Energy management information systems: utility bills, interval data, demand charges

Reference article · 6 min read

Most agencies already hold the data they need to manage energy costs. It just sits in three or four places that do not talk to each other: utility bills routed as PDFs through accounts payable, interval consumption data held by the utility, trend logs inside a building automation system, and a spreadsheet one person maintains for the annual benchmarking report. An energy management information system, usually shortened to EMIS, is the software layer that brings those sources together and keeps them current.

The term covers a wide range of products. At the simple end, an EMIS is utility bill tracking: accounts, meters, rate schedules, consumption, demand, and cost over time. At the capable end it adds interval meter analytics, submetering, weather normalization, automated anomaly rules, and measurement and verification for capital projects. Knowing which end you are buying matters, because the procurement, the data work, and the staffing all look different.

The data sources an EMIS pulls together

Utility bill data. Account number, meter identifier, service address, rate schedule, billing period, consumption, billed demand, and the individual line-item charges. Bills can arrive by utility electronic data interchange, scraped billing portals, a third-party bill processing service, or manual entry. The bill is the system of record for money, so an EMIS that only stores a total dollar amount is not doing much for you.
Interval meter data. Usage recorded by the utility revenue meter at short intervals, commonly fifteen minutes or one hour. This is what turns a monthly number into a load shape: overnight base load, morning startup ramp, the exact moment the monthly peak occurred. Access typically comes through a utility data sharing agreement or a standardized export such as Green Button.
Submeters. Agency-owned meters at the building, wing, or system level. On a campus served by one master meter, submetering is the only honest way to allocate cost to tenants, departments, or funds.
Building automation system points. Setpoints, schedules, equipment runtimes, valve and damper positions. Bills and interval data tell you what happened. BAS points usually tell you why.
Weather. Observations from a nearby station, expressed as heating and cooling degree days or as hourly temperature, so consumption can be compared across seasons and years.
Facility context. Gross floor area, operating hours, space type, and occupancy. Without it you cannot normalize, benchmark, or explain a change to anyone outside the facilities office.

How an EMIS differs from the BAS and from the financial system

A building automation system controls equipment in one building in near real time. Its trend storage is often short, its points are not billed quantities, and it has no idea what a kilowatt-hour costs. An EMIS controls nothing. It reconciles billed and metered quantities across an entire portfolio over multiple years.

The financial system pays the bill. It knows vendor, invoice number, amount, fund, and account code, and it usually does not know kilowatt-hours, billed demand, meter number, or rate schedule. That is why questions like "what are we paying per unit of energy at this facility, and is that the right tariff" cannot be answered from accounts payable alone. The cleanest arrangement is to let the EMIS hold the energy detail, let the financial system remain the record of payment, and reconcile the two on invoice number and amount so neither drifts.

The questions a portfolio EMIS can actually answer

Unexplained demand spikes. Demand charges are typically set by the highest short-interval peak in the billing period, so a single event can carry a cost for a full month. Interval data shows the day, the time, and often the equipment pattern behind it. Some tariffs also include ratchet provisions that carry a peak forward for months, which raises the stakes further.
Rate schedule mismatches. Buildings change use, hours, and load over decades while their tariff stays where it was set. Comparing actual load shape against available schedules can surface accounts that would cost less on a different rate. Tariffs and eligibility rules vary by utility and change over time, so confirm any candidate switch with the serving utility before acting.
Vacant and orphan accounts. Accounts for demolished buildings, closed pump stations, vacated leases, and construction temporary service often keep billing quietly. A portfolio-wide account inventory is frequently the first thing an EMIS pays for.
Base load that never drops. Flat overnight and weekend consumption in a building that is closed points at scheduling, override switches left in hand position, or equipment nobody remembers.
Billing errors. Estimated reads, duplicate invoices, wrong meter multipliers, and misapplied taxes or exemptions are visible only when you compare bills against each other and against metered use.

