What are the best tools for monitoring energy usage in a building?

Based on my experience, effective energy monitoring can be a valuable tool when used appropriately. This is especially true in large facilities with numerous devices and various energy sources. It's crucial that the systems installed are open source, allowing clients to upgrade as needed to meet current demands. Often, we find ourselves locked into proprietary software and control devices, which can lead to deficiencies over time due to mandatory supplier upgrades. In an open-source environment, you still require upgrades, but you have more flexibility in terms of functionality and cost. Investing in training for in-house operators and retaining skilled personnel is a wise long-term investment.

Most likely means to get reliable info (needing a tolerable amount of maintenance & repair to keep useful) would be electrical watt hour submeters that allow recording and downloading 15 min KWH usage, or at least breaking usage up into multiple time of day intervals. Obviously, target service entry and the first breakouts of loads at main switchboard. Then downstream on incoming for motor control centers and chillers. Steam meters & energy meters are much more problematic to keep accurate, or sometimes just running at all. If DDC is widely available, you might be able to extract granular data on thermal by refined calculations from inputs. True differential temp & pressure sensors are better than subtracting two independent values.

If you want to manage energy consumption you need to know where, when and who is using it and at what cost. A main utility meter is not enough, one needs submeters. Where should the meters be located? I always find the easiest way by following the electrical Single Line Drawing - that is from the electrical supply through to the various distribution boards. One can easily see the large energy consumers. Consider meters that can be used for billing and measure all electrical parameters, not just kWhrs. However, the meter display is useless if sitting in the basement. One needs to get the data to the stakeholders. Meters need to be networked to an Energy Management System. The system should act as a virtual energy manager watching out 24/7.

Meter data, when networked to smart energy management software can provide much more than just kWhrs. Stakeholders can be notified in real time when there are power problems which could harm a facility or cause disruptions to business and processes. Consider poor power factor, over or under voltage, loss of supply, excessive maximum demand, overloading. The meter data could tell someone a specific area is overloaded which could trip out the load in a certain time. The meter could alarm someone there is a loss of supply say in a critical cold storage area way ahead of the normal alarms depending on temperature. Bad connections cause overheating , the meter data can alarm someone in time to avoid disaster. What is the payback of that meter?

The information from energy audits is almost always valuable but, depending on the capability and motivation of the on-site O&M resources, can lead to a nice inventory of things that just don't get fixed. Just a something to consider: an "audit" which also has capability to actually perform low cost repairs or simpler repairs even if somewhat more costly leads to actually getting things done. Example: an energy retrofit project installed LED exterior fixtures with incompatible photocells where a significant fraction of the fixtures just stay illuminated. If an auditor/repairer discovered similar simple things we did not know about, it would eliminate the trouble we have awarding a convenient vehicle to just get the "wrench turned".

Audit finds are very important as developing countries... technology is not up to the mark in so many areas. But carrying out perfect audits is not easy...as so many areas you have to cover and coordination among them are very difficult. It depends upon the agency (Under UNDP is one of them.)... energy efficiency beuro...not upgraded alongside... So it's important to select a perfectly available agency..... which can perform tasks alongside the industry 4.0.....too.

I have always tried to stay away from the word or usage of "audit" as it seems to have a negative connotation to it. "No one likes an audit". Instead, I try to stick with "assessment" as it seems to be less judgemental.