MidAmerican Energy Company

To facilitate a quick and efficient program process, it is necessary to have the bid properly completed with justified savings calculations attached for each project measure.

Preparation Basics

When preparing a bid summary you must assume that the individual reviewing your application, while having a technical background in energy efficiency, will not have direct knowledge of your specific application. Therefore the description(s) that you provide should contain sufficient detail to enable the reviewer to understand the processes involved, the proposed savings measure and how the measure will achieve the stated savings. To facilitate the review process the Sponsor should:

		Break up calculations and associated descriptions into smaller steps since this will make the thought process easier to follow,
		Fully describe any simulations/software used,
		Attach (and be able to electronically submit) printouts/reports summarizing both the inputs and results of simulations or other software used in preparing the calculation(s), and
		Attach any manufacturer's data, production data and/or other documentation that supports the inputs and assumptions used in calculations or descriptions. Note that spot measurements of load, whether in kW or amps, under realistic operating conditions are preferred over assumed loads and/or use of manufacturer's design values.

The process of preparing and documenting your savings estimate can be further divided into four basic steps, which are described in detail in the following sections.

Step 1. Process / Measure Description

The importance of providing a detailed description of the process and associated energy-saving measure cannot be overstated since it provides the reviewer with the necessary background information to understand the calculations that follow. The measure description should be divided into the following three sections:

1.		Existing process/equipment;
2.		Proposed new equipment retrofit or enhancement; and
3.		Resultant equipment and/or process (post installation).

In each section you should include sufficient information on the process and equipment involved so that it will be clear to the reviewer how the proposed measure will be implemented and how it will achieve the stated savings. For instance, if energy savings will be achieved using an energy management system that implements a new control strategy, then you must provide a complete description of the energy management system, the existing and proposed control strategies, and the controlled equipment.

Step 2. Establish Baseline Annual Energy Use

The Efficiency Bid Program provides incentives to Sponsors who install equipment/improvements that go beyond standard efficiency or baseline equipment. Standard efficiency refers to equipment that meets either state/federal efficiency requirements or current industry practice. Thus baseline energy use is established using accepted standards for currently available equipment. For instance, the Energy Policy Act of 1992 established federal guidelines for electric motor efficiency.

The simplified equation used for the baseline energy use calculation is shown below.

Baseline Energy Use¹ = (Op Hours * Equipment Load²)

1.		kWh or therms/year
2.		kW or therms/hr

Note that it may be necessary to develop a table of equipment loads and the annual operating hours at each load to arrive at an annual energy use estimate. The table should accompany the Sponsor's bid.

The baseline energy use calculation is critical to the savings calculation so it is important that your calculation and associated description provide sufficient information on the process, equipment and applicable standards to justify the proposed baseline energy use. In many instances the baseline energy use will coincide with the energy use of the existing equipment/process prior to implementation of the savings measure. However, this will not always be the case since existing equipment may not comply with currently accepted efficiency standards.

Therefore, to obtain the baseline value it may be necessary to adjust the energy use estimate for the existing equipment to account for "standard equipment" efficiency. For example, a Sponsor who proposes to replace an existing 50-hp motor with a nominal full-load efficiency of 90.2 percent, with a premium efficiency motor having an efficiency of 94.1 percent, must establish the baseline energy using the accepted standard motor efficiency. In this case, the previously mentioned Energy Policy Act of 1992 guideline for a 50-hp motor is 93 percent. The baseline energy use of the existing motor therefore must be calculated based on the higher 93 percent efficiency value, which reduces the baseline (and associated savings) value.

Step 3. Establish Post-Installation Annual Energy Use

The simplified equation used for the post-installation energy use calculation is essentially the same as for the baseline calculation.

Post-Install Energy Use = (Op Hours¹ * Equip Load²)

1.		kWh or therms/year
2.		kW or therms/hr

Note that, as in the case of the baseline system, it may be necessary to develop a table of equipment loads and the annual operating hours at each load to arrive at an annual energy use estimate. The table should accompany the Sponsor's bid.

The post-installation calculation is based on the projected performance of the new equipment or process. Use of simulation software such as eQUEST or another DOE2-based software package is acceptable as long as the inputs and associated assumptions (if any) are clearly stated and can be verified. Use of a manufacturer-specific simulation product may be acceptable but will require additional information on the underlying principles used by the software. Again it is important that the description provide sufficient detail so that the application reviewer will understand the basis for your projection. It is important to note that the reviewer may substitute an alternative method of estimating the post-installation energy use if it is deemed necessary.

Step 4. Calculate Energy Savings

Once the baseline and post-installation annual energy use estimates are completed, the savings estimate is simply the difference between the annual baseline and post-installation estimates.

Savings¹ = Baseline Energy Use - Post-Installation Energy Use

kWh/year or therms/year