Weather normalization and a defensible savings baseline

Raw year-over-year comparisons are not credible, because weather and occupancy move. Normalization fits a model of consumption against degree days and other drivers, then reports what usage would have been under common conditions.

This matters most when you need to prove savings. Widely used frameworks include the International Performance Measurement and Verification Protocol and ASHRAE Guideline 14, both of which describe how to set a baseline period, choose a measurement approach, and handle non-routine adjustments when a building changes. If you are entering a guaranteed energy savings or performance contract, define the baseline, the data sources, the adjustment rules, and who computes them in the contract itself. Requirements for such contracts are set in state law and vary, so confirm the current rules with your procurement office and counsel.

What to ask vendors and put in the contract

Which utilities in our service area do you already receive data from, and by what method.
Do you handle interval data, or only monthly bills.
How are billing anomalies detected, and can we configure the rules ourselves.
What happens to our data if we leave. Require a full export of bills, interval data, meter inventory, and configuration in an open format, on demand and at termination, at no added charge.
Who obtains the utility data authorizations, and who maintains them when accounts change.
Where is the data hosted, and how does the system meet our security and accessibility requirements, including state and local procurement and accessibility standards.
Can the system export to the benchmarking format we are obligated to file. Many jurisdictions with benchmarking ordinances use the federal ENERGY STAR Portfolio Manager tool for reporting; confirm what applies to your buildings.

How to start

Build an account and meter inventory first. List every utility account, its meter, its service address, and the facility it belongs to. Expect the list to be wrong, and expect that to be the finding.
Load two to three years of bills so you have history to compare against.
Request interval data authorization from the utility for your largest electric accounts.
Pick a small number of anomaly rules, verify them by hand for a few cycles, then expand.
Name one person accountable for keeping the account inventory current, because that single task determines whether the system stays useful.

HQT works with state and local agencies on data integration and analytics systems of this kind, including utility data pipelines, reporting, and the architecture and procurement planning around them.

Frequently asked questions

What is the difference between an EMIS and a building automation system?

A building automation system controls equipment in a single building in near real time, using setpoints, schedules, and sensor points. An energy management information system does not control anything; it collects utility bills, interval meter data, and weather across an entire portfolio and analyzes cost and consumption over months and years. Most agencies need both, and the two are complementary rather than competing. The BAS explains why a pattern occurred, while the EMIS finds the pattern and attaches a cost to it.

Why do demand charges matter more than total usage on some utility bills?

Demand charges are generally based on the highest short-interval power draw during a billing period, not on total energy consumed, so one brief peak can raise the bill for the whole month. Some tariffs also include ratchet provisions that carry a high peak forward into later billing periods. Interval meter data is what lets you see exactly when a peak happened and what was running at that moment. Tariff structures vary by utility, so confirm the specific terms on your own rate schedule.

How do we get interval meter data from our utility?

Interval data is held by the serving utility and normally released through a customer data authorization, a data sharing agreement, or a standardized export such as Green Button. The process differs between investor-owned utilities, municipal utilities, and cooperatives, and the authorization usually has to be renewed or reassigned when accounts change hands. Start with your utility account representative and ask specifically what forms are required and what interval length and history are available.

Do we need an EMIS if we already track utility costs in our financial system?

The financial system records what was paid: vendor, invoice, amount, and account code. It generally does not record kilowatt-hours, billed demand, meter number, or rate schedule, so it cannot tell you whether a cost increase came from more usage, a colder month, or a tariff problem. An EMIS holds that energy detail and can be reconciled against accounts payable on invoice number and amount, keeping the financial system as the record of payment.

How do we prove that an energy project actually saved money?

Savings are measured against a normalized baseline rather than a raw comparison to last year, because weather and occupancy change. Widely used frameworks such as the International Performance Measurement and Verification Protocol and ASHRAE Guideline 14 describe how to set a baseline period, select a measurement approach, and adjust for building changes. If the savings are contractually guaranteed, define the baseline, the data sources, and the adjustment rules in the contract, and confirm applicable state requirements with your procurement office and counsel.