Solar + Battery = Energy Nirvana?

Climate change is an existential threat to humans, which is why it is our mission at BlueRoof Foundation to educate consumers on how to reduce their carbon footprint. It is important that everyone make changes in their lives to address this problem before we are forced to make more drastic changes.

In this article we will explore the pros and cons of adding an energy storage system, like a battery, to your solar system. It is important to note that in the past decade both solar and battery costs have reduced by more than 80% and will continue to do so in the following decade. Costs of both these energy systems have reached a level where it makes financial sense for some homes to install a battery. Both a solar system and battery storage, that charges from this solar system, will qualify for a 30% federal tax credit in 2019, but this is reducing to 26%, 22% and 10% in the next 3 years respectively. The next few years are a good time to take advantage of this combo system. There are multiple battery storage chemistry options available in the market today, but the market is quickly consolidating around Lithium-Ion battery technology for the residential market. These batteries will last for at least 10 years, and they can last even longer if the battery is not charged and discharged every day.

Let us explore some of the most common reasons for a homeowner to install a battery system. The most common reason is to offer energy backup to your home in case of a power failure. Given the frequency of natural disasters these days, it does make sense to backup your home energy needs with a battery if you can afford it. Without a battery system, when there is a power failure during day time your solar system will be cut off to prevent electrocution of any crew working on the power grid outside of your home to fix the power outage. This is a standard practice all over the country and is required by law. Unfortunately, if the power failure happens during day, you will lose all the energy generated during a power failure event without a battery. Installing a battery prevents this problem. With a battery, when there is a power failure the battery system is smart enough to detect the outage and disconnect your home from the grid and continue to feed the solar energy to your home, or when required after dark, feed backup power to your home.

Some of the other reasons for installing a battery system are peak demand shaving and off-grid home. Peak demand shaving is relevant in places where the price of electricity uses a Time-of-Use rate plan. Most battery systems allow for home owners to setup time windows for peak and off-peak energy costs. Once setup, the battery system will automatically try to optimize your energy usage cost by switching your home to consume energy stored in the battery during peak cost time windows and charge the battery during off-peak windows.

The BlueRoof Foundation always tries to provide a financial Return on Investment (ROI) for all your energy investments. Let us now understand what the financial ROI looks like for your battery system. The initial cost for installing a battery can be somewhat high and it largely depends on the size of the battery. The size of the battery you need depends on how much electricity your home consumes and how many hours of power backup is desirable. A battery system installer should be able to look at your home energy consumption and come up with a recommended battery size. Typically, battery costs run anywhere between $600 to $800 per KWh installed, not including any tax credits, and an average home can make do with a 10KWh battery size for power backup. Please include your federal and state tax credit to come up with the final cost. ROI for a power backup battery system really depends on the time of year and cost of inconvenience for you. It is fair to say, however, that a single multi-day power failure will more than pay for your battery installation. Consider how many times you have experienced power outages over the past decade (the average lifespan of a battery system) – certainly a few days for most people.

Now let us look at the ROI for a peak shaving battery system. Most Time-of-Use rate plans are setup to incentivize electricity use when the demand for electricity is low. Under this plan for about 6 to 12 hours during the middle of the day the energy cost is 1.5 to 2 times the off-peak cost during the summer season. For the sake of simplicity let us assume that a typical home consumes 1,500 KWh per month during the summer, which averages to about 50KWh per day. Let us also assume the peak price window is about 6 hours and the cost is twice that of the off-peak cost. At a peak energy cost of 30c/KWh and assuming 25% of the daily consumption during peak hours, the energy cost works out to $3.75/12.5KWH or an increase of $1.88 over off-peak rate. If the battery can supply all the energy needs during the peak cost window then it amounts to savings of about $250 per year for about 5 months of summer. Assuming your battery installation cost of about $7,500 for 15KWh, after tax credit, the ROI for your battery works out to 30 years. Your battery system will last for about 10-15 years so there is not much financial incentive for installing a battery system for peak shaving purposes alone. Since a battery system is typically coupled with solar, your peak cost window should be covered by solar generation and hence your battery is not a good investment for peak shaving purposes. Finally, if your home is off-grid, a battery storage system becomes absolutely essential and a survival tool.

It is obvious from this article that the best use case for your battery is off-grid home, followed by power backup in areas prone to power outages. It is hard to justify a battery system cost for managing your energy cost in a Time-of-Use rate plan, though if you also desire power backup in case of an outage, it may still be worth the cost for you.

