Whether it’s a residential, commercial or utility solar project, contractors strive to install systems that generate the most energy at the lowest lifecycle cost. Solar panels operate at their peak output when the sun is perpendicular to the panel. So for maximum energy collection, tilting the solar panels at the local latitude (37 degrees here in San Jose) facing south is generally best.
Because of existing building structures, compromises are necessary when installing solar panels. Residential systems are generally installed flush to the roof because tilting the panels is unsightly, and the efficiency benefit of tilting the panels is not worth the additional mounting system costs. Commercial systems on flat roofs are generally installed on racking at a relatively low tilt so that more panels can be installed — but almost never horizontal since flat surfaces collect dirt and debris.
But large-scale solar installations do not need to compromise when it comes to tilt angle and orientation. Systems can be more easily oriented due south and tilted at the angle of the local latitude. Taking things one step further, since the sun moves throughout the day, an additional 10-25% efficiency can be achieved if the panels track the sun.
Single axis solar tracker systems generally towards the east in the morning and west in the afternoon. More complicated dual axis solar tracker systems tilt east-west daily and adjust north-south seasonally. Because of the increase in efficiency, trackers have become a standard feature on large solar farms. Essentially, the added complexity of moving parts is worth the big increase in energy output.
NEXTracker was recently ranked the number one tracker company globally. They provide tracking systems and engineering for large utility scale projects all over the world. My guest on this week’s Energy Show is Alex Au, CTO and co-founder of NEXTracker. Alex was one of the pioneers in the solar industry as a key member of the team that developed the first integrated racking AC solar module, and then developed NEXTracker’s core tracking technology.
Please listen up to this week’s Energy Show as Alex shares his insights on NEXTracker, their technology and their recent work in incorporating flow battery technology to help eliminate the imbalance between peak demand and renewable energy production for utility scale applications.
On this week’s The Energy Show, we’re talking about energy — duh. And power. Not just because we’re short on both energy and power. But because solar and battery customers need to understand these properties so they can properly size and operate their systems. This show is a bit on the geeky side, so buckle up.
Power is the measure of the amount of work that can get done over a period of time. We measure power in units of watts in the metric system, and in units of horsepower in the English system. Even though the English use the metric system and horses are basically just recreational vehicles for rich people. Commonly we refer to the power of a car in horsepower, or the power requirements of an appliance in watts.
Energy is the measurement of work, or force over distance, or an amount of heat. Not a watt, but instead a watt hour or kilowatt hour (kwh). Your utility bills you for electrical energy in terms of kilowatt hours, and for natural gas thermal energy in terms of Therms (geeky rhyme). A Therm is 100,000 BTUs, which stand for British Thermal Units — which is a measure of energy in the English system — which only the Americans still use (my high school English teacher would have referred to this sentence as a which hunt).
In the solar world, we measure the power output of a solar panel in watts (360 watts per solar panel under ideal conditions), or the total size of a 20 panel system as 7,200 watts. Home battery storage systems are measured in terms of kwh (most commonly a 10 kwh or 13.5 kwh battery), and commercial systems are measured in terms of mwh (megawatt hours).
Feel free to download this week’s Energy Show for more information about the energy and power terms we use in the solar and storage industry to measure size and performance of solar and battery storage systems.
In today’s accelerated and politicized news cycle it is easy to confuse White House pronouncements with the policies that government employees are actually implementing. The U.S. has about two million hard working government employees (disparagingly referred to as the “deep state”) who are dedicated to their jobs and following well-established laws and policies.
There is perhaps no better example of this dedication and progress than the 100,000 people at the Department of Energy (DOE). Although based on recent events I would say EPA employees are in the running for the hardest working and politically least recognized branch of our government. But I digress.
As a result of long established policies and investments, the U.S. is continuing its worldwide leadership in energy and efficiency technology. Although we could obviously be doing a lot more on many dimensions, it is not complete gloom and doom. Once new energy technologies prove they are better and cheaper, no amount of political backsliding can bring back the old ways of doing things. We are no more likely to resort to heating our homes and offices with wood than we are to replace LED bulbs with short-lived, hot and energy-wasting incandescent light bulbs (regardless of the affects they may have on our complexion).
For 2019 Congress authorized $35 billion in funding to the DOE – more than the $30 billion the President recommended. This $35 billion will be spent as follows:
$15b for the National Nuclear Security Administration — basically for weapons and cleanup from past nuclear programs (almost half of the DOE’s budget)
$7.2b for environmental management
$6.6b for pure science
$5b for energy programs – of which $2.5b is for energy efficiency and renewable energy, $1.3b for nuclear energy research, $1b for fossil fuel research and the rest for miscellaneous programs.
The good news is that the DOE is continuing great research into a broad range of renewable energy technologies. The even better news is that there are almost a hundred thousand people hard at work at the DOE striving to make solar, storage and newer technologies better and cheaper – regardless of temporary political headwinds. To learn more about the work being done by the committed people at the DOE, please tune in to this week’s Energy Show.
Unless you have rooftop solar, you’re probably incredibly unhappy about rising electric bills. This misery is even worse for commercial customers since — in addition to energy charges (billed on a kilowatt-hour basis) — they also pay for peak demand charges (billed on the maximum kilowatt demand each month).
For example, let’s say your business uses industrial equipment and a variety of office equipment. Your company uses 50,000 kwh of energy per month; at a rate of $0.15/kwh, your electric bill is $7,500 per month. In addition, your peak demand may be 300 kilowatts in a typical month; at a peak demand rate of $20 per kilowatt, you also pay $6,000 in demand charges every month.
