Deployment Guide/Workbook

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This is a workbook for estimating the cost of a large-scale deployment of One Laptop Per Child. It is a working document that reflects lessons learned from our initial pilots and deployments. Additional ideas will be incorporated as we learn from each other.

It is available in Microsoft Excel format: Deployment_Workbook.xls

Introduction

The One Laptop per Child (OLPC) Deployment Workbook contains six worksheets. There are two worksheets for use in planning: Country and School. The Country worksheet takes information about overall number of laptops and rough percentages of schools and provides a rough estimate of the costs. The School worksheet takes detailed information about a particular school and provides an estimate of the required infrastructure, power, and costs given different power scenarios.

These estimated costs depend on the accuracy of the system component costs specified in the Laptop Costs, Program Costs, and Other Costs worksheets. While the defaults provided are based on commercially available components, these must be updated to reflect current and local prices for these components before using this workbook to estimate costs.

How to use the workbook

• Determine local prices for items such as school servers, generators, wireless access points, wireless switches, the cost of running a Cat5 network cable or power cable for 30m in a typical school, and update the Other Costs worksheet.

• If estimating costs across the entire deployment, the Program Costs worksheet should also be updated.

• At this point, you can estimate costs across the entire deployment using the Country Expenses Estimate worksheet.

• If you want to see the estimated cost of a single school, and compare the costs of different methods of powering the laptops, use the Individual School Expenses Estimate worksheet.

Workbook Description

Individual School Expenses Estimate

This worksheet calculates the estimated expenses for a particular school, illustrating the costs of different power generation and distribution schemes. It has two sections. The first contains six fields that describe the school, the remainder of the worksheet shows estimated power usage and costs.

To be filled by the Country

These are the variables that describe the school for which power and cost estimates are being made.

Number of laptops in the school

The total number of XO laptops deployed at the school, including teachers and students.

Internet Connectivity

How the school will be connected to the Internet. Allowed options are:

• DSL - A DSL broadband connection
• VSAT - A satellite connection
• GSM - A cellular telephone data connection, GPRS, EDGE, or other (3G)
• Other - An alternative local method may be specified
• None - no Internet connection will be provided

The local costs of each of these options, in terms of money and power, must be specified in the Other Costs worksheet.

Laptop Usage

The number of times a laptop in the school will be charged in a day. To specify a usage model where laptops are continuously connected (both charging and operating) throughout the day, specify 2. Fractional values --- such as 0.5, indicating one charge every two days --- may be specified. This workbook assumes that if multiple charges per day are supplied to the laptops, they are supplied sequentially, not simultaneously (for example, using a multi-battery charger in addition to the laptop).

Laptops simultaneously charging

The percentage of the laptops in a school that will be charging (or connected to power) at any one time. If all laptops are always going to be always connected to external power, this is 100%.

Infrastructure Usage

The number of hours in a school day that networking infrastructure and the school server are operated.

How much storage

The number of days of electrical power storage that is provided in solar powered schools. Fractional portions of a day (0.5, 0.2) may be specified.

Hours of sunlight per day

The number of hours per day that the school receives sunlight acceptable for generating solar power.

Suggested Infrastructure

This is information provided by the worksheet about the school infrastructure.

Number of Servers - The number of school servers that are recommended for this school, and its size. The number of servers is one in most cases. Even when two is specified, this may be viewed as encouragement to buy one server with twice the disk space and memory. The size of the server depends on the number of laptops being supported.

Number of Access Points - The number of 802.11 WiFi Access Points (APs) in a school is roughly determined by the number of laptops in the school. This laptop/AP ratio is assumed to be 50:1 for small schools, but increases for larger schools.

Number of Switches - The number of network switches required for a school. These are assumed to be eight port switches, with four ports providing power (for access points). The number required is determined by the number of access points.

Power Requirements

Laptops - This is the real power required for laptops in a school, expressed both as a peak power and the total power per day. The peak power, expressed in kiloWatts, is calculated as the number of laptops simultaneously charging in the school times the real power (in Watt Hours) required to charge a laptop, divided by the time it takes to charge. The total power, expressed in kiloWatt Hours per day, is the number of laptops in the school times the number of charges per day times the real power (in Watt Hours) required to charge a laptop.

Laptops (assuming XO power adapter) - This is the apparent power required for laptops in a school, expressed both as a peak power and the total power per day. This takes into account irregularities in the way that the power adapter consumes power. If a large number of them are the main consumers of electricity in a system, it is necessary to use the apparent power in estimating power requirements. The apparent power, expressed in kiloVolt Amps, is calculated as the number of laptops simultaneously charging in the school times the real power (in Watt hours) required to charge a laptop, divided by the time it takes to charge times the laptop power adapter's power factor. The total apparent power, expressed in kiloVolt Amp Hours per day, is the number of laptops in the school times the number of charges per day times the real power (in Watt Hours) required to charge a laptop, divided by the laptop power adapter's power factor.

Servers - This is the apparent power required for the school server, expressed both as a peak power (in kiloVolt Amps) and the total power per day (in kiloVolt Amp hours).

Networking - This is the apparent power required for the school networking infrastructure, expressed both as a peak power (in kiloVolt Amps) and the total power per day (in kiloVolt Amp hours). The networking infrastructure includes the 802.11 access points, the network switches, and any Internet access equipment (DSL/VSAT/GSM modem).

Peak Power Draw at this school

Specified in kiloWatts. This is estimated as the power required to continuously power the server and networking infrastructure, plus that required to power the "Simultaneous Charging" portion of the laptops in a school. If multiple charges per day are supplied to the laptops, it is assumed that they are not supplied simultaneously.

Power per day required by this school

Specified in kiloWatt Hours. This is the total amount of energy required to operate the schools laptops and associated infrastructure for a single day.

Server

These are characteristics of the recommended school server:

Processor - A rough recommendation of processor speed

Minimum Memory (DRAM) - The minimum amount of memory (DRAM) the server should have.

Minimum Disk Storage - The minimum amount of disk storage that the server should have.

Estimated Costs

With Grid & MBC

The number of Multi Battery Chargers could be based on how many charges you required each day, how long people are in school to swap batteries and how many hours it takes the MBC to charge a battery. It is instead currently based on the Simultaneous_Charging ratio specified as a constant in the Other Costs worksheet.

Other Costs

This worksheet specifies the equipment costs and power requirements used for estimates across the workbook. It contains all costs, other than those associated directly with the XO laptop (specified in Laptop Costs), or with the pedagogical aspects of a deployment (specified in Program Costs). While example prices are provided, actual prices quoted on the local market must be substituted before using this workbook for budget estimates. All prices should include shipping costs and duties.

Power Infrastructure

XOP Distributed or Rack - This is the Belkin XOP Distributed power system for the laptops. It is a power supply which supports four laptops per node, and may be chained to simply accomodate more laptops. It includes a rack for creating a charging station for the laptops. This is an estimated price of $150 ex-works, and $15 shipping

Multi Battery Charger - This is the OLPC multi battery charging system for the laptops. It is a battery charger which charges up to fifteen laptop batteries at a time, and takes either an AC input or a DC input direct from an array of solar panels. This is an estimated price of $300 ex-works, with $50 shipping.

System Constants

Number of Laptops Charging - This is the number of laptops simultaneously charging in a school at one time. This ratio should be 100% if all of the students are capable of plugging their laptops in simultaneously. This is used to estimate the peak power draw, necessary when estimating the required generators, inverters, and school power infrastructure.

Examples

This worksheet contains an abbreviated version of the individual school cost estimates for the various example schools used in generating an estimate for a country. These should only be changed in order to refine the country estimate. Use the School Expenses Estimate worksheet to experiment with school parameters.

Several school infrastructure parameters, such as the number of sunlight hours, the number of laptop charges per day, and the various types of internet connections are defined in common in the Country worksheet.

The costs of Internet connections are not present in these example school estimates. Their cost is represented separately in the country estimate, and their power is appropriately averaged and accounted for in the calculations on this worksheet.

Example #1: Small School

This is a school with 30 students. This sample point illustrates the higher cost of providing infrastructure to small schools.

Example #2: Medium School

This is a school with 200 students. This sample point is representative of a wide range of school sizes between the small school and the large schools (500 or more students).

Example #3: Large School

This is a school with 500 students. Our models do not take advantage of any economies of scale present in schools larger than this, making this an appropriate sample point.