Top Three Changes you can make to Reduce your Carbon Footprint – Air Travel (Part III)

Climate change is an existential threat to humans, which is why it is our mission at BlueRoof Foundation to educate consumers on how to reduce their carbon footprint. It is important that everyone make changes in their lives to address this problem before we are forced to make more drastic changes.

In the first two parts of this series, we talked about Electric Vehicles (EVs) and Solar Panels. In this post, we will talk about the impact of air travel and how to mitigate its impact on the environment. This is the most difficult one to reduce of all the major carbon emitters. Humans are travelling more each year. Even though the global carbon emissions of air travel is only 2% of total emissions, it is soon expected to exceed 10% in the coming decades.

In this article we will discuss air travel related emissions in the US, some worthy carbon offset solutions to compensate for the emissions from your travel, and finally some promising technologies that could help air travel in the future.

It is important to acknowledge the emissions reduction efforts implemented by airlines and airplane manufacturers in the past decade. According to the International Air Travel Association (IATA) website, the fuel efficiency of airplanes improved more than 10% between 2009 and 2016, roughly equating to 1.5% improvement each year. This trend will continue for the next few years before it becomes increasingly challenging to improve efficiency through currently available technologies.

According to the Federal Aviation Administration (FAA), a government organization, US airlines schedule nearly 29,000 flights per day, consuming about 49 million gallons of jet fuel each day! This roughly equates to 52% of the total jet fuel consumed every day with the rest being consumed by private, military, and cargo planes. US airlines carry nearly 2.7 million paying passengers per day with an average fuel consumption of 1,700 gallons per flight. With an average paid passenger count of 91 people per flight, the fuel efficiency works out to 80 miles per gallon per passenger, which roughly equates to one metric ton of carbon emission for every 7,000 miles of air travel.

On the surface this seems like it’s not that bad, but it is important to keep in mind that some planes can carry up to 500 passengers and are capable of flying nearly 9,000 miles non-stop, which can result in carbon emissions of more than 500 tons per flight. It is obvious a plane can burn an immense amount of fuel very quickly, and thus they are a big source of carbon emissions. However, it is only fair to state that air travel is lower in carbon emissions than driving alone in a car for the same distance.

Now that we have established the facts of carbon emissions, let us review how to reduce your air travel related carbon emissions. The best option is to travel less or travel only when necessary. If you must travel, here are some simple things you can do to reduce your air travel carbon emissions. Since taxiing and takeoff can burn up to 25% of the total fuel for a given flight, flying non-stop minimizes fuel consumption. Given all the delays these days with air travel, it makes more sense to pay a little extra to fly non-stop when possible. Plus, it’s worth the time it saves you and the convenience of not having to make (or miss) your connecting flight in an unfamiliar airport. It also helps to fly the latest version the available planes, though this is not always in your control. Within the US, generally low-cost airlines do indeed fly the most fuel-efficient planes to keep their own costs low, so it is better to fly with one of these airlines when possible. Outside of these suggestions, there is really not much you can do to reduce your air travel carbon emissions today.

Buying carbon offsets are the only way to neutralize your carbon emissions from air travel today. The big challenge with buying carbon offsets is the lack of certified, high quality options. One good option is to install solar panels on your own roof. Please refer to our Part II of this series to calculate the size of the solar panel system you will need to offset your travel, as it varies from state to state. Since solar panels last for over 20 years, your offset will be effective for a long time. Investing in an electric car is another good option to offset your air travel emissions. Please refer to Part I of this series to calculate your carbon offset with your electric car. Installing a Nest or similar smart thermostat, replacing your older light bulbs with LED bulbs, and replacing your gas lawn equipment with electric versions are all good options.

Finally, if you are wondering what is in the future for air travel, there are a few promising low carbon emission options on the horizon. Biojet fuel or jet fuel derived from plant-based materials is looking quite promising. Biojet will allow us to be carbon neutral, and most biojet fuels are drop-in replacements for jet fuel based on fossil fuels. It is our hope that airlines will encourage development of biojet fuels in the next decade. Electric planes are also an option for smaller planes with short haul flights, but the technology is not mature enough to be used in larger planes like the Boeing 747 or Airbus 380.

All numbers cited in this article were obtained from government web sites for the year 2017. This article concludes the three-part series “Top three changes you can make to reduce your carbon footprint”. We hope you found this series educational and informative. Please contact us for any questions or comments.