As a conscientious and generous employer, you decide to install 20 EV chargers in your parking lot so your employees can charge up their cars while at work. Each employee may charge up their car with about 10 kwh per day — or $1.50 worth of electricity each, or $600 for all employees each month. A nice employee perk, and not too expensive. However, since 20 employees plug in their cars at about the same time every morning, and each charger draws about 5kw, your extra electricity peak demand will be 100 kw, or an extra $2,000 per month. Ouch!
So for many commercial customers, peak demand charges are a bigger cost than energy charges. Ordinary rooftop solar systems may not have a big impact on demand charges. However, batteries or special control systems in conjunction with rooftop solar can significantly reduce these demand charges.
To learn how your company can reduce peak demand charges, listen to this week’s Energy Show as we speak with John Powers with Extensible Energy. Extensible Energy has software that helps commercial solar buildings to use electricity intelligently and reduce peak demand charges.
PG&E, our local utility in Silicon Valley, caused a number of wildfires — including the recent Camp fire that destroyed the town of Paradise, killed 86 people and destroyed over 13,000 homes.The primary reason for this and other similar fires is that PG&E skimped on power line maintenance while enjoying record profits. Now they are bankrupt (again), and are scrambling to deal with the upcoming wild fire season.
Public Safety Power Shutoffs may happen far from fire danger areas. And these shutoffs could last for 48 hours or longer. So anyone relying on electricity for the necessities of life must prepare for an extended outage. Unfortunately, their recommendations ignore the cleanest, cheapest and safest backup power solution – solar and battery storage. Instead, PG&E recommends gas generators and stockpiling several days of fuel. Dumb idea to store all this extra fuel in fire-prone areas. Not to mention the challenges of connecting, starting and operating a gas generator safely.
Here is the letter that PG&E sent to my home:
Given the growing threat of extreme weather, we want all of our customers to be prepared for power outages. If elevated weather conditions, including potential fire risk, threaten a portion of the electric system serving your community, it will be necessary for us to turn off electricity in the interest of public safety. This is called a Public Safety Power Shutoff. We know how much our customers rely on electric service and want to work together to help you prepare for power outages.
A Public Safety Power Shutoff could impact any of our more than 5 million electric customers, including your home or business. Because elevated weather conditions can last several hours or days, we suggest preparing for outages that could last longer than 48 hours. Electric backup generators can keep the lights on, help appliances stay running, preserve perishable foods, and power essential equipment and electronics during a power outage.
Generators can also pose safety hazards, so it is important to understand how to safely operate your generator before an emergency occurs. This means doing regular safety checks and being sure you have enough fuel to last a few days.
As you can see from their letter above, PG&E recommends a gas generator for backup power (remember, the “G” in their name stands for “GAS”). No mention at all about using a cleaner, cheaper, quieter and safer battery backup system. Simple reason: they don’t want you to install solar or batteries since that reduces their revenue and profits. And if you buy an automatic natural gas generator they’ll make even more money selling you natural gas.
So Listen up to this week’s Energy Show as we discuss your options for dealing with these Public Safety Power Shutoffs — as well as considerations for selecting the best battery backup system to protect you and your family during these outages.
To slow the global warming trend, a number of states have committed to the aspirational goal of 100% carbon-free energy. As a species that literally evolved from burning wood and hydrocarbons, how can we possibly run our modern lives and economy without fossil fuels?
We can indeed achieve this transition quickly and economically. First, by converting all power generation to renewable, non-carbon sources. And second, by converting all fossil-fuel burning vehicles and appliances to electricity. Steady progress towards these conversions is being made. For example, 32% of California’s retail power came from renewable energy in 2018. The state is well on the way to converting to 100% renewable electricity. Use of EVs is growing steadily, and new building codes mandate the use of rooftop solar and electric appliances instead of natural gas.
The challenge is with the existing stock of residential and commercial buildings. Homes and businesses predominantly use natural gas for space heating, hot water heating and cooking. That’s where the concept of Whole House Electrification come in. Whole House Electrification is conceptually simple: replace gas appliances with electric appliances. In reality, one needs an energy audit to prioritize these conversions, then hire five different specialty contractors to do the work: insulation, solar, HVAC, plumbing, electrical and pool. It can be a daunting task.
Fortunately there are some pioneers out there – one of whom is my friend Howard Wenger. Howard was also a pioneer in the solar industry, with stints at AstroPower, PowerLight and SunPower. Please listen up to this week’s Energy Show as Howard discusses his experiences as he converted his house to 100% electricity, supplied — naturally — by solar.
Barry Cinnamon has been blogging about the Solar Industry since 2007.
Barry hosts The Energy Show, a weekly 30 minute talk show that runs every Saturday at 1:30 PM on KDOW Radio AM in San Jose California.
Every week Barry provides practical money-saving tips on ways to reduce your home and business energy consumption.
Barry Cinnamon heads up Cinnamon Solar (a San Jose residential and commercial solar and energy storage contractor) and Spice Solar (suppliers of built-in solar racking technology). After 10,000+ installations at Akeena Solar and Westinghouse Solar, he’s developed a pretty good perspective on the real-world economics of rooftop solar — as well as the best products and services for homeowners, manufacturers and installers. His rooftop tinkering led to the development of integrated racking (released in 2007), AC solar modules (released in 2009), and Spice Solar (the fastest way to install rooftop solar modules).
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