Putting solar panels on your roof is probably a good investment, no matter where you live. But adding a home battery may do more harm than good. //

The energy produced over the lifetime of rooftop solar panels more than makes up for the energy it takes to make, mount, and eventually recycle them. But adding a home battery can lower those dividends, new research finds. //

Previous studies estimated the energy output at about nine times the energy invested in solar panels. The new study, which appears in Sustainable Energy & Fuels, however, examined the output from a typical rooftop system installed in five diverse American states. Researchers found that the energy payout ratio ranges from a low of 14 in Alaska to a high of 27 in sunny Arizona—but only when homeowners are able to send surplus power to the grid.

When homeowners install a battery and charge it with excess electricity before sending leftovers to the grid, however, the energy return on investment for the entire system is 21 percent less than solar panels alone, researchers found.

When homeowners have no battery and no grid outlet, it just wastes extra electricity. Then, the system’s return on invested energy falls to seven in Alaska and a high of 14 in Florida—on par with earlier studies. Because homeowners in that scenario need to purchase electricity during the evening, adding a standard lithium-ion home battery improves the energy payback. //

Adding batteries to a home photovoltaic system reduces the energy payback of the entire system by 21 percent on average due to two factors. First, adding batteries means more energy in the form of fossil fuels invested in making the entire system. Second, a battery discharges 8 percent less electricity than the amount of electricity required to charge it—a loss compared to sending electricity directly to a larger electricity system with customers who can use the power immediately.

The current study acknowledges the dilemma. “As rooftop solar and large, photovoltaic power stations grow, electricity grids will not be able to accept more afternoon power, unless new uses of cheap afternoon electrons grow,” Benson says.

Modeling 101

Learn more about everything that goes into modeling the output of a photovoltaic (PV) solar array

While each array is unique, advanced performance modeling follows a standard approach for calculating the energy production of an array. The process begins with data on the environmental conditions, then calculates the irradiance that will be collected by the solar modules, then computes the performance of the solar modules, and finally models the system effects of all of the electrical components.
The core mathematics is based on industry-standard approaches for modeling each step in the system performance. None of the steps described here are proprietary or secret, instead, they are all based on research and analysis published by academic research institutions and national labs.

By understanding the drivers of performance in more detail, system engineers can make better decisions about the components and designs they deploy. The approach described in this guide is the exact math used in HelioScope.

The Modeling 101 Guide describes the high-level relationships between the drivers of system performance modeling. For a more quantitative view of the exact equations, see the Mathematical Formulation available in HelioScope.

The Green New Deal is anything but 'clean' or 'green.' Even the relatively modest numbers of solar and wind installations in the United States today are causing serious environmental damage. //

A few minutes of serious thought from self-described environmentalists would prompt a realization that if the Green New Deal, a program championed by Rep. Alexandria Ocasio-Cortez, were implemented, it would create an environmental disaster.

In recent decades, policymakers have forced public utilities to generate increasingly more electricity from fashionable “renewable energy” sources, especially wind and solar, and pushed automakers to manufacture more electric vehicles. Their chief goal is to eliminate reliable, affordable, generally clean fossil fuels, including natural gas, even though they generate most of America’s electricity and power most U.S. transportation.

Environmentalists claim to worry that carbon dioxide from these fuels will cause devastating global warming. Many would also eliminate nuclear power, which they say is inherently unsafe. //

environmentalists have paid too little attention to the serious harm Green New Deal policies would inflict on the environment — including scenic lands, wildlife habitats, and threatened and endangered species. Implementing the Green New Deal would undermine the very values environmentalists have espoused for decades.

America faces a dilemma. Will it focus on real environmental problems that do measurable harm to human and ecological wellbeing, or will it mandate policies to head off climate disasters that are based on warming predictions have been repeatedly proven wrong by real-world empirical observations? Will it recognize that harnessing intermittent, weather-dependent wind and solar energy requires enormous amounts of raw materials and mining, resulting in massive land-use impacts and human rights abuses, and is anything but clean, green, renewable, and sustainable? Or will it ignore all this? //

Solar farms generate only 1.5 percent of the nation’s electricity and would be an inefficient way to generate the more than 8 billion megawatt-hours of power that fossil fuels and nuclear provide each year to meet industrial, commercial, residential, and automotive transportation needs and charge backup-power batteries. Using cutting-edge Nellis Air Force Base solar panels to generate that electricity would require completely blanketing 57,000 square miles of land — equivalent to the land area of New York and Vermont — with 19 billion photovoltaic solar panels. //

Turbines ruin scenic views, kill countless birds and bats, and harm marine mammals, which is why environmentalists — and even the late leftist icon Sen. Ted Kennedy — have long opposed the planned Vineyard Wind facility off the Massachusetts coast. To provide enough power for the country, Green New Deal advocates would have to build hundreds of thousands of truly gigantic offshore turbines. //

Solar panels require many toxic materials, and wind turbines require enormous amounts of steel, concrete, copper, and rare earth elements. Storing a week’s worth of power for periods when the sun is not shining or the wind isn’t blowing would require some 2 billion half-ton Tesla car battery packs. Meeting these needs would require a massive expansion of mining for lithium, cobalt, and other substances in the United States or in Asia, Africa, and South America. Operations in the latter countries involve extensive child labor, create environmental disasters, and even lead to premature death.

What’s more, disposing of obsolescent solar panels, wind turbines, and batteries is already causing problems in the United States and in countries such as Germany. Green New Deal advocates ignore this problem, which would multiply substantially under their plan.

A secretive startup backed by Bill Gates has achieved a solar breakthrough aimed at saving the planet. //

Heliogen, a clean energy company that emerged from stealth mode on Tuesday, said it has discovered a way to use artificial intelligence and a field of mirrors to reflect so much sunlight that it generates extreme heat above 1,000 degrees Celsius. //

The breakthrough means that, for the first time, concentrated solar energy can be used to create the extreme heat required to make cement, steel, glass and other industrial processes. In other words, carbon-free sunlight can replace fossil fuels in a heavy carbon-emitting corner of the economy that has been untouched by the clean energy revolution. //

Heliogen uses computer vision software, automatic edge detection and other sophisticated technology to train a field of mirrors to reflect solar beams to one single spot.

"If you take a thousand mirrors and have them align exactly to a single point, you can achieve extremely, extremely high temperatures," Gross said, who added that Heliogen made its breakthrough on the first day it turned its plant on.

Heliogen said it is generating so much heat that its technology could eventually be used to create clean hydrogen at scale. That carbon-free hydrogen could then be turned into a fuel for trucks and airplanes.

A significant part of Tesla’s business relies heavily on the durability and longevity of its battery packs, and in the spirit of disruptive innovation, the Silicon Valley-based company has continued to make improvements to its battery technology to make them more durable and more efficient. Tesla was able to achieve this through several ways, one […]

Fantasy time: solar farming

If a breakthrough of solar technology occurs and the cost of photovoltaics came down enough that we could deploy panels all over the countryside, what is the maximum conceivable production? Well, if we covered 5% of the UK with 10%-efficient panels, we’d have 10% × 100 W/m2 × 200 m2 per person ≈ 50 kWh/day/person.

I assumed only 10%-efficient panels, by the way, because I imagine that
solar panels would be mass-produced on such a scale only if they were
very cheap, and it’s the lower-efficiency panels that will get cheap first.
The power density (the power per unit area) of such a solar farm would be 10% × 100 W/m2 = 10 W/m2.

This power density is twice that of the Bavaria Solarpark (5W/m2)

ThorCon electric power cost:

Lower capital cost and lower fuel cost than coal.
Competitive with pipelined natural gas.
Lower electricity cost than shipped LNG (liquified natural gas).
Cheaper than solar and wind including natural gas backup.
Cheaper electricity than storage-buffered wind and solar sources. //

Batteries have been proposed to replace CO2-emitting natural gas generators. Storing intermittent electric energy for later dispatch adds expensive storage buffering costs. A 2018 Science article by Steven Davis and 32 other renowned scientists analyzed storage costs. Using low-cost, mass-market, lithium-ion batteries for daily buffering raises electricity costs from 3.5 cents/kWh to 14 cents/kWh. For weekly buffering the cost grows to 50 cents/kWh. Even if future battery costs are halved, that cost will be 29 cents/kWh. Even free intermittent electricity would not significantly reduce storage-buffered, dispatchable electricity costs. ThorCon generated electricity is cheaper than storage-buffered wind and solar electricity. //

ThorCon power should-cost about half as much as coal where coal is cheap. But the did-cost depends on how we regulate nuclear power. The bottom line is simple: will we build nuclear power plants the way the U.S. Navy builds ships or the way the Koreans build ships? If it’s the former, then nuclear will never beat coal regardless of the technology. If it’s the latter, then ThorCon is easily cheaper than coal.

“This is the lowest solar-photovoltaic price in the United States,” said James Barner, the agency’s manager for strategic initiatives, “and it is the largest and lowest-cost solar and high-capacity battery-storage project in the U.S. and we believe in the world today. So this is, I believe, truly revolutionary in the industry.” //

It’s half the estimated cost of power from a new natural gas plant. //

The Eland Project will not rid Los Angeles of natural gas, however. The city will still depend on gas and hydro to supply its overnight power. But the batteries in this 400-megawatt project will take a bite out of the fossil share of LA’s power pie. //

The plant will be developed by 8minute Solar Energy on 2,653 acres of privately-owned land in the Barren Ridge renewable corridor in Kern County. //

Seven years ago the first major projects were brought forward to this board. They’re in service now, they’re the ones that are referred to in or near Nevada. And they were between $90 and $100 a megawatt hour or 9 and 10 cents a kilowatt hour. Now we’re seeing solar projects under 2 cents a kilowatt hour.

You can build a "poor man's" pyranometer that works pretty well out of inexpensive and readily available components. Although it will not be of laboratory quality, it will suffice for comparative measurements and educational purposes.

Making the Meter
The obvious component to consider as the basis for our meter is a silicon photovoltaic cell. When sunlight strikes it, it produces electricity, and the more sunlight strikes it, the more electricity it produces.

At first glance, you might think that you could just hook a voltmeter up to it and measure the output voltage. Unfortunately, if you do this, you will get very erroneous results (visit the Appendix if you want to understand why).

Instead, you will need to measure the cell's output current. If you short out (hook a perfect wire between) the positive and negative terminals of your cell, a current flows through that wire. That is the current that you would like to measure. It varies linearly with the amount of sunlight striking the surface of the cell. This is actually a little trickier than one might think, for reasons that are explained in the Appendix.

It will turn on automatically at night, and turn off at sunrise.

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In South Australia, though, Tesla's giant 100MW/129MWh battery has seen a lot of success—not by selling power to meet general demand but by providing so-called "frequency response services." And a company called Restore has just partnered with Tesla to replicate that success for itself in Belgium.

In South Australia, Tesla Powerpacks are charged by the energy from a nearby wind farm, and the battery installation dispatches electricity to the grid when grid frequency suddenly drops. Grid frequency—a measure of current that must be held constant for the grid to work properly—is vitally important to the functioning of any grid system.
In Europe, for example, a recent power dispute between Serbia and Kosovo led average frequency on the Continental Europe Power System to drop to 49.996Hz instead of the required 50Hz, which resulted in oven and microwave clocks everywhere across Europe being six minutes slow after just a month of these conditions.

Grid operators will generally pay a premium for frequency response services, which are often provided by natural gas plants or other generators that can reliably ramp up and begin sending power to the grid in minutes' time. But in South Australia, Tesla's battery has been valuable in that it's able to nearly instantaneously send power to the grid as soon as frequency fluctuates. Compared to other spinning generators that might compete with the battery, it's very fast.

That has allowed Tesla's battery to take advantage of frequency response pricing, which has piqued the interest of investors. And according to a recent presentation by some McKinsey analysts, the battery has been able to cut South Australia's frequency-maintaining costs by up to 90 percent. In addition, the battery has taken over nearly 55 percent of the Frequency Control Ancillary Services (FCAS) market on that grid, according to McKinsey.