Top 3 Changes you can Make to Reduce your Carbon Footprint – Rooftop Solar (Part II)

Solar Panels on RoofClimate change is an existential threat to humans, which is why it is our mission at BlueRoof Foundation to educate consumers on how to reduce their carbon footprint. It is important that everyone make changes in their lives to address this problem before we will be forced to make drastic changes. In Part 2 of this series, we will evaluate installing Solar on your home and its impact on your carbon footprint with an eye towards financial Return on Investment (ROI).

I am sure you might be wondering why BlueRoof would write about another solar article when there are thousands already available for free on the internet. At BlueRoof it is not only our goal to educate consumers about solar technology but also to outline the financial ROI on these investments. Rooftop solar energy generation is quite simple, but calculating the ROI can sometimes be overwhelming. We have done extensive research to gather all the necessary data to help you calculate the ROI on your solar project. All numbers used in this post is from various government websites outlined at the end of this article.

The concept of solar energy is quite simple, and the technology works flawlessly anywhere on earth with enough sunshine. The cost of solar panels has plummeted more than 80% in this decade and has made this technology amazingly affordable. As part of our ‘Top three changes you can make to reduce your carbon footprint’ series, we recommend this as the second big change.

Today there are hundreds of vendors all over the country who are willing to install solar on your home. We have covered more than 120 population centers in the country with our calculation to give you an estimated ROI for your solar investment. As a homeowner, there are a few things you need to understand before you contact a vendor to install solar in order to get best results.

  • Orientation or Azimuth – Indicates which direction your solar panels are facing. South is the most preferred in northern hemisphere and is indicated by 180°, followed by West indicated by 270°, followed by East indicated by 90° and finally North indicated by 0°.
  • Tilt – Indicates the angle at which sun’s rays will hit the panel. For most places in the lower 48 states within US a tilt angle of 20-30° is considered ideal. Obviously, this depends on the pitch of your roof.
  • Net Metering – This assumes your solar panels will be tied to the grid. Most solar installations produce more energy than needed at certain times of the day. This excess energy is typically fed back to the grid for which your utility company should give you credit. This is called Net Metering and is extremely important for your ROI. Our ROI calculations assume that your local utility offers full Net Metering credit.
  • Solar size – Indicates the total size of your system usually expressed in Kilowatts (KW).  One way to look at this is percentage of your home’s total consumption that will be met by your solar installation. Lots of factors go into this calculation. But suffice it to say that trying to attain 100% offset is a fool’s errand and not worth the cost. Knowing this we recommend offsetting not more than 90% with an ideal value between 60-80%.
  • Tax credits and incentives – This can have a big impact on your ROI number. Federal tax credit is 30% of the total cost till end of 2019 and thereafter reducing to 26%, 22% and 10% respectively over the subsequent three years for residential installations. Your vendor should inform you of any local or state incentives as part of the sales process.

We have glanced over many other technical details of the installation, but your vendor should present the same to you prior to installation. Below is a list of cities and states with ROI for same solar installation. Please note size of the installation does not change your ROI.

Assumptions: Solar installation cost = $2750/KW; Federal tax credit = 30% with no local/state incentives; Solar lifetime = 20 years; Solar energy degradation = 1%/year; Energy cost inflation = 2%/year; System size = 1 KW. If your system size is greater than 1 KW, ROI remains the same but energy generated will be a multiple of your size.

