30 Oct 2013 12:10:12
What does 'normalising' your energy use against the weather actually mean?
Weather can have a big impact on energy consumption in buildings, but how do you know there's not another reason for those spikes or dips in usage?
How do you know when a surge, or in fact dip, in energy consumption is not related to the weather?
Many businesses are keen to cut energy costs and emissions and as a result are proficient at energy monitoring as the first step in their energy management strategy. However, how many of these companies apply weather data to their energy performance and use it as a tool for alerting the building or facilities manager to the culprit of unnecessary consumption?
Put another way, it’s okay to turn the heating on when the weather is colder, but how do you know when a surge, or in fact dip, in energy use is not related to the weather and instead could be the result of something else?
You might already be aware that the greatest energy use in UK buildings is for space conditioning - predominantly for heating. The greatest driver of this energy use is the external temperature, as the internal thermostat regulates the heating system to attempt to match the energy from the radiators to the energy loss through the building fabric (walls, roof, windows and doors) and via air changes for ventilation.
In order to manage this energy properly an account needs to be taken of the external temperature. Having up-to-date and relevant weather data will allow energy managers the ability normalize energy use against the weather – in other words take the weather into account - and dig deeper into energy usage, patterns, trends and even more importantly, identify waste for corrective measures to be taken.
Using weather data also allows energy managers to compare one year (or month, or week) to another. It is standard to normalize the energy use for the weather so a proper comparison can be made. When looking at weekly data, jumps in energy use can be caused by changes in external temperature or changes to the heating system and its use. Occupants changing heating settings, valves sticking and changes in building use, for example, can only be properly analyzed when the weather has been properly accounted for. Weather data can help answer these questions: How do I know if our heating controls are suitably set? How much energy can we save from heating? How do I know if this year we saved energy compared to last year?
This weather accounting is performed via degree-day analysis, which compares the energy use with the degree-days for the same time period. Degree-day data can be obtained and added to a spreadsheet or specialized software plots and visualizes energy use against the weather to bring the data to life and pinpoint wastage for savings to be made.
Using degree-day data energy managers and facilities managers in businesses with large property portfolios, such as the leisure and retail sector, and local authorities, are able to look at their energy use with a different perspective. Pilio, as a provider of software that incorporates weather analysis together with its consultancy arm if needed, can work across all sectors to produce evidence based energy data adjusted against weather to suit the needs of an organization together with benchmarking around CIBSE building classifications and its own member's data.
Pilio Ltd announce that we have teamed up with Whitbread Plc, on its Premier Inn brand across a portfolio of around 650 hotels. We are delivering weather adjusted consumption data to create better targets and benchmarks based on its own estate, while creating more intuitive and automated reporting systems from existing interval energy data.
Delivering a solution to assist Whitbread with its 25% carbon reduction target for 2017, our software and consultancy provides the evidence base for the progression and goals as well as helping form a strategy. Whitbread is provided with analysis of the significance of weather on energy demand in its portfolio, assessing the effectiveness of energy efficiency interventions and tracking the progress of the carbon reduction target.
Dave Dunbar, energy manager at Whitbread Hotels & Restaurants sums it up: “With a complex blend of hotels throughout all parts of the UK it was becoming more important to benchmark each site in an accurate and consistent way. By utilizing Pilio's advanced weather analytics we were able to compare hotels, wherever they were in the UK, on a level playing field. Enabling a far more accurate targeting mechanism individually tailored for each site."