded our participation in DSR to 29 hotels in the UK with more hotels potentially being added this year in France, Belgium, Germany and Switzerland.

The concept is that small reductions in demand from our hotels, and the other businesses that we are aggregated with by KiWi Power, add up to a significant overall reduction. This allows National Grid to keep the system in balance during times of high demand or when additional flexibility is called for. The key for us is to reduce demand without affecting our operations.

It underlines our credibility as a business committed to sustainable energy use and it has resulted in some very positive media coverage.

NO COMPLAINTS

For us the initial focus was on large pieces of electrical equipment such as the chillers that we use for air conditioning and refrigeration. Shutting these down for short periods of time within agreed parameters can be done with little or no effect on our operations, certainly as far as our guests are concerned.

As an illustration, if you turn off a domestic freezer for an hour it will still hold its temperature for a period of time without any problems. The same concept holds good on a larger scale. Over the period we’ve been providing a demand response service we’ve never had any adverse reaction from our guests.

A GOOD FIT

The idea wasn’t entirely new to us. We knew our hotels in the USA have been active in DSR for some time. Once we became aware there was a market opportunity in the UK we started to look at how we could unlock it.

KiWi Power was recommended to us as a forward-thinking, innovative partner. Initially we were wary as KiWi Power is a relatively small company with a flat hierarchy where decisions are made very quickly, whereas with a large corporation like ours we sometimes need longer to ensure the concept is fully tested. However, it’s turned out to be a very good fit and we’re now in our fourth year of working with them.

ALMOST EFFORTLESS

In the first year of working with KiWi Power it was a case of understanding the concept and how it would affect our operations. In the second year we ran the pilot at four hotels in the UK to make sure they were comfortable with the concept and to give them time to get used to it. Then the following year we extended it into 29 hotels.

Typically a hotel is contacted by KiWi Power and given a couple of hours’ notice of a turn-off lasting for around an hour. The relevant equipment has controls fitted which allow KiWi Power to turn it off and on remotely. All our hotels have separate contracts with KiWi Power so they agree at a local level how much capacity they are committing to provide. Once the system is up and running it’s almost effortless on our part.

PROUD TO BE INVOLVED

We receive a payment for making ourselves available for DSR and again whenever we are asked to turn down our equipment. There’s a net benefit for each hotel and we’ve set a target of £0.5m for the group over the next five years.

However, the major benefit for us is that it underlines our credibility as a business committed to sustainable energy use and it has resulted in some very positive media coverage. Marriott is very proud to participate in a scheme that is helping to ensure security of supply for the UK.

As well as extending DSR to more of our hotels in Europe in the coming year, we’re also working with KiWi Power to bring more pieces of equipment within the scheme, right down to things like ice machines, so we can maximise the potential of our assets.

FIND OUT MORE

For more information on how your business could benefit from demand side response participation, email the Power Responsive team: [email protected]

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