StateAC Energy, KWh/yr 1Energy Price, c/KWh 2Lifetime Energy per KW, $ROI, YrsCO2 saved lifetime, Metric Tons 3
Arizona - Phoenix172510.6401810.515.7
Arkansas-Hot Springs13478.3245717.216.2
California - Los Angeles166816.159027.27.9
California - San Francisco159816.156547.57.6
California-San Diego167316.159197.17.9
California-San Jose159816.156547.57.6
Colorado - Aurora153610337612.522.4
Colorado - Colorado Springs164110360611.723.9
Colorado - Denver16041035251223.4
Colorado - Fort Collins146310321513.221.3
Connecticut-New Haven128917.649868.56.5
Florida - Miami151210.4345612.215
Florida - Orlando152610.4348812.115.1
Florida - Tampa155110.4354511.915.4
Indiana-Fort Wayne13209.8284314.924.1
Iowa-Cedar Rapids13568.7259316.315.8
Iowa-Des Moines13928.7266115.916.2
Kansas-Kansas City143510.6334312.713.8
Kansas-Overland Park142810.6332612.713.7
Louisiana-New Orleans14797.8253516.716.6
Michigan-Grand Rapids127211.3315913.414.6
Michigan-Sterling Heights131511.332661315
Missouri-Saint Louis13781030281424.6
Missouri-Spring Field140110307913.725
Nebraska - Lincoln14399.1287814.719.9
Nevada - Las Vegas17008.8328812.912.9
New Hampshire-Concord128716.245829.23.2
New Jersey - Elizabeth132113.33861117
New Jersey-Jersey City127713.3373211.36.7
New Jersey-Newark132013.33858117
New Jersey-Paterson128513.3375611.36.8
New Mexico-Albuquerque17609.6371311.426.5
New Mexico-Las Cruces18399.6388010.927.7
New Mexico-Santa Fe17239.6363511.625.9
New York - Buffalo120414.7389010.95.3
New York - New York131314.74242105.8
New York - Rochester122814.7396710.75.4
New York - Syracuse119114.73848115.2
North Carolina - Charlotte13839273515.511.5
North Carolina - Raleigh13949275715.311.6
North Caroline - Durham13909274915.411.6
North Caroline - Greensboro1430928281511.9
North Dakota13508.8261116.221.5
Ohio - Cincinnati12679.8272915.518.6
Ohio - Cleveland12799.8275515.418.8
Ohio - Columbus13219.8284514.919.4
Oklahoma - Oklahoma City15318.2275915.314.8
Oregon - Eugene11888.8229718.43.3
Oregon - Portland11278.8218019.43.2
Oregon - Salem11648.8225118.83.3
Pennsylvania - Philadelphia134010.1297414.210.9
Pennsylvania - Pittsburgh121510.1269715.79.9
Rhode Island - Providence130216.44693911.2
South Carolina - Columbia144010316513.48.6
South Carolina - Charlotte138910305213.98.3
South Caroline - Charleston138310303913.98.3
South Dakota - Sioux falls139410.1309413.77
Tennessee - Chattanooga13479.528121513.4
Tennessee - Memphis14279.5297914.214.2
Tennessee - Nashville13749.5286914.713.7
Tennessee- Knoxville13609.5283914.913.5
Texas - DFW15048.4277615.217.5
Texas - Houston14378.4265315.916.8
Texas - Midland17368.4320513.220.2
Texas - SA14998.4276715.317.5
Utah - West Valley City14928.628201524.3
Utah-Salt Lake City15088.6285014.824.6
Virginia - Virginia Beach14289.2288714.710.8
Virginia - Chesapeake14209.2287014.710.8
Virginia - Norfolk14369.2290314.610.9
Virginia -Richmond13869.2280215.110.5
Washington - Bellevue10727.9186122.72.2
Washington - Kent10597.91839232.2
Washington - Tacoma10617.91842232.2
Washington - Vancouver10557.9183223.12.2
West Virginia12459246217.224.3
Wisconsin - Green Bay132410.8314213.519.2
Wisconsin - Milwaukee133910.8317813.319.4
Wisconsin - Madison133910.8317813.319.4

As you can see, Solar ROI varies widely across the country. If you are interested in installing solar panels for financial reasons, most installations in the US today will take at least 10 years to reach your ROI. But if you live in your house for more than 10 years, you will enjoy free energy for many years. If you are installing for environmental reasons, some cities and states make more sense than others due to high carbon intensity of the energy generation in some states. Finally, it is important to note that if you are upgrading or fixing your roof for any reason it may be the best time to evaluate solar option for your roof, as it might reduce your cost of installation slightly.

1Energy calculations were done using PVWatts calculator offered a government website

2Energy prices were as reported on website and the numbers are from 2017

3CO2 emissions numbers were as reported on and the numbers are from 2017

Top 3 Changes you can Make to Reduce your Carbon Footprint – Electric Vehicles (Part I)

Climate change is an existential threat to humans, which is why it is our mission at BlueRoof Foundation to educate consumers on how to reduce their energy and carbon footprint. It is important that everyone make small changes in their lives to address this problem before we will be forced to make drastic changes. Let’s take a look at the top 3 changes you can make to reduce his or her carbon footprint.

