Archive for November, 2009
The more things that the wedding participants can do on their own, the more money they will save. Get money-saving tips for a beach-themed wedding from a wedding planner in this free wedding video.
Expert: Lori Randall
Contact: www.SimplyDevineEvents.com
Bio: Lori Randall established Simply Divine Events after working as an event producer in Tampa, Fla. managing dozens of corporate affairs throughout the state and across the country.
Filmmaker: Christopher Rokosz
Duration : 0:1:38
Before using any switching site, you should read the advice from EnergyWatch and OFGEM below.
Some sites are not totally impartial as they receive an incentive for recommending one supplier above another.
To ensure you get accurate comparisons, make sure you have some recent bills to hand, at least 3 months, 12 months is better.
I have a 1500wt utility heater, is it cheaper to run it all day or my central heat(gas). Gas bill runs about 85 dollars a month.
One year I used central heat with heat my 3 bedroom house and it cost me $300,00 dollars for the winter at 70 degrees. The next winter I used a space heater when needed in only rooms to heat and only rooms needed and it cost me $150.00 for that winter. It depends on what rooms are heated and how much heat you use and how long you turn on the heat. Everytime you turn on and off the thermostat on central heatingis is when the energy bill gets a boost higher when using central air.That does not happen with a space heater.
BioDiesel has been getting more and more popular as it has become another fuel saving alternative than PetroDiesel. Simply convert your diesel engine to BioDiesel and you can expect greater average fuel saving if you make the BioDiesel yourself.
How Does It Work?
BioDiesel is simply produced from vegetable oils or animal fats. When converting your diesel engine to BioDiesel, you can choose whether to let your diesel engine to run with bio-fuel using vegetable oils, animal fats or a combination of both. You may re-use used vegetable oils from your daily cooking so you can imagine how much saving you can get from fuel itself.
How Much Can It Save?
The cost of vegetable oil to make BioDiesel is definitely much cheaper than PetrolDiesel. If you make your own BioDiesel, you can expect an average fuel saving of more than 50%. More-ever, since diesel engines that run on BioDiesel are healthier, you can save on your vehicle maintenance costs as well.
What Other Benefits Are There?
Pollution is greatly reduced when powering diesel engine with BioDiesel, as it is a clean-burning fuel that does not produce emission of greenhouse gases thus keeping our planet green. That is the reason why BioDiesel is favored by environmentalists all over the world.
What Are The DownSides?
However, BioDiesel does have its downsides too. It decreases the car performance due to its low energy content. It requires modern diesel engines that come with synthetic seals instead of old rubber seals. Lastly, you may smell the taste of french fries when the engine is running with BioDiesel but who cares, as long as your car can bring you from point A to B, these issues are no longer considered as a problem.
Conclusion :
With constantly increasing fuel costs, car owners over the globe are always looking for alternative fuel to reduce on their fuel expenses. BioDiesel is definitely one of the best money saving fuel alternatives. Start saving on your fuel expenses today and enjoy living debt free in life today!
Introduction: Energy Savings Tracking Methods
After installing energy conservation measures (ECMs), Energy Service Companies (ESCOs) often determine the energy savings resulting from the project and present the savings results to their customers. A common way to calculate energy savings is to measure the flows of energy associated with the ECM, and then to apply spreadsheet calculations to determine savings. For example, a chiller retrofit would might require measurements of chilled water supply and return temperatures and kW. The benefit of this approach is that the ECM is isolated, and that only energy flows associated with the ECM itself are considered.
This method is described as Option A or Option B in the International Performance Measurement and Verification Protocol (IPMVP). Table 1 presents the different options. Option A requires some measurement and allows for estimations of some parameters. Option B requires measurement of all parameters. In both options, calculations are done (typically in spreadsheets) to determine what energy savings. Option C uses utility bills to determine energy savings.
Some ESCOs Have Limited Options
There are many situations where Option A or Option B (Metering and Calculating) is the best approach to measuring energy savings, however, some ESCOs insist upon only using Option A or Option B, when clearly Option C would be most appropriate. If the ESCO was a lighting contractor, then Option A should work in all cases. Spot measurements of fixtures before and after, agreed upon hours of operation, and simple calculations can be inserted into a spreadsheet that can calculate savings. The same spreadsheet can be used over and over. However, for ESCOs that offer a variety of different retrofits, it is necessary to be able to employ all options so that the best option can be selected for each individual job. Controls Retrofits, or retrofits to HVAC systems are typically excellent candidates for Option C.
However there are drawbacks with metering and calculating savings and these can include:
- Greater expense
- Difficulties convincing the customer of the appropriateness and veracity of the method and savings numbers
- Inability to handle interactive or many difficult ECMs.
ESCOs that do not have the capacity to employ all options are at a disadvantage over those ESCOs that can employ them all. Specifically, we want to address those ESCOs that only employ Option A and Option B. These ESCOs may encounter the following problems due to their limited offerings:
- Measurement and Verification costs can be greater, which lead to higher project costs, which can limit the energy projects that the ESCO can sell. The lack of Measurement and Verification options overall can make the ESCO less competitive, and hurt the financial performance of the ESCO.
- Using Options A or B sometimes require the customer to understand and approve of complex energy calculations. These options are often difficult to explain to customers who insist upon seeing savings in their utility bills. Customer satisfaction can suffer if Option C is not made available to customers who want to see savings on their bills.
- Options A and B cannot handle difficult ECMs. The methods used to determine savings are inaccurate, and make large assumptions that cannot be borne out if a third party consultant is hired to oversee the savings determination process.
These issues are discussed in more detail below.
Cost of Utility Bill Analysis vs. Metering and Calculating
Measurement and Verification should cost between 1% and 15% of the project cost. Metering and calculating savings often has costs associated with labor and equipment. As many project configurations are different, projects typically require unique configurations of sensors, placements of sensors and savings calculations. On more complicated ECMs, only highly skilled energy professionals can determine which measurement devices should be applied, and to what components. Manipulating data, and finally creating spreadsheets with engineering calculations also requires skilled personnel who command high wages. Metering equipment also has a cost, and for many projects, metering equipment, or control points, have to be purchased, and remain on the job for years.
Of course, there are cases where metering and calculating is the least expensive and the most desirable method. If an ESCO only provides a lighting retrofit, then measuring a selection of lighting fixtures before and after the retrofit, and producing a spreadsheet that determines savings is the best option.
On the other hand, utility bill analysis is inexpensive. With specialized utility bill analysis software, clerical workers can create the Measurement and Verification analysis. Bills are entered, weather imported, a linear regression performed, and reports made. Capital need not be sunk into metering equipment or control points or into long hours of analysis and data manipulation. Typically for utility bill analysis, measurement and verification costs are a fraction of what costs for retrofit isolation savings are – ranging between 1 and 5% of project costs.
Explaining Savings Numbers to Customers
Customers understand utility bills. The reason they entered into an energy savings contract is often triggered by the desire to lower their energy bills. Retrofit Isolation methods do not address the customer’s utility bill. A project may be saving energy, but the utility bill may actually be increasing. Retrofit Isolation does not address this at all. ESCOs need to be responsive to customer’s needs, and this is done through communicating in a manner that the customer’s understand. They want to see the savings on their utility bills – this is a method they would trust.
In addition, customers are sometimes mistrustful of energy service companies that provide savings numbers that the customer cannot understand. Although the calculations in the spreadsheet may appear perfectly reasonable to the energy analyst, to a customer who is not well-versed in math, the calculations may remain incomprehensible, and the customer is thereby required to trust the energy service company, sometimes leading to mistrust. Energy savings calculations should remain as simple as possible and explained in a manner that the customer can understand. This makes the customer’s job easier, and reassures the customer that the energy service company is acting in a truthful manner.
For these reason, more and more customers ask for Measurement and Verification using utility bills.
Difficult and Interactive Energy Conservation Measures
For many energy conservation measures, Retrofit Isolation is the best option. This would include lighting savings, savings from energy efficient motors, and from other non-weather dependent energy users.
However it is very difficult or impossible to measure savings for some energy conservation measures. Still, some ESCOs insist on using Retrofit Isolation for these difficult measures. For example, engineering calculations can be made estimating the savings to be had by shutting down air handlers at night. But, assuming that the air handlers receive chilled water from a chilled water loop shared with other air handlers, how is one to measure energy savings? Fan savings are easy (assuming the unit is constant volume), but in order to calculate savings, several estimations need to be made, which result in an estimate of energy savings, just as accurate before the retrofit took place as after it took place. Suppose the unit is a VAV system, at what percentage would the fan have been running? Suppose the cooling coil and/or heating coil modulated to meet a changing supply air set point – how are the fan CFM, cooling and heating loads to be calculated if the unit is not running and measurements can not be made?
Controls retrofits are difficult to measure and quantify directly. Usually, however, when a controls or commissioning measure is enacted, more than one item is adjusted, which further complicates an already difficult task. Suppose a partially working economizer was fixed, in addition to putting the fan on a variable speed drive, in addition to shutting off the air handler during unoccupied hours, and finally upgrading the chiller plant. Each of these measures would interfere with the savings calculations of the other. How can one calculate chiller savings, when the loads have changed so dramatically via the economizer, reduced hours and reduced air flow? This is a very difficult task, that most likely cannot be done with an acceptable degree of certainty.
Complicated cases like this require utility bill analysis to measure and quantify savings. The procedure is very simple, inexpensive, and easy to explain relative to many Retrofit Isolation methods.
Benefits of Utility Bill Analysis
The benefits of utility bill analysis to calculate energy project savings are as follows:
- Utility Bill Analysis, by its nature, is relatively simple, and does not require complicated engineering analysis.
- Utility Bill Analysis is relatively inexpensive, as it requires less skilled workers, less time and no dedicated equipment.
- Utility Bill Analysis provides savings numbers in a format and method that makes sense to the customer.
- Utility Bill Analysis is the best method to handle complicated energy conservation projects, or projects which interact with each other, making assessment of individual measures impossible.
- ESCOs can use the fact that energy savings is determined using the customers’ utility bills as a selling point.
Utility Bill Analysis and Changes in Weather
Unfortunately, a simple comparison of pre-retrofit and post-retrofit utility bills is usually not an effective method to determine energy savings from ECMs. Weather varies from year to year, and affects the amount of heating or cooling energy usage, which can interfere with actual utility savings numbers. For a fair analysis, utility bills should be “corrected” for weather data, which results in a reasonable savings determination. Linear regression is applied to utility usage versus degree days to determine pre-retrofit utility usage patterns, which are then compared to post-retrofit utility usage to determine savings. Unfortunately, the scope of this paper is limited, and cannot present the method in detail. Weather-correcting for weather is easy, however, as specialized software, used by ESCOs around the world, simplifies the weather correction process and presents savings reports.
Drawbacks of Utility Bill Analysis
Facilities may change their energy usage patterns, by installing more equipment, building additions, occupancy changes, etc. This upsets the existing utility bill comparison of pre-retrofit to post-retrofit usage. These changes need to be monitored and accounted for with Baseline Modifications.
There is a certain amount of randomness in utility bill comparison. So many factors influence the amount of energy usage in any given month, and they cannot all be accounted for. As a result, if you are trying to show savings that is less than 10% of the total electricity load, then the randomness in the bills may seriously interfere with the accuracy of your savings calculations.
If you track savings by comparing utility bills, you will only be able to track total savings for a given meter, but you will not be able to separate out the savings for different Energy Conservation Measures (ECMs). For example, if you installed a lighting retrofit, an energy efficient chiller and a control system in a hospital, you will not be able to tell how much energy is being saved by the control system. Energy analysts try to do break out the savings for each ECM occasionally, but they are only making educated guesses.
Conclusion
When an ESCO approaches a performance contract, there are several measurement and verification options available. Those ESCOs that only have at their disposal a limited set of options are often spending too much money on measurement and verification, and therefore are held back from selling larger projects, and limit their own success.
Customer satisfaction may suffer when ESCOs only offer Retrofit Isolation approaches to Measurement and Verification, as customers may want to see savings in their utility bills. ESCOs who refuse to speak in the same language or terms as the customer may suffer decreased customer satisfaction.
As the use of broadband continues to grow in the UK, so the packages available continue to develop. It is important to shop around and understand what you need before taking the plunge.
Broadband, a contraction of ‘broad bandwidth’, is the provision of high-speed data-transmission rates over a phone line, digital cable or satellite connection. It enables faster Internet connectivity and email, and has changed the way people use the Internet, for various things like shopping, gaming, communicating and general entertainment.
When you’re thinking about broadband, you need to think about what you’re going to use it for, and what’s important to you.
Price may be important, but you know you’ve got to get broadband if only to free up the house telephone that can’t be used when the computer is connected to the Internet. In such a situation, you might want to simply opt for one of the cheaper broadband packages.
The chances are, however, that you will find wider use for broadband, and that will mean looking more deeply into what each broadband provider can deliver.
Things to look for are:
• Usage
• Speed
• Download limits
• Set-up costs
• Contract period
• Monthly cost
• Costs after one year
Usage varies from light usage through medium usage to heavy internet usage.
Speeds can vary from 2Mbps through 8, 10, 16 and 20Mbps all the way to the fastest speed of 24Mbps. However, speeds in excess of 2 Meg are only available in certain areas, and top speeds vary significantly, one variant being how far away you live from the exchange.
Limits on downloads can be as low as 2GB, and as high as unlimited.
Set-up costs can be £30, but in many cases set up is free.
Contract periods can be monthly, or as long as 24 months in some cases.
Costs, of course, vary with the package you have. They can be as low as £3.75 per month, or as high as £37 per month.
Broadband is a big growth area and all broadband providers are competing for your business.
Start electricity saving today with solar power generator as scientists predicted that the energy and electricity prices will rise by up to 50% by end of this year. You should hence start looking for alternatives and ways of decreasing the cost of energy at home. A solution has been found and people around the globe have started to use it, and that is, to use solar power energy, one of the alternative energy solutions. You heard it right, you can start electricity saving with this new technology.
How Does It Work?
There are many ways of alternative energies and the most efficient and money saving is solar power energy which produces energy from the power of the sun. This is made possible by installing home built solar power generator at home.
How Much Does It Cost?
Typically, a home built solar power generator is rather costly to purchase as the market is really new and it would be more cost-effective if you build them on your own.
How Much Can It Save For Me?
In general, you would expect to save up to 80% per month of your energy consumption with home built solar power generator and of course, the amount of money you saved depends on the amount of energy you consume.
Is It Very Difficult To Build One?
Building and installing your own solar power generator is not as hard as it sounds because they would usually come with step by step guides which describe everything in details how to build and install one. The guides are easy to understand and follow even for people without any kind of technical experience.
Conclusions :
Though it is not cheap to buy a solar power panel and generator but considering the fact that energy and electricity prices are ever increasing, solar power energy will be a more electricity saving approach in the long run and I am sure it is worth the investment now. Start saving on your electricity bills and enjoy living debt free in life today!
Telecom Plus (The Parent Company of The Utility Warehouse) is a major
British PLC and continues to be one of the fastest growing companies in the UK even during these hard times. Founded in 1998, they are listed on the London stock exchange (FTSE 250) and follow full OFCOM guidelines.
The Utility Warehouse Discount Club offer their personal and business clients significant savings on their electricity, gas, mobile phone and internet services, all united in one unique, simple monthly bill. Customers can also benefit from a 5% discount at Sainsbury’s (food and petrol), Boots, Argos and many other major retailers with the Utility Warehouse cashback card the ensuing savings are taken off their monthly utility bill.
The Utility Warehouse triple guarantee promises that they will always be cheaper than British Gas, that they will always be cheaper than the local provider for electricity and that they will always stay competitive in comparison with ‘the big six’ UK suppliers. Which Consumer Magazine has vote them best value for their Gas, Electricity and Broadband services. They came out on top for both their basic and premium Internet bundles, with 77% of clients very satisfied.
The Utility Warehouse no not advertise on TV or via other conventional advertising channels, enabling them to keep their prices low. Instead, they rely on independent distributors to spread the word. Distributors build an ongoing residual incomewithout giving up their day job by introducing others to the Telecom Plus/ Utility warehouse opportunity and by signing up customers. Nearly 30,000 customers across the UK are already reaping the benefits.
The Utility Warehouse are so certain customers will be happy with their service that there is no contract term on most of their services. Club membership begins from just £1.50 a month. The more services customers take up, the more money they save (free calls for instance). They can take up some or all of the services on offer.
Customers can phone each other at no charge, any time. Free calls can also be made to any UK landline as well as 10 overseas numbers depending on the services taken. BroadCall, which joins broadband with home phone, offers the best value package of its kind in the UK.
The Utility Warehouse Discount Club for business was launched in 2005, so that small and medium-sized businesses could also benefit from the great value and service provided by the Utility Warehouse.
Business Club members benefit from great savings on their utilities. As well as their gas, electricity, phone and broadband services, the Utility Warehouse can offer them non-geographic numbers (e.g. 0845, 0870 and 0800) and office mobile deals. Business clients can also use the cashback card for 5% off both their personal and business shopping bills.
To start earning a residual income, you just need to sign up and keep a minimum of six customers, but the sky’s the limit! Every new client can generate a one off payment of up to £45. You can do as much or as little as you choose. High achieving distributors have qualified for all expenses paid holidays, ownership of a Utility Warehouse branded Mini, cash bonuses, and the loan of a Porsche for a month! When you sign up other distributors, you are moreover entitled to commission on what their clients spend.
If you don’t fancy being a distributor but you are a customer you can earn an ongoing monthly discount of 0.5% by recommending friends and family, for each service they take up. If they opt for the full range of services this goes up to 2%. All your friends have to do is call the Utility Warehouse, citing their membership number. Ten friends could give you up to 20% off your bill!
Membership also entitles clients to a series of discounts and offers on services such as AA breakdown cover, insurance, holidays & shopping courtesy of the benefits directory.
To sign up as a customer go to www.betterbills.net
Just like solar energy, wind energy is another environment-friendly and economical energy source. With almost 40% of wind energy sources of Europe in the United Kingdom, there is immense potential to use wind energy as a source of energy.
Generating power through wind is not only efficient but also renewable like solar energy. The only downside is that a tall, moderately sized generator can be a sore eye and spoil the visual landscape, leading to murmurs of disapproval among neighbours. Think about this before you go ahead and think about how to generate wind energy in your area. However, if you do not live in a very populated area and your neighbors consent to your wind energy project, there could be nothing more beneficial to harness the potential of such a natural and renewable resource called wind.
Getting Help in the Start
If you are wondering how to generate wind energy, the British Wind Energy Association or BWEA is a good professional source of services and information for initiating projects related to wind energy. This professional body continuously organizes and manages several initiatives to propagate the use of wind as a source of energy across the country and its residences. It has information on local suppliers of wind systems and information on grants and permissions.
The ‘Energy Saving Trust’ which is backed by the government also provides provide advice on several issues for both companies and individuals and companies desiring to install wind generators on a small scale.
Other Practicalities like Cost and Savings
The cost of wind generators should fall in the range of 3000 pounds -15000 pounds for each kilowatt. This is as competitive as solar and actually slightly cheap when compared to the high output it generates. It is also expected to generate higher output in a year compared to its output in the previous year. Your wind generator should break even in about five years and the way the prices of normal energy sources are increasing, the returns of a wind generator will surely increase over a period of time.
How to Position Your Turbine
It is best to place the turbine high if you want to get the most of the wind strength without any obstructions. Also make sure to measure the wind strength in your locality so that you can place the turbine facing the direction where the wind is prevailing. To measure the wind strength, you can either buy or hire an anemometer. You can also get the person installing your wind generator to do that.
Battery or Grid?
A battery can be connected to wind generators of small scale to provide electricity to your house. The other option is to connect the wind generator to the National Grid. The decision to do the former or the latter depends totally on the circumstance. As such there is no major difference except that it will affect the direction of your energy. If you happen to stay in an area that is remote with no access to the National Grid, energy should then be directed to the battery which in turn will be connected to your residence’s mains. If you can easily access the National Grid, get the generator connected to the grid. By connecting to the grid not only will you be benefited from power savings by not using the supply of electricity from the grid, you will also be able to sell surplus electricity to the grid.
Read the whole ebook - Home Made Energy
ABSTRACT
Utility bill tracking is at the heart of an effective energy management program. Merely comparing utility bills can yield inaccurate indications of the amount of savings from energy management programs due to the unaccounted influence of weather or other factors. Correcting utility bills for weather data will give more accurate representations of savings that were accrued. This paper presents the how and why of weather correction for those who want to become more familiar with the concepts and methodology.
WHAT UTILITY BILL TRACKING CAN DO FOR YOU
Jim Faes from Jefferson County School District wrote to me “energy accounting is the backbone of our school district’s energy management program.” Why would he write that?
An energy accounting system is much like an airplane’s control panel. In order to correctly navigate your airplane, you need to understand where it is, where it was and where it is going. If you fly the plane without the control panel, you have a good chance of crashing the plane. It is the same with energy management. You need to know where you are, where you were, where you are going, and how where you are now fits with expectations of your progress.
With utility bill tracking systems, Energy managers can:
- Enter target usage and costs and track their actual performance against their targets
- Discover large increases in energy usage and take corrective actions
- Identify the buildings that are using more $/SQFT than the others, and concentrate energy management activities on those buildings.
- Determine whether your meters are on the best rates
- Check to see if you are being billed correctly by the utility
- Create bills for your tenants (if you have any)
- Determine whether you have saved any energy from your energy conservation measures
- Aggregate your usage and costs and pass this aggregated data to potential energy suppliers
- Create utility budgets
More generally, if you keep aware of the state of your utility accounting, you will know where your facility is and how it is faring towards your goals.
UTILITY BILL TRACKING: THE REPORT CARD FOR FACILITIES AND FACILITY MANAGERS
Energy Managers and some Facility Managers all to often have to justify their existence to management. How much did we save last year? Is that more than what we pay our energy manager? Did your recommendations give reasonable paybacks? Why do we even have an energy manager?
There are several methods to determine whether you have saved energy from your energy conservation efforts, as described in the literature. You can wave your hands in the air, and decide upon a number; calculate your savings based upon data logger and control points; compare utility bills to determine savings; and finally, employ a building model. (These are referred to as Option A, B, C and D in the IPMVP, FEMP Guidelines and other literature.)
Most likely, the simplest and most palatable method for the facility manager to determine whether you are saving energy is Option C, comparing utility bills. Why? Well, although some utility managers do present calculations given to them by the friendly sales rep, this method is hardly reliable, as they may produce inflated numbers. Placing dataloggers and using existing control points seems easy enough, but converting these inputs into savings numbers can sometimes prove to be outside of the scope of the facility manager’s skillset. Building modeling, while it can be useful, requires hours of time to construct the model, and may represent how much the building should be using, and may not really represent what the building truly is using. If those objections hold, that leaves utility bills as the last remaining method to quantify your performance as an energy manager. Plus, in the end, it is all about the utility bills, as the bills reflect how much you are paying.
Since most facility managers are already tracking their utility bills, it is only one additional small step to see whether you have saved any energy and costs from your energy management program. Just compare prior year bills to current year’s bills, and you will see if you have saved.
Well, it isn’t that easy. Let’s find out why.
WHY BILL COMPARISON DOESN’T WORK, OR, WHY USE WEATHER CORRECTION
Suppose you want to see savings from the new efficient chilled water system you installed this January. A simple comparison of prior and post bills should show the savings right? Well, not exactly. Suppose last year had a relatively cool summer, and this summer was devilishly hot. Would you see the savings? Maybe not.
There are a couple of ways we can plot the usage from year to year. Suppose we just looked at the usage vs. time, like most people do.
We have marked two regions in Figure 1. The bottom (darker) region, we call non-weather sensitive usage. This usage can be attributed to computers, lights, constant volume pumps and other loads that are on regardless of what the weather is. For an all year operation, this amount is steady. (In this case, the non-weather sensitive usage is very low, since this meter serves a mechanical plant. Typically, the non-weather sensitive usage would be higher.)
We call the top (lighter) region weather sensitive usage. This is usage directly related to, in this case, air conditioning the facility. Usage in this region could be attributed to chillers, cycling chilled water pumps, cooling towers, condenser water pumps, condenser fans, and possibly fans and pumps that cycle or are on a variable frequency drive.
If last summer was cool, and this summer was hot, then the non-weather sensitive usage would likely not change from year to year, but the weather sensitive usage would change. Figure 2 is the same as Figure 1, except that it presents 2 years of data. Notice how in the second year, the weather sensitive portion is much greater due to the hot summer’s increased cooling load.
Now suppose that the new chilled water system reduced weather sensitive consumption by 20%. With the weather variation shown in Figure 2, an annual comparison of the usage may not show any energy savings at all, as we can see in Figure 3. (In Figure 3, we removed 20% of the weather sensitive usage from 2002 data, which is what we might see with a chilled water system retrofit.)
Imagine showing management these results after you invested a half million dollars. It is hard to inspire confidence in management with graphs like Figure 3. So much for utility bill comparison.
To explain these results, you might provide them with a graph of CDDs (as in Figure 4), and then they could see that, the post-retrofit year (2002) was indeed much hotter, and required more cooling and therefore led to increased usage. This might let you off the hook, but you still need to quantify how much you saved, don’t you? Management will only accept arm waving for so long.
You can quantify your savings by correcting your utility bill savings equation for weather. Had you done so you could have presented Figure 5, rather than Figure 3.
HOW WEATHER CORRECTION WORKS
Rather than compare last year’s usage to this year’s usage, when we use weather correction, we compare how much energy we would have used this year to how much energy we did use this year. Many in our industry do not call the result of this comparison, Savings, but rather Usage Avoidance or Cost Avoidance. But, since we are trying to keep this paper at an introductory level, we will use the word Savings.
When we tried to compare last year’s usage to this year’s usage, we saw Figure 3, and a disastrous project. We used the equation:
Savings = last year’s usage – this year’s usage
When we use weather correction, we end up with Figure 5, and use the equation:
Savings = How much energy we would have used this year – how much energy we did use this year**
**where this year’s usage from the 1st equation is the same as how much energy we did use this year from the 2nd equation
The next question is, how do we figure out how much energy we would have used this year. This is done using weather correction as shown below.
First, we select a year of utility bills we want to compare future usage to. This would typically be the year before you started your energy efficiency program, or the year before you, the new facility manager, were hired, or some chosen year. In this example, we would select the year of utility data before the installation of the chilled water system. We will call this year the Base Year.
As shown in Figure 6, we graph Base Year usage versus weather (in the form of Cooling Degree Days or Heating Degree Days). The blue dots represent the utility bills.
Then we find the Best Fit Line between usage and weather. The Best Fit Line is the line that comes closest to all the utility bills as shown in Figure 6. We can tell it is the Best Fit Line by looking at some statistical indicators (such as R2 value, Net Mean Bias Error and CVRMSE, which are not covered in this introductory paper) .
This Best Fit Line has an equation, which we call the Fit Line Equation, or in this case the Baseline Equation. Once we have this equation, we are done with this regression process.
Let’s recap what we have done:
- We graphed a Base Year of utility data versus weather data
- We found a Best Fit Line through the data. The Best Fit Line then represents the utility bills.
- The Best Fit Line Equation, which represents the Best Fit Line, which in turn represents the Base Year of utility data. The Fit Line Equation represents how your facility used energy during the Base Year, and would continue to use energy in the future (varying with changing weather conditions) assuming there were no significant changes occurred in building consumption patterns, such as new equipment, area or operating hours.
Base Year bills – Best Fit Line = Fit Line Equation
In our example:
Baseline Equation = Fit Line Equation
Once you have the Baseline Equation, you can determine if you saved any energy.
How? You take a bill from some billing period after the Base Year. You (or your software) plug in the number of days and the number of degree days from the bill into your Baseline Equation. Remember, the Baseline Equation represents how your building used to use energy in the Base Year. So, with the new inputs of number of days and number of degree days, the Baseline Equation will tell you how much energy the building would have used this year based upon Base Year usage patterns and this years conditions (weather and number of days). We call this usage that is determined by the Baseline Equation, Baseline Usage.
Now, to get a fair comparison of this year versus last year, we compare:
Savings = How much energy we would have used this year – How much energy we did use this year
or if we change the terminology a bit:
Savings = Baseline Energy Usage – Actual Energy Usage
where Baseline Energy Usage is calculated using the Baseline Equation and current month’s weather and number of days, and Actual Energy Usage is the current month’s bill. Both equations are one and the same, Baseline = How much energy we would have used this year, and Actual represents how much energy we did use this year.
CORRECTING FOR OTHER VARIABLES
Facility Managers in the industrial sector may want to correct for production rather than (or in addition to) weather data. This works if you have a simple variable that quantifies your production. For example, an automobile manufacturing plant can track number of automobiles produced. If your factory makes several different things, for example, disk drives, desktop computers, printers and main frame computers, it is difficult to come up with a single variable that could be used to represent production for the entire plant. However, if your printer manufacturing unit was served by a different meter or submeter than the other units, then you could use the number of printers produced as a variable for the meter (or submeter) that serves the printing unit.
WEATHER CORRECTION IN EXCEL VS. CANNED SOFTWARE
Weather correction can be done in Excel, however it can be laborious, and oftentimes may not be as rigorous as when done using specialized software. Excel will give regressions, fit line equations, and statistical indicators which show how well your usage is represented by the fit line. However, it is difficult to find the best balance point in Excel, as you can in specialized software. Excel may force you have to choose just one balance point, and possibly then you would iterate with different balance points, whereas canned software will allow you to easily find the best fit line using different balance points. In addition, if you enter your weather data in high low temperatures or average temperatures, it can be difficult to apply the correct weather data to the correct billing periods. Try it, and you will see.
AVAILABLE WEATHER CORRECTION DESKTOP SOFTWARE
All of the major desktop utility bill tracking software packages will now correct for weather data. Nearly all of them will correct for your own variables as well. The major desktop programs are Energy CAP, Metrix, Stark Essentials, and Utility Manager Pro. You can find information on all of them online.
CONCLUSION
Weather changes from year to year. If wish to use utility bills to show energy savings from energy management programs with any degree of accuracy, it is important to correct your utility bills for fluctuations in weather.