The United States emits roughly 5.5 gigatons of CO2 per year, which amounts to roughly 15 tons per person. The three big components of these emissions are personal automobiles, home energy, and air travel. Food, clothing and other smaller items are important but difficult to change easily. We will explore the Big Three and identify changes necessary to reduce our carbon impact. In Part 1 of this post we will focus on electric vehicles (EV) and its impact on your carbon footprint. With each of these changes we will focus on financial ROI to make sure it is a financially sound investment.

An average US automobile travels 12,000 miles per year and at about 22 miles/gallon of gas the automobile will emit roughly about 5.5 tons of CO2 per year. Unless you are willing to buy an EV and generate your own solar energy, it is difficult to eliminate your carbon footprint. According to the EIA, a government agency, based on 2017 data your EV carbon footprint per mile can vary quite widely from one state to another. For example, in Vermont which is the lowest carbon footprint for electricity, every 1,000 EV miles will result in only 6 pounds of CO2, which is extremely low. On the other hand, in Wyoming the same 1000 EV miles will result in 750 pounds of CO2. US average for the same 1,000 EV miles is about 360 pounds of CO2. Below is a list of all states and their carbon footprint per 1,000 EV miles along with carbon footprint for some of the most popular vehicles. For reference, a Toyota Prius will emit 320 pounds for 1,000 miles and a Ford F150 pickup truck will emit about 1,000 pounds per 1,000 mile.

StateCO2 lbs/1000 MileMPG Equivalent
New Hampshire91221
New York160125
South Dakota183109
New Jersey192104
South Carolina21892
North Carolina30366
Rhode Island31364
Toyota Corolla52638
New Mexico54837
North Dakota57935
West Virginia70928

As you can see there is a wide variation in EV footprint by state. EVs are slightly more expensive to buy compared to an equivalent gasoline car, but between reduced or zero annual maintenance cost and reduced annual fuel cost the difference in initial cost can be made up in less than 5 years with certain EVs.

A typical EV can save approximately $1,200.00 per year over a gasoline powered car. If you take the environmental impact into consideration, buying an EV becomes a no-brainer – even at a lower ROI.

Used EVs are some of the best value cars in the market available today as per multiple car valuation websites like Edmunds and Kelley Bluebook. This is the single greatest change you can make to reduce your personal carbon footprint. Since our grid is becoming cleaner by the day, your EV carbon footprint will only reduce in the future!

We will discuss the other 2 components of your carbon footprint in a follow up post, so check back soon.

Three Simple Ways to Reduce Your Home Energy Footprint

It is our mission at Blueroof Foundation to educate consumers on how to reduce their energy and carbon footprint. In this post we want to focus on 3 things that homeowners can do that are quite inexpensive to implement and have a return on investment that is less than 2 years. 

LED Lightbulbs 

This is one of the easiest changes to make with a big impact. About 6-8% of our energy usage nationwide goes towards lighting. It’s a shockingly big number when you think about it. Most lightbulbs are still incandescent bulbs that Thomas Edison first invented, and they waste a lot of energy in the form of heat. LEDs are generally much cooler and emit almost the same quality and quantity of light. A typical LED bulb might cost around $4 and you will earn your money back in less than 2 years, while also reducing your carbon footprint for a long time. LEDs also have a long life which will result in reduced maintenance costs over time. Assuming you have 50 bulbs to replace, this is a simple and easy change to make for less than $250 for immediate payback. 

Smart Thermostat 

This change might require a little bit of professional help but it’s well worth the trouble. Our personal favorite is the Nest thermostat from Google, but any brand should have the same impact. These thermostats are smart and can be managed from your mobile device via an app. They are called “smart” because they know when no one is home and they switch to eco mode to reduce your wasted energy consumption. During summers and winters these devices can easily save 12-15% on your energy bill. Lots of local utilities offer rebates and incentives that can reduce the upfront cost. Typically, these devices cost around $250 with an installation cost of $150. The return on investment for this device is also less then 2 years, and we strongly recommend you make this change. 

Pool Pump with Variable Speed 

If you have a pool, you have probably been frustrated by your electricity bill in the summer.  The typical pool pumps are AC motors and they consume a lot of energy. Switching the pump to a variable speed DC motor will dramatically reduce your energy costs. A typical variable speed pump costs less than $1,200 in parts and an additional $750 in labor to install. It may sound like a lot, but these little pumps are so efficient that they can pay you back in less than 2 summers. This is another great investment to make if you are serious about reducing your home energy footprint and reducing your electric bill in the process! 

Check back soon as we continue to share more ways you can reduce your energy footprint, including some ideas that are a little more expensive with a longer return